显示样式:     当前期刊: "能源"类期刊    排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • A Novel ZnO-based Inorganic/Organic Bilayer with Low Resistance for Li Metal Protection
    Energy Storage Mater. (IF 0) Pub Date : 2018-06-19
    Yitao He, Yaohui Zhang, Xifei Li, Zhe Lv, Xianjie Wang, Zhiguo Liu, Xiqiang Huang
    更新日期:2018-06-22
  • 更新日期:2018-06-22
  • BaNb3.6O10 Nanowires with Superior Electrochemical Performance towards Ultrafast and Highly Stable Lithium Storage
    Energy Storage Mater. (IF 0) Pub Date : 2018-06-20
    Xing Cheng, Shangshu Qian, Haoxiang Yu, Haojie Zhu, Ying Xie, Runtian Zheng, Tingting Liu, Miao Shui, Jie Shu
    更新日期:2018-06-22
  • Rechargeability of Aqueous Sulfate Zn/MnO2 Batteries Enhanced by Accessible Mn2+ ions
    Energy Storage Mater. (IF 0) Pub Date : 2018-06-20
    Mylad Chamoun, William R. Brant, Cheuk-Wai Tai, Gunder Karlsson, Dag Noréus
    更新日期:2018-06-22
  • A new catalyst of Co/La2O3-doped La4Ga2O9 for direct ethanol synthesis from syngas
    Fuel Process. Technol. (IF 3.752) Pub Date : 2018-06-20
    Qilei Yang, Ang Cao, Na Kang, Kang An, Zhao-Tie Liu, Yuan Liu
    更新日期:2018-06-22
  • Comparative Study of Solar-Powered Underfloor Heating System Performance in Distinctive Climates
    Renew. Energy (IF 4.357) Pub Date : 2018-06-20
    Mohammad Sadjad Karimi, Farivar Fazelpour, Marc A. Rosen, Mehrzad Shams

    According to the International Energy Agency, buildings are the largest energy-consuming sector globally, producing over one-third of greenhouse gas emissions in 2013. Renewable energies such as solar can be harnessed to fully or partially meet the energy demands of buildings. In this study, solar thermal collectors are used in a building to provide the hot water required for an underfloor heating system. Three cities in Iran, namely Tabriz, Tehran and Kish island, with distinctive climatic conditions are considered to gain a better understanding of the performance of solar-powered underfloor heating systems in different climates. Moreover, an economic analysis is conducted to assess the feasibility of the proposed system. DesignBuilder software is applied to simulate the energy performance of the building. The results indicate that the annual fuel consumption of the building with a solar collector located in Tehran, Tabriz and Kish island is reduced by 125.39, 303.58 and 1.41 MWh compared to that of without collector, respectively. The payback period of the system for Tehran, Tabriz and Kish Island is found to be 8.2, 9.4 and 12.1 years, respectively.

    更新日期:2018-06-22
  • Iranian agriculture advisors’ perception and intention toward biofuel: green way toward energy security, rural development and climate change mitigation
    Renew. Energy (IF 4.357) Pub Date : 2018-06-20
    Jafar Yaghoubi, Masoud Yazdanpanah, Nadejda Komendantova

    Agricultural professionals play an important role in informing and educating farmers about biofuel through teaching or extension work. One of the questions commonly asked is if they are knowledgeable and possess positive attitude towards renewable energy sources. The aim of this article is to investigate Agricultural professionals’ attitude and willingness towards biofuel using a random sample of professionals (n =180) in a survey conducted in Zanjan province in Iran. Structural equation modeling showed that “Outcome efficacy”, “problem perception” and “perceived benefits” can significantly predict just about 38% variance of Agricultural professionals’ personal norm. In turn, personal norm can predict 35% variance of Agricultural professionals’ willingness. The findings yield public policy recommendations for stimulating biofuel extension and deployment among Agricultural professionals.

    更新日期:2018-06-22
  • Hybrid solar power system versus photovoltaic plant: A comparative analysis through a life cycle approach
    Renew. Energy (IF 4.357) Pub Date : 2018-06-20
    Fabio Magrassi, Elena Rocco, Stefano Barberis, Michela Gallo, Adriana Del Borghi

    The sun is considered to be one of the most environmentally sound sources of clean and renewable energy. Nevertheless, new hybrid solar plants - combining solar power with another source of energy - have never been compared to traditional solar technologies. Therefore, the aim of this work is to compare the potential environmental impact of a 100 kWp photovoltaic plant (PV) with a 100 kW hybrid solar-gas turbine system (SHGT) using a life cycle assessment methodology. To the best of our knowledge, this type of comparison is the first of its kind. The analysis is performed considering three different scenarios for the SHGT. Additionally, a deep sensitivity analysis is undertaken, focusing on those parameters that mostly influence the outcomes. The results highlight that, using the currently available technology, PV resulted to be the best environmental choice, with greenhouse gas (GHG) emission of 0.043 kg CO2eq/kWh. SHGT plant emissions resulted to be higher, equal to 0.236 kg CO2eq/kWh when running at nominal power 12 h/day, mainly due to the fuel contribution. However, improvements in receiver technology could make it possible to reach higher receiver outlet temperatures and consequently save fuel, reducing the overall environmental impact. Moreover, replacing the natural gas used as turbine running fuel with solar radiation leads to a reduction in GHG emissions, which become comparable to PV plant gases.

    更新日期:2018-06-22
  • Hydro-abrasive erosion in Pelton turbine injectors: A numerical study
    Renew. Energy (IF 4.357) Pub Date : 2018-06-20
    Gianandrea Vittorio Messa, Simone Mandelli, Stefano Malavasi

    Numerical simulations were performed to investigate how the design and the operation conditions of a Pelton turbine injector affect its vulnerability to hydro-abrasive erosion, alongside with its flow control capacity. Use was made of a Volume Of Fluid (VOF) model for simulating the free nozzle jet, a Lagrangian particle tracking model for reproducing the trajectories of the silt particles, and two erosion models for estimating the mass removal. The comparison against earlier studies and the experimental evidence, integrated with a careful sensitivity analysis, gave strength to the reliability of the numerical model. Nozzle seat and needle were the injector components most vulnerable to erosion. As the valve was closing, the erosion of the needle strongly increased, whilst that of the nozzle seat remained broadly constant. The influence of the injector design was also explored, suggesting that a reduction of the needle vertex angle is likely to enhance the risk of erosive wear. Finally, it was found that the possibility to condense the effects of the needle stroke and the needle vertex angle in a single parameter (i.e. the effective opening area) is no more allowed when hydro-abrasive erosion is considered, thereby assessing the need for case-specific wear prediction analyses.

    更新日期:2018-06-22
  • Optimization of 4th generation distributed district heating system: Design and planning of combined heat and power
    Renew. Energy (IF 4.357) Pub Date : 2018-06-20
    Mohammad Sameti, Fariborz Haghighat

    This study applies a mathematical programming procedure to model the optimal design and planning of a new district which satisfies two features of the 4th generation district heating systems: energy reciprocity and on-site generation. The aim of the computational model is to investigate the effect of energy reciprocity (energy exchange among the buildings) as well as to find the best way to select the equipment among various candidates (capacities), the pipeline network among the buildings, and their electrical connections. The objective function includes the annualized overall capital and operation costs for the district along with the benefits of selling electricity to the grid. The distributed energy supply consists of heating, cooling, and power networks, several CHP technologies, solar array, chillers, and auxiliary boilers. The performance of the model for poly-generation was evaluated for designing the new part of Suurstoffi district situated in Risch Rotkreuz, Switzerland with seven residential and office complexes under four different scenarios. Allowing heat exchange among the buildings leads to 25% reduction in total annualized cost and 5% reduction in emission compared to the conventional districts. Removing the network and installation of PV and CHPs results in 9% reduction in emission and 11% reduction in cost. Simultaneous heat and electricity exchange results in a higher reduction in total annualized cost equal to 40% of the base scenario.

