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  • Molecularly imprinted PEDOT on carbon fiber paper electrode for the electrochemical determination of 2,4-dichlorophenol
    Synth. Met. (IF 2.87) Pub Date : 2020-01-25
    Ann Maria C G; Akshaya K B; Sherin Rison; Anitha Varghese; Louis George

    A highly selective electrochemical sensor has been developed for the determination of the pesticide molecule, 2,4-dichlorophenol (2,4-DCP) using molecularly imprinted conducting polymer. 2,4-dichlorophenol imprinted polymer films were prepared by electropolymerising 3,4-ethylenedioxythiophene (EDOT) on surface of carbon fiber paper electrode (CFP) in presence of 2,4-dichlorophenol. Electrochemical over-oxidation was carried out for the controlled release of 2,4-DCP templates and to generate definite imprinting sites. Surface morphology of the imprinted electrode was analysed by Scanning Electron Microscopy-Energy Dispersive X-ray Spectrometry, Fourier Transform Infrared and Raman spectroscopy. In optimized conditions, the voltammetric sensor gave a linear response in the range of 0.21 nM – 300 nM. The significantly low detection limit (0.07 nM) demonstrates the ultra-low sensitivity of the method. The imprinted sensor displayed higher affinity and selectivity towards the target 2,4-DCP over similar structural analogical interference than the non-imprinted sensor. MIP sensor was efficaciously employed for the selective determination of 2,4-DCP in real samples of water.

  • Composite sulfur cathode for Li-S batteries comprising hierarchical carbon obtained from waste PET bottles
    Synth. Met. (IF 2.87) Pub Date : 2020-01-24
    Paulina Półrolniczak; Dawid Kasprzak; Justyna Kaźmierczak-Raźna; Mariusz Walkowiak; Piotr Nowicki; Robert Pietrzak

    Waste PET bottles have been processed towards carbonaceous material through pyrolysis at 500 °C in nitrogen atmosphere followed by chemical activation with K2CO3. The obtained carbon was found to feature hierarchical pore structure, as evidenced by nitrogen sorption isotherm analysis. Composite sulfur-carbon electrode has been prepared using this carbon by means of simple dry-mixing technique and subjected to electrochemical testing in model Li-S cells with electrolyte being 0.5 M lithium trifluoromethanesulfonate (LiTf) and 0.5 M lithium nitrate (LiNO3) in mixture of 1,2dimethoxyethane (DME) and 1,3-dioxolane (DOL). The Li-S cells assembled with obtained composite sulfur-carbon cathode demonstrated a large initial specific discharge capacity of about 829 mA h g−1 at 0.05 C current rate and delivered ca. 712 mA h g−1 after subsequent 50 charge and discharge cycles, which corresponds to 86% capacity retention. Generally, the investigated Li-S cells have exhibited good cycling stability and excellent reversibility. Thus, the obtained waste-derived activated porous carbon can be considered as a promising component for the composite cathode material of Li–S batteries.

  • 更新日期:2020-01-22
  • Study on the effect of tailoring the segmented PU molecules on electrically conductive properties and percolation threshold of PU/MWCNTs nanocomposites
    Synth. Met. (IF 2.87) Pub Date : 2020-01-21
    Peng Zhang; Bin-bin Wang; Qiu-jin Xia; Jian Zou

    Herein, a series of electrically conductive polyurethane composites with multi-walled carbon nanotubes (PU/MWCNTs) were in-situ polymerized according to tailoring the segmented PU molecules. The ultralow percolation threshold of MWCNTs (0.057 wt%) in the composites was achieved and the electrically conductive properties were markedly enhanced. The conductivity in [email protected] % and [email protected] % was lower than 1.0 × 10−1° S m-1. While [email protected] % had the conductivity of over 1.0 × 10-6 S m-1, almost 4 orders of significance, which was attributed to the increasing of hard segments on the PU molecule. Furthermore, the high piezoresistive properties of the composites were also observed. Therefore, this work had the important sense in decreasing the low percolation thresholds of conductive polymer composites.

  • Structurally designed hierarchical carbon nanotubes vertically anchored on elliptical-like carbon nanosheets with enhanced conduction loss as high-performance electromagnetic wave absorbent
    Synth. Met. (IF 2.87) Pub Date : 2020-01-21
    Lei Wang; Bo Wen; Yun Qiu; Haibo Yang

    Designing an effective conducting network to arouse conduction loss is an effective strategy to boost the microwave absorption properties while decreasing the filler weight fraction of absorbers in the matrix. Here, hierarchical carbon nanotubes vertically anchored on elliptical-like carbon nanosheets (Co/C [email protected] composite) have been successfully prepared sintering of ZIF-67 in Ar/H2 flow, where the density and length of CNTs on Co/C nanosheet surfaces were effectively controlled by adjusting the heating temperature. When the pyrolysis temperature was 700 °C, high density of curved CNTs were formed on the surface of Co/C nanosheet surfaces and constructed an interconnected network, which resulted in the enhanced conduction loss as irradiated by microwave. Accordingly, it exhibited high-performance microwave absorbing, and the maximum reflection loss reached -51.8 dB GHz and the effective absorbing bandwidth (EAB) achieved 5.9 GHz with only 5 wt% additive in paraffin, which is even superior to the corresponding Co/C nanosheet composite with 10 wt% filler content. This work provides a new direction to fabricate carbon-based absorber with high-performance at low filler loading.

