High-Performance Electrocatalysis Using Metallic Cobalt Pyrite (CoS2) Micro- and Nanostructures

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• 作者：Matthew S. Faber ; Rafal Dziedzic ; Mark A. Lukowski ; Nicholas S. Kaiser ; Qi Ding ; Song Jin
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：July 16, 2014
• 年：2014
• 卷：136
• 期：28
• 页码：10053-10061
• 全文大小：565K
• ISSN：1520-5126

文摘

The development of efficient and robust earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) is an ongoing challenge. We report metallic cobalt pyrite (cobalt disulfide, CoS<sub>2sub>) as one such high-activity candidate material and demonstrate that its specific morphology鈥攆ilm, microwire, or nanowire, made available through controlled synthesis鈥攑lays a crucial role in determining its overall catalytic efficacy. The increase in effective electrode surface area that accompanies CoS<sub>2sub> micro- and nanostructuring substantially boosts its HER catalytic performance, with CoS<sub>2sub> nanowire electrodes achieving geometric current densities of 鈭?0 mA cm<sup>鈥?sup> at overpotentials as low as 鈭?45 mV vs the reversible hydrogen electrode. Moreover, micro- and nanostructuring of the CoS<sub>2sub> material has the synergistic effect of increasing its operational stability, cyclability, and maximum achievable rate of hydrogen generation by promoting the release of evolved gas bubbles from the electrode surface. The benefits of catalyst micro- and nanostructuring are further demonstrated by the increased electrocatalytic activity of CoS<sub>2sub> nanowire electrodes over planar film electrodes toward polysulfide and triiodide reduction, which suggests a straightforward way to improve the performance of quantum dot- and dye-sensitized solar cells, respectively. Extension of this micro- and nanostructuring strategy to other earth-abundant materials could similarly enable inexpensive electrocatalysts that lack the high intrinsic activity of the noble metals.