    更新日期:2018-06-22
  • Microbial oil production by Mortierella isabellina from sodium hydroxide pretreated rice straw degraded by three-stage enzymatic hydrolysis in the context of on-site cellulase production
    Renew. Energy (IF 4.357) Pub Date : 2018-06-21
    Chen Zhao, Bing Xie, Runze Zhao, Hao Fang

    Lignocellulosic single cell oil (SCO) is profound and promising in response to the increasing concerns on sustainable energy supply and environmental protection. Different bioprocesses from sodium hydroxide pretreated rice straw (SHPRS) to SCO were compared and the bioprocess c using the three-stage enzymatic hydrolysis was found to be the most efficient. It had the lowest enzyme input 153.1 FPIU cellulase/g SCO and the shortest time 222 h, but produced 42.0 g dry cell biomass and 23.4 g SCO from 342.0 g dry SHPRS. It had the highest lipid content 55.7%, and its productivities and yields were the highest. This study verified that on-site cellulase production by the mixed culture of Trichoderma reesei and Aspergillus niger and the three-stage enzymatic hydrolysis have the application value in SCO production from lignocelluloses by Mortierella isabellina.

    更新日期:2018-06-22
  • Timescales of Energy Storage Needed for Reducing Renewable Energy Curtailment
    Renew. Energy (IF 4.357) Pub Date : 2018-06-21
    Paul Denholm, Trieu Mai

    Integrating large amounts of variable generation (VG) resources such as wind and solar into a region's power grid without causing significant VG curtailment will likely require increased system flexibility via changing grid operation and deploying enabling technologies such as energy storage. This article analyzes the storage duration required to reduce VG curtailment under high-VG scenarios. The three analysis scenarios assume VG provides 55% of the electricity demand in the largely isolated Electricity Reliability Council of Texas grid system in 2050, with three different proportions of wind and solar generation. Across the three scenarios, 11%–16% of VG energy is curtailed without storage due to system-generation constraints. When 8.5 GW of storage capacity with 4 hours of duration are added, curtailment is reduced to 8%–10% of VG. Additional storage duration further reduces curtailment, but with rapidly diminishing returns. At least half the potential avoided-curtailment benefits are realized with 8 hours of storage, and the first 4 hours provide the largest benefit. At VG penetrations up to 55%, there appears to be little incremental benefit in deploying very-long-duration or seasonal storage.

    更新日期:2018-06-22
  • Simulation of a power system with large renewable penetration
    Renew. Energy (IF 4.357) Pub Date : 2018-06-21
    T. Fiedler

    This paper presents a simulation software initially developed by the author for educational purposes. The computational tool supports the design of power systems with large penetration by renewable energy sources. In particular, the problematic of power intermittency and its counter strategies are targeted. The main innovation of this simulation is the detailed transient analysis of the essential balance between power generation and consumption. Even so, the focus of the simulation tool is simple usage and interpretation of results, it successfully captures important characteristics of renewable power systems. The user selects the composition of a power system from conventional power plants, photovoltaic, windpower and tidal power. Following system definition, power generation and power demand are calculated based on local weather data. Energy storage can be added to balance mismatches between power demand and supply. Following the completion of a simulation system autonomy, carbon emission and electricity cost are evaluated to assess the performance of energy systems.

    更新日期:2018-06-22
  • A real-time energy management system for smart grid integrated photovoltaic generation with battery storage
    Renew. Energy (IF 4.357) Pub Date : 2018-06-21
    Chee Lim Nge, Iromi U. Ranaweera, Ole-Morten Midtgård, Lars Norum, Lars Norum

    This paper proposes a real-time energy management system (EMS) suitable for rooftop PV installations with battery storage. The EMS is connected to a smart grid where the price signals indirectly control the power output of the PV/battery system in response to the demand variation of the electricity networks. The objective of the EMS is to maximize the revenue over a given time period while meeting the battery stored energy constraint. The optimization problem is solved using the method of Lagrange multipliers. The uniqueness of the proposed EMS remains in the reactive real-time control mechanism that compensates for the PV power forecast error. The proposed EMS requires only forecasting the average PV power output over the total optimization period. This is in contrast to the predictive power scheduling techniques that require accurate instantaneous PV power forecast. The proposed EMS method is verified by benchmarking against the predictive brute-force dynamic programming (DP) approach. The simulation analysis considers days with varying solar irradiance profiles. The simulation analysis shows the proposed EMS operating under practical assumptions, where the battery storage capacity is subject to constraints and the PV power output is not known a priori.

    更新日期:2018-06-22
  • A novel beta parameter based fuzzy-logic controller for photovoltaic MPPT application
    Renew. Energy (IF 4.357) Pub Date : 2018-06-21
    Xingshuo Li, Huiqing Wen, Yihua Hu, Lin Jiang

    In this paper, a novel beta parameter three-input one-output fuzzy-logic based maximum power point tracking (MPPT) algorithm is presented for the photovoltaic (PV) system application. The conventional fuzzy-logic controllers (FLCs) exhibit obvious limitations such as their dependence on the user's knowledge about the system and complicated rules. Furthermore, they show inherent dilemma between the rules number of FLC and the universality for various operating conditions, which is revealed and explained with details in this paper. Thus, a novel FLC is proposed by introducing a third input: an intermediate variable β. It can simplify the fuzzy rule membership functions and cover wider operating conditions. The dependence on the user's knowledge about the system is reduced. The converging speed for transients is improved and oscillations around the MPPs are completely eliminated compared with conventional MPPT methods. Typical operation conditions such as varying solar irradiation and load resistance are tested for fair comparison of various algorithms. An experimental prototype was designed and main experimental results were presented to verify the advantages of the proposed algorithm.

    更新日期:2018-06-22
  • A comprehensive investigation of using mutual air and water heating in multi-functional DX-SAMHP for moderate cold climate
    Renew. Energy (IF 4.357) Pub Date : 2018-06-21
    Elamin Mohamed, Saffa Riffat, Siddig Omer, Rami Zeinelabdien

    Solar energy assisted heat pump systems (SAHP) have been used in this application. SAHP system with solar collectors and the heat pump are combined into one unit so as to convey the solar energy to the refrigerant. The solar collector is used as the evaporator, where the refrigerant is directly vaporized by solar energy input. Due to the complicated technical issues associated with a combined system that provides air for space heating and domestic hot water, most of the previous studies have concentrated on water heater heat pump mechanism. The current work is aimed at examining the use of a new multi-functional heat pump (DX-SAMHP), air for space heating mutually with solar for domestic hot water without employing an auxiliary heater. Comprehensive experimental and analytical studies in the first of its kind have been performed on the new system. The novel system with ternary panels and the thermal performance of the collector has been examined in this study. Results indicate that the DX-SAMHP using solar inner and outer panels for space and water heating is a promising substitute for the existing DX-SAHP water heater. Compared to the conventional solar-assisted SAHP heat pump systems, the coefficient performance of the new design doubles that of the conventional DX-SAHP systems.