  • Preparation of an improved performance FeTiO3-based lithium-ion battery anode
    Synth. Met. (IF 2.87) Pub Date : 2020-01-18
    Feng Zhang; Yanbin Chen; Qinghua Tian
  • Effects of interfacial modification for vapor phase polymerized PEDOT on glass substrate
    Synth. Met. (IF 2.87) Pub Date : 2020-01-13
    Boxiao Li; Kenneth H. Skorenko; Haian Qiu; Jeffrey M. Mativetsky; Derek B. Dwyer; William E. Bernier; Wayne E. Jones

    Optically transparent and highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) thin films were grown through vapor phase polymerization on (3-Mercaptopropyl)trimethoxysilane functionalized 3,4-Ethylenedioxythiophene (MPTMS functionalized EDOT) grafted glass substrates. Compared to bare glass, the EDOT grafted surface led to enhancements in both electrical conductivity and adhesion of PEDOT thin films. A quinoid-rich structure with increased crystallinity and a further enhanced conductivity was induced by post-deposition sulfuric acid doping. X-ray diffraction showed different orientations of the PEDOT crystals grown on substrates with and without EDOT grafting. The highest conductivity of 2690 S/cm, with an average optical transmittance of 95.4 % in the visible range, was achieved when PEDOT was vapor phase polymerized on EDOT grafted substrates and doped with 98 % sulfuric acid. Photostability was tested using a xenon arc light source and characterized by attenuated total reflection Fourier-transform infrared spectroscopy, showing that photo-induced degradation is associated with a decrease in CC double bond content.

  • Amine-selective gas sensor based on organic field-effect transistor with the porphyrin monolayer receptor
    Synth. Met. (IF 2.87) Pub Date : 2020-01-13
    Nikita A. Lukashkin; Diana K. Sagdullina; Ivan S. Zhidkov; Ernst Z. Kurmaev; Pavel A. Troshin

    Efficient gas sensors have been designed using a versatile platform based on organic field-effect transistors incorporating a monomolecular film of receptor compounds at the interface between the semiconductor and dielectric layers. Using a substituted porphyrin as a receptor component allowed us to increase substantially sensitivity of the sensors and induce group selectivity with respect to ammonia and substituted amines. Designed devices demonstrated good operational stability and might be used for food quality control and have also a potential in medical diagnostics in the context of analysis of exhailed air components.

  • Photo- and electroluminescence features of films and field effect transistors based on inorganic perovskite nanocrystals embedded in a polymer matrix
    Synth. Met. (IF 2.87) Pub Date : 2020-01-13
    Andrey N. Aleshin; Igor P. Shcherbakov; Olga P. Chikalova-Luzina; Leo B. Matyushkin; Maksat K. Ovezov; Anastasia M. Ershova; Irina N. Trapeznikova; Vasily N. Petrov

    The optical and electrical properties of films and field-effect transistors (FETs) based on pure MEH-PPV, neat CsPbBr3 nanocrystals (NCs), and MEH-PPV:CsPbBr3 NCs composites with different contents of CsPbBr3 NCs are investigated. The films were characterized by absorbance, atomic-force microscope and current-voltage characteristics (I-Vs) techniques. Relative PL and EL intensities and PL spectra of the pure MEH-PPV, neat CsPbBr3 NCs and MEH-PPV:CsPbBr3 NCs films were measured at 300 K at various levels of optical and electrical excitation power; these dependencies of the PL and EL intensities turned out to be sublinear and superlinear respectively. FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films exhibit I-Vs at 290 – 100 K a dominant hole transport mechanism. The mobility of charge carriers was determined at 290 K for neat CsPbBr3 NCs (for electrons: 2.7 10−2 cm2/Vs) and MEH-PPV:CsPbBr3 NCs (1:1) (for holes: 9 cm2/Vs). The temperature dependence of the hole mobility μFET(T) of FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films characteristic of the hopping mode. It was found that the superlinearity of the dependence of EL of MEH-PPV:CsPbBr3 NCs LE-FETs at 290 K increases with increasing concentration of CsPbBr3 NCs due to efficient energy transfer between CsPbBr3 NCs and the MEH-PPV polymer matrix, and also because of the probability of electron tunneling through the potential barrier to electrode. It is expected that the obtained MEH-PPV:CsPbBr3 NCs nanocomposite films will be useful for efficient applications in nanotechnology LEDs, FETs and LE-FETs.

  • Preparation and microwave absorption properties of carbon nanotubes/iron oxide/polypyrrole/carbon composites
    Synth. Met. (IF 2.87) Pub Date : 2020-01-10
    Kaichuang Zhang; Xuefang Chen; Xinbao Gao; Liang Chen; Shizhou Ma; Changyou Xie; Xinggao Zhang; Wei Lu

    Carbon nanotubes/iron oxide/polypyrrole/carbon composites were prepared by in situ polymerization. The weight percentage of the iron oxide nanoparticles was only 8.8 %. The microwave absorption performance of the carbon nanotubes/iron oxide/polypyrrole/carbon composites was researched and the corresponding filler loading of paraffin in the tested samples was 80 wt%. The reflection loss appeared at 13.92 GHz, which was -53.07 dB, the corresponding effective absorption bandwidth was 6.4 GHz, and the matching thickness was 2.2 mm. The synthetic composite materials have both magnetic loss and dielectric loss. The combination between different materials and the improved impedance matching can enhance the electromagnetic wave performance. At the same time, the composite materials have multiple interface and multilayer core-shell structure, which was beneficial to absorbing electromagnetic waves.

  • Relationship between microstructure and electrochemical properties of 2lignin-derived carbon nanofibers prepared by thermal treatment
    Synth. Met. (IF 2.87) Pub Date : 2020-01-08
    Ji Hwan Jeong; Yun Ho Lee; Bo-Hye Kim

    Low-cost porous carbon nanofibers with MnO2 are developed via simple and inexpensive processes by using lignin as an affordable carbon precursor and generator of porous structures through one-step electrospinning and carbonization without requiring any other activating agent and process. The lignin-based carbon nanofiber/MnO2 composites carbonized at high temperature have a high mesoporosity induced by pore opening effect, and thus exhibit a high capacitance retention of 87 % and optimum cycling stability with 93 % retention due to the excellent chemical reversibility. Further, the large surface area with many micropores derived from the low carbonization temperature affords high capacitive performance with a maximum specific capacitance of 212 Fg−1 at low current density and a high energy density of 26.5 Whkg−1 at a power density of 400 Wkg−1. These eco-friendly, low-cost, and pore-controlled MnO2/CNF composites have been designed with optimized carbonization temperature and lignin addition to enhance their capacitive properties.

