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  • Spectroscopic study on multicyclic and long-time stability of CO2 adsorbent in flue gas conditions
    Catal. Today (IF 4.636) Pub Date : 2017-11-21
    Jhulimar M. Celedonio, Rose Mardie Pacia, Young Soo Ko

    Since the development of amine-functionalized adsorbent is critical for its large-scale implementation, an investigation on the stability in realistic process condition is significantly important. The amine-functionalized CO2 adsorbents were prepared via impregnation of primary amine (1NS-P/SiO2), secondary amine (1NS-S/SiO2) and diamines (2NS/SiO2) into a silica support. The degradation products that could have caused the deactivation of the adsorbents are determined and quantified by in-situ FT-IR measurement and deconvoluted FT-IR spectra. The adsorbents were evaluated for their stability in multiple temperature swing adsorption (TSA) cycles and long-time CO2 or air exposure at elevated temperature. It revealed that the degradation of adsorbents and its rate depended on the amine structure and gas conditions and that two main degradation species were urea and amide. Primary amine was more prone to CO2-induced degradation than secondary amine. Secondary amine was less stable than primary amine for O2-induced degradation. Diamine showed both CO2- and O2-induced degradations. To determine which has a more detrimental effect on the stability of the adsorbents among CO2 and O2 gases, the effect of long-time exposure of the adsorbents in pure CO2 or air was determined at 150 °C using both TG and in-situ FT-IR measurement. The long-time exposure of 1NS-P/SiO2 to CO2 caused about 50% loss in CO2 uptake with the faster accumulation of linear urea. The long time exposure to air caused just about 13% loss in CO2 uptake with the slower accumulation of amide. 1NS-S/SiO2 showed better stability for CO2 than 1NS-P/SiO2 without any decrease in capacity and without any changes in its spectra. 2NS/SiO2 showed that urea formed faster than amide. It was degraded more in air than in CO2 with about 92% and 51% loss of CO2 uptake, respectively. It can be inferred from the results that O2-induced degradation is more detrimental than CO2-induced degradation.

    更新日期:2017-11-21
  • Benzyl methyl ether production from benzyl alcohol and methanol in carbonic water
    Catal. Today (IF 4.636) Pub Date : 2017-11-21
    Hidetaka Nanao, Hiroki Sasaki, Osamu Sato, Aritomo Yamaguchi, Masayuki Shirai

    Synthesis of benzyl methyl ether from benzyl alcohol and methanol in high-temperature carbonic water was studied in a batch reactor. Benzyl methyl ether formation was not observed by reacting benzyl alcohol with only methanol under supercritical conditions at 573 K. On the other hand, benzyl methyl ether was formed by the treatment of benzyl alcohol in an aqueous methanol solution at 573 K. 12% of benzyl methyl ether yield was obtained in aqueous methanol solution (methanol to water molar ratio of 0.025 mol/0.11 mol) at 573 K in 60 min and the yield enhanced to 33% by the addition of 18 MPa of carbon dioxide to the aqueous solution. As the etherification is an acid catalyzed reaction, the protons derived from the dissociation of water molecules could be responsible for the etherification of benzyl alcohol in an aqueous methanol solution at 573 K. The enhancement of benzyl methyl ether yield by the addition of carbon dioxide in aqueous methanol solution is caused by the increase of the number of protons derived from carbonic acid, which is formed in high-temperature liquid water under high-pressured carbon dioxide.

    更新日期:2017-11-21
  • Improvement of Thermal Stability of Microporous TiO2 for NH3-SCR Reaction Using Multivalent Cations
    Catal. Today (IF 4.636) Pub Date : 2017-11-16
    Soon Hee Park, Seung Gwan Lee, Sung June Cho

    The thermal stability of polycrystalline microporous TiO2 (m-TiO2) has been improved by incorporating multivalent cations such as La3+ and Ce3+. The changes in the crystal structure upon heating were monitored using X-ray powder diffraction and N2 adsorption-desorption isotherms. The presence of multivalent cations significantly increased the thermal stability of TiO2, as inferred from the changes in the surface area, pore volume, and X-ray diffraction pattern. The catalytic performance of the pristine V/m-TiO2 catalyst in the NH3-SCR reaction increased from 40% to 70% and 80% by using the V/m-TiO2 catalyst containing La3+ and Ce3+, respectively, after thermal treatment at 500 °C for 2 h. Further it was demonstrated that the addition of WOx onto La3+ or Ce3+ modified m-TiO2 affected the corresponding thermal stability and the catalytic performance, suggesting that the Ce3+ seemed to be best for the improvement of thermal stability.

    更新日期:2017-11-20
  • High Performance Diesel Oxidation Catalysts using Ultra-low Pt Loading on Titania Nanowire Array integrated Cordierite Honeycombs
    Catal. Today (IF 4.636) Pub Date : 2017-11-15
    Son Hoang, Xingxu Lu, Wenxiang Tang, Sibo Wang, Shoucheng Du, Chang-Yong Nam, Yong Ding, Rodrigo D. Vinluan III, Jie Zheng, Pu-Xian Gao

    High performance of an ultra-low Pt loading diesel oxidation catalyst can be achieved by using a combination of novel nano-array structured support, precise control of ultrafine active Pt particles, and an addition of H2 as a promoter into the exhausts. Highly stable mesoporous rutile TiO2 nano-array was uniformly grown on three-dimensional (3-D) cordierite honeycomb monoliths using a solvothermal synthesis. Atomic layer deposition was employed for precise dispersion of ultrafine Pt particles (0.95 ± 0.24 nm) on TiO2 nano-array with a Pt loading of 1.1 g/ft3. Despite low Pt loading, the Pt/TiO2 nano-array catalyst shows impressive low-temperature oxidation reactivity, with the conversion of CO and total hydrocarbon (THC) reaching 50% at 224 and 285 °C, respectively, in the clean diesel combustion (CDC) simulated exhaust conditions. The excellent activity is attributed to the unique nano-array structure that promotes gas-solid interaction and ultra-small Pt particle dispersion that increase surface Pt atoms. We also demonstrate that addition of more H2 into the exhaust can lower light-off temperature for CO and THC by up to ∼60 °C and ∼30 °C, respectively.

