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Dengfeng Wu, Wei Zhang, Daojian Cheng
The design and development of low-cost Pt-free, high-active and durable noble-metal-free electrocatalysts for methanol electrooxidation is highly desirable but remains a challenge. Herein, unique Cu/NiCu nanowires (NWs) integrating alloy, core-shell and one-dimensional structures are prepared by a facile one-pot strategy. It is found that Ni-Cu surface alloying structure can effectively change the charge distribution of atomic configuration, core-shell structure can be optimally the usage of Ni and Cu, and one-dimensional structure can effectively enhance the charge transfer between electrode surface and active sites, making the prepared NWs as promising electrocatalysts...
May 24, 2017: ACS Applied Materials & Interfaces
Zhen Chen, Ning Minghui, Ge Ma, Qingguo Meng, Yongguang Zhang, Jinwei Gao, Mingliang Jin, Zhihong Chen, Mingzhe Yuan, Xin Wang, Junming Liu, Guofu Zhou
We report the first demonstration of a high-efficiency photoelectrochemical (PEC) water splitting reaction using a novel Si NWs/WO3 core/shell photoanode prepared by a mild and inexpensive metal-catalyzed electroless etching (MCEE) process followed by dip-coating, airing and annealing methods. The dense and vertically aligned Si NWs/WO3 core/shell nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In comparison to planar n-Si, Si NWs and planar Si/WO3, the Si NWs/WO3 samples showed significantly enhanced photocurrent over the entire potential sweep range...
May 22, 2017: Nanotechnology
Qiuguo Li, Xinzhou Ma, Huiqiang Liu, Zuxin Chen, Hao Chen, Sheng Chu
Epitaxial two-demensional GaTe nanosheets on ZnO nanowires were routinely prepared via a two-step chemical vapour deposition procedure. The epitaxial relationship and growth mechanism of the GaTe/ZnO core/shell structures were explored and attributed to a layer-over-layer model. The hybrid structures increased the surface area and the favorable p-n heterojunction enhanced the charge separation for photoelectrochemical performance in water splitting. The above synergistic effects boosted the photocurrent density from -0...
May 19, 2017: ACS Applied Materials & Interfaces
Kuangzhou Du, Lirong Zheng, Tanyuan Wang, Junqiao Zhuo, Zhiwei Zhu, Yuanhua Shao, Meixian Li
Molybdenum sulfides are considered to be one kind of the promising candidates as cheap and efficient electrocatalysts for hydrogen evolution reaction (HER). But this is still a gap on electrocatalytic performance toward Pt. In order to further enhance electrocatalytic activity of molybdenum sulfides, in this work, Mo3S13 films with high ratio of sulfur to molybdenum were prepared by electrodeposition. The Mo3S13 films exhibit highly efficient electrocatalytic activity for HER and achieve a current density of 10 mA/cm2 at an overpotential of 200 mV with an onset potential of 130 mV vs...
May 19, 2017: ACS Applied Materials & Interfaces
Ying Yin, Yumin Zhang, Tangling Gao, Tai Yao, Xinghong Zhang, Jiecai Han, Xianjie Wang, Zhihua Zhang, Ping Xu, Peng Zhang, Xingzhong Cao, Bo Song, Song Jin
MoSe2 is a promising earth-abundant electrocatalyst for the hydrogen-evolution reaction (HER), even though it has received much less attention among the layered dichalcogenide (MX2 ) materials than MoS2 so far. Here, a novel hydrothermal-synthesis strategy is presented to achieve simultaneous and synergistic modulation of crystal phase and disorder in partially crystallized 1T-MoSe2 nanosheets to dramatically enhance their HER catalytic activity. Careful structural characterization and defect characterization using positron annihilation lifetime spectroscopy correlated with electrochemical measurements show that the formation of the 1T phase under a large excess of the NaBH4 reductant during synthesis can effectively improve the intrinsic activity and conductivity, and the disordered structure from a lower reaction temperature can provide abundant unsaturated defects as active sites...