  • 更新日期:2020-01-09
  • Optical ammonia gas sensor of poly(3,4-polyethylenedioxythiophene), polyaniline and polypyrrole: A comparative study
    Synth. Met. (IF 2.87) Pub Date : 2020-01-09
    Abdul Hadi Ismail; Nor Akmar Mohd Yahya; Mohd Hanif Yaacob; Mohd Adzir Mahdi; Yusran Sulaiman

    In this work, the optical sensing performance of three different types of conducting polymers, polyaniline (PANI), poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) towards ammonia (NH3) gas has been evaluated. The sensing analyses of the respective conducting polymers were measured in the optimised wavelength ranges that manifest absorbance response upon exposure to NH3 gas. Based on the dynamic response where the respective conducting polymers were exposed to NH3 gas within the concentration range of 0.0625 % to 1 %, PEDOT exhibited the highest sensitivity (9.03/%) towards NH3 gas comparing to PANI and PPy with the detection limit of 2.73 ppm, which is in agreement with their respective conductivity trends.

  • Selective sensing of dopamine by sodium cholate tailored polypyrrole-silver nanocomposite
    Synth. Met. (IF 2.87) Pub Date : 2020-01-08
    Arpita Adhikari; Sriparna De; Dipak Rana; Jyotishka Nath; Debatri Ghosh; Koushik Dutta; Subhadip Chakraborty; Sanatan Chattopadhyay; Mukut Chakraborty; Dipankar Chattopadhyay
  • 更新日期:2020-01-08
  • Highly sensitive OFET-based gas sensors using fluorinated naphthalenediimide semiconductor films
    Synth. Met. (IF 2.87) Pub Date : 2020-01-07
    Diana Sagdullina; Nikita Lukashkin; Alexei Parfenov; Konstantin Lyssenko; Pavel Troshin

    Naphthalene diimide bearing fluorinated alkyl side chains (FNDI) was synthesized and characterized by NMR spectroscopy. FNDI demonstrated good semiconductor characteristics and was used to fabricate gas sensors based on organic field-effect transistors (OFETs). The designed sensor devices exhibited fast response to low concentrations (1 ppm and less) of ammonia and some aliphatic amines. The revealed high sensitivity of the sensors in combination with the group-selectivity (with respect to amines) and good operational stability makes promising their practical application for food (e.g. fish) quality control or for medical diagnostics.

  • Carbon nanotubes-ruthenium as an outstanding catalyst for triiodide ions reduction
    Synth. Met. (IF 2.87) Pub Date : 2020-01-08
    Hai-Linh Thi Dang; Nam Anh Tran; Van-Duong Dao; Ngoc Hung Vu; Dang Viet Quang; Hong Ha Thi Vu; Thi Hanh Nguyen; Thanh-Dong Pham; Xuan-Co Hoang; Hien Thi Nguyen; Pham Anh Tuan

    Ru nanoparticles with a range size of 2∼6 nm are successfully immobilized on the surface of carbon nanotubes (CNTs) through liquid plasma reduction. The CNT-Ru nanohybrid exhibits an excellent catalyst for the redox reaction in dye-sensitized solar cells with the electrolyte of triiodide/iodide ions.

  • Pseudo-capacitive performance enhancement of α-MnO2 via in situ coating with polyaniline
    Synth. Met. (IF 2.87) Pub Date : 2020-01-02
    Xinjun Bao; Zejie Zhang; Debi Zhou

    A core/shell polyaniline (PANI)/MnO2 composite (denoted as “[email protected]2”) was prepared and evaluated as electrode material for supercapacitor applications. In the composite, α-MnO2 showed chrysanthemum-like and spherical structure, which were coated in situ with PANI. In this process, α-MnO2 serves as a scaffold and also acts as an oxidant to induce aniline polymerization. Scanning electron microscopy and transmission electron microscopy images clearly showed the core/shell structure of the [email protected]2 composite, which was further characterized by X-ray powder diffraction, Fourier transformation infrared spectroscopy and Raman spectroscopy. In addition, the thermo-gravimetric analysis illustrates that the composite has a good thermal stability and the mass ratio of PANI and MnO2 is 0.11. Electrochemical properties of the composite and its components were evaluated using cyclic voltammetry, electrochemical impedance spectra and chronopotentiometry. The specific capacitance of the high-mass loading [email protected]2 electrode is 75 Fg−1, 1.1 times higher than that of MnO2 electrode (67 Fg−1), at a current density of 0.1Ag−1. Moreover, the composite electrode retains 90% of the initial capacitance after 3000 cycles, while this is only 75% for α-MnO2. The improved electrochemical performance may be attributed to the synergistic effect between PANI and α-MnO2.

  • Perovskite solar cells based on a perovskite film with improved film coverage
    Synth. Met. (IF 2.87) Pub Date : 2020-01-02
    Denice N. Feria; Che-Yu Chang; K.P.O. Mahesh; Ching-Ling Hsu; Yu-Chiang Chao

    Organic-inorganic halide perovskite solar cells have attracted considerable attention because of its high efficiency, low-cost fabrication, and flexibility. The film morphology has to be well controlled since the presence of pinholes in the perovskite films deteriorates the performance of the devices. Therefore, a variety of methods have been developed to realize high quality perovskite films and excellent device performance. In this work, hot-casting technique and additive engineering were investigated for obtaining a better film morphology. Optical microscopy, electron scanning microscopy and X-ray diffraction were used to monitor the morphology and the crystallinity of the perovskite films. We found that pinhole-free perovskite films cannot be obtained by the hot-casting technique alone. By using the hot-casting technique and incorporating the additive in the perovskite precursor, perovskite films with minimum pinholes were obtained when optimum hot-casting temperature and the amount of the additive were used. A reproducible average power conversion efficiency of 9.24 % was observed. The findings showed that the perovskite films depend not only on the usage of hot-casting technique but also through the incorporation of additives which can be used for other perovskite materials utilizing as solar cells.