    更新日期:2018-06-22
  • 更新日期:2018-06-22
  • Mechanisms of mercury transformation over α-Fe2O3(0 0 1) in the presence of HCl and/or H2S
    Fuel (IF 4.601) Pub Date : 2018-06-20
    Yu Chen, Xin Guo, Fan Wu, Yu Huang, Zhanchi Yin
    更新日期:2018-06-22
  • Effect of diesel late-injection on combustion and emissions characteristics of diesel/methanol dual fuel engine
    Fuel (IF 4.601) Pub Date : 2018-06-20
    Taoyang Wu, Anren Yao, Chunde Yao, Wang Pan, Hongyuan Wei, Chao Chen, Jian Gao

    The late-injection strategy (close after main-injection) of common-rail diesel engine is capable of enhancing combustion turbulence and reducing particulate matter (PM) emissions. In this work, experimental study was performed to investigate the effect of diesel late-injection on combustion and emissions characteristics of diesel/methanol dual fuel (DMDF) engine. The experiments were carried out at a constant engine speed of 1340 rpm and a medium load of 1.0 MPa brake mean effective pressure (BMEP) with various methanol substitution ratio (MSR) on a common rail DMDF engine. The results reveal that higher MSR caused simultaneous decrease of nitric oxides (NOx) and accumulation mode PM emissions in spite of late-injection strategy. In particular, an augment of up to 12.8% in nucleation mode particle number (PN) was observed as MSR increased from 15% to 50%. A small late-injection of diesel (<7.5 mg/cycle) had little impact on in-cylinder pressure and heat release rate (HRR). However, enhanced or retarded late-injection led to a decline in peak gas mean temperature (GMT) but an increase in later combustion temperature. With late-injection quantity (LIQ) increased from 1.5 mg/cycle to 7.5 mg/cycle, both NOx and accumulation mode PM decreased. Meanwhile, nucleation mode PM was almost unchanged and even rebounded slightly with overmuch LIQ (7.5 mg/cycle) in DMDF mode. Retarded late-injection led to a continuous reduction of 12.9% at most in NOx emissions in DMDF operation. As the interval between main-late injections (MLII) increased from 800 μs to 1200 μs, a trade-off relation appeared between nucleation mode and accumulation mode particles due to the mutual transformation of them. Furthermore, too delayed late-injection (MLII > 1200 μs) induced a simultaneous increase of particles with different size.

    更新日期:2018-06-22
  • Water catalyzed pyrolysis of oxygen functional groups of coal: A density functional theory investigation
    Fuel (IF 4.601) Pub Date : 2018-06-20
    Sathish Kumar Mudedla, Choutipalli Venkata Surya Kumar, A. Suresh, Prathap Baskar, Pratik Swarup Dash, Venkatesan Subramanian

    The pyrolysis mechanism of carboxylic and hydroxyl groups which are present in the coal has been investigated with the help of density functional theory calculations. The role of water in the pyrolysis reaction mechanisms has also been investigated by the calculation of activation energy barriers. The activation energy barriers for the water mediated reactions are less when compared to thermal pyrolysis process. The results show the significant decrease in the energy barriers for decarboxylation reactions than the hydroxyl groups in the presence of water. Therefore, water can significantly decrease the oxygen content in the non-coking coals with high content of carboxylic groups.

    更新日期:2018-06-22
  • Preparation and characteristic of the fly ash cenospheres/mullite composite for high-temperature application
    Fuel (IF 4.601) Pub Date : 2018-06-20
    Sue Ren, Xin Tao, Xiqing Xu, Anran Guo, Jiachen Liu, Jinpeng Fan, Jingran Ge, Daining Fang, Jun Liang
    更新日期:2018-06-22
  • Numerical simulation of premixed combustion using the modified dynamic thickened flame model coupled with multi-step reaction mechanism
    Fuel (IF 4.601) Pub Date : 2018-06-21
    Shilong Guo, Jinhua Wang, Xutao Wei, Senbin Yu, Meng Zhang, Zuohua Huang

    Thickened flame (TF) model is one of the effective methods to resolve the flame front in turbulent premixed combustion modeling. The multi-step reaction mechanism is becoming increasingly important for combustion simulations such as pollutant formation, ignition and extinction. The effect of TF model on flame structures when coupling with multi-step reaction mechanism was investigated. The simulation results show that, no matter in laminar or turbulent condition, the global TF model coupling with multi-step reaction mechanism results in an incomplete combustion, which is mainly due to the enhanced species diffusion. Although Durand and Polifke’s dynamic thickened flame (DTF) sensor performs well for predicting laminar flame structure when coupling with multi-step reaction mechanism, it underestimates the effective thickening factor. In turbulent premixed flame simulation, the underestimated thickening factor leads to a faster local fuel consumption speed because of the over-predicted sub-grid flame wrinkling factor. A modified DTF sensor suitable for multi-step reaction mechanism is proposed. This sensor using the hyperbolic tangent function of progress variable to calculate thickening factor dynamically. It ensures that both the preheated and reaction zones are thickened effectively. The sub-grid wrinkling factor is hence estimated corresponding to the calculated flame thickness. Results of 1D laminar and 3D turbulent flame show that this method performs well for predicting both burned gas temperature and species concentration in burnt gas, which is important for predicting emissions.

    更新日期:2018-06-22
  • Simulations on recoverability performances for a coalbed methane field in SE edge of Ordos basin, China
    Fuel (IF 4.601) Pub Date : 2018-06-21
    Mingjun Zou, Simin Wei, Zhiquan Huang, Xiaochun Lv, Biao Guo

    This paper mainly studies the recoverability performances for a coalbed methane (CBM) field located in the southeastern edge of the Ordos basin of China. Geological models are established, and drainage performances for four typical wells are described in detail. Single well simulations for the four wells are conducted to check accuracies of parameters and predict well drainage performances, and optimizations of well spaces are simulated to determine the most suitable well space. Results indicate that the reservoir parameters used in this study are quite accurate, and the well space of 350 × 300 m is most suitable in this area. Furthermore, the fifteen years’ field simulation under the well space of 350 × 300 m is conducted, which shows that the well number, average production and cumulative production are 1944, 7.01 × 108 m3/d and 105.22 × 108 m3, respectively. To validate the well space used in this study, analyses of recoverability and economic profit are conducted, both of which demonstrate that the well space of 350 × 300 m is most suitable in this area and can bring a stable drainage performance for a long time and get a high gas production.