    更新日期:2017-11-16
  • Computational and experimental study of the second metal effect on the structure and properties of bi-metallic MeMoS-sites in transition metal sulfide catalysts
    Catal. Today (IF 4.636) Pub Date : 2017-11-14
    E.A. Permyakov, V.S. Dorokhov, V.V. Maximov, P.A. Nikulshin, A.A. Pimerzin, V.M. Kogan

    Bimetallic (Me)MoS2 (Me = Nb, Fe, Co, Ni) sulfide systems, both modified and non-modified by potassium, were investigated by the DFT method. Geometric and electronic structures of active sites were compared in terms of CO and hydride hydrogen adsorption. Most of the studied metals are electron density acceptors on the S-edge of the crystallite, which inhibits hydride hydrogen adsorption and deactivates the S-edge. The CO adsorption energy on the Me-edge decreased in the order Fe > Co > Ni. Computational data were verified by experimental tests in syngas conversion. Modification by potassium was shown to hinder σ-bonding of the adsorbed molecule and to stabilize hydride hydrogen.

    更新日期:2017-11-16
  • Catalytic combustion of vineyard pruning waste in a conical spouted bed combustor
    Catal. Today (IF 4.636) Pub Date : 2017-11-11
    María J.San José, Sonia Alvarez, Raquel López

    The feasibility of a conical spouted bed combustor for the thermal catalytic exploitation of vineyard pruning waste, under different operating conditions has been analyzed. Stable-flow regimes of vine shoot beds with a Pd catalyst were determined over a wide range of combustion conditions. With the aim of improving the combustion yield, thermal exploitation of vine shoots was performed in batch mode, in a conical spouted bed combustor at temperatures ranging from 250 to 550 °C, with and without the Pd catalyst. The influence of the catalyst and inlet gas temperature on the flue gas concentration was analyzed. The experimental vine shoot combustion yield with the Pd catalyst at different inlet gas temperatures were compared with those obtained without the catalyst. The high experimental combustion efficiency calculated from the flue gases concentrations demonstrates the favorable performance of the conical spouted bed combustor for the catalytic combustion of vine shoots.

    更新日期:2017-11-13
  • Visible-light Photooxygenation of α-Terpinene in a Falling Film Microreactor
    Catal. Today (IF 4.636) Pub Date : 2017-11-11
    Oksana Shvydkiv, Klaus Jähnisch, Norbert Steinfeldt, Alexander Yavorskyy, Michael Oelgemöller

    The photooxygenation of α-terpinene was investigated in a falling film microreactor. The formation of microfilms and the flow operation allowed for a safe and controllable production of the bioactive endoperoxide ascaridole. Stepwise investigation of the process parameters resulted in the selective formation of ascaridole of up to 89% and a productivity of 2.5–3.2 mol L−1 h−1, respectively.

    更新日期:2017-11-13
  • Two-Dimensional MXene/A-TiO2 Composite with Unprecedented Catalytic Activation for Sodium Alanate
    Catal. Today (IF 4.636) Pub Date : 2017-11-11
    Yanping Fan, Zhenluo Yuan, Guodong Zou, Qingrui Zhang, Baozhong Liu, Qiuming Peng

    Differing from graphene with a carbon element component, analogous metallic-graphene two-dimensional layered titanium carbide (2D MXene) provides more opportunities to achieve better surface functionalization. Herein, a thin layered 2D MXene/A-TiO2 composite was prepared by chemical exfoliation and hydrothermal decomposition. The 2D MXene/A-TiO2 composite exhibits high catalytic activity in the adsorption and desorption of hydrogen kinetics for NaAlH4. The critical dehydrogenation temperature of NaAlH4 is ∼90 °C. The first-stage dehydrogenation (∼3.0 wt.%) is accomplished in 50 min at 110 °C. After the first activated cycle, a constant cycling capacity of 4.7 wt.% is remained for a minimum of five cycles tests. It is found that the excellent catalytic activation should be ascribed to the synergistic effect between homogenous distributed Ti-H and TiC, which are originated from MXene/A-TiO2. The results represent a new step forward in the applications of MXene catalytic dehydrogenation and provide new strategies in the quest for new functional MXene derivatives by in-situ modification.

    更新日期:2017-11-13
  • Synthesis of Bimetallic SnPt-Nanoparticle Catalysts for Chemoselective Hydrogenation of Crotonaldehyde: Relationship between SnxPty Alloy Phase and Catalytic Performance
    Catal. Today (IF 4.636) Pub Date : 2017-11-11
    Keita Taniya, Chih Hao Yu, Hiromu Takado, Taiki Hara, Atsushi Okemoto, Takafumi Horie, Yuichi Ichihashi, Shik Chi Tsang, Satoru Nishiyama