  • Electropolymerized poly(3,4-ethylenedioxyselenophene) on flexible substrate: A comparative study of electronic and electrochromic properties with sulfur analogue and rigid substrate
    Synth. Met. (IF 2.87) Pub Date : 2019-12-31
    Preeti Yadav; Sanchita Singhal; Asit Patra

    Recently, significant efforts have been devoted on poly(3,4-ethylenedioxyselenophene) (PEDOS) and its derivatives due to their promising properties for various optoelectronic applications. Surprisingly, no study has been reported on electrochemical synthesis of PEDOS on flexible substrate, and its optoelectronic properties. In this work, electropolymerization of 3,4-ethylenedioxyselenophene (EDOS) on flexible (ITO/PET) as well as rigid (ITO/glass) substrates, followed by cyclic voltammetry, electrochemical stability, morphology, spectroelectrochemical, and electrochromic properties of the PEDOS films were studied. For comparison purpose, poly(3,4-ethylenedioxythiophene) (PEDOT) films were also prepared on both flexible and rigid substrates and a throughout comparison was made. It has been observed that the polymer films on flexible substrates are relatively more stable, rough, and show blue shift in absorption spectra as compared to the polymer films on rigid substrates. On repeated bending, polymers films on flexible substrate exhibits good mechanical stability. Moreover, polymer film on flexible substrate has improved contrast ratio than that of polymer film on rigid substrate, whereas no significant change of response time has been observed. To the best of our knowledge, electropolymerization of EDOS on flexible substrate has been reported for the first time.

  • Facile fabrication and enhanced properties of copper-based metal organic framework incorporated with graphene for non-enzymatic detection of hydrogen peroxide
    Synth. Met. (IF 2.87) Pub Date : 2019-12-31
    Amir Moradi Golsheikh; Guan-Yeow Yeap; Fong Kwong Yam; Hwee San Lim

    Present work demonstrates the fabrication of a copper-based metal-organic framework (Cu-MOF) incorporated with graphene oxide (Cu-BTC-MOF/GO) (BTC = 1,3,5-benzene-tricarboxylate and GO = graphene oxide) via the reflux method. The X-ray diffraction and Fourier transform infrared spectroscopy confirmed the formation of Cu-BTC-MOF in the presence of GO nanosheets. The modification of indium tin oxide (ITO) electrode was carried out by drop-casting of Cu-BTC-MOF/GO composite and electrochemical reduction of GO to electrochemically reduced graphene oxide (ERGO). The Cu-BTC-MOF/ERGO/ITO electrode exhibited notable electrocatalytic activity for the reduction of H2O2 leading to a non-enzymatic electrochemical sensor and this phenomenon can be ascribed to the synergetic effects of Cu-BTC-MOF and graphene. The corresponding calibration curve of the current response showed a linear detection range of 4 μM to 17.334 mM (R2 = 0.996) and the limit of detection was estimated to be 0.44 μM.

  • Study on the synthesis and optoelectronic properties of the homopolymer of 2,8-bis(octyloxy)-dibenzothiophene-S,S-dioxide
    Synth. Met. (IF 2.87) Pub Date : 2019-12-31
    Huiping Xiao; Jiaqing Cao; Jianping Zhou; Wei Zhong; Yunying Wang; Wei Yang; Gang Wang; Wugui Jiang
  • Comparison of novel tetra-substituted phthalocyanines with their quaternized derivatives: Antioxidant and antibacterial properties
    Synth. Met. (IF 2.87) Pub Date : 2019-12-31
    Armağan Günsel; Ahmet T. Bilgiçli; Canberk Kandemir; Rüveyda Sancak; Gulnur Arabaci; M. Nilüfer Yarasir
  • Photoemission studies of C8-BTBT/La0.67Sr0.33MnO3 interface
    Synth. Met. (IF 2.87) Pub Date : 2019-12-25
    Haipeng Xie; Dongmei Niu; Yuan Zhao; Shitang Wang; Baoxing Liu; Yuquan Liu; Han Huang; Peng Wang; Di Wu; Yongli Gao
  • 更新日期:2019-12-26
  • Synthesis of hybrid ZIF-derived binary ZnS/CoS composite as high areal-capacitance supercapacitor
    Synth. Met. (IF 2.87) Pub Date : 2019-12-12
    Behnam Chameh; Morteza Moradi; Sanaz Kaveian

    Bimetal sulfide nanoparticle synthesized via a facile hydrothermal method using hybrid zeolitic imidazolate framework (ZIF-Co.Zn) and the made composites were analyzed using Field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer, Emmett, and Teller (BET) analysis. In addition, the electrode materials were electrochemically assessed through galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods in 6 M KOH electrolyte. Because of the synergistic impact of sulfur and metal, the prepared specimens showed excellent performance. Here, Zn-Co-S exhibited a high specific capacitance of 1646 F/g at 1 A/g current density. Furthermore, in our study, an asymmetric supercapacitor was developed successfully where active carbon and Zn-Co-S served as negative and positive electrodes, respectively. In the asymmetric device, a power density of 7080 W/kg and an energy density of 39.41 Wh/kg can be delivered with an 89 % capacitance retention followed by 2000 charge-discharge cycles. The results showed that the MOF-derived bimetal sulfide composite can be a promising candidate for the advanced electrode materials in supercapacitor applications.

  • Electrosynthesis and characterizations of electrochromic and soluble polymer films based on N- substituted carbazole derivates
    Synth. Met. (IF 2.87) Pub Date : 2019-12-12
    Hassan Elamin Elkhidr; Zeliha Ertekin; Yasemin Arslan Udum; Kadir Pekmez

    Carbazole derivatives are a class of nitrogen-containing aromatic heterocyclic compounds and they not only have various biological activities but also exhibit useful properties as organic materials due to their special structures. In this study, the compounds based on carbazole derivatives (N-positions were occupied by methanol, carboxylic acid, and cyanoethyl) were synthesized via a simple method. The electrochemistry and electropolymerization of these three monomers were investigated and compared with those of different N-substituted with groups attaching on the active sites of the carbazole units. The polymeric films were prepared on ITO/glass substrate by repetitive cyclic voltammetry (CV) scanning of the monomer solutions containing NaClO4-LiClO4 electrolyte dissolved in acetonitrile. The structures of the monomers and polymers were characterized by 1H-NMR, 13C-NMR, and FTIR. The electro-generated polycarbazole films exhibited redox-activity and multichromic properties with increasing potential. The remarkable electrochromic behavior of the films was explained in detail with the help of spectroelectrochemical studies. Photoluminescence spectra and quantum yields were given of polycarbazole samples in solution. In addition, solubility, molecular weight, and conductivity properties of polymers containing N-substituted groups have been discussed further.