    更新日期:2018-06-22
  • Geochemical behavior of hazardous volatile elements in coals with different geological origin during combustion
    Fuel (IF 4.601) Pub Date : 2018-06-21
    Guangqing Hu, Guijian Liu, Dun Wu, Biao Fu

    The geochemical behaviors of hazardous elements in the combustion process of Chinese coals with different geological origins at different temperatures were studied. The analyzed coal samples were placed in a fixed bed reactor with a quartz tube and heated to six desired temperature points, from 400 °C to 900 °C with 100 °C for each interval. The mineral morphology and composition of coal and coal ash were determined by X-ray fluorescence (XRF), scanning electron microscope-X-ray Energy Dispersive Spectrom (SEM-EDS) and X-ray powder diffraction techniques (XRD). Sequential chemical extraction procedure was used to describe the modes of occurrence of selected hazardous elements in coal. The content of arsenic (As) in coal and coal ash was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and the content of selenium (Se) and mercury (Hg) in coal ash was analyzed by atomic emission spectrometry (AES) and atomic fluorescence spectrometry (AFS). The volatile characteristics of As, Se and Hg in coal were studied by thermogravimetry (TG). The results show that: 1) the mineral phases of Liuzhuang (LZ) and Huajiahu (HJH) coal samples are mainly composed of clay minerals and silicate minerals and the contents of As, Se and Hg were closely related to the organic matter and inorganic mineral in coal; 2) As mainly exists in organic matter and Se, Hg mainly exists in silicate minerals. The organic As in coal is closely related to the low-rank, low ash content and low As content of coal. The modes of occurrence of Se and Hg may be related to the low element content, low sulfide content in coal and stable sedimentary environment; 3) the relationship between volatilization rate (Vr) of As, Se and Hg elements and combustion temperature is the closest. The differences of Vr of As, Se and Hg elements in coal of different geological origin are mainly related to elements concentration and coal quality; 4) at different heating rates, the Vr curves of As, Se and Hg elements have the characteristics of “S” type, logarithmic type and linear type, respectively; The Initial stable temperature of Vr is different under the influence of element geochemical characteristics. The volatility of As reaches the maximum at 800 °C, and Se and Hg reach the maximum at 700 °C and 600 °C, respectively; 5) The heating rate and the difference of coal quality under different geological origin are important factors affecting the Vr of As, Se and Hg. The maximum weight loss temperature (TP) can be used as an important index to reflect the influence of coal quality and heating rate on the Vr of hazardous elements (As, Se and Hg).

    更新日期:2018-06-22
  • Iron precipitated onto ceria-zirconia nanoparticle mixtures for the production of hydrogen via two-step thermochemical water splitting
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-19
    Samantha J. Roberts, Nathan G. Carr, Jonathan McLaughlin, Helena E. Hagelin-Weaver

    Several novel materials were synthesized by precipitating iron oxide (using the previously optimized 10% Fe loading by weight) onto mixtures of nanoparticle zirconia and ceria to investigate the effects of adding CeO2 to FeOx/ZrO2 materials in the thermochemical water splitting reaction. At water splitting temperatures of 1000 °C (after thermal reduction at 1450 °C), the stability of the CeO2-containing materials was lower than for the FeOx/ZrO2 material, and there was no advantage to adding CeO2 to the FeOx/ZrO2 material. However, when operating at a water splitting (WS) temperature of 1200 °C, the stability increased and the hydrogen production was significantly higher over most materials compared with a water splitting temperature of 1000 °C. At a WS temperature of 1200 °C the FeOx/Zr75Ce25O2 (75% Zr75O2 and 25% CeO2 by weight) and FeOx/Zr50Ce50O2 materials performed slightly better than the FeOx/ZrO2 material, and X-ray photoelectron spectroscopy data revealed that the surface concertation of iron is less important compared with water splitting at 1000 °C. The temperature programmed reduction data indicated that the FeOx-CeO2 interactions were weaker compared with FeOx-ZrO2 interactions, since the FeOx reduction occurred at lower temperatures for the CeO2-containing materials. The weaker interactions can explain why the stability was lower for the materials containing CeO2 (sintering of FeOx was likely more pronounced) The X-ray diffraction data revealed that ZrO2-CeO2 solid solutions formed after activation at 1450 °C and lattice volume calculations indicated that iron did incorporate into the ZrO2-CeO2 matrices. More incorporation was observed after water-splitting at 1200 °C compared with a lower temperature (1000 °C), and likely explains why the materials were more stable during water-splitting at 1200 °C.

    更新日期:2018-06-22
  • Solid solution limits and electrical properties of scheelite SryLa1-yNb1-xVxO4-δ materials for x = 0.25 and 0.30 as potential proton conducting ceramic electrolytes
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-19
    Ana D. Brandão, Narendar Nasani, Aleksey A. Yaremchenko, Andrei V. Kovalevsky, Duncan P. Fagg

    The proton conductivity and solid solubility limits of acceptor strontium doped vanadium stabilised lanthanum niobate (SryLa1−yNb1-xVxO4-δ, x = 0.25, 0.30 and y = 0 to 0.10) were explored as potential proton conducting ceramic electrolytes. All samples were synthesized via a solid-state method. The phase purity, microstructure and thermal expansion behaviour of the materials were studied using powder X-ray diffraction, scanning electron microscopy and dilatometry, respectively. A maximum solid solution limit of 5% Sr in the A-site of SryLa1−yNb1-xVxO4-δ samples is observed for a vanadium content of x = 0.25, while further increases in the Sr or vanadium contents lead to the presence of Sr3(VO4)2 as a secondary phase. This acceptor dopant content of 5%Sr in the current scheelite material exceeds that possible in the parent vanadium-free fergusonite SryLa1−yNbO4-δ material by a factor of 5. All Sr doped scheelite materials show linear thermal expansion behaviour, successfully avoiding the scheelite to fergusonite structural phase change during thermal cycling. The average grain size is shown to be increased by increasing vanadium content. In humid conditions, all phase pure samples show predominantly proton conductivity at lower temperatures, while p-type conductivity is noted at higher temperatures under dry oxidising conditions. In the low temperature range, the Sr0.05La0.95Nb0.75V0.25O4-δ sample, containing the largest acceptor dopant concentration, exhibits slightly higher bulk and specific grain boundary conductivities in comparison to other phase pure compositions.

    更新日期:2018-06-22
  • Detonation behaviors of syngas-oxygen in round and square tubes
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-19
    Lu-Qing Wang, Hong-Hao Ma, Zhao-Wu Shen, Yang-Fan Cheng, Dai-Guo Chen

    The present study reports the detonation behaviors of syngas-oxygen mixtures in three 2 m long tubes, including two circular tubes (DD = 32 mm and 18.5 mm, DD is the inner diameter) and a square tube (HH = 32 mm, HHis the inner side). Three stoichiometric syngas-oxygen mixtures, i.e., CO+H2+O2, 2CO+H2+1.5O2, 3CO+H2+2O2 were used. Evenly spaced photodiodes were used to determine the detonation velocity while the soot foil technique was adopted to record the cellular structure. The results indicate that well with the limits, the detonation propagates at a steady velocity close to the Chapman-Jouguet value. The velocity deficits are more prominent at decreased initial pressure (equivalently, larger cell size and less sensitivity). At the limiting pressure, the velocity deficits of three mixtures in various tubes are approximate 14%–17%. The experimental velocity deficits were compared with a modified model based on Fay's theory, in which the cell size as well as the corresponding cell length are measured. The experimental velocity deficit is in excellent agreement with the theoretical prediction. The effective diameter, DeDe, rather than the hydraulic diameter, is found to be a more appropriate parameter for the characterization of the detonation velocity in both round and square tubes. Further, a linear correlation between the normalized detonation velocity and (De·p0)−1(De·p0)−1 is observed. The cellular structure shows that the single-headed spin occurs in all tubes when the detonation limits are approached.

