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2019, Vol. 37, No. 10　Online: 2019-10-15

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Interface-strengthened CoP nanosheet array with Co2P nanoparticles as efficient electrocatalysts for overall water splitting Yanping Hua, Qiucheng Xu, Yanjie Hu, Hao Jiang, Chunzhong Li 2019, 37(10): 1-6.  DOI: 10.1016/j.jechem.2018.11.010 摘要 ( 5 )   Highly active and durable bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) play a pivotal role in overall water splitting. Herein, we demonstrate the construction of interface-strengthened CoP nanosheet array with Co2P nanoparticles as such an electrocatalyst through a facile hydrothermal reaction and the subsequent phosphorization process. The twodimensional (2D) nanosheets with thickness of~55 nm expose a great number of active sites. The surface chemical state indicates that the strongly coupled CoP/Co2P electrocatalysts can adsorb or generate more targeted intermediates (e.g. OH- or OOH*) for both HER/OER. As a result, the CoP/Co2P electrocatalysts exhibit small overpotentials of 68 and 256 mV to drive 10 mA cm-2 for HER and OER, respectively, outperforming most of the recently reported Co-based electrocatalysts. Furthermore, an alkaline electrolyzer assembled by using CoP/Co2P as both cathode and anode can achieve a current density of 10 mA cm-2 at a low voltage of 1.57 V and work continuously for over 58 h. This work provides a feasible structural design for transition metal phosphides electrocatalysts with efficient and stable overall water splitting.

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Integrated Co3O4/carbon fiber paper for high-performance anode of dual-ion battery Lu Sui, Xiaoyuan Shi, Ting Deng, He Yang, Hongyan Liu, Hong Chen, Wei Zhang, Weitao Zheng 2019, 37(10): 7-12.  DOI: 10.1016/j.jechem.2018.11.009 摘要 ( 6 )   In dual-ion batteries (DIBs), energy storage is achieved by intercalation/de-intercalation of both cations and anions. Due to the mismatch between ion diameter and layer space of active materials, however, volume expansion and exfoliation always occur for electrode materials. Herein, an integrated electrode Co3O4/carbon fiber paper (CFP) is prepared as the anode of DIB. As the Co3O4 nanosheets grow on CFP substrate vertically, it promotes the immersion of electrolyte and shortens the pathway for ionic transport. Besides, the strong interaction between Co3O4 and CFP substrate reduces the possibility of sheet exfoliation. An integrated-electrode-based DIB is therefore packaged using Co3O4/CFP as anode and graphite as cathode. As a result, a high energy density of 72 Wh/kg is achieved at a power density of 150 W/kg. The design of integrated electrode provides a new route for the development of high-performance DIBs.

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N-doped CoO nanowire arrays as efficient electrocatalysts for oxygen evolution reaction Kaili Zhang, Xinhui Xia, Shengjue Deng, Dong Xie, Yangfan Lu, Yadong Wang, Jianbo Wu, Xiuli Wang, Jiangping Tu 2019, 37(10): 13-17.  DOI: 10.1016/j.jechem.2018.11.013 摘要 ( 10 )   Rational design of cost-effective high-performance electrocatalysts for oxygen evolution reaction (OER) is of great significance for electrochemical water splitting. Herein, we adopt a nitrogen doping method to fabricate self-supported N-doped CoO nanowire arrays (N-CoO) as active electrocatalysts via a facile hydrothermal combined doping method. The N-CoO nanowires are strongly composited with the carbon cloth substrate forming free-standing electrode with reinforced stability and high electronic conductivity. Owing to the increased accessible and electroactive areas, rich/short pathways for charge transfer and enhanced electronic conductivity, the N-CoO electrode exhibits excellent electrocatalytic performance for OER with a low overpotential (319 mV at 10 mA cm-2 and 410 mV at 100 mA cm-2) and a low Tafel slope of 74 mV dec-1 as well as superior long-term stability with no decay in 24 h continuous test in alkaline solution. Our reported design and optimization strategy provide a promising way to construct interesting well-aligned arrays for application in energy storage and conversion.