  • Conducting polymer composite aerogel with magnetic properties for organic dye removal
    Synth. Met. (IF 2.87) Pub Date : 2019-12-13
    Patrycja Bober; Islam M. Minisy; Udit Acharya; Jiří Pfleger; Vladimir Babayan; Natalia Kazantseva; Jiří Hodan; Jaroslav Stejskal

    Multifunctional conducting polyaniline/hexaferrite aerogels supported by poly(vinyl alcohol) have been prepared by simple one-step procedure. The incorporation of magnetic particles into aerogel matrix was successfully proven with scanning electron microscopy and by examination of magnetic properties. Such novel hybrid aerogels showed better resistance against elastic deformation when stress is applied, increased conductivity compared to neat polyaniline/poly(vinyl alcohol) cryogels, and also enhanced coercive force compared with neat hexaferrite due to increased effective magnetic anisotropy by magnetostriction. Moreover, the efficient adsorption of Reactive Black 5 dye by aerogel has been illustrated. Therefore, this work offers new type of macroporous dye adsorbents which can be efficiently separated from the aqueous medium and thus used for wastewater treatment.

  • Unraveling the mechanism behind air instability in thin semiconducting polymer layers p-doped with molybdenum dithiolene complexes
    Synth. Met. (IF 2.87) Pub Date : 2019-12-13
    Tamara Nunes Domschke; Olivier Bardagot; Anass Benayad; Renaud Demadrille; Alexandre Carella; Raphael Clerc; Alexandre Pereira
  • Thermoelectric properties of flexible composite fabrics prepared by a gas polymerization combining solution coating process
    Synth. Met. (IF 2.87) Pub Date : 2019-12-13
    Yong Du; Tian Tian; Qiufeng Meng; Yunchen Dou; Jiayue Xu; Shirley Z. Shen

    Several flexible thermoelectric composite fabrics, including poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/PEDOT/cotton, PEDOT:PSS/PEDOT/silk, and PEDOT:PSS/PEDOT/wool have been prepared by a gas polymerization combining solution coating process, and their thermoelectric properties have been measured from 300 to 360 K. The results show that both electrical conductivity and Seebeck coefficient of PEDOT/cotton, PEDOT/silk, and PEDOT/wool composite fabrics are significantly improved after the PEDOT:PSS coating treatment, leading to significant enhancement of power factors of the composite fabrics. In addition, both electrical conductivity and Seebeck coefficient of all the composite fabrics are insensitive to the temperature increasing from 300 to 360 K. A highest power factor of 0.5 μWm−1 K-2 has been achieved for the PEDOT:PSS/PEDOT/wool composite at 360 K. This work provides an effective method to endow fabrics with thermoelectric properties.

  • Synthesis of silver/reduced graphene oxide for antibacterial activity and catalytic reduction of organic dyes
    Synth. Met. (IF 2.87) Pub Date : 2019-12-17
    Nguyen Minh Dat; Phung Ngoc Bao Long; Duong Chau Uyen Nhi; Nguyen Nhat Minh; Le Minh Duy; Le Ngoc Quan; Hoang Minh Nam; Mai Thanh Phong; Nguyen Huu Hieu

    The present study involved the preparation of silver-reduced graphene oxide (Ag/rGO) using co-precipitation method. The characteristics of Ag/rGO were confirmed by X-ray Diffraction patterns, Fourier transformation infrared spectroscopy, Raman spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area, scanning electron microscopy, and energy-dispersive spectroscopy. The results demonstrated that silver nanoparticles (AgNPs) having diameter of 16 ± 3.7 nm were uniformly integrated on reduced graphene oxide (rGO) The as-synthesized Ag/rGO had a specific area of 54m2/g and 67.36 wt% silver. Antibacterial and catalytic properties of Ag/rGO were then further investigated. Ag/rGO was found to effectively inhibit the developing of gram-negative and gram-positive bacteria such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa with the bactericidal rates of 89.35, 95.67, and 99.99 %, respectively. In addition, the catalytic property of Ag/rGO in the reduction of organic dyes was tested with different dosage of reducing agent, amount of catalyst, type of dye, and reaction time. More than 99 % of dyes in aqueous solution at 20 mg/L concentration were reduced after 30 min with amounts of Ag/rGO and sodium borohydride of 10 and 30 mg successively. All results confirmed the potential application of Ag/rGO in the treatment of infected water and dye contamination.

  • Chemically functionalized multi-walled CNTs induced phase behaviors of poly(vinylidene fluoride) nanocomposites and its dielectric properties
    Synth. Met. (IF 2.87) Pub Date : 2019-12-20
    Lin Chen; Lei Yan; Yi Guo; Hong-Cai Liu; Huan Huang; Hai-Lan Lin; Jun Bian; Yun Lu
  • Design and evaluation of SnO2-Pt/MWCNTs hybrid system as room temperature-methane sensor
    Synth. Met. (IF 2.87) Pub Date : 2019-12-19
    S Navazani; M Hassanisadi; M.M Eskandari; Z Talaei
  • Theoretical comparative study of promising semiconducting aromatic molecules and their fluorinated counterparts
    Synth. Met. (IF 2.87) Pub Date : 2019-12-20
    Denisa Cagardová; Ján Matúška; Martin Michalík; Peter Poliak; Vladimír Lukeš
  • 更新日期:2019-12-26
  • 更新日期:2019-12-11
  • Competing charge trapping and percolation in core-shell single wall carbon nanotubes/ polyaniline nanostructured composites
    Synth. Met. (IF 2.87) Pub Date : 2019-12-09
    Rakibul Islam, Anthony N. Papathanassiou, Roch Chan-Yu-King, Carole Gors, Frédérick Roussel

    Core-shell single wall carbon nanotube (SWCNT)/ polyaniline (PANI) nanocomposites were chemically synthesized and their structural, morphological, and dielectric properties were investigated as a function of the nanofiller content. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images confirm the core-shell nanostructural features of the composites. Broadband dielectric spectroscopy allows the detection of an interfacial dielectric relaxation mechanism which is quite dependent on the dispersion of nanoparticles into the semi-conducting polyaniline matrix. Furthermore, the relaxation process analysed through Kohlrausch-William-Watts (KWW) model, is found to take place at lower nanofiller loading but progressively fades away on increasing the amount of SWCNT, yielding relaxation spectra which gradually resemble that of a pure conductor. In addition, it is found that competing processes between electrical percolation and interfacial capacitance effects are inherently dependent on the carbon-filler content. Such a behaviour is ascribed to charge trapping and de-trapping phenomena occurring at core-shell interfaces. The possibility of tuning the composition of the nanocomposites in order to trigger an interplay between capacitance and dc-electrical conduction can be envisioned for their application in the next generation of organic-based supercapacitor or gate memory devices.

