School of Optical and Electronic Information, Huazhong University of Science and Technology , Wuhan 430074, P. R. China.
Department of Physics and Engineering Physics, Morgan State University , Baltimore, Maryland 21254, United States.
ACS Appl Mater Interfaces. 2017 Oct 4;9(39):33833-33840. doi: 10.1021/acsami.7b08917. Epub 2017 Sep 20.
Exploring active, stable, earth-abundant, low-cost, and high-efficiency electrocatalysts is highly desired for large-scale industrial applications toward the low-carbon economy. In this study, we apply a versatile selenizing technology to synthesize Se-enriched CoFeSe catalysts on nickel foams for oxygen evolution reactions (OERs) and disclose the relationship between the electronic structures of CoFeSe (via regulating the atom ratio of Co/Fe) and their OER performance. Owing to the fact that the electron configuration of the CoFeSe compounds can be tuned by the incorporated Fe species (electron transfer and lattice distortion), the catalytic activity can be adjusted according to the Co/Fe ratios in the catalyst. Moreover, the morphology of CoFeSe is also verified to strongly depend on the Co/Fe ratios, and the thinner CoFeSe nanosheets are obtained upon selenization treatment, in which it allows more active sites to be exposed to the electrolyte, in turn promoting the OER performance. The CoFeSe nanosheets not only exhibit superior OER performance with a low overpotential of 217 mV at 10 mA cm and a small Tafel slope of 41 mV dec but also possess ultrahigh durability with a dinky degeneration of 4.4% even after 72 h fierce water oxidation test in alkaline solution, which outperforms the commercial RuO catalyst. As expected, the CoFeSe nanosheets have shown great prospects for practical applications toward water oxidation.
探索活性高、稳定、丰富、低成本和高效率的电催化剂对于向低碳经济的大规模工业应用是非常需要的。在本研究中，我们应用一种通用的硒化技术在泡沫镍上合成富硒 CoFeSe 催化剂，用于析氧反应（OER），并揭示了 CoFeSe 电子结构（通过调节 Co/Fe 原子比）与其 OER 性能之间的关系。由于 CoFeSe 化合物的电子构型可以通过掺入的 Fe 物种（电子转移和晶格畸变）来调节，因此可以根据催化剂中 Co/Fe 比来调整催化活性。此外，CoFeSe 的形态也被证实强烈依赖于 Co/Fe 比，并且在硒化处理后获得更薄的 CoFeSe 纳米片，这使得更多的活性位点暴露在电解质中，从而促进 OER 性能。CoFeSe 纳米片不仅表现出优异的 OER 性能，在 10 mA cm 时具有 217 mV 的低过电势和 41 mV dec 的小塔菲尔斜率，而且在碱性溶液中经过 72 h 激烈的水氧化测试后具有超高的耐久性，退化率仅为 4.4%，优于商业 RuO 催化剂。不出所料，CoFeSe 纳米片在水氧化方面具有很大的实际应用前景。