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Photocatalytic performance of K2Ti6O13 whiskers to H2 evolution and CO2 photo-reduction L. F. Garay-Rodríguez, L. M. Torres-Martínez, E. Moctezuma 2019, 37(10): 18-28.  DOI: 10.1016/j.jechem.2018.11.014 摘要 ( 6 )   K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with different particle sizes and to modify their optical, textural and electrochemical properties. These modifications improved their photocatalytic activity for H2 evolution and CO2 photo-reduction. Long K2Ti6O13 whiskers prepared by ultrasound assisted sol-gel method are the most active photocatalysts for the hydrogen evolution reaction using pure water as reactant (U-SG, 10,065 μmol g-1). In contrast, an opposite behavior was observed using a mixture of ethanol-water, where the highest activity was achieved by the shortest and less crystalline K2Ti6O13 whiskers (C-SG, 3,2871 μmol g-1). In case of CO2 photo-reduction, long whiskers that were also prepared by the sono-chemical assisted sol-gel method were the most active to transform CO2 to formaldehyde, methane, methanol and hydrogen. The EFB value of this catalyst is located very close to the potential for formaldehyde production and favors the selectivity to this organic product.

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Lithium-matrix composite anode protected by a solid electrolyte layer for stable lithium metal batteries Xin Shen, Xinbing Cheng, Peng Shi, Jiaqi Huang, Xueqiang Zhang, Chong Yan, Tao Li, Qiang Zhang 2019, 37(10): 29-34.  DOI: 10.1016/j.jechem.2018.11.016 摘要 ( 16 )   Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendrites and infinite volume change during repeated plating/stripping cycles hinder its practical applications immensely. Herein, a house-like Li anode (housed Li) was designed to circumvent the above issues. The house matrix was composed of carbon fiber matrix and affords a stable structure to relieve the volume change. An artificial solid electrolyte layer was formed on composite Li metal, just like the roof of a house, which facilitates uniform Li ions diffusion and serves as a physical barrier against electrolyte corrosion. With the combination of solid electrolyte layer and matrix in the composite Li metal anode, both dendrite growth and volume expansion are remarkably inhibited. The housed Li|LiFePO4 batteries exhibited over 95% capacity retention after 500 cycles at 1.0 C in coin cell and 85% capacity retention after 80 cycles at 0.5 C in pouch cell. The rationally combination of solid electrolyte layer protection and housed framework in one Li metal anode sheds fresh insights on the design principle of a safe and long-lifespan Li metal anode for Li metal batteries.

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Kinetics and mechanistic investigation of epoxide/CO2 cycloaddition by a synergistic catalytic effect of pyrrolidinopyridinium iodide and zinc halides Abdul Rehman, Valentine C. Eze, M. F. M. Gunam Resul, Adam Harvey 2019, 37(10): 35-42.  DOI: 10.1016/j.jechem.2018.11.017 摘要 ( 16 )   Formation of styrene carbonate (SC) by the cycloaddition of CO2 to styrene oxide (SO) catalysed by pyrrolidinopyridinium iodide (PPI) in combination with zinc halides (ZnCl2, ZnBr2 and ZnI2) was investigated. Complete conversion of the SO to SC was achieved in 3 h with 100% selectivity using 1/0.5 molar (PPI/ZnI2) catalyst ratio under mild reaction conditions i.e., 100℃ and 10 bar CO2 pressure. The synergistic effect of ZnI2 and PPI resulted in more than 7-fold increase in reaction rate than using PPI alone. The cycloaddition reaction demonstrated the first-order dependence with respect to the epoxide, CO2 and catalyst concentrations. Moreover, the kinetic and thermodynamic activation parameters of SC formation were determined using the Arrhenius and Eyring equations. The positive values of △H‡ (42.8 kJ mol-1) and △G‡ (102.3 kJ mol-1) revealed endergonic and chemically controlled nature of the reaction, whereas the large negative values of △S‡ (-159.4 J mol-1 K-1) indicate a highly ordered activated complex at the transition state. The activation energy for SC formation catalyzed by PPI alone was found to be 73.2 kJ mol-1 over a temperature range of 100-140℃, which was reduced to 46.1 kJ mol-1 when using PPI in combination with ZnI2 as a binary catalyst. Based on the kinetic study, a synergistic acid-based reaction mechanism was proposed.