    Bimetallic SnPt-nanoparticle (SnPt-NP) catalysts with several types of SnxPty alloy structures were prepared using a polyalcohol reduction process; the catalytic behavior of each SnxPty alloy phase toward the selective hydrogenation of unsaturated aldehydes to the corresponding unsaturated alcohols was elucidated. Atomic absorption spectroscopy (AAS) and transmission electron microscopy (TEM) indicate that SnPt-NP catalysts with various Sn/Pt atomic ratios can be successfully prepared by a polyalcohol reduction process using Pt(acac)2 and Sn(AcO)2 as the metal precursors. X-ray diffraction (XRD) results reveal that the Sn1Pt3, Sn1Pt1, and Sn2Pt1 alloy phases are formed through control of the Sn/Pt atomic ratio of the starting mixture during preparation. The Sn1Pt3 alloy phase enhanced the hydrogenation of both the C double bond; length as m-dash C and C double bond; length as m-dash O bonds during the selective hydrogenation of crotonaldehyde. When only Sn1Pt1 alloy phases (Sn/Pt = 1.40), accompanying with separated Sn phase, were formed in the SnPt-NP catalysts, the highest unsaturated alcohol (UOL) selectivity (71.5% at 37.6% conversion) was observed. The formation of the Sn2Pt1 alloy phase led to decreased UOL selectivity. We suggest that the Sn1Pt1 alloy phase is an effective bimetallic SnPt hydrogenation catalyst for the selective formation of unsaturated alcohols.

    更新日期:2017-11-11
  • Effects of preparation technique and lanthana doping on Ni/La2O3-ZrO2 catalysts for hydrogen production by CO2 reforming of coke oven gas
    Catal. Today (IF 4.636) Pub Date : 2017-11-11
    Hongwei Cheng, Guangshi Li, Hongbin Zhao, Xionggang Lu, Qian Xu, Wei Tao

    A series of Ni/La2O3-ZrO2 catalysts were prepared by homogeneous precipitation, template or sol-gel technique and used for hydrogen production from coke oven gas by CO2 reforming. The catalysts were characterized by BET, XRD, TPR, TPH, TEM and TG–DSC. A study is also carried out to observe the effect of lanthana loading on the reforming reaction. TPH results indicated the presence of more than two types of carbonaceous species on the used catalysts, which are categorized based on temperature difference. The low-temperature carbon species could be considered as the active sites for the reforming reaction. Experiments and TG-DSC results revealed that all of the catalysts present good catalytic performance and excellent anti-carbon property. The test results showed that the catalysts prepared by sol-gel method exhibited the highest catalytic activity due to their suitable pore size distribution. The Ni/La2O3-ZrO2 catalyst with 8 wt% lanthanum oxide loading provides the best catalytic activity, which will be promising application on catalytic CO2 reforming of COG in the future.

    更新日期:2017-11-11
  • Pd doped CaCoxZr1-xO3-δ perovskites for automotive emissions control
    Catal. Today (IF 4.636) Pub Date : 2017-11-11
    Qinghe Zheng, Marty Lail, Kelly Amato, Jonathan Todd Ennis

    CaCoxZr1-xO3-δ (x = 0, 0.3, 0.5, 0.7 and 0.9) perovskites with and without Pd doping were synthesized for the first time and reported here to show outstanding redox property and oxygen storage capacity (OSC) compared to the ceria-based oxygen storage materials (OSMs). The studied perovskites retain their main phase of orthorhombic Lakargiite CaZrO3 structure, and were characterized by x-ray fluorescence (XRF), x-ray diffraction (XRD), temperature programmed reduction (TPR) and dynamic redox cycle measurements. Partial substitution of Co by Zr at B sites enhanced the perovskite structural crystallinity and stability, material reducibility and OSC properties, giving optimized OSM composition when x was around 0.5. Further kinetic studies showed a first order reaction mechanism with an activation energy (Ea) of 0.159 eV for CaCo0.5Zr0.5O3-δ. For Pd-containing samples, Pd was present in both forms of bulk Pd2+ and surface Pd0, and the amount of surface Pd0 increased with increasing Pd loading. Pd dopant also facilitated the Co reduction and improved the catalyst reducibility. Under simulated exhaust conditions at fuel lean-rich conditions (stoichiometric numbers of 1.16, 1.07 and 0.95), Pd-doped CaCo0.6-yZr0.4PdyO3 (y = 0.05 and 0.1) samples showed profound catalytic activity towards C3H6 and CO oxidation (T50s < 280 °C at fuel lean-rich), suggesting their potential application for automotive emissions control.

    更新日期:2017-11-11
  • Photoelectrodeposition Effect of Lanthanum oxide-Modified Ceria Particles on The Removal of Lead (II) Ions from Water
    Catal. Today (IF 4.636) Pub Date : 2017-11-10
    Jiratchaya Ayawanna, Kazunori Sato

    The photocatalytic capabilities of La2O3 incorporated in CeO2 for the removal of Pb(II) ions in water are reported in this work. La2O3–modified CeO2 particles are prepared by a solid-state reaction method at calcination temperature of 1000 °C and 1400 °C. The x-ray diffraction result demonstrates a solid solution Ce0.9La0.1O1.95 phase coexisting with the CeO2 matrix phase (Ce0.9La0.1O1.95–CeO2) obtained at a calcination of 1400 °C, while the mixed La2O3/La(OH)3–CeO2 phase is obtained at 1000 °C. The UV-photocatalytic activity for Pb(II) ion removal of the La2O3–modified CeO2 particles is significantly higher than that of pure CeO2. Ce0.9La0.1O1.95–CeO2 particles show stronger visible light absorption capacity and higher ability of photoelectrodeposition for the Pb(II) ion removal than the mixed La2O3/La(OH)3–CeO2 particles and pure CeO2. The high photocatalytic activity is supported by a strong photoluminescence signal from the Ce0.9La0.1O1.95–CeO2 particles, suggesting a high efficiency of photogenerated charge separation. A formation of p-type Ce0.9La0.1O1.95 and n-type CeO2 heterojunctions in Ce0.9La0.1O1.95–CeO2 particles also promote photogenerated charge transfer and efficiency restraining recombination of the charges.

