Xu Wei, Wang Beibei, Ni Xingming, Liu Huiyan, Wang Wei, Zhang Lunjia, Zhang Hui, Peng Zheng, Liu Zhi
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Science, Beijing 100049, China.
ACS Appl Mater Interfaces. 2021 Mar 24;13(11):13838-13847. doi: 10.1021/acsami.1c00945. Epub 2021 Mar 15.
Water dissociation in alkaline solutions is one of the biggest challenges in hydrogen evolution reactions (HERs). The key is to obtain a catalyst with optimal and balanced OH adsorption energy and H adsorption/H desorption energy. Herein, we synthesized a NiW/WO catalyst on the Ni foam that optimized the coverage and size of NiW alloys decorated on the NiWO/WO substrate. Our experiments showed that NiW-NiWO interfaces could accelerate water dissociation, and NiW-WO interfaces facilitate adsorbed H atoms spillover and H desorption. In addition, we applied a suite of characterization techniques to analyze surface evolution processes in catalysts under various cathodic potentials so as to illustrate the competition between chemical oxidation and electrochemical reduction reactions. The results demonstrated that high coverage of large NiW nanoparticles resulted in a greater stable interface. The two efficient interfaces synergetically promote the Volmer-Tafel reaction. NiW/WO catalysts exhibited extraordinary HER activity with a low overpotential of 48 mV at a 10 mA cm current density and a Tafel slope of 33 mV dec. This work has shown that low-cost catalysts with proper hierarchical interfaces can be engineered and can be optimized into a tandem system, which will significantly promote HER activity in alkaline electrolytes.
碱性溶液中的水离解是析氢反应（HERs）面临的最大挑战之一。关键在于获得一种具有最佳且平衡的OH吸附能和H吸附/H脱附能的催化剂。在此，我们在泡沫镍上合成了一种NiW/WO催化剂，该催化剂优化了装饰在NiWO/WO基底上的NiW合金的覆盖率和尺寸。我们的实验表明，NiW - NiWO界面可加速水离解，而NiW - WO界面则促进吸附的H原子溢出和H脱附。此外，我们应用了一系列表征技术来分析催化剂在各种阴极电位下的表面演化过程，以阐明化学氧化和电化学还原反应之间的竞争。结果表明，大尺寸NiW纳米颗粒的高覆盖率导致了更稳定的界面。这两个高效界面协同促进了Volmer - Tafel反应。NiW/WO催化剂表现出非凡的析氢活性，在10 mA cm电流密度下过电位低至48 mV，塔菲尔斜率为33 mV dec。这项工作表明，可以设计具有适当分级界面的低成本催化剂，并将其优化成串联体系，这将显著促进碱性电解质中的析氢活性。