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Defect engineering: A versatile tool for tuning the activation of key molecules in photocatalytic reactions Ning Zhang, Chao Gao, Yujie Xiong 2019, 37(10): 43-57.  DOI: 10.1016/j.jechem.2018.09.010 摘要 ( 12 )   Many photocatalytic reactions such as CO2 reduction and N2 fixation are often limited by the activation of some key molecules. Defects in solid materials can robustly introduce coordinately unsaturated sites to serve as highly active sites for molecular chemisorption and activation. As a result, rational defect engineering has endowed a versatile approach to further develop photocatalytic applications beyond water splitting. The subtly designed defects in photocatalysts can play critical and decisive roles in molecular activation as proven in recent years. The defects cannot only serve as active sites for molecular chemisorption, but also spatially supply channels for energy and electron transfer. In this review, we aim to summarize the diversiform photocatalytic applications using defects as active sites, including but not limited to CO2 reduction, O2 activation, H2O dissociation, N2 fixation as well as activation of other molecules. In particular, we emphatically outline how the parameters of defects (e.g., concentration, location, geometric and electronic structures) can serve as the knobs for maneuvering molecular adsorption and activation as well as altering subsequent reaction pathway. Moreover, we underline the remaining challenges at the current stage and the potential development in the future. It is anticipated that this review consolidates the in-depth understanding towards the structure-activity relationship between defects and related reactions.

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Fused thienobenzene-thienothiophene electron acceptors for organic solar cells Ye Xu, Haotian Jiang, Tsz-Ki Lau, Jingshuai Zhu, Jiayu Wang, Xinhui Lu, Xiaowei Zhan, Yuze Lin 2019, 37(10): 58-65.  DOI: 10.1016/j.jechem.2018.12.002 摘要 ( 12 )   Small molecule ladder-type heteroarenes IHBT-2F is designed and synthesized with strong electrondonating and molecular packing properties, where the central unit, fused thienobenzene-thienothiphene (IHBT), is attached with the strong electron-deficient 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as the end group. The counterpart IDBT-2F with indancenodibenzothiophene (IDBT) mainchain is sythesized for comparison, in which thieno[3,2-b]thiophene (TT) core of IHBT is replaced by benzene core. Relative to benzene-core IDBT-2F, TT-core IHBT-2F shows a much higher highest occupied molecular orbital energy level (IHBT-2F:-5.46 eV; IDBT-2F:-5.72 eV) and significantly redshifted absorption, due to the π-donor capability of the sulfur atom, the larger π-conjugation and stronger intermolecular π-π stacking. The as-cast organic solar cells (OSCs) based on blends of PTB7-Th donor and IHBT-2F acceptor without additional treatments exhibit power conversion efficiencies (PCEs) as high as 8.74%, which is much higher than that of PTB7-Th:IDBT-2F (6.73%).

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High-performance self-assembly MnCo2O4 nanosheets for asymmetric supercapacitors Jianwei Li, Dongbin Xiong, Linzhe Wang, Maleki Kheimeh Sari Hirbod, Xifei Li 2019, 37(10): 66-72.  DOI: 10.1016/j.jechem.2018.11.015 摘要 ( 14 )   In this study, MnCo2O4 nanosheets were proposed to be utilized as an electrode material for supercapacitors. A two-step hydrothermal method with post-annealing treatment was employed in preparation of the nanostructures. MnCo2O4 electrode delivered a high specific capacitance of 2000 F g-1 at 0.5 A g-1, remarkable high-rate capability of 1150 F g-1 at 20 A g-1, and an excellent cycling stability of 92.3% at 5 A g-1 after 5000 cycles. It is found that a three-electrode supercapacitor based on MnCo2O4 exhibits a promising electrochemical performance, better than the other similar materials, benefited from the synergistic effects of MnCo2O4 nanosheets. In fact, the self-assembly of nanosheets structure with high specific surface area and mesoporous structure can potentially enhance the electrochemical performance of supercapacitors.