May 19, 2017: Advanced Materials
Hong Yu, Haosen Fan, Jiong Wang, Yun Zheng, Zhengfei Dai, Yizhong Lu, Junhua Kong, Xin Wang, Young Jin Kim, Qingyu Yan, Jong-Min Lee
3D ordered porous structures of MoxC are prepared with different Mo to C ratios and tested for two possible promising applications: hydrogen evolution reaction (HER) through water splitting and lithium ion batteries (LIBs). Mo2C and MoC with 3D periodic ordered structures are prepared with a similar process but different precursors. The 3D ordered porous MoC exhibits excellent cycling stability and rate performance as an anode material for LIBs. A discharge capacity of 450.9 mA h g(-1) is maintained up to 3000 cycles at 10...
May 18, 2017: Nanoscale
Xiaobin Liu, Wenxiu Que, Peng Chen, Yapeng Tian, Jie Liu, Zuoli He, Huanfu Zhou, Ling Bing Kong
Exfoliated hexaniobate nanosheets E-H2K2Nb6O17-x (E-HKNO) with broad light absorption (up to 850 nm) and high adsorption properties were prepared via ion exchange and transient annealing processes with micron-size K4Nb6O17 powders as the precursor. The as-prepared E-HKNO nanosheets show excellent visible light photodegradation performances when compared to degussa P25, which was evaluated in terms of degradation of Rhodamine B (Rh B). High adsorption and broad light absorption characteristics could be attributed to the exfoliation behavior and the reduction of surface Nb(5+) to Nb(4+), which was confirmed by x-ray photoelectron spectroscopy (XPS) and Raman spectra...
May 18, 2017: Nanotechnology
Lianzhou Wang
BiVO4 films with (040) facet grown vertically on fluorine doped SnO2 (FTO) glass substrates are prepared by a seed-assisted hydrothermal method. A simple electrochemical treatment process drastically enhances the photocatalytic activity of BiVO4, exhibiting a remarkable photocurrent density of 2.5 mA cm-2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination, which is approximately 10 folds higher than that of the pristine one. Loading cobalt borate (CoBi) as cocatalyst, the photocurrent density of the BiVO4 photoanode can be further improved to 3...
May 17, 2017: Angewandte Chemie
Li Zhao, Biliang Dong, Shaozhou Li, Lijun Zhou, Linfei Lai, Zhiwei Wang, Shulin Zhao, Min Han, Kai Gao, Min Lu, Xiaoji Xie, Bo Chen, Zhengdong Liu, Xiangjing Wang, Hao Zhang, Hai Li, Juqing Liu, Hua Zhang, Xiao Huang, Wei Huang
Two-dimensional (2D) metal-organic framework (MOF) nanosheets have been recently regarded as the model electrocatalysts due to their porous structure, fast mass and ion transfer through the thickness, and large portion of exposed active metal centers. Combining them with electrically conductive 2D nanosheets is anticipated to achieve further improved performance in electrocatalysis. In this work, we in situ hybridized 2D cobalt 1,4-benzenedicarboxylate (CoBDC) with Ti3C2Tx (the MXene phase) nanosheets via an interdiffusion reaction-assisted process...
May 22, 2017: ACS Nano
Hsin-Yi Tiffany Chen, Jyh-Pin Chou, Cheng-Yang Lin, Chih-Wei Hu, Ya-Tang Yang, Tsan-Yao Chen
A ternary metallic CuPdPt nanocatalyst (NC) is synthesized using a wet chemical reduction method, which is sequentially designed, in the presence of acid treated carbon nanotubes. This NC is a nanocrystal with a configuration of a Cu@Pd core and atomic Pt clusters (∼9 wt%) on the top (Cu@Pd/Pt). A residual current of 92.6%, 5.2 times higher than that of commercial Pt catalysts (at 0.85 V vs. RHE), is retained after 40 000 cycles of an accelerated degradation test (ADT). Atomic and electronic structure analyses show that such exclusive stability mainly results from electron localization at Pt clusters in heterogeneous interfaces of the Cu-Pd core...