    更新日期:2017-11-10
  • Ultra-thin Al2O3 coatings on BiVO4 photoanodes: impact on performance and charge carrier dynamics
    Catal. Today (IF 4.636) Pub Date : 2017-11-10
    Andreas Kafizas, Xueting Xing, Shababa Selim, Camilo A. Mesa, Yimeng Ma, Claire Burgess, Martyn A. McLachlan, James R. Durrant

    Bismuth vanadate (BiVO4) has emerged as one of the most promising photoanode materials for oxidising water due to its visible light activity and low cost. Recent studies have shown that the performance of BiVO4 photoanodes can be remarkably improved when coated with ultra-thin passivation layers. In this article we investigate the use of ultra-thin Al2O3 layers grown using atomic layer deposition (ALD). At an optimum thickness (∼0.33 nm, 3 ALD cycles), the Al2O3 layer favourably shifted the onset potential by ∼200 mV and increased photocatalytic currents for the water oxidation reaction. When held at 1.23 VRHE, we observe a remarkable increase in the theoretical solar photocurrent; from ∼0.47 mAcm−2 in uncoated BiVO4 to ∼3.0 mAcm−2 in Al2O3-coated BiVO4. Using transient photocurrent (TPC) and transient absorption spectroscopy (TAS) the charge carrier dynamics in Al2O3-coated BiVO4 photoanodes were examined for the first time. TPC showed that photogenerated electrons in the BiVO4 layer were extracted within ∼1 ms. TAS showed that the remaining holes oxidised water from ∼100 ms to 1 s. Ultra-thin Al2O3 coatings did not improve the reaction kinetics towards water oxidation, but rather, suppressed bi-molecular recombination on the μs-ms timescale in BiVO4, and increased the yield of long-lived holes on the ms-s timescale required to oxidise water. This is attributed to an inhibition of surface recombination on BiVO4 by Al2O3, which inhibited the early timescale recombination of charge carriers formed within the space charge layer.

    更新日期:2017-11-10
  • Assessing Photocatalytic Activity Using Methylene Blue without Dye Sensitisation
    Catal. Today (IF 4.636) Pub Date : 2017-11-07
    Soo-Keun Lee, Andrew Mills, Nathan Wells

    The anaerobic photocatalysed reduction of methylene blue, MB, by glycerol to leuco methylene blue, LMB, is studied using UV-absorbing, P25 TiO2, and visible-absorbing, CdS, semiconductor powder particles as the photosensitizer. In both cases, the photo-reductive bleaching of the dye to LMB, is very rapid, typically < 2 min. The photobleaching of the MB is readily and simply reversed in the dark by allowing air into the system, so as to let the ambient oxygen to oxidise the photogenerated LMB back to its original blue, oxidized form, MB. Action spectra are recorded for both systems and reveal no evidence of dye-sensitisation, nor dye photolysis over the time scale of the reaction (i.e. ca. 2 min). Instead, the action spectra exhibit spectral profiles that match very well that of the diffuse reflectance spectra of the respective semiconductor photocatalysts. The MB/glycerol system appears to offer a simple, quick, unambiguous way to assess the photocatalytic activity of both visible and UV absorbing photocatalyst powders using a dye, such as MB.

    更新日期:2017-11-10
  • Second metals (Lanthanum, Cerium, and Yttrium) modified W/SiO2 catalysts for metathesis of ethylene and 2-butene
    Catal. Today (IF 4.636) Pub Date : 2017-11-07
    Narongrat Poovarawan, Kongkiat Suriye, Joongjai Panpranot, Wimonrat Limsangkass, Adisak Guntida, Francisco José Cadete Santos Aires, Piyasan Praserthdam

    Lanthanum, cerium, and yttrium were added as a second metal on the WO3/SiO2 catalysts by the incipient wetness impregnation method with the atomic ratio between the second metal and tungsten 0.083 in order to improve the catalytic performances of W-based catalysts in the metathesis of ethylene and 2-butene. As revealed by various characterization results from X-ray diffraction, nitrogen physisorption, inductively coupled plasma optical emission spectrometry, ion-exchange titration, FT-Raman, ammonia temperature programmed desorption (NH3-TPD), and reactant-TPD, the dispersion of tungsten and adsorption properties were significantly improved by adding of the second metals, especially the adsorption of the mixed cis/trans-2-butene isomers. Hence, their catalytic performances were higher than the non-modified one when mixed cis/trans-2 butene isomers were used as the feeds. In addition, the presence of La as the second metal could also reduce coke formation on the catalysts probably by decreasing the ensemble site effect.

    更新日期:2017-11-10
  • Spectroelectrochemical analysis of TiO2 electronic states – implications on the photocatalytic activity of anatase and rutile
    Catal. Today (IF 4.636) Pub Date : 2017-11-07
    Marcin Kobielusz, Kacper Pilarczyk, Elżbieta Świętek, Konrad Szaciłowski, Wojciech Macyk

    The information on the electronic structure of nano- and microstructured semiconductors is crucial for their applications in photovoltaics, optoelectronics and photocatalysis. The distribution of intra-bandgap electronic states is one of the most relevant parameters which may be tuned in order to provide desired properties of a photoactive material. We propose the use of a modified spectroelectrochemical method for the characterisation of vacant electronic states distributed close to the edge of the titanium dioxide conduction band. These additional levels localized within the bandgap were semi-quantitatively characterized for several samples made of different polymorphs (or their blends) of TiO2. The applicability of the method for the determination of deep and shallow electron traps was confirmed. A quantitative analysis of the latter was also conducted for the selected samples. The presented approach provides also the information on the stability of electronic states, which is crucial for numerous practical applications.