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Reduced irreversible capacities of graphene oxide-based anodes used for lithium ion batteries via alkali treatment Danhua Jiao, Zhengwei Xie, Qi Wan, Meizhen Qu 2019, 37(10): 73-81.  DOI: 10.1016/j.jechem.2018.11.018 摘要 ( 14 )   The large irreversible capacities of graphene oxide-based anodes hinder commercial applications of GO materials although the high specific capacity of it has been universally accepted. In this paper, GO was treated under alkaline condition and the composite consisting of the modified GO and graphite was used as anode for lithium ion batteries (LIBs), resulting in an improved initial coulombic efficiency. Electrochemical tests also showed that the modified GO/graphite electrode possessed 86.0% of initial coulombic efficiency, which was 15% higher than that of pristine GO/graphite electrode. The species and the content of functional groups were investigated via XPS, FTIR characterizations in detail, which certified that the ring-opening reaction of epoxides under alkaline condition could greatly reduce the irreversible capacity of GO/graphite anode, in addition, the reversible capacity was guaranteed at the same time. This modified GO/graphite electrodes in the LIBs exhibit superior rate capability and long cycle life. The uniqueness of this electrode lied in its chemical stability, which benefits from the transition of epoxide group and unstable functional groups removal.

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Highly efficient production of 2,5-dihydroxymethylfuran from biomass-derived 5-hydroxymethylfurfural over an amorphous and mesoporous zirconium phosphonate catalyst Lei Hu, Ning Li, Xiaoli Dai, Yuqi Guo, Yetao Jiang, Aiyong He, Jiaxing Xu 2019, 37(10): 82-92.  DOI: 10.1016/j.jechem.2018.12.001 摘要 ( 5 )   The development of high-efficiency and low-cost catalysts is very crucial for the MeerweinPonndorf-Verley (MPV) reduction of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF). In this work, an amorphous and mesoporous zirconium phosphonate catalyst (Zr-DTMP), which is a zirconium-containing organic-inorganic nanohybrid, was successfully designed and synthesized by the simple assembly of zirconium tetrachloride (ZrCl4) and diethylene triaminepenta(methylene phosphonic acid) (DTMP). Satisfactorily, when Zr-DTMP was employed for the MPV reduction of HMF in the presence of 2-butanol (secBuOH), DHMF yield could be achieved as 96.5% in 3 h under a relatively mild reaction temperature of 140℃. Systematic investigations indicated that this high catalytic activity should be mainly due to the cooperative role of enhancive Lewis acid site (Zr4+) and Lewis base site (O2-) in activating the carbonyl group of HMF and dissociating the hydroxyl group of secBuOH, respectively. Additionally, Zr-DTMP showed excellent catalytic stability, when it was successively used 5 recycles, its surface characteristics and textural properties still remained almost unchanged, and so, the catalytic activity was not obviously affected. More interestingly, Zr-DTMP could also be applied for the selective reduction of other biomass-derived carbonyl compounds, such as 5-methylfurfural (MF), furfural (FF), levulinic acid (LA), ethyl levulinate (EL) and cyclohexanone (CHN), into the corresponding products with high yields, which is beneficial to the effective synthesis of various valuable bio-based chemicals.

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Selective electrocatalytic CO2 reduction enabled by SnO2 nanoclusters Hui Yang, Yang Huang, Jun Deng, Yunling Wu, Na Han, Chenyang Zha, Leigang Li, Yanguang Li 2019, 37(10): 93-96.  DOI: 10.1016/j.jechem.2018.12.004 摘要 ( 8 )   The development of high-performance electrocatalysts holds the decisive key to the electrochemical CO2 reduction toward value-added products. Formic acid or formate is a desirable reduction product, but its selective production is often challenging. Tin based-materials have attracted great attention for formate production, and yet their performances are far from satisfactory. In this study, we reported the preparation of SnO2 nanoclusters from the controlled self-polymerization of dopamine together with SnO32-, followed by the mild-temperature calcination. The final product consisted of large primary particles that were further made of small secondary SnO2 nanocrystals. When evaluated as the electrocatalyst for CO2 reduction in 0.5 M NaHCO3, our material exhibited impressive activity, selectivity and stability for the selective CO2 reduction to formate. A peak formate Faradaic efficiency of~73% and large partial current density of 16.3 mA/cm2 was achieved at -0.92 V versus reversible hydrogen electrode.