  • Poly(3-methyl thiophene)-graphene nanocomposites for asymmetric supercapacitors
    Synth. Met. (IF 2.87) Pub Date : 2019-12-07
    P. Sivaraman, Avinash P. Thakur, K. Shashidhara
  • Fabrication of a Ni foam-supported platinum nanoparticles-silver/polypyrrole electrode for aqueous ammonia sensing
    Synth. Met. (IF 2.87) Pub Date : 2019-12-06
    Liang Zhang, Jishun Liu, Xiaolei Peng, Qiang Cui, Dong He, Chun Zhao, Hui Suo

    Herein, an electrochemical ammonia sensor based on Ni foam-supported silver/polypyrrole and platinum nanoparticles electrode (Pt-Ag/PPy-NiF) was designed and constructed. The Ag/PPy layer was firstly grown on Ni foam surface via oxidation reduction reaction, and then Pt nanoparticles with great electrocatalytic activity were electrodeposited on the surface of Ag/PPy-NiF via cyclic voltammetry methodology. Electrochemical experiments demonstrated that the Pt-Ag/PPy-NiF electrode showed a great electrocatalytic ability of the oxidation of ammonia and an electrochemical aqueous ammonia sensor was proposed accordingly. The ammonia sensor showed a sensitivity of 0.089 mA μM−1, a detection limit of 37 nM (S/N = 3) and a wide linear range, as well as presenting a good anti-interference capability against many common ions in water. These excellent performances can be mainly attributed to large specific surface of electrode and great electrocatalytic ability of Pt nanoparticles.

  • Selective polymerization of a new bifunctional monomer via free radical polymerization and oxidative route
    Synth. Met. (IF 2.87) Pub Date : 2019-12-05
    Alain S. Conejo-Dávila, Claudia A. Hernández-Escobar, Alejandro Vega-Rios, Isis Rodríguez-Sánchez, Anayansi Estrada-Monje, Ramón E. Díaz de León-Gómez, E. Armando Zaragoza-Contreras
  • Effect of structural features of polypyrrole (PPy) on electrical conductivity reflected on 13C ssNMR parameters
    Synth. Met. (IF 2.87) Pub Date : 2019-12-03
    Andrii Mahun, Sabina Abbrent, Patrycja Bober, Jiri Brus, Libor Kobera
  • Molybdenum disulfide with poly(dopamine) and epoxy groups as an efficiently anticorrosive reinforcers in epoxy coating
    Synth. Met. (IF 2.87) Pub Date : 2019-12-03
    Yujuan Jing, Pingquan Wang, Qiangbin Yang, Yi He, Yang Bai
  • Molecularly imprinted poly (4,4′-methylenedianiline) as electrochemical sensor for determination of 1-benzothiophene
    Synth. Met. (IF 2.87) Pub Date : 2019-12-04
    Esmail Mohseni, Mohammad Reza Yaftian, Hassan Shayani-jam, Abbasali Zamani, Farideh Piri
  • Hole transport layers based on metal Schiff base complexes in perovskite solar cells
    Synth. Met. (IF 2.87) Pub Date : 2019-11-24
    Yuzhen Wang, Wenkang Ye, Xiongbo Yang, Ehsan Rezaee, Haiquan Shan, Songhe Yang, Siyuan Cai, Jia-Hong Pan, Jiaju Xu, Zong-Xiang Xu

    In this report a new series of metal Schiff base complexes (MMePy, M = Pt, Pd and Cu) were synthesized and used as hole transport materials (HTMs) in perovskite solar cells (PSCs), as an attempt to realize the hole extraction and transport ability of these materials in PSCs. The energy levels of the materials can be easily tuned by changing the central metal, leading to a better alignment with the perovskite absorber. The well matching of energy level along with lower surface roughness and higher crystallinity of the thin film give rise to the highest PCE of 8.07 % for the CuMePy-based device among the MMePy-based devices. The result indicates the promising application of this series of metal complexes for the use as HTM in PSCs.

  • Gamma irradiated electro-conductive polylactic acid/polyaniline nanofibers
    Synth. Met. (IF 2.87) Pub Date : 2019-11-22
    Seyed Sajad Ashraf, Masoud Frounchi, Susan Dadbin

    In this study, polyaniline nanoparticles (PANI NPs) in emeraldine base (EB) form were prepared by a modified method and characterized by FTIR and UV–vis spectroscopies. The average size of the nanoparticles was 140 nm measured by DLS method. The nanoparticles were embedded into polylactic acid (PLA) nanofibers prepared by electrospinning method. It was found that inclusion of PANI NPs in PLA resulted in reduced diameter of the fibers during the electrospinning process. Also, the surface of nanofibers appeared smooth in FE-SEM images without formation of beads. Improvement in mechanical and electrical properties of PLA/PANI nanofibers over the neat PLA nanofibers implied a good dispersion of PANI NPs in PLA matrix and existence of fairly strong interactions between two polymers. Also, wettability tests revealed that PLA/PNAI nanofibers were less hydrophobic than neat PLA. To explore the effect of irradiation on physical properties of the nanofibers, the nanofibers were exposed to gamma ray at 25 kGy which is a typical dose for sterilization of bio-implants. Then, the physical properties of irradiated nanofibers were compared with the non-irradiated counterparts in terms of electrical, mechanical and thermal properties. Also, morphology and hydrophilicity of the surface of the nanofibers after irradiation were compared with non-irradiated ones. It was concluded that gamma irradiation contributed to stronger interfacial interactions between PLA and PANI NPs that resulted in further improvements on the desired properties of the nanofibers such as wettability, electrical conductivity and tensile strength.

