Wang Lan, Liu Xiaokang, Cao Linlin, Zhang Wei, Chen Tao, Lin Yue, Wang Huijuan, Wang Yi, Yao Tao
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P.R. China.
School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, P.R. China.
J Phys Chem Lett. 2020 Aug 20;11(16):6691-6696. doi: 10.1021/acs.jpclett.0c01943. Epub 2020 Aug 6.
Electrochemical water splitting in alkaline media is an attractive way to produce the clear and renewable hydrogen fuel H. In this work, we report a single-atom Fe/NC catalyst, where the Fe-N moiety works as the active site, for high-efficiency alkaline hydrogen evolution reaction (HER). The Fe/NC electrocatalyst exhibits a low overpotential of 111 mV at the current density of 10 mA cm, with a Tafel slope of 86.1 mV dec in 1 M KOH solution. Operando X-ray absorption spectroscopy reveals that, under the working states, the Fe-support interaction weakened as the Fe-N coordination number and Fe oxidation state decreased. As such, the evolved single-atom Fe site with more d electrons provides a favorable structure for boosting HER performance. This work gives insight into the structural evolution of the active site under the alkaline HER and provides a strategy for the design of non-noble metal electrocatalysts.
在碱性介质中进行电化学水分解是一种生产清洁可再生氢燃料H的有吸引力的方法。在这项工作中，我们报道了一种单原子Fe/NC催化剂，其中Fe-N部分作为活性位点，用于高效碱性析氢反应（HER）。该Fe/NC电催化剂在1 M KOH溶液中，电流密度为10 mA cm时表现出111 mV的低过电位，塔菲尔斜率为86.1 mV dec。原位X射线吸收光谱表明，在工作状态下，随着Fe-N配位数和Fe氧化态的降低，Fe-载体相互作用减弱。因此，具有更多d电子的析出单原子Fe位点为提高HER性能提供了有利结构。这项工作深入了解了碱性HER下活性位点的结构演变，并为非贵金属电催化剂的设计提供了策略。