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Two dimensional metal halide perovskites: Promising candidates for light-emitting diodes Lu Zhang, Yucheng Liu, Zhou Yang, Shengzhong(Frank)Liu 2019, 37(10): 97-110.  DOI: 10.1016/j.jechem.2018.12.005 摘要 ( 13 )   Two dimensional halide perovskites are emerging as attractive electroluminescent materials for developing high-performance light-emitting devices owing to their unique structures and/or superior optoelectronic properties. This review begins with an introduction to the working principles of and the key figures for evaluating the performance of LEDs. Secondly, the structure and optoelectronic properties of two dimensional perovskites are summarized and discussed. Their advantages in LED application over their 3D counterparts are systematically analyzed. Following the theoretically discussion, the progresses on the preparation of two dimensional perovskite materials as well as their performances in LEDs have been summarized. At last, several challenges and prospects are presented for achieving high performance 2D perovskite-based LEDs.

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Facile synthesis of Li2S@C composites as cathode for Li-S batteries Xin Chen, Linfeng Peng, Lixia Yuan, Rui Zeng, Jingwei Xiang, Weilun Chen, Kai Yuan, Jie Chen, Yunhui Huang, Jia Xie 2019, 37(10): 111-116.  DOI: 10.1016/j.jechem.2018.12.008 摘要 ( 8 )   Lithium sulfide (Li2S) provides a promising route for lithium storage due to high theoretical specific capacity (1166 mAh g-1). The electrochemical performance of Li2S can be significantly enhanced by forming Li2S-carbon composites with the introduction of carbon. However, the complex synthesis method of Li2S-carbon composites restrains the large-scale productivity. Herein, we propose a facile route to prepare carbon coated Li2S-carbon nanotube composites (Li2S@C-CNT) via spray drying and heat treatment, which is a low-cost and large-scale method for facile synthesis of Li2S-carbon composites. For the Li2S@C-CNT composites, Li2S nanoparticles are contacted with surrounding particles due to the 3D CNTs framework. The novel construction not only suppresses the diffusion of polysulfides during cycling, but also remarkably accelerates the transport of electron and ion, resulting in a high specific capacity (1100 mAh g-1) and good cycling performance. The rational designed architecture and good electrochemical performance of Li2S@C-CNT will pave the avenue for realizing high energy density of Li2S-based batteries.

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Enhanced coking resistance of a Ni cermet anode by a chromates protective layer Hong Chang, Huili Chen, Guangming Yang, Wei Zhou, Jianping Bai, Sidian Li, Zongping Shao 2019, 37(10): 117-125.  DOI: 10.1016/j.jechem.2018.12.007 摘要 ( 6 )   Ni-based anodes of SOFCs are susceptible to coking, which greatly limits practical application of direct methane-based fuels. An indirect internal reformer is an effective way to convert methane-based fuels into syngas before they reach anode. In this work, catalytic activity of a redox-stable perovskite La0.7Sr0.3Cr0.8Fe0.2O3-δ (LSCrFO) for methane conversion was evaluated. The catalyst was fabricated as an anodic protective layer to improve coking resistance of a Ni cermet anode. Using wet CH4 as a fuel, the LSCrFO-modified cell showed excellent power output and good coking resistance with peak power density of 1.59 W cm-2 at 800℃. The cell demonstrated good durability lasting for at least 100 h. While the bare cell without the protective layer showed poor durability with the cell voltage fast dropped from 0.75 V to 0.4 V within 30 min. Under wet coal bed methane (CBM) operation, obvious performance degradation within 35 h (1.7 mV h-1) was observed due to the influence of heavy carbon compounds in CBM. The pre-and post-mortem microstructures and carbon analysis of the anode surface and catalyst surface were further conducted.

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Recent advances in gel polymer electrolyte for high-performance lithium batteries Ming Zhu, Jiaxin Wu, Yue Wang, Mingming Song, Lei Long, Sajid Hussain Siyal, Xiaoping Yang, Gang Sui 2019, 37(10): 126-142.  DOI: 10.1016/j.jechem.2018.12.013 摘要 ( 38 )   Lithium batteries (LBs) have become increasingly important energy storage systems in our daily life. However, their practical applications are still severely plagued by the safety issues from liquid electrolyte, especially when the batteries are exposed to mechanical, thermal, or electrical abuse conditions. Gel polymer electrolytes (GPEs) are being considered as an effective solution to replace currently available organic liquid electrolyte for building safer LBs. This review provides recent advancements in GPEs applied for high-performance LBs. On the one hand, from the environmental and economic point of view, the skeletons of GPEs changed from traditional polymer to renewable and degradable polymer. On the other hand, in addition to being as a component with good electrochemical and physical characterizations, the GPEs also need to provide some functions for addressing the concerns of lithium (Li) dendrites, unstable cathode electrolyte interface, dissolution and migration of transition metal ions, "shuttle effect" of polysulfides, and so on. Finally, to synchronously meet the challenges from the advanced cathode and Li metal anode, the bio-based GPEs with multi-functionality are proposed to develop high-energy/powerdensity batteries in the future.