  • Effect of ultrasound pretreatment on bromination of double-walled carbon nanotubes
    Synth. Met. (IF 2.87) Pub Date : 2019-11-21
    L.G. Bulusheva, E.V. Lobiak, Yu.V. Fedoseeva, J.-Y. Mevellec, A.A. Makarova, E. Flahaut, A.V. Okotrub

    Bromination of double-walled carbon nanotubes (DWCNTs) was carried out using a saturated vapor of Br2 at room temperature with or without a pretreatment in bromine water. X-ray photoelectron spectroscopy revealed that ultrasound pretreatment modified the chemical state of bromine in the product. The binding energies of the Br 3d electrons in the pre-sonicated DWCNT sample were between those characteristic of the covalent C–Br bonds and the negatively charged Br2 molecules, observed when the pretreatment was not performed. Raman spectroscopy, however, clearly evidenced Br–Br vibrations in both brominated samples. Calculations of CNT–Br2 models within density functional theory were used to propose that the electronic state of a Br2 molecule depends on the adsorption site. The bromine molecules prefer to be located near edge hydroxyl groups, which acept the electron density from Br2. This increases the binding energy of Br 3d levels as compared to that for Br2 molecules in other adsorption sites.

  • Structural, optical and photocatalytic studies of trimetallic oxides nanostructures prepared via wet chemical approach
    Synth. Met. (IF 2.87) Pub Date : 2019-11-21
    Abdur Rahman, Humera Sabeeh, Sonia Zulfiqar, Philips Olaleye Agboola, Imran Shakir, Muhammad Farooq Warsi

    Multi metal based photocatalyst (CdO-MgO-Fe2O3) was synthesized via wet chemical approach i.e. co-precipitation method. The single transition metal oxides like CdO, MgO and Fe2O3 were also prepared for comparative studies. Structural elucidation of all prepared powder catalysts (CdO, MgO, Fe2O3 and CdO-MgO-Fe2O3) was conducted by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). XRD showed the presence of the MgO (cubic) – Fe2O3 (rhombohedral)– CdO (cubic) phase with an average crystallite size of MgO (9 nm), Fe2O3 (12 nm), CdO (23 nm). FTIR proved the existence of Mg–O, Fe2-O3 and Cd-O by distinctive vibrational bands at 772 cm−1, 581 cm−1 and 480 cm−1 respectively. UV–vis spectral studies showed that the bandgap for CdO-MgO-Fe2O3 nanocomposite was 1.76 eV which made it an efficient photocatalyst for use both in the UV and visible regions. Two probe I–V measurements confirmed the pure semiconducting behavior and possible formation of heterojunction in the CdO-MgO-Fe2O3 nanocomposite. The photocatalytic performance of the CdO-MgO-Fe2O3 nanocomposite with equal metal ion concentration of Mg, Fe and Cd at different pH values was explored by visible light illumination on methylene blue (MB) dye as a standard organic pollutant. The CdO-MgO-Fe2O3 nanocomposite with metal ion ratio 1:1:1 in an alkaline medium showed the maximum photocatalytic performance. The rate constant (kMB) value for the degradation of MB was ∼ 0.0820 min−1. The photocatalytic activity has been improved due to the effective decrease in the recombination rate of charge carriers. The possible mechanism for improvement of the photocatalytic performance using visible light illumination has also been suggested and discussed.

  • Electrochromic materials based on novel polymers containing triphenylamine units and benzo[c][1,2,5]thiadiazole units
    Synth. Met. (IF 2.87) Pub Date : 2019-11-21
    Fanghong Ma, Fuhan Liu, Yanjun Hou, Haijun Niu, Cheng Wang
  • A selective turn-on fluorescent probe for Al3+ based-on a diacylhydrazone deritive in aqueous medium and its cell imaging
    Synth. Met. (IF 2.87) Pub Date : 2019-11-21
    Zheng Li, Fucai Dai, Jing Wang, Shujun Wang, Liwei Xiao, Lele Li
  • Effects of π-spacer and fluorine loading on the optoelectronic and photovoltaic properties of (X-DADAD)n benzodithiophene-based conjugated polymers
    Synth. Met. (IF 2.87) Pub Date : 2019-11-21
    Alexander V. Akkuratov, Ilya E. Kuznetsov, Petr M. Kuznetsov, Nikita V. Tukachev, Ilya V. Martynov, Sergey L. Nikitenko, Artyom V. Novikov, Alexander V. Chernyak, Andriy Zhugayevych, Pavel A. Troshin
  • Fine tuning of the Fermi level of single-walled carbon nanotubes with onium salts and application for thermoelectric materials
    Synth. Met. (IF 2.87) Pub Date : 2019-11-19
    Hiroki Sugiura, Yoshinori Kanazawa, Kimiatsu Nomura, Toshiaki Aoai

    Fermi level is one of the most important parameters for control of semiconductor polarity and improvement of thermoelectric performances. Although single-walled carbon nanotubes (SWCNTs) are promising candidates for thermoelectric materials, control of the Fermi level of SWCNTs with chemical dopants is still challenging. Reported here is the fine-tuning of the Fermi level of SWCNTs with onium salts. The Fermi level of SWCNTs was very sensitive to substituent size on the cation and nucleophilicity of the anion, and the Seebeck coefficients markedly changed between −50 μV K−1 and 68 μV K−1. The optimum Fermi level of p-type SWCNTs that exhibits the maximum power factor was realized by ammonium chloride or pyridine hydrochloride, and the power factor (PF) was improved by about 7 times as compared with non-doped SWCNTs. SWCNTs doped with onium salts were stable in both p-type and n-type states, and thermoelectric performances did not change more than 100 days in the air.