    更新日期:2017-11-10
  • Sulfamethoxazole mineralization by solar photo electro-Fenton process in a pilot plant
    Catal. Today (IF 4.636) Pub Date : 2017-11-06
    J.C. Murillo-Sierra, E. Ruiz-Ruiz, L. Hinojosa-Reyes, J.L. Guzmán-Mar, F. Machuca-Martínez, A. Hernández-Ramírez

    The sulfamethoxazole (SMX) mineralization through the solar photo electro-Fenton (SPEF) process in a pilot plant containing 20 L of 50 mg L−1 SMX solution was investigated. The process was carried out at pH 3 under different operational conditions varying temperature, volumetric flow and applied current density. Box-Behnken experimental design and response surface methodology (RSM) were used to optimize the experimental variables of the SPEF process. Under the optimal conditions, the SPEF was compared with electro-Fenton (EF) and anodic oxidation (AO- H2O2) processes. Under optimum design variables of 47 mA cm−2, 45 °C and 571 L h−1 of flow rate, SPEF was more efficient yielding 90% of TOC removal after 360 min of reaction with a maximum of 83% of mineralization current efficiency (MCE). The main by-products detected on the final solution treated by SPEF were oxalic, maleic, oxamic and fumaric acids, while NH4+ and NO3− were the main inorganic nitrogen ions released during the process.

    更新日期:2017-11-10
  • Electronic properties of photocatalytic improved Degussa P25 titanium dioxide powder
    Catal. Today (IF 4.636) Pub Date : 2017-11-06
    M. Hantusch, V. Bessergenev, M.C. Mateus, M. Knupfer, E. Burkel

    The defect structures of photocatalytic improved Degussa P25 powder were evaluated by X-Ray photoelectron spectroscopy (XPS), paramagnetic resonance spectroscopy (EPR) and in-situ studies of the electrical resistivity in order to understand the charge carrier transport inside the material. Annealing the titanium dioxide in vacuum at temperatures below the phase transition temperature did not increase the oxygen defect concentration drastically. However, annealing Degussa P25 powder in vacuum resulted in a redistribution of Ti3+-lattice states and lattice oxygen vacancies. The diffusion of these lattice oxygen vacancies from the bulk to the surface of the material forms charge carrier trapping sites. Such transformation of the defect structure of TiO2 leads to switching from an insulating state to a conducting state.

    更新日期:2017-11-10
  • Thermal sulfidation of α-Fe2O3 hematite to FeS2 pyrite thin electrodes: correlation between surface morphology and photoelectrochemical functionality
    Catal. Today (IF 4.636) Pub Date : 2017-11-06
    Hana Kmentova, Stepan Kment, Zdenek Hubicka, Zdenek Remes, Jiri Olejnicek, Martin Cada, Josef Krysa, Radek Zboril

    The pyrite iron disulfide thin films are regarded as suitable candidates for construction of low-cost photoelectrochemical (PEC) solar cells. Iron oxide hematite has attracted much attention as possibly convenient material for hydrogen production via PEC water splitting. We refer on preparation of pyrite thin films via thermal sulfidation of hematite films synthetized by a physical methodology of high power impulse magnetron sputtering (HiPIMS) and purely chemical approach of sol-gel. We studied for the first time the correlation between PEC functionality of hematite films and after their sulfidation into pyrite. The highest PEC activity of hematite films of 560 μAcm−2 at 700 mV vs. Ag/AgCl was achieved with the HiPIMS photoelectrodes. The photoefficiency dropped dramatically to 4 μA cm−2 at 600 mV vs. Ag/AgCl after the sulfidation. A significant increase of grains‘ size, residual unreacted hematite, surface defects were the main reasons for the poor photoactivity. The sol-gel produced hematite yielded photocurrent of 30 μA cm−2 and a slight increase to 40 μA cm−2 (recorded at 500 mV vs. Ag/AgCl) of the corresponding pyrite version. Both these electrodes showed also similar morphological characteristics. The structural, electronic and optical properties of the deposited films were determined using various methods e.g. Raman spectroscopy, SEM, and PDS.

    更新日期:2017-11-10
  • Deactivation of Cu-SSZ-13 in the presence of SO2 during hydrothermal aging
    Catal. Today (IF 4.636) Pub Date : 2017-11-06
    Yulong Shan, Xiaoyan Shi, Zidi Yan, Jingjing Liu, Yunbo Yu, Hong He

    Cu2+-exchanged zeolite catalysts with the chabazite (CHA) structure have been thought to be optimal candidates for selective catalytic reduction of NOx with NH3. In real applications, however, SCR catalysts readily undergo hydrothermal aging and sulfur poisoning. In this work, the co-effect of SO2 and hydrothermal aging at high temperature was investigated. Different from the reversible inhibition of SO2 poisoning that occurs at low temperatures, the sulfur poisoning at high temperature is permanent due to the destruction of the zeolite structure, and no deposit of sulfate is observed. Cu-SSZ-13 catalysts were characterized through solid state 27Al nuclear magnetic resonance (27Al-NMR), X-ray diffraction (XRD), temperature-programmed desorption of NH3 and NO (NH3/NO-TPD), electron paramagnetic resonance (EPR), temperature-programmed reduction by H2(H2-TPR), in situ DRIFTS, and thermogravimetric analysis with mass spectrometric detection (TG-Mass) to develop an understanding of the degradation mechanisms during hydrothermal aging and sulfurization at high temperature. The results indicated that SO2 dislodged the extra-framework Al atoms that resulted from the dealumination process that occurs during hydrothermal aging. More Cu2+ species were accumulated as CuOx for Cu-SSZ-13 after sulfurization at high temperature compared to that treated by hydrothermal aging only. The dealumination and accumulation of Cu2+ species caused a loss of acid and active sites for the Cu-SSZ-13 catalyst, and resulted in degradation of NH3-SCR performance.