May 17, 2017: Nanoscale
Jizhang Yang, Zhi Yang, Lu Hua Li, Qiran Cai, Huagui Nie, Mengzhan Ge, Xi'an Chen, Ying Chen, Shaoming Huang
The oxygen evolution reaction (OER) has been viewed as a critical step in electrochemical energy conversion and storage devices. However, searching for cheap and efficient OER electrocatalysts still remains an urgent task. Herein, we develop a new strategy involving a one-step electrochemical deposition and dissolution method to fabricate hydrophilic porous CoS2/carbon nanotube (CNT) composites (CNT-CoS2). X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy measurements confirm the formation of hydrophilic groups on the surface of the porous CoS2 during electrochemical oxidation...
May 25, 2017: Nanoscale
Chunhui Xiao, Xu Chen, Yuhai Tang
Fe-N/C composites are considered one of the most promising non-precious-metal electrocatalysts for oxygen reduction reaction (ORR). In this paper, we fabricate a novel and efficient carbon nanotube (CNT)-supported Fe-N/C composite catalyst, via the surface-self-polymerization of polydopamine and then the incorporation with Fe species on CNTs, followed by the pyrolysis process. The obtained catalyst demonstrates excellent electrocatalytic performance towards ORR in alkaline media. The modification of Fe-incorporated nitrogen-rich-carbons (Fe-CNx) on CNTs lowers the ORR half-wave-potential by ∼190 mV, giving this catalyst with an onset ORR potential of 0...
June 2, 2017: Nanotechnology
Xiao Ma, Xue Zhao, Jianshe Huang, Litai Sun, Qun Li, Xiurong Yang
Herein, we develop a novel method to synthesize evenly dispersed fine Co nanoparticles (NPs) (particle size of ~ 42 nm) encapsulated in N-doped porous carbon matrix (NPCM) with superficial N-doped porous carbon nanofibers (NPCNF) (denoted as Co@NPCM/CNF-850) as an oxygen reduction reaction (ORR) electrocatalyst. Such electrocatalyst is the direct pyrolysis product of the novel pine needle-like ZIF-67-based metal-organic framework nanowire array (MOFNWA) prepared by inorganic cobalt carbonate hydroxide (Co(CO3)0...
May 10, 2017: ACS Applied Materials & Interfaces
Mingyong Cai, Peixun Fan, Jiangyou Long, Jinpeng Han, Yi Lin, Hongjun Zhang, Minlin Zhong
Hydrogen production from water based on photoelectrochemical (PEC) reactions is feasible to solve the urgent energy crisis. Herein, hierarchical 3D self-supporting WO3 micro-nano architectures in situ grown on W plates are successfully fabricated via ultrafast laser processing hybrid with thermal oxidation. Owing to the large surface area and efficient interface charge transfer, the W plate with hierarchical porous WO3 nanoparticle aggregates has been directly employed as the photoanode for excellent PEC performance, which exhibits a high photocurrent density of 1...
May 9, 2017: ACS Applied Materials & Interfaces
Jing-Jing Lv, Jun Zhao, Hua Fang, Li-Ping Jiang, Ling-Ling Li, Jing Ma, Jun-Jie Zhu
A noble-metal-free electrocatalyst is fabricated via in situ formation of nanocomposite of nitrogen-doped graphene quantum dots (NGQDs) and Ni3 S2 nanosheets on the Ni foam (Ni3 S2 -NGQDs/NF). The resultant Ni3 S2 -NGQDs/NF can serve as an active, binder-free, and self-supported catalytic electrode for direct water splitting, which delivers a current density of 10 mA cm(-2) at an overpotential of 216 mV for oxygen evolution reaction and 218 mV for hydrogen evolution reaction in alkaline media. This bifunctional electrocatalyst enables the construction of an alkali electrolyzer with a low cell voltage of 1...