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High electrocatalytic hydrogen evolution activity on a coupled Ru and CoO hybrid electrocatalyst Jia-Xin Guo, Dong-Yang Yan, Kang-Wen Qiu, Chuan Mu, Dian Jiao, Jing Mao, Hui Wang, Tao Ling 2019, 37(10): 143-147.  DOI: 10.1016/j.jechem.2018.12.011 摘要 ( 3 )   Hydrogen evolution reaction (HER) is an essential step in converting renewable energy to clean hydrogen fuel. Exploring highly efficient, stable and cost-effective electrocatalysts is of crucial significance for sustainable HER. Here, we report the design of a coupled ruthenium/cobalt oxide (Ru/CoO) hybrid electrocatalyst for alkaline HER. In this hybrid metal/oxide system, the complicated alkaline HER pathways are overall facilitated; oxygen (O)-vacancy-abundant oxide enhances water splitting and Ru promotes successive hydrogen intermediates to generate hydrogen. The resulting Ru/CoO hybrid electrocatalyst exhibits significantly promoted catalytic activity compared with benchmark Ru catalyst, displaying an overpotential of 55 mV to generate a HER current density of 10 mA cm-2, comparable with the state-of-the-art Pt/C catalyst and the most efficient alkaline HER electrocatalysts. Furthermore, the strong interaction of Ru nanoparticles with oxide support and the in-situ growth of oxide support on conductive substrate guarantee the long-term stability of as-fabricated Ru/CoO hybrid electrocatalyst. This newly designed hybrid catalyst with abundant metal/oxide interfaces may pave a new pathway for exploring efficient and stable HER electrocatalysts.

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Morphology and efficiency enhancements of PTB7-Th: ITIC nonfullerene organic solar cells processed via solvent vapor annealing Robert S. Gurney, Wei Li, Yu Yan, Dan Liu, Andrew J. Pearson, Tao Wang 2019, 37(10): 148-156.  DOI: 10.1016/j.jechem.2018.12.015 摘要 ( 25 )   The nanoscale morphology within the photoactive layer of organic solar cells is critical in determining the power conversion efficiency (PCE). Here, we draw attention to the roles of molecular arrangement, and domain size in improving performance, which can be tuned by subjecting the photovoltaic materials to solvent vapor annealing (SVA). In our PTB7-Th:ITIC devices, the PCE can be improved by exposing the device to solvent vapor for 60 s after solution casting. The solvent vapor prolongs reorganizational time and increases molecular ordering and domain size/phase separation, which are sub-optimal in pristine PTB7-Th:ITIC blend films. This improved morphology results in better charge mobility, reduced recombination, and ultimately an improved PCE from 7.1% to 7.9% when using CS2 as the annealing solvent. This simple SVA technique can be applied to a range of OPV systems where the molecular ordering is inferior within the as-cast photoactive layer.

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Highly active PtAu alloy surface towards selective formic acid electrooxidation Liang Liang, Fateev Vladimir, Junjie Ge, Changpeng Liu, Wei Xing 2019, 37(10): 157-162.  DOI: 10.1016/j.jechem.2019.02.015 摘要 ( 12 )