    更新日期:2017-11-10
  • Removal of an X-Ray contrast chemical from tertiary treated wastewater: Investigation of persulfate-mediated photochemical treatment systems
    Catal. Today (IF 4.636) Pub Date : 2017-11-06
    Idil Arslan-Alaton, Olga Kolba, Tugba Olmez-Hanci

    The degradation of 2.6 μM (2 mg/L) iopamidol (IOPA), a commercially important nonionic, iodinated X-ray contrast chemical and model micropollutant, by UV-A and UV-C photo-assisted persulfate (PS) oxidation in real, tertiary treated municipal wastewater (Organic carbon = 12.4 mg/L; Alkalinity = 130 mg CaCO3/L; pH = 7.0) was investigated. Preliminary baseline experiments conducted in pure (distilled) water indicated that IOPA could be rapidly and completely removed even by UV-C treatment alone. In the presence of UV-A light, 100% IOPA removal could still be achieved in pure water by PS/UV-A treatment which was studied at varying conditions (0.10–1.00 mM; pH3-11). However, in real wastewater, addition of at least 0.10 mM and 1.00 mM PS was required to achieve high (>90%) IOPA removals by the PS/UV-C and PS/UV-A treatment systems, respectively. PS consumption rates increased under UV-C radiation compared with UV-A radiation and in real wastewater compared to pure water. Organic carbon removals were appreciable for PS/UV-C (48%) and UV-C (40%) treatments in real wastewater. Toxicity assays carried out with the marine photobacteria Vibrio fischeri revealed that the toxicity response did not change significantly after photochemical treatment. According to the bioassay conducted with the freshwater microalga Pseudokirchneriella subcapitata, the toxicity increased after 155 min UV-C photolysis.

    更新日期:2017-11-10
  • Pre-surface leached cordierite honeycombs for MnxCo3-xO4 nano-sheet array integration with enhanced hydrocarbons combustion
    Catal. Today (IF 4.636) Pub Date : 2017-11-03
    Wenxiang Tang, Sibo Wang, Wen Xiao, Shoucheng Du, Xingxu Lu, Son Hoang, Jun Ding, Pu-Xian Gao
    更新日期:2017-11-05
  • Microstructure evolution and constitutive equation for the hot deformation of LZ91 Mg alloy
    Catal. Today (IF 4.636) Pub Date : 2017-11-02
    Liu Junwei, Zhao Zhigang, Lu Shiqiang
    更新日期:2017-11-03
  • Equilibrium thermodynamic predictions of coking propensity in membrane-based dehydrogenation of hydrocarbons and alcohols
    Catal. Today (IF 4.636) Pub Date : 2017-11-02
    Huayang Zhu, Benjamin L. Kee, Canan Karakaya, Ryan O’Hayre, Robert J. Kee
    更新日期:2017-11-02
  • In situ formation of Al3Ti, MgF2 and Al and their superior synergetic effects on reversible hydrogen storage of MgH2
    Catal. Today (IF 4.636) Pub Date : 2017-11-01
    Yuepeng Pang, Tao Yuan, Junhe Yang, Mingxia Gao, Hongge Pan, Yongfeng Liu, Shiyou Zheng
    更新日期:2017-11-02
  • 更新日期:2017-11-01
  • Influence of the supporting electrolyte on the removal of ionic liquids by electrolysis with diamond anodes
    Catal. Today (IF 4.636) Pub Date : 2017-11-01
    Ismael F. Mena, Salvador Cotillas, Elena Díaz, Cristina Sáez, Ángel F. Mohedano, Manuel A. Rodrigo
    更新日期:2017-11-01
  • Hydrogen storage of casting MgTiNi alloys
    Catal. Today (IF 4.636) Pub Date : 2017-11-01
    Yongzhi Li, Feng Hu, Long Luo, Jianyi Xu, Zengwu Zhao, Yanghuan Zhang, Dongliang Zhao

    The as-cast Mg85Ni15-0.2 wt. % Ti and Mg68Ti9Ni23 alloys were produced with vacuum induction levitation melting furnace. The Mg85Ni15-0.2 wt. % Ti alloy had a reversible hydrogen storage capacity of 5.22 wt. % at 653 K. Intersection of hydrogen absorption curves at different temperatures, which could be found during the initial hydrogenation process, indicated two competed kinetic mechanism took part in the original hydrogenation. Pressure-composition isothermal (PCI) curves showed two pressure plateaus for all applied temperatures. The enthalpies, obtained by PCI data, of hydrogenation for these two alloys were estimated to be about 5 kJ/mol lower than MgH2. Results of Kissinger plots, based on DSC data, showed the activation energy of dehydrogenation were 51.69 kJ/mol and 57.75 kJ/mol, which were much lower than pure MgH2, for Mg85Ni15-0.2 wt. % Ti and Mg68Ti9Ni23 alloys, respectively.