May 8, 2017: Small
Yu-Jia Tang, Chun-Hui Liu, Wei Huang, Xiao-Li Wang, Long-Zhang Dong, Shun-Li Li, Ya-Qian Lan
The development of highly efficient and low-cost oxygen evolution electrocatalysts is extremely imperative for the new energy technology. Transition metal carbides have been investigated as remarkable hydrogen evolution reaction (HER) electrocatalysts but undesired oxygen evolution reaction (OER) electrocatalysts and need further study. Here, a cobalt-molybdenum-based bimetallic carbide coated by N-doped porous carbon and anchored on N-doped reduced graphene oxide film (Co6Mo6C2/NCRGO) is synthesized by directly carbonizing the Co-doped polyoxometalate/conductive polymer/graphene oxide (Co-PCG) precursors...
May 10, 2017: ACS Applied Materials & Interfaces
Yong Wang, Fei Li, Xu Zhou, Fengshou Yu, Jian Du, Lichen Bai, Licheng Sun
Molecular Co4 O4 cubane water oxidation catalysts were combined with BiVO4 electrodes for photoelectrochemical (PEC) water splitting. The results show that tuning the substituent groups on cobalt cubane allows the PEC properties of the final molecular catalyst/BiVO4 hybrid photoanodes to be tailored. Upon loading a new cubane complex featuring alkoxy carboxylato bridging ligands (1 h) on BiVO4 , an AM 1.5G photocurrent density of 5 mA cm(-2) at 1.23 V vs. RHE for water oxidation was obtained, the highest photocurrent for undoped BiVO4 photoanodes...
May 5, 2017: Angewandte Chemie
Nina Erini, Vera Beermann, Martin Gocyla, Manuel Gliech, Marc Heggen, Rafal E Dunin-Borkowski, Peter Strasser
Direct ethanol fuel cells are attractive power sources based on a biorenewable, high energy-density fuel. Their efficiency is limited by the lack of active anode materials which catalyze the breaking of the C-C bond coupled to the 12-electron oxidation to CO2 . We report shape-controlled PtNiRh octahedral ethanol oxidation electrocatalysts with excellent activity and previously unachieved low onset potentials as low as 0.1 V vs. RHE, while being highly selective to complete oxidation to CO2 . Our comprehensive characterization and in situ electrochemical ATR studies suggest that the formation of a ternary surface site ensemble around the octahedral Pt3 Ni1 Rhx nanoparticles plays a crucial mechanistic role for this behavior...
June 1, 2017: Angewandte Chemie
Alberto Ganassin, Paula Sebastián, Víctor Climent, Wolfgang Schuhmann, Aliaksandr S Bandarenka, Juan Feliu
Studies over the entropy of components forming the electrode/electrolyte interface can give fundamental insights into the properties of electrified interphases. In particular, the potential where the entropy of formation of the double layer is maximal (potential of maximum entropy, PME) is an important parameter for the characterization of electrochemical systems. Indeed, this parameter determines the majority of electrode processes. In this work, we determine PMEs for Ir(111) electrodes. The latter currently play an important role to understand electrocatalysis for energy provision; and at the same time, iridium is one of the most stable metals against corrosion...
April 28, 2017: Scientific Reports
Zhibin Luo, Chengcheng Li, Shanshan Liu, Tuo Wang, Jinlong Gong
Hematite (α-Fe2O3) is a promising candidate for solar-to-hydrogen energy conversion. However, the low carrier mobility and extremely high charge recombination rate limit the practical application of hematite in solar water splitting. This paper describes the fabrication of a Fe2O3 photoanode with gradient incorporation of phosphorus (P) employing a facile dipping and annealing method to improve the charge separation for enhanced photoelectrochemical water oxidation. This gradient P incorporation increases the width of band bending over a large region in Fe2O3, which is crucial for promoting the charge separation efficiency in the bulk...
January 1, 2017: Chemical Science
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