    更新日期:2018-06-22
  • Application of catalytic membrane reactor for pure hydrogen production by flare gas recovery as a novel approach
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-20
    Majid Saidi

    In the present study, application of catalytic membrane reactor as a novel approach for the flare gas recovery is proposed. A comprehensive two-dimensional non-isothermal model has been constructed to evaluate the performance of flare gas recovery process in the membrane reactor. The model is developed by taking into accounts the main chemical kinetics, heat and mass transfer phenomena and hydrogen permeation in the radial direction across a Pd–Ag membrane. The model predictions are validated based on different experimental results reported in literature. The impact of reactor operating conditions on the recovery process such as temperature and pressure, feed molar ratio and sweep gas ratio are investigated and discussed. The modeling results confirm that the flare gas conversion and hydrogen recovery improves with increasing the operating temperature, pressure and sweep ratio as a consequence of increasing the driving force for H2 permeation through membrane. The environmental consideration revealed that by application of catalytic membrane reactor for the flare gas recovery of Asalouyeh gas processing plant (Iran), not only the equivalent mass of greenhouse gases emission reduces from 2179 kg/s to 36 kg/s, but also, 12.7 kg/s pure hydrogen will be produced by flare gas recovery at 750 K, 5 bar, sweep ratio of 5 and feed molar ratio of 4.

    更新日期:2018-06-22
  • Monodisperse PtCu alloy nanoparticles as highly efficient catalysts for the hydrolytic dehydrogenation of ammonia borane
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-20
    Manyi Gao, Weiwei Yang, Yongsheng Yu

    Pt-M alloy nanoparticles (NPs) with well-defined size and compositions exhibit dramatically catalytic performance in chemical reactions. In this work, monodisperse PtCu NPs with controlled size and compositions were synthesized by the co-reduction method in the presence of oleylamine. These NPs have excellent catalytic activities in the hydrolytic dehydrogenation of ammonia borane (AB) and their activities were composition dependent. Among the different-composition PtCu NPs, the Cu50Pt50 NPs exhibit the highest catalytic activity with an initial turnover frequency of 102.5 mol(hydrogen)·mol(catalyst)−1·min−1 and an apparent activation energy of 36 kJ·mol−1, which demonstrate the validity of partly replacing Pt by a first-row transition metal on constructing high performance heterogeneous nanocatalysts for the hydrolytic dehydrogenation of AB.

    更新日期:2018-06-22
  • Encapsulation of metal precursor within ZIFs for bimetallic N-doped carbon electrocatalyst with enhanced oxygen reduction
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-20
    Mengchen Wu, Xianxiang Hu, Congling Li, Jian Li, Haijun Zhou, Xia Zhang, Rui Liu

    High-performance non-precious metal-doped carbon catalysts for oxygen reduction reactions (ORR) are viable candidates in lieu of platinum-based catalysts. It has been universally reported that active Co–N sites combined with Fe–N sites embedded in carbon matrix represent the most promising active sites for ORR process. Benefiting from the cage-encapsulated-precursor pyrolysis strategy, herein, we fabricated a Fe–N and Co–N homogeneously doped carbon framework by one step. TEM demonstrated the ultimate product had well-defined morphology with Fe (0.54 at%), Co (0.31 at%) and N (2.94 at%) uniformly distributed into the carbon skeleton. The N2 absorption-desorption isotherms indicated the MOF-derived catalyst had a high specific surface area of 647.6 m2 g−1 and inherit hierarchical porosity. Significantly, such FeCo–NC catalyst outperformed a current density (5.6 mA cm−2) at 0.70 V (vs reversible hydrogen electrode) 1.18 times higher than that of a commercial 20 wt% Pt/C (5 mA cm−2) catalyst in alkaline medium, and more positive peak potential of 0.63 V than its counterparts. Its high cycling stability and immunity towards methanol crossover in a wide range pH value showed good potential to be used as cathodes in proton exchange membrane fuel cells (PEMFCs) for long term operation. This simple synthesis strategy would to some degree leverage a cage-encapsulated-precursor for tailored utility of active sites for ORR in a porous carbon framework.

    更新日期:2018-06-22
  • Multi-criteria optimization of an integrated energy system with thermoelectric generator, parabolic trough solar collector and electrolysis for hydrogen production
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-20
    Ali Habibollahzade, Ehsan Gholamian, Pouria Ahmadi, Amirmohammad Behzadi

    In this research paper, a newly energy system consisting of parabolic trough solar collectors (PTSC) field, a thermoelectric generator (TEG), a Rankine cycle and a proton exchange membrane (PEM) is proposed. The integration is performed by establishing a TEG instead of the condenser as power generation and cooling unit thereafter surplus power output of the TEG is transferred to the PEM electrolyzer for hydrogen production. The integrated renewable energy system is comprehensively modeled and influence of the effective parameters is investigated on exergy and economic indicators through the parametric study to better understand the system performance. Engineering equation solver (EES) as a potential engineering tool is used to simulate the system and obtain the desired results. In order to optimize the system, a developed multi-objective genetic algorithm MATLAB code is applied to determine the optimum operating conditions of the system. Obtained results demonstrate that at optimum working condition from exergy viewpoint, exergy efficiency and total cost are 12.76% and 61.69 $/GJ, respectively. Multi-objective optimization results further show that the final optimal point which is well-balanced between exergy efficiency and total cost, has the maximum exergy efficiency of 13.29% and total cost of 63.96 $/GJ, respectively. The corresponding values for exergy efficiency and total cost are 10.01% and 60.21 $/GJ for optimum working condition from economic standpoint. Furthermore, hydrogen production at well-balanced operating condition would be 2.28 kg/h. Eventually, the results indicate that establishing the TEG unit instead of the condenser is a promising method to optimize the performance of the system and reduce total cost.

    更新日期:2018-06-22
  • Developing titanium micro/nano porous layers on planar thin/tunable LGDLs for high-efficiency hydrogen production
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Zhenye Kang, Gaoqiang Yang, Jingke Mo, Shule Yu, David A. Cullen, Scott T. Retterer, Todd J. Toops, Michael P. Brady, Guido Bender, Bryan S. Pivovar, Johney B. Green Jr., Feng-Yuan Zhang
    更新日期:2018-06-22
  • Mini CHP based on the electrochemical generator and impeded fluidized bed reactor for methane steam reforming ☆
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    A.M. Dubinin, S.E. Shcheklein, V.G. Tuponogov, M.I. Ershov

    The paper presents a configuration of mini CHP with the methane reformer and planar solid oxide fuel cell (SOFC) stacks. This mini CHP may produce electricity and superheated steam as well as preheat air and methane for the reformer along with cathode air used in the SOFC stack as an oxidant. Moreover, the mathematical model for this power plant has been created. The thermochemical reactor with impeded fluidized bed for autothermal steam reforming of methane (reformer) considered as the basis for the synthesis gas (syngas) production to fuel SOFC stacks has been studied experimentally as well. A fraction of conversion products has been oxidized by the air fed to the upper region of the impeded fluidized bed in order to carry out the endothermic methane steam reforming in a 1:3 ratio as well as to preheat products of these reactions. Studies have shown that syngas containing 55% of hydrogen could be produced by this reactor. Basic dimensions of the reactor as well as flow rates of air, water and methane for the conversion of methane have been adjusted through mathematical modelling.The paper provides heat balances for the reformer, SOFC stack and waste heat boiler (WHB) intended for generating superheated water steam along with preheating air and methane for the reformer as well as the preheated cathode air. The balances have formed the basis for calculating the following values: the useful product fraction in the reformer; fraction of hydrogen oxidized at SOFC anode; gross electric efficiency; anode temperature; exothermic effect of syngas hydrogen oxidation by air oxygen; excess entropy along with the Gibbs free energy change at standard conditions; electromotive force (EMF) of the fuel cell; specific flow rate of the equivalent fuel for producing electric and heat energy. Calculations have shown that the temperature of hydrogen oxidation products at SOFC anode is 850 °C; gross electric efficiency is 61.0%; EMF of one fuel cell is 0.985 V; fraction of hydrogen oxidized at SOFC anode is 64.6%; specific flow rate of the equivalent fuel for producing electric energy is 0.16 kg of eq.f./(kW·h) while that for heat generation amounts to 44.7 kg of eq.f./(GJ). All specific parameters are in agreement with the results of other studies.