    更新日期:2017-11-01
  • Oxidation of Cyclic Hydrocarbons with Hydrogen Peroxide over Iron Complexes Encapsulated in Cation-exchanged Zeolite
    Catal. Today (IF 4.636) Pub Date : 2017-10-31
    Syuhei Yamaguchi, Yuki Miyake, Keiko Takiguchi, Daijiro Ihara, Hidenori Yahiro
    更新日期:2017-11-01
  • Degradation of Organic Compounds in Wastewater Matrix by Electrochemically Generated Reactive Chlorine Species: Kinetics and Selectivity
    Catal. Today (IF 4.636) Pub Date : 2017-10-31
    Chong Min Chung, Seok Won Hong, Kangwoo Cho, Michael R. Hoffmann
    更新日期:2017-11-01
  • Synthesis of CuO catalyst derived from HKUST-1 temple for the low-temperature NH3-SCR process
    Catal. Today (IF 4.636) Pub Date : 2017-10-31
    Bo Peng, Chao Feng, Shanshan Liu, Runduo Zhang
    更新日期:2017-11-01
  • Inactivation of a wild isolated Klebsiella pneumoniae by photo-chemical processes: UV-C, UV-C/H2O2 and UV-C/H2O2/Fe3+
    Catal. Today (IF 4.636) Pub Date : 2017-10-31
    Silvio Aguilar, Daniel Rosado, Javier Moreno-Andrés, Luis Cartuche, Darío Cruz, Asunción Acevedo-Merino, Enrique Nebot
    更新日期:2017-11-01
  • 更新日期:2017-11-01
  • Wild bacteria inactivation in WWTP secondary effluents by solar photo-fenton at neutral pH in raceway pond reactors
    Catal. Today (IF 4.636) Pub Date : 2017-10-31
    B. Esteban García, G. Rivas, S. Arzate, J.A. Sánchez Pérez
    更新日期:2017-11-01
  • Fenton-based processes for the regeneration of catalytic adsorbents
    Catal. Today (IF 4.636) Pub Date : 2017-10-29
    A.M. Díez, M.A. Sanromán, M. Pazos
    更新日期:2017-10-30
  • Degradation of herbicide S-metolachlor by electrochemical AOPs using a boron-doped diamond anode
    Catal. Today (IF 4.636) Pub Date : 2017-10-29
    Diego Roberto Vieira Guelfi, Fábio Gozzi, Amílcar Machulek Jr., Ignasi Sirés, Enric Brillas, Silvio C. de Oliveira
    更新日期:2017-10-30
  • The effect of hot liquid water treatment on the properties and catalytic activity of MWW zeolites with various layered structures
    Catal. Today (IF 4.636) Pub Date : 2017-10-28
    Barbara Gil, Wieslaw J. Roth, Justyna Grzybek, Aleksandra Korzeniowska, Zbigniew Olejniczak, Milan Eliáš, Maksym Opanasenko, Jiři Čejka
    更新日期:2017-10-28
  • Me-ZSM-5 monolith foams for the NH3-scr of NO
    Catal. Today (IF 4.636) Pub Date : 2017-10-28
    Nicola Gargiulo, Domenico Caputo, Giorgio Totarella, Luciana Lisi, Stefano Cimino

    Self-supported ZSM-5 zeolite monolith foams (ZMFs) with different Si/Al ratios have been successfully prepared by hydrothermal synthesis with a polyurethane foam (PUF) template followed by calcination in air at 550 °C to harden. Cu or Mn have been introduced on preformed ZMF samples to obtain monolithic catalysts that have been fully characterized by morphological (XRD and SEM), textural (BET and Pore size distribution), mechanical (compressive strength) and chemical (ICP-MS) analyses, and eventually tested in the Selective Catalytic Reduction of NO with NH3 in the temperature range 100–450 °C. The zeolite monolith foams are characterized by a well crystallized ZSM-5 structure, a BET surface area ca. 420 m2 g−1 and remarkable mechanical resistance even without any binder. Those structured catalysts show specific catalytic activity in line with powdered counterparts, but they can guarantee improved NO conversion due to the higher amount of catalyst per unit volume of reactor and to their enhanced mass transfer coefficients coupled to low internal diffusion limitations.

    更新日期:2017-10-28
  • 更新日期:2017-10-27
  • Antibiotics abatement in synthetic and real aqueous matrices by H2O2/natural magnetite
    Catal. Today (IF 4.636) Pub Date : 2017-10-27
    Macarena Munoz, Javier Conde, Zahara M. de Pedro, Jose A. Casas
    更新日期:2017-10-27
  • Optimization of electro fenton process for effective degradation of organochlorine pesticide lindane
    Catal. Today (IF 4.636) Pub Date : 2017-10-27
    Carmen M. Dominguez, Nihal Oturan, Arturo Romero, Aurora Santos, Mehmet A. Oturan
    更新日期:2017-10-27
  • Highly active and stable multi-walled carbon nanotubes-graphene-TiO2 nanohybrid: An efficient non-noble metal photocatalyst for water splitting
    Catal. Today (IF 4.636) Pub Date : 2017-10-27
    Sankeerthana Bellamkonda, Nithya Thangavel, Hafeez Yusuf Hafeez, B. Neppolian, G. Ranga Rao
    更新日期:2017-10-27
  • Sand supported TiO2 photocatalyst in a tray photo-reactor for the removal of emerging contaminants in wastewater
    Catal. Today (IF 4.636) Pub Date : 2017-10-27
    Yasmine K. Abdel-Maksoud, Emad Imam, Adham R Ramadan
    更新日期:2017-10-27
  • Selective adsorption of nitrogen compounds using silica-based mesoporous materials as a pretreatment for deep hydrodesulfurization
    Catal. Today (IF 4.636) Pub Date : 2017-10-26
    J.C. García-Martínez, H.A. González Uribe, M.M. González-Brambila, J.A. Colín-Luna, Y.E. Escobedo-García, A. López-Gaona, L. Alvarado-Perea
    更新日期:2017-10-27
  • Type I vs Type II Photodegradation of Pollutants
    Catal. Today (IF 4.636) Pub Date : 2017-10-26
    R. Martinez-Haya, M.A. Miranda, M.L. Marin
    更新日期:2017-10-27
  • Semi-crystalline Fe-BTC MOF material as an efficient support for enzyme immobilization
    Catal. Today (IF 4.636) Pub Date : 2017-10-26
    Victoria Gascón, Mayra B. Jiménez, Rosa M. Blanco, Manuel Sanchez-Sanchez
    更新日期:2017-10-27
  • Substituent effects of 4,6-DMDBT on direct hydrodesulfurization routes catalyzed by Ni-Mo-S active nanocluster-A theoretical study
    Catal. Today (IF 4.636) Pub Date : 2017-10-26
    Sijia Ding, Yasong Zhou, Qiang Wei, Shujiao Jiang, Wenwu Zhou
    更新日期:2017-10-27
  • Membrane-based reactive separations for process intensification during power generation
    Catal. Today (IF 4.636) Pub Date : 2017-10-26
    Ashkan Garshasbi, Huanhao Chen, Mingyuan Cao, Seçgin Karagöz, Richard J. Ciora Jr., Paul K.T. Liu, Vasilios I. Manousiouthakis, Theodore T. Tsotsis
    更新日期:2017-10-27
  • CoFe2O4 nanoparticles decorated carbon nanotubes: air-cathode bifunctional catalysts for rechargeable zinc-air batteries
    Catal. Today (IF 4.636) Pub Date : 2017-10-24
    Nengneng Xu, Jinli Qiao, Qi Nie, Min Wang, He Xu, Yudong Wang, Xiao-Dong Zhou