  • Effect of different ratios of polyaniline:poly(styrene sulfonate) on the hole extraction ability in perovskite solar cells
    Synth. Met. (IF 2.87) Pub Date : 2019-11-20
    A. Abdelmagid, A. El Tahan, M. Habib, M. Anas, M. Soliman

    In this work, synthesis and characterization of polyaniline:poly (styrene sulfonate) (PANI:PSS) is prepared with different ratios of the doping PSS for producing an efficient hole extraction layer in inverted planar perovskite solar cells. The PANI to PSS ratios are investigated using ratios of 1:3, 1:4, 1:5, 1:6 and 1:7 to find the optimum ratio for high performance perovskite cells. It is observed that decreasing the PSS content leads to increase the conductivity, which reached the maximum value at 1:4 ratio, then a slight decrease happens for 1:3 ratio. The hole extraction ability also increases with decreasing the PSS concentration. The optimum ratio of PANI:PSS is 1:4, which shows the best performance as HTL, the average short-circuit current density and fill factor are enhanced compared with the cells of the performance of 1:3 and 1:5 ratios. The highest cell performance for the cell with the ratio of 1:4 which has Jsc, Voc, FF and efficiency 22.5 mA/cm2, 0.87 V, 0.42 and 8.22 % respectively.

  • 更新日期:2019-11-20
  • Preparation and Electrochemical Behavior of Graphene-Oxide/Zinc-Phosphate Composite Coatings on as-Cast Al-Zn (5.0 wt.%)-Mg (2.5 wt.%) Alloy
    Synth. Met. (IF 2.87) Pub Date : 2019-11-19
    M.M. Sadawy, E.A. Eid

    Graphene-oxide/zinc-phosphate composite coatings (GO/ZP) have been synthesized on as-cast Al-Zn (5.0 wt. %)-Mg (2.5 wt.%) alloy substrate using the chemical conversion coatings technique. X-ray diffraction (XRD), electron microscopy (SEM) associated with energy-dispersive X-ray spectroscopy unit (EDX) and X-ray photoelectron spectroscopy (XPS) were utilized for characterizing the microstructure of GO/ZP composite coating films. The electrochemical behavior of GO/ZP composite coatings was studied using potentiodynamic polarization and potentiostatic techniques. The results revealed that the incorporation of GO sheets in the ZP coating bath up to 1.0 g/L led to increasing the coating weight (g/m2) and the corrosion protection efficiency (%). The improvement of corrosion resistance could be attributed to the regular distribution of GO which closed up the free spaces in coating films and inhibited the penetration of corrosive ions into alloy substrate. Nevertheless, a further incorporating of GO (1.25 and 1.5 g/L) gave an adverse effect on the coating weight and the corrosion resistance.

  • Regulated micro-leaf like nickel pyrophosphate as a cathode electrode for asymmetric supercapacitor
    Synth. Met. (IF 2.87) Pub Date : 2019-11-18
    Supriya J. Marje, Pranav K. Katkar, Sachin S. Pujari, Suraj A. Khalate, Abhishek C. Lokhande, Umakant M. Patil
  • 更新日期:2019-11-18
  • Enhancing the dielectric properties of polymethyl methacrylate by using low loading graphene encapsulated styrene-butyl acrylate copolymer microspheres
    Synth. Met. (IF 2.87) Pub Date : 2019-11-16
    Xueliang Jiang, Wenwen Guo, Feng You, Zhimin Dang, Chu Yao, Junlong Yao, Fangjun Liu, Yuhong Zhang
  • Facile synthesis of porous nanostructures of NiCo2O4 grown on rGO sheet for high performance supercapacitors
    Synth. Met. (IF 2.87) Pub Date : 2019-11-14
    Arvind Singh, Saurav K. Ojha, Animesh K. Ojha

    Porous nanowires (NWs) and nanoflowers (NFs) type structures of nickel cobaltite (NiCo2O4) were synthesized on rGO sheet (rGO@NiCo2O4) as supercapacitor electrode material. The synthesized materials are characterized using different experimental techniques. The growth of NiCo2O4 over rGO sheet is confirmed by the appearance of D and G bands in the Raman spectrum. The rGO@NiCo2O4 NFs electrode revealed relatively high value of specific capacity (436 C/g at current density of 1 A/g) with good capacity retention compared to other electrodes. The improved electrochemical activity of the rGO@NiCo2O4 NFs electrode may be due to the porous nanostructure of NiCo2O4 on rGO sheet. The rGO sheets provide easy access to ions, large surface area and large active sites with stable structural integrity. The Nyquist plot of the rGO@NiCo2O4 NFs electrode shows relatively low values of Rs and Rct compared to other electrodes, which essentially refer to its improved electrical conductivity. Thus, the rGO@NiCo2O4 NFs may be used as a supercapacitor electrode material for device fabrication.

  • Low-temperature properties of thermoelectric generators using molecular conductors
    Synth. Met. (IF 2.87) Pub Date : 2019-11-13
    Yasuhiro Kiyota, Tadashi Kawamoto, Takehiko Mori
  • Hydrogen bonding enhanced thermally conductive carbon nano grease
    Synth. Met. (IF 2.87) Pub Date : 2019-11-13
    Greg Christensen, Hammad Younes, George Hong, Ding Lou, Haiping Hong, Christian Widener, Craig Bailey, Rob Hrabe

    Grease made from carbon nanotubes (CNTs) and carbon nanofibers (CNFs) have shown superior thermal conductivity. Thermal conductivity enhancements up to 545.9% over the base fluid are reported by loading 12 wt% of carbon nanofiber into NYE Blank Grease. The unexpected results in this paper also lead to an improved way to significantly enhance the thermal conductivity of greases while reducing the nanotube loading percentage. A carbon nanofiber loading of only 5 wt% leads to a 163.3% increase in thermal conductivity in NYE 758G grease. A loading of 1.4 wt% hydroxyl functionalized multi-wall nanotube (MWNT-OH) in Krytox XHT750 oil leads to a 37.8% increase in thermal conductivity. The new discovery detailed in this paper is that hydrogen bonding between nanotube and oil is the key element for a good conductivity performance. The introduction of hydrogen bonding in any form into the grease increases thermal conductivity. The grease structure is created by the sole thickeners which are carbon nanotubes and nanofibers. This makes the grease unique and valuable.

Contents have been reproduced by permission of the publishers.
上海纽约大学William Glover