    更新日期:2018-06-22
  • Significantly improve photoelectrochemical performance of Ti:Fe2O3 with CdSe modification and surface oxidation
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Jinyun Xiong, Jiale Xie, Pingping Yang, Xiaorong Liang, Chang Ming Li

    Significant interest has been arisen to explore photoanodes for full optical absorption spectrums and good stability in photoelectrochemistry. Herein CdSe is used to modify Ti:Fe2O3 photoanode forming Ti:Fe2O3/CdSe heterojunction. Combining with an air annealing treatment, Ti:Fe2O3/CdSe exhibits a 6.5 times higher photocurrent density that of the pristine Ti:Fe2O3 to achieve 3.25 mA cm−2 at 1.2 V vs. RHE. The photoelectrochemical (PEC) stability of Ti:Fe2O3/CdSe annealed in air shows great improvement comparable to both unannealed and annealed ones in Ar. The enhancement mechanisms for both heterojunction and annealing are explored for fundamental insights, which reveal that the surface oxide layer can significantly increase the PEC stability of Ti:Fe2O3/CdSe photoanode. X-ray photoelectron spectra and transmission electron microscope results further confirms the surface oxidation on CdSe layer after annealing in air.

    更新日期:2018-06-22
  • Polyol synthesis of reduced graphene oxide supported platinum electrocatalysts for fuel cells: Effect of Pt precursor, support oxidation level and pH
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Lee Pak Hoe, Marta Boaventura, Tiago Lagarteira, Loh Kee Shyuan, Adélio Mendes

    In this work, a comprehensive study on the polyol synthesis of platinum supported on reduced graphene oxide (Pt/rGO) catalysts, including both ex-situ and in-situ characterizations of the prepared Pt/rGO catalysts, was performed. The polyol synthesis was studied considering the influence of the platinum precursor, oxidation level of graphite oxide and pH of reaction medium. The as-prepared catalysts were analyzed using thermo-gravimetric (TG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and cyclic voltammetry (CV). The best results in terms of platinum particle size and distribution were obtained when the synthesis was performed in acidic medium, using chloroplatinic acid as precursor and using graphene oxide with high oxidation level. The most promising graphene-supported catalyst was used to prepare a polymer electrolyte membrane fuel cell electrode. The membrane electrode assembly (MEA) prepared with graphene-based electrode was compared with a MEA prepared with catalyst based on commercial platinum supported in carbon black (Pt/C). Single cell characterization included polarization curves and in-situ electrochemical impedance spectroscopy (EIS). The graphene-based electrode presented promising albeit unstable electrochemical performance due to water management issues. Additionally, EIS measurements revealed that the MEA made with Pt/rGO catalyst presented a lower mass transport resistance than the commercial Pt/C.

    更新日期:2018-06-22
  • Influences of equivalence ratio, oxygen concentration and fluidization velocity on the characteristics of oxygen-enriched gasification products from biomass in a pilot-scale fluidized bed
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Changqi Liu, Yaji Huang, Miaomiao Niu, Haipeng Pei, Lingqin Liu, Yongxing Wang, Lu Dong, Ligang Xu

    The influences of equivalence ratio (ER), oxygen concentration (OC) and fluidization velocity (FV) on the gasification performance in a pilot-scale fluidized bed with capacity of 1 ton biomass (the mixture of agricultural residue) per day were investigated using oxygen-enriched air as gasification agent and high-alumina bauxite as bed material. The characteristics of syngas (lower heating value (LHV), gas yield (Y), carbon conversion (CC) and cold gas efficiency (CGE)), bio-char (LHV and Proximate analysis) and tar (tar yield and LHV) were used to evaluate the gasification performance in this study. The results showed that 0.161 was the optimal ER due to the high quality of syngas produced and relatively lower tar generation with ER changing from 0.115 to 0.243 at OC ≈ 40% and FV ≈ 1.20.29.7% was the optimal OC due to the highest Y and CC and relatively low tar generation when OC varied from 21% to 44.7% at ER ≈ 1.40 and FV ≈ 1.15. Although higher FV could improve syngas quality, it also resulted in the higher tar yield and heavier wear, therefore, the optimal gasification performance was achieved at moderate FV (FV = 1.13). This study proved that oxygen-enriched gasification in a large-scale fluidized bed was an effective option to produce gaseous biofuels with high quality.

    更新日期:2018-06-22
  • Co<img border="0" alt="single bond" src="https://cdn.els-cdn.com/sd/entities/sbnd">Al spinel oxide modified ordered mesoporous alumina supported cobalt-based catalysts for Fischer–Tropsch synthesis
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Jin Wang, Jungang Wang, Xin Huang, Congbiao Chen, Zhongyi Ma, Litao Jia, Bo Hou, Debao Li

    A series of Co<img border="0" alt="single bond" src="https://cdn.els-cdn.com/sd/entities/sbnd">Al spinel oxide modified ordered mesoporous alumina with different CoAl2O4 contents were synthesized by a facile one-pot evaporation induced self-assembly (EISA) method. Then they were first investigated as supports for Cobalt-based catalysts for Fischer–Tropsch synthesis (FTS). The results from testing the catalysts clearly showed that the catalysts modified with CoAl2O4 exhibited higher catalytic activity than the common ordered mesoporous alumina catalysts. A volcano-type dependence of the catalytic activity with the contents of CoAl2O4 in the supports was observed. The results from in situ XRD revealed that the cobalt phase of the reduced catalysts modified with CoAl2O4 were more likely to be HCP rather than FCC. As inferred from in situ CO-FTIR and CO-TPD results, the CO dissociation ability was enhanced by increasing the content of the CoAl2O4 modification in the supports. Such a volcano-type dependence of catalytic activity with the contents of CoAl2O4 in the supports was due to the combination of two factors. One was the generation of the HCP cobalt, which exhibited a higher CO dissociation ability. The other was the synergistic effect of lower reducibility and the degree of dispersion. Meanwhile, when the Co/Al ratios was 0.08 and 0.12 in the supports, the catalysts showed higher C5+ selectivity than other catalysts, which was mainly due to their high Co site density on the catalysts surface.