    Exploring highly efficient bifunctional oxygen electrocatalysts are urgently for realizing rechargeable zinc-air batteries. Although CoFe2O4 as bifunctional oxygen electrocatalyst has been involved in less previous studies, CoFe2O4@CNTs as the high performance air cathode has not been reported. In this paper, the influences of temperature, time and the weight ratio of CNT to CoFe2O4 on the morphology, crystallographic forms and electrochemical performances of the final products are thoroughly investigated. The conclusion that amorphous form is efficient for ORR and, the crystalline structure is beneficial for OER was proposed. Particularly, a novel class of CoFe2O4@CNTs with amorphous form and crystalline structure has been successfully synthesized and exhibited excellent activity and stability in three electrodes test. More importantly, the CoFe2O4@CNTs cathodes are made and applied to zinc-air battery, which is demonstrated to be superior performances to Pt/C and IrO2 catalysts. The high power density (333.7 mW cm−2), larger specific capacity (732 mAh g−1), and excellent rechargeability (1200 stable charge-discharge cycles) proves the feasibility of CoFe2O4@CNTs application in large power energy-storage and conversion electronics.

    更新日期:2017-10-25
  • Spatial, temporal and quantitative assessment of catalyst leaching in continuous flow
    Catal. Today (IF 4.636) Pub Date : 2017-10-18
    Elena M. Barreiro, Zhimian Hao, Luis A. Adrio, J. Rudd van Ommen, Klaus Hellgardt, King Kuok Mimi Hii
    更新日期:2017-10-19
  • 更新日期:2017-10-18
  • ASPHALTENES DIFFUSION/ADSORPTION THROUGH CATALYST ALUMINA SUPPORTS − INFLUENCE ON CATALYTIC ACTIVITY
    Catal. Today (IF 4.636) Pub Date : 2017-10-18
    Bertrand Guichard, Florine Gaulier, Jérémie Barbier, Thibaut Corre, Jean-Louis Bonneau, Pierre Levitz, Didier Espinat
    更新日期:2017-10-18
  • An investigation on AuPt and AuPt-Bi on granular carbon as catalysts for the oxidation of glycerol under continuous flow conditions
    Catal. Today (IF 4.636) Pub Date : 2017-10-18
    Davide Motta, Felipe Sanchez, Nikolaos Dimitratos, Alberto Villa, Laura Prati
    更新日期:2017-10-18
  • Pd catalysts supported on hydrogen titanate nanotubes for Suzuki-Miyaura cross-coupling reactions
    Catal. Today (IF 4.636) Pub Date : 2017-10-16
    Mark E. Martínez-Klimov, Patricia Hernández-Hipólito, Marcos Martínez-García, Tatiana E. Klimova
    更新日期:2017-10-16
  • One-pot synthesis of benzimidazole using DMF as a multitasking reagent in presence CuFe2O4
    Catal. Today (IF 4.636) Pub Date : 2017-10-16
    Kalidas B. Rasal, Ganapati D. Yadav
    更新日期:2017-10-16
  • Membrane assisted propane dehydrogenation: experimental investigation and mathematical modelling of catalytic reactions
    Catal. Today (IF 4.636) Pub Date : 2017-10-16
    Antonio Ricca, Francesca Montella, Gaetano Iaquaniello, Emma Palo, Annarita Salladini, Vincenzo Palma
    更新日期:2017-10-16
  • Preparation of Sn-doped semiconducting Fe2O3 (hematite) layers by aerosol pyrolysis
    Catal. Today (IF 4.636) Pub Date : 2017-10-13
    J. Krýsa, T. Kotrla, Š. Paušová, M. Zlámal, M. Neumann-Spallart
    更新日期:2017-10-14
  • CO2 Adsorption over modified AC samples: A New Methodology for Determining Selectivity
    Catal. Today (IF 4.636) Pub Date : 2017-10-13
    Burcu Acar, Melek Selcen Başar, B. Merve Eropak, Burcu Selen Caglayan, A. Erhan Aksoylu
    更新日期:2017-10-14
  • Sustainable Fe-BTC catalyst for efficient removal of mehylene blue by advanced fenton oxidation
    Catal. Today (IF 4.636) Pub Date : 2017-10-12
    Fernando Martínez, Pedro Leo, Gisela Orcajo, Manuel Díaz-García, Manuel Sanchez-Sanchez, Guillermo Calleja
    更新日期:2017-10-13
  • Valorization of alginate for the production of hydrogen via catalytic aqueous phase reforming
    Catal. Today (IF 4.636) Pub Date : 2017-10-07
    Giuseppe Pipitone, Davide Tosches, Samir Bensaid, Alessandro Galia, Raffaele Pirone
    更新日期:2017-10-08
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.
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