排序方式: 共有115条查询结果,搜索用时 15 毫秒
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(33):9899-9903
A fundamental understanding of the behavior of non‐noble based materials toward the hydrogen evolution reaction is crucial for the successful implementation into practical devices. Through the implementation of a highly sensitive inductively coupled plasma mass spectrometer coupled to a scanning flow cell, the activity and stability of non‐noble electrocatalysts is presented. The studied catalysts comprise a range of compositions, including metal carbides (WC), sulfides (MoS2), phosphides (Ni5P4, Co2P), and their base metals (W, Ni, Mo, Co); their activity, stability, and degradation behavior was elaborated and compared to the state‐of‐the‐art catalyst platinum. The non‐noble materials are stable at HER potentials but dissolve substantially when no current is flowing. Through pre‐ and post‐characterization of the catalysts, explanations of their stability (thermodynamics and kinetics) are discussed, challenges for the application in real devices are analyzed, and strategies for circumventing dissolution are suggested. The precise correlation of metal dissolution with applied potential/current density allows for narrowing down suitable material choices as replacement for precious group metals as for example, platinum and opens up new ways in finding cost‐efficient, active, and stable new‐generation electrocatalysts. 相似文献
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Hong Nhan Nong Hyung‐Suk Oh Tobias Reier Elena Willinger Marc‐Georg Willinger Valeri Petkov Detre Teschner Peter Strasser 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(10):3018-3022
Active and highly stable oxide‐supported IrNiOx core–shell catalysts for electrochemical water splitting are presented. IrNix@IrOx nanoparticles supported on high‐surface‐area mesoporous antimony‐doped tin oxide (IrNiOx /Meso‐ATO) were synthesized from bimetallic IrNix precursor alloys (PA‐IrNix /Meso‐ATO) using electrochemical Ni leaching and concomitant Ir oxidation. Special emphasis was placed on Ni/NiO surface segregation under thermal treatment of the PA‐IrNix /Meso‐ATO as well as on the surface chemical state of the particle/oxide support interface. Combining a wide array of characterization methods, we uncovered the detrimental effect of segregated NiO phases on the water splitting activity of core–shell particles. The core–shell IrNiOx /Meso‐ATO catalyst displayed high water‐splitting activity and unprecedented stability in acidic electrolyte providing substantial progress in the development of PEM electrolyzer anode catalysts with drastically reduced Ir loading and significantly enhanced durability. 相似文献
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Chengxiang Xiang Adam Z. Weber Shane Ardo Alan Berger YiKai Chen Robert Coridan Katherine T. Fountaine Sophia Haussener Shu Hu Rui Liu Nathan S. Lewis Miguel A. Modestino Matthew M. Shaner Meenesh R. Singh John C. Stevens Ke Sun Karl Walczak 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(42):13168-13183
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Guigang Zhang Minghui Liu Tobias Heil Spiros Zafeiratos Aleksandr Savateev Markus Antonietti Xinchen Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15092-15096
Polymeric carbon nitride (PCN) is usually synthesized from nitrogen‐rich monomers such as cyanamide, melamine, and urea, but is rather disordered in many cases. Now, a new allotrope of carbon nitride with internal heterostructures was obtained by co‐condensation of very electron poor monomers (for example, 5‐amino‐tetrazole and nucleobases) in the presence of mild molten salts (for example, NaCl/KCl) to mediate the polymerization kinetics and thus modulate the local structure, charge carrier properties, and most importantly the HOMO and LUMO levels. Results reveal that the as‐prepared NaK‐PHI‐A material shows excellent photo‐redox activities because of a nanometric hetero‐structure which enhances visible light absorption and promotes charge separation in the different domains. 相似文献
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Dr. Jin Soo Kang Yoonsook Noh Jin Kim Dr. Hyelim Choi Tae Hwa Jeon Dr. Docheon Ahn Prof. Jae-Yup Kim Dr. Seung-Ho Yu Hyeji Park Dr. Jun-Ho Yum Prof. Wonyong Choi Prof. David C. Dunand Prof. Heeman Choe Prof. Yung-Eun Sung 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6683-6688
Nanostructured metal oxide semiconductors have shown outstanding performances in photoelectrochemical (PEC) water splitting, but limitations in light harvesting and charge collection have necessitated further advances in photoelectrode design. Herein, we propose anodized Fe foams (AFFs) with multidimensional nano/micro-architectures as a highly efficient photoelectrode for PEC water splitting. Fe foams fabricated by freeze-casting and sintering were electrochemically anodized and directly used as photoanodes. We verified the superiority of our design concept by achieving an unprecedented photocurrent density in PEC water splitting over 5 mA cm−2 before the dark current onset, which originated from the large surface area and low electrical resistance of the AFFs. A photocurrent of over 6.8 mA cm−2 and an accordingly high incident photon-to-current efficiency of over 50 % at 400 nm were achieved with incorporation of Co oxygen evolution catalysts. In addition, research opportunities for further advances by structual and compositional modifications are discussed, which can resolve the low fill factoring behavior and improve the overall performance. 相似文献
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Ran Su H. Alex Hsain Ming Wu Dawei Zhang Xinghao Hu Zhipeng Wang Xiaojing Wang Fa‐tang Li Xuemin Chen Lina Zhu Yong Yang Yaodong Yang Xiaojie Lou Stephen J. Pennycook 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15220-15225
Piezocatalysis, converting mechanical vibration into chemical energy, has emerged as a promising candidate for water‐splitting technology. However, the efficiency of the hydrogen production is quite limited. We herein report well‐defined 10 nm BaTiO3 nanoparticles (NPs) characterized by a large electro‐mechanical coefficient which induces a high piezoelectric effect. Atomic‐resolution high angle annular dark field scanning transmission electron microscopy (HAADF‐STEM) and scanning probe microscopy (SPM) suggests that piezoelectric BaTiO3 NPs display a coexistence of multiple phases with low energy barriers and polarization anisotropy which results in a high electro‐mechanical coefficient. Landau free energy modeling also confirms that the greatly reduced polarization anisotropy facilitates polarization rotation. Employing the high piezoelectric properties of BaTiO3 NPs, we demonstrate an overall water‐splitting process with the highest hydrogen production efficiency hitherto reported, with a H2 production rate of 655 μmol g?1 h?1, which could rival excellent photocatalysis system. This study highlights the potential of piezoelectric catalysis for overall water splitting. 相似文献