    更新日期:2018-06-22
  • Combustion and emission characteristics of a hydrogen-diesel dual-fuel engine
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Pavlos Dimitriou, Madan Kumar, Taku Tsujimura, Yasumasa Suzuki

    Hydrogen generated from renewable sources is an eco-friendly fuel that can be used in automotive industry or for energy generation purposes. Hydrogen is a high-energy content gas and its carbonless chemical structure can provide significant benefits of high thermal efficiency and near zero or very low carbon emissions when combusted with other fuels.In this study, the implementation of hydrogen fuel was tested at low and medium operating loads in a heavy-duty hydrogen-diesel dual-fuel engine. The paper provides a detailed experimental analysis of the effects of hydrogen energy share ratio and various combustion strategies such as exhaust gas recirculation, diesel injection pressure and diesel injection patterns.At low load conditions, engine operation with an H2 energy share ratio of up to 98% was achieved without any engine operation implications. This condition provided a simultaneous reduction of carbon and NOx emission of over 90% while soot emissions were dropped by 85% compared to the conventional diesel-only operation. At medium load, the increased NOx emission due to the high energy content of hydrogen fuel was found to be the primary challenge.

    更新日期:2018-06-22
  • Gasification of guaiacol in supercritical water: Detailed reaction pathway and mechanisms
    Int. J. Hydrogen Energy (IF 3.582) Pub Date : 2018-06-21
    Chao Zhu, Liejin Guo, Hui Jin, Zhisong Ou, Wenwen Wei, Jianbing Huang

    Supercritical water gasification of guaiacol as a model compound for lignin was conducted in quartz reactors. The formation and degradation pathways of intermediates were discussed. The results show that the gasification efficiency of guaiacol in supercritical water increased as the reaction time increased. The intermediates in the residual liquid consisted mainly of phenols, arenes, cyclopentanones, alcohols and organic acids. Phenols and arenes were difficult to be gasified in supercritical water and easily turned into char and tar while cyclopentanones, alcohols and organic acids could be easily gasified and turn into hydrogen-rich gas. The Ru/Al2O3 catalyst promoted the degradation of phenols and arenes and thus inhibited the formation of char and tar.

    更新日期:2018-06-22
  • 更新日期:2018-06-22
  • Self-Powered Nanodevices for Fast UV Detection and Energy Harvesting using Core-Shell Nanowire Geometry
    Nano Energy (IF 12.343) Pub Date : 2018-06-19
    Chun-Ho Lin, Hui-Chun Fu, Der-Hsien Lien, Chia-Yang Hsu, Jr-Hau He
    更新日期:2018-06-22
  • Comprehensive contact analysis for vertical-contact-mode triboelectric nanogenerators with micro-/nano-textured surfaces
    Nano Energy (IF 12.343) Pub Date : 2018-06-20
    Weixu Yang, Xiaoli Wang, Hanqing Li, Jun Wu, Yanqiang Hu
    更新日期:2018-06-22
  • Visualizing the Knowledge Profile on Self-Powered Technology
    Nano Energy (IF 12.343) Pub Date : 2018-06-20
    Munan Li, Yuan Zhou
    更新日期:2018-06-22
  • Piezoelectric diphenylalanine peptide for greatly improved flexible nanogenerators
    Nano Energy (IF 12.343) Pub Date : 2018-06-20
    Kory Jenkins, Steve Kelly, Vu Nguyen, Ying Wu, Rusen Yang
    更新日期:2018-06-22
  • 更新日期:2018-06-22
  • Inflammation-free and gas-permeable on-skin triboelectric nanogenerator using soluble nanofibers
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Wenqian Du, Jinhui Nie, Zewei Ren, Tao Jiang, Liang Xu, Shijie Dong, Li Zheng, Xiangyu Chen, Hexing Li
    更新日期:2018-06-22
  • ZnO-Cu2O core-shell nanowires as stable and fast response photodetectors
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Pedram Ghamgosar, Federica Rigoni, Shujie You, Illia Dobryden, Mojtaba Gilzad Kohan, Anna Lucia Pellegrino, Isabella Concina, Nils Almqvist, Graziella Malandrino, Alberto Vomiero
    更新日期:2018-06-22
  • A Comprehensively Theoretical and Experimental Study of Carrier Generation and Transport for Achieving High Performance Ternary Blend Organic Solar Cells
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Zi Shuai Wang, Xingang Ren, Xiaopeng Xu, Qiang Peng, Wei E.I. Sha, Wallace C.H. Choy
    更新日期:2018-06-22
  • Near-Infrared Irradiation Induced Remote and Efficient Self-Healable Triboelectric Nanogenerator for Potential Implantable Electronics
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Qingbao Guan, Yiheng Dai, Yanqin Yang, Xiangyu Bi, Zhen Wen, Yue Pan
    更新日期:2018-06-22
  • Highly-Sensitive and Highly-Correlative Flexible Motion Sensors based on Asymmetric Piezotronic Effect
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Jae Won Lee, Byeong Uk Ye, Zhong Lin Wang, Jong-Lam Lee, Jeong Min Baik
    更新日期:2018-06-22
  • Capillary-Driven Liquid Film Boiling Heat Transfer on Hybrid Mesh Wicking Structures
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Rongfu Wen, Shanshan Xu, Yung-Cheng Lee, Ronggui Yang
    更新日期:2018-06-22
  • Electric-field Control of Li-Doping Induced Phase Transition in VO2 Film with Crystal Facet-Dependence
    Nano Energy (IF 12.343) Pub Date : 2018-06-21
    Yuliang Chen, Zhaowu Wang, Shi Chen, Hui Ren, Bowen Li, Wensheng Yan, Guobin Zhang, Jun Jiang, Chongwen Zou
    更新日期:2018-06-22
  • A comprehensive review of measurements and data analysis of laminar burning velocities for various fuel+air mixtures
    Prog. Energy Combust. Sci. (IF 17.382) Pub Date : 2018-06-20
    Alexander A. Konnov, Akram Mohammad, Velamati Ratna Kishore, Nam Il Kim, Chockalingam Prathap, Sudarshan Kumar

    Accurate measurement and prediction of laminar burning velocity is important for characterization of premixed combustion properties of a fuel, development and validation of new kinetic models, and calibration of turbulent combustion models. Understanding the variation of laminar burning velocity with thermodynamic conditions is important from the perspective of practical applications in industrial furnaces, gas turbine combustors and rocket engines as operating temperatures and pressures are significantly higher than ambient conditions. With this perspective, a brief review of spherical flame propagation method, counterflow/stagnation burner method, heat-flux method, annular stepwise method, externally heated diverging channel method, and Bunsen method is presented. A direct comparison of power exponents for temperature (α) and pressure (β) obtained from different experiments and derived from various kinetic mechanisms is reported to provide an independent tool for detailed validation of kinetic schemes. Accurate prediction of laminar burning velocities at higher temperatures and pressures for individual fuels will help in closer scrutiny of the existing experimental data for various uncertainties due to inherent challenges in individual measurement techniques. Laminar burning velocity data for hydrogen (H2), gaseous alkane fuels (methane, ethane, propane, n-butane, n-pentane), liquid alkane fuels (n-heptane, isooctane, n-decane), alcohols (CH3OH, C2H5OH, n-propanol, n-butanol, n-pentanol) and di-methyl ether (DME) are obtained from literature of last three decades for a wide range of pressures (1–10 bar), temperatures (300–700 K), equivalence ratios and mixture dilutions. The available experimental and numerical data for H2 and methane fuels compares well for various pressures and temperatures. However, more experimental and kinetic model development studies are required for other fuels. Comparison of laminar burning velocity data obtained from different measurement techniques at higher initial pressures and temperatures showed significant deviations for all fuels. This suggests to conduct focused measurements at elevated pressure and temperature conditions for different fuels to enable the development of accurate kinetic models for wider range of mixtures and thermodynamic conditions.