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Isomerization of linear C5-C7 over Pt loaded on protonated fibrous silica@Y zeolite (Pt/HSi@Y) S. Triwahyono, A. A. Jalil, S. M. Izan, N. S. Jamari, N. A. A. Fatah 2019, 37(10): 163-171.  DOI: 10.1016/j.jechem.2019.02.016 摘要 ( 2 )   A novel fibrous silica Y zeolite (HSi@Y) loaded with Pt has been studied based on its ability to produce protonic acid sites originating from molecular hydrogen. The Pt/HSi@Y was prepared using seed assisted crystallization followed by protonation and Pt-loading. The product formed had a spherical morphology with bicontinuous lamellar with a diameter in the range of 500-700 nm. The catalytic activity of the Pt/HSi@Y has been assessed based on light linear alkane (C5-C7) isomerization in a micro-catalytic pulse reactor at 423-623 K. A pyridine IR study confirmed that the introduction of fibrous silica on Y zeolite increased the Lewis acid sites corresponding with the formation of extra-framework Al which led to the generation of more protonic acid sites. A hydrogen adsorbed IR study showed that the protonic acid sites which act as active sites in the isomerization were formed via dissociative-adsorption of molecular hydrogen releasing electrons to the nearby Lewis acid sites. Thus, it is suggested that the presence of Pt and HSi@Y with a high number of Lewis acid as well as weak Bronsted acid sites improved the activity and stability in C5, C6 and C7 isomerization via hydrogen spill-over mechanism.

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Investigation of sodium vanadate as a high-performance aqueous zinc-ion battery cathode Binghong She, Lutong Shan, Huijie Chen, Jiang Zhou, Xun Guo, Guozhao Fang, Xinxin Cao, Shuquan Liang 2019, 37(10): 172-175.  DOI: 10.1016/j.jechem.2019.03.024 摘要 ( 31 )

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Low-overpotential selective reduction of CO2 to ethanol on electrodeposited CuxAuy nanowire arrays Weiwei Zhu, Kuangmin Zhao, Suqin Liu, Min Liu, Feng Peng, Pengda An, Binhao Qin, Huimin Zhou, Hongmei Li, Zhen He 2019, 37(10): 176-182.  DOI: 10.1016/j.jechem.2019.03.030 摘要 ( 24 )   Direct electrochemical reduction of CO2 to multicarbon products is highly desirable, yet challenging. Here, we present a potentiostatic pulse-electrodeposition of high-aspect-ratio CuxAuy nanowire arrays (NWAs) as high-performance electrocatalysts for the CO2 reduction reaction (CO2RR). The surface electronic structure related to the Cu:Au ratio in the CuxAuy NWAs could be facilely modulated by controlling the electrodeposition potential and the as-fabricated CuxAuy NWAs could be directly used as the catalytic electrode for the CO2RR. The morphology of the high-aspect-ratio nanowire array significantly lowers the onset potential of the alcohol formation due to the diffusion-induced enhancement of the local pH and CO concentration near the nanowire surface. Besides, the properly adjusted surface electronic structure of the CuxAuy NWA enables the adsorption of CO and facilitates the subsequent CO reduction to ethanol via the C-C coupling pathway. Owing to the synergistic effect of morphology and electronic structure, the optimized CuxAuy NWA selectively reduces CO2 to ethanol at low potentials of -0.5——0.7 V vs. RHE with a highest Faradaic efficiency of 48%. This work demonstrates the feasibility to optimize the activity and selectivity of the Cu-based electrocatalysts toward multicarbon alcohols for the CO2RR via simultaneous adjustment of the electronic structure and morphology of the catalysts.

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Boosting redox activity on MXene-induced multifunctional collaborative interface in high Li2S loading cathode for high-energy Li-S and metallic Li-free rechargeable batteries Zhiyu Wang, Nan Zhang, Mingliang Yu, Junshan Liu, Song Wang, Jieshan Qiu 2019, 37(10): 183-191.  DOI: 10.1016/j.jechem.2019.03.012 摘要 ( 7 )   Use of metallic Li anode raises serious concerns on the safety and operational performance of Li-S batteries due to uncontrolled hazard of Li dendrite formation, which is difficultly eliminated as long as the metallic Li exists in the cells. Pairing lithium sulfide (Li2S) cathode with currently available metallic Lifree high-capacity anodes offers an alternative solution to this challenge. However, the performance of Li2S cathode is primarily restricted by high activation barrier upon initial charge, low active mass utilization and sluggish redox kinetics. Herein, a MXene-induced multifunctional collaborative interface is proposed to afford superb activity towards redox solid-liquid/liquid-liquid phase transformation, strong chemisorption, high conductivity and fast ionic/charge transport in high Li2S loading cathode. Applying collaborative interface effectively reduces initial voltage barrier of Li2S activation and regulates the kinetic behavior of redox polysulfide conversion. Therefore, stable operation of additive-free Li2S cathode with high areal capacities at high Li2S loading up to 9 mg cm-2 can be achieved with less sacrifice of high capacity and rate capability in Li-S batteries. Rechargeable metallic Li-free batteries are successfully constructed by pairing this high-performance Li2S cathode with high-capacity metal oxide anodes, which delivers superior energy density to current Li-ion batteries.