    更新日期:2018-06-22
  • Self-Passivation of a LiNiO2 Cathode for a Lithium-Ion Battery through Zr Doping
    ACS Energy Lett. Pub Date : 2018-06-21
    Chong S. Yoon, Un-Hyuck Kim, Geon-Tae Park, Suk Jun Kim, Kwang-Ho Kim, Jaekook Kim, Yang-Kook Sun
    更新日期:2018-06-22
  • Porphyrin Dimers as Hole-Transporting Layers for High-Efficiency and Stable Perovskite Solar Cells
    ACS Energy Lett. Pub Date : 2018-06-20
    Yu-Hsien Chiang, Hsien-Hsin Chou, Wei-Ting Cheng, Yun-Ru Li, Chen-Yu Yeh, Peter Chen
    更新日期:2018-06-22
  • Rational Design of Hierarchical SnO2/1T-MoS2 Nanoarray Electrode for Ultralong-Life Li–S Batteries
    ACS Energy Lett. Pub Date : 2018-06-20
    Maoxu Wang, Lishuang Fan, Da Tian, Xian Wu, Yue Qiu, Chenyang Zhao, Bin Guan, Yan Wang, Naiqing Zhang, Kening Sun
    更新日期:2018-06-22
  • Layered MOFs Derived Metal Oxide/Carbon Nanosheet Arrays for Catalyzing the Oxygen Evolution Reaction
    ACS Energy Lett. Pub Date : 2018-06-21
    Jian Zhou, Yibo Dou, Awu Zhou, Lun Shu, Ya Chen, Jian-Rong Li

    The oxygen evolution reaction (OER) in water splitting plays critical role in some clean energy production systems. The development of efficient OER electrocatalysts is thus highly demanded. Transition metal oxides as one of the most common candidates were widely explored; however their activity is limited by electrical conductivity, slow mass transfer, and inadequate active sites. Herein, we develop a feasible strategy that layered two-dimensional metal-organic frameworks (2D MOFs) act as templates to construct metal oxide/carbon (MOx/C, M = Co, Ni, and Cu) nanosheet arrays for OER. Owning to both more exposed active sites and fast mass transfer afforded by their 2D structures with rich hierarchical pores, as well as improved conductivity and structural stability offered by strong connection between MOx and carbon, these 2D MOFs derived MOx/C arrays represent high electrocatalytic activities and excellent durability. Particularly, the Co3O4/CBDC, NiO/CBDC, and Cu2O/S-CTDC exhibit low overpotentials of 208, 285, and 313 mV at the current density of 10 mA cm−2, respectively, outperforming all of previously reported corresponding metal oxides based catalysts.

    更新日期:2018-06-22
  • Boosting Photoelectrochemical Water Oxidation Activity and Stability of Mo-doped BiVO4 through the Uniform Assembly Coating of NiFe-Phenolic Networks
    ACS Energy Lett. Pub Date : 2018-06-20
    Yanmei Shi, Yifu Yu, Yu Yu, Yi Huang, Bohang Zhao, Bin Zhang

    Photocorrosion is a key factor that greatly hinders the stability of the photoanodes. Depositing appropriate cocatalysts can effectively protect the semiconductors from the photocorrosion, as well as improve the photoelectrochemical (PEC) activity. However, the formation of cocatalysts is mostly under island growth, making the semiconductors partially unprotected, thus leading to a poor stability. Herein, we demonstrate the complex assembly film composed of phenolic ligands (tannic acid) coordinated with Ni and Fe ions as a robust cocatalyst (TANF) for Mo-doped BiVO4 (Mo:BiVO4@TANF) towards PEC water oxidation. The photocurrent density of Mo:BiVO4@TANF at 1.23 V vs. reversible hydrogen electrode (RHE) reaches a value of 5.10±0.13 mA cm-2. Furthermore, because the complete coverage of TANF film can effectively protect the semiconductor from photocorrosion, 92 % photocurrent of the integrated photoanode retains after operating at harsh 1.23 V vs. RHE for 3 h. The outstanding activity and stability of the integrated photoanode surpass many existing cocatalysts such as ferrihydrite (Fh) and cobalt phosphate (Co-Pi). And the TANF cocatalyts can be also applied to other semiconductors (non-doped BiVO4 and TiO2), indicating the TANF to be a promising cocatalyst alternative for solar energy conversion.

    更新日期:2018-06-22
  • Hierarchical Nickel-Carbon Structure Templated by Metal-Organic Frameworks for Efficient Overall Water Splitting
    Energy Environ. Sci. (IF 29.518) Pub Date : 2018-06-21
    Hao Sun, Yuebin Lian, Cheng Yang, Likun Xiong, Pengwei Qi, Qiaoqiao Mu, Xiaohui Zhao, Jun Guo, Zhao Deng, Yang Peng

    The development of high-performance and cost-effective catalysts for hydrogen and oxygen evolution reactions is key for efficient electrocatalysis of water, which offers a promising solution to convert and store those green but unsteady energies. Herein, we report a hierarchical nickel-carbon composite, fabricated by directly growing sheet-like Ni-MOFs on the commercial nickel foam prior to high-temperature annealing, as a highly efficient bifunctional catalyst. This composite shows remarkable catalytic activities for both hydrogen and oxygen evolution reactions in an alkaline electrolyte, affording a current density of 10 mA cm-2 at overpotentials of 37 mV for HER and 265 mV for OER. Furthermore, an electrolyzer employing the composite as a bifunctional catalyst in both cathode and anode delivers a current density of 35.9 mA cm-2 at a cell voltage of 1.60 V with extended stability, which is even superior to the integrated Pt/C and RuO2 counterparts. This excellent performance is believed a result of a concerted synergy from its hierarchical structure, enabling excellent reaction kinetics. Further ex-situ XRD and XPS analysis reveal that while metallic nickel is responsible for HER, Ni nanoparticles with an oxide shell encapsulated in graphitic carbon are the OER catalytic-active sites formed in-situ.

    更新日期:2018-06-22
  • Combined high alkalinity and pressurization enable efficient CO2 electroreduction to CO
    Energy Environ. Sci. (IF 29.518) Pub Date : 2018-06-21
    Christine M. Gabardo, Ali Seifitokaldani, Jonathan P. Edwards, Thang Cao Dinh, Thomas Burdyny, Md Golam Kibria, Colin O'Brien, Edward H Sargent, David Sinton

    The electroreduction of CO2 to CO is a promising strategy to utilize CO2 emissions while generating a high value product. Commercial CO2 electroreduction systems will require high current densities (>100 mA/cm2) as well as improved energetic efficiencies (EEs), achieved via high CO selectivity and lowered applied potentials. Here we report a silver-based system that exhibits the lowest overpotential among CO2-to-CO electrolyzers operating at high current densities, 300 mV at 300 mA/cm2, with near unity selectivity. We achieve these improvements in voltage efficiency and selectivity via operation in a highly alkaline reaction environment (which decreases overpotentials) and system pressurization (which suppresses the generation of alternative CO2 reduction products), respectively. In addition, we report a new record for the highest half-cell EE (>80%) for CO production at 300 mA/cm2.

    更新日期:2018-06-22
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
化学 • 材料 期刊列表