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Facile synthesis strategy of NicorePtshell electrocatalyst for oxygen reduction reaction Yi Wang, Gui-Fa Long, Jin-Hua Piao, Zhi-Yong Fu, Zhen-Xing Liang 2019, 37(10): 192-196.  DOI: 10.1016/j.jechem.2019.03.015 摘要 ( 8 )

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Porous LiF layer fabricated by a facile chemical method toward dendrite-free lithium metal anode Yanxia Yuan, Feng Wu, Guanghai Chen, Ying Bai, Chuan Wu 2019, 37(10): 197-203.  DOI: 10.1016/j.jechem.2019.03.014 摘要 ( 20 )   Lithium metal is supposed to be critical material for constructing next-generation batteries due to extremely high capacity and ultralow redox potential. However, the perplexing issue of lithium dendrite growth impedes the commercial application. The initial nucleation and low Li ions diffusion rate in the electrolyte/electrode interface dominate the deposition behavior. Therefore, a uniform and flexible interface is urgently needed. Here, a facile method is proposed to prepare a thin and porous LiF-rich layer (TPL) by the in-situ reaction of small amount of ammonium hydrogen difluoride (NH4HF2) and Li metal. The deposition morphology on Li metal anode with LiF layer is significantly flat and homogeneous owning to low lateral diffusion barrier on LiF crystals and the porous structure of TPL film. Additionally, the symmetrical cells made with such TPL Li anodes show significantly stable cycling over 100 cycles at high current density of 6 mA/cm2. The TPL Li|LiFePO4 full cells keep over 99% capacity retention after 100 cycles at 2.0 C. This approach serves as a facile and controllable way of adjusting the protective layer on Li metal.

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In situ synthesis of biomass-derived Ni/C catalyst by self-reduction for the hydrogenation of levulinic acid to γ -valerolactone Shuqi Fang, Zhibing Cui, Yuting Zhu, Chenguang Wang, Jing Bai, Xinghua Zhang, Ying Xu, Qiying Liu, Lungang Chen, Qi Zhang, Longlong Ma 2019, 37(10): 204-214.  DOI: 10.1016/j.jechem.2019.03.021 摘要 ( 6 )   Herein, we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel. Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature. The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process. For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.

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Electrochemically-driven interphase conditioning of magnesium electrode for magnesium sulfur batteries Yaqi Li, Pengjian Zuo, Ruinan Li, Mengxue He, Yulin Ma, Yingxin Shi, Xinqun Cheng, Chunyu Du, Geping Yin 2019, 37(10): 215-219.  DOI: 10.1016/j.jechem.2019.03.032 摘要 ( 24 )

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Efficient nonfullerene organic solar cells with active layers fabricated by water transfer printing Lulu Sun, Xueshi Jiang, Yinhua Zhou 2019, 37(10): 220-224.  DOI: 10.1016/j.jechem.2019.04.001 摘要 ( 5 )   Preparation of high-quality films plays an important role to achieve high-performance nonfullerene (NF) organic solar cells. NF active layer films are typically fabricated by spin coating. Novel fabrication methods to process the NF active layer are desirable to be compatible with large-area production. Herein, we report on the fabrication of NF active layer films via a water transfer printing method. This method delivers a uniform film with controllable film thicknesses. NF active layers of PDBD-T:ITIC and PBDB-T-2F:IT-4F were fabricated via the method to validate its effectiveness. Solar cells with the water transfer-printed active layers show comparable performance (up to 11.7%) to the cells with spin-coated active layers. Furthermore, NF solar modules containing 4-sub cells with the active area of 3.2 cm2 are also fabricated via the method. The module shows VOC of up to 3.4 V and a power conversion efficiency of 8.1% with the PBDB-T-2F:IT-4F active layer.