Zhang Yechuan, Gu Zhengxiang, Bi Jingxiu, Jiao Yan
Huaxi MR Research Center (HMRRC), Department of Radiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
School of Chemical Engineering and Advanced Materials, University of Adelaide, SA 5005, Australia.
Nanoscale. 2022 Aug 4;14(30):10873-10879. doi: 10.1039/d2nr02568j.
The sluggish kinetics of the oxygen evolution reaction (OER) restrains the development of water splitting technologies and the efficiency of producing sustainable resources. To this end, the introduction of iron and molybdenum in catalytic systems has been employed as a crucial strategy for the enhancement of catalytic activity toward the oxygen evolution reaction (OER), but the relationship between catalyst components and catalytic performance is still evasive. In this study, by doping iron and molybdenum into cobalt hydroxide a cation-exchange method, rich oxygen vacancies and active metal centers are introduced to the trimetallic oxyhydroxide, endowing the catalyst with a low overpotential of 223 mV at 10 mA cm, a low Tafel slope of 43.6 mV dec, and a long stable operation time (>50 h) in alkaline media, comparable to the current best OER catalyst. Moreover, it is demonstrated that the doping of iron favors the generation of oxygen vacancies. It is also found in this work that using a certain amount (5 mg) of iron dopant can alter the electronic structure of the catalyst by tuning the electronic density around the metal ions, thus optimizing the binding energy of intermediates. The present work unveils the doping effect of iron and molybdenum on the construction of trimetallic oxyhydroxide catalysts, and sheds light on the relationship between the catalyst components and catalytic performance of the OER.
析氧反应（OER）缓慢的动力学限制了水分解技术的发展以及可持续资源生产的效率。为此，在催化体系中引入铁和钼已被用作提高析氧反应（OER）催化活性的关键策略，但催化剂组分与催化性能之间的关系仍不明确。在本研究中，通过阳离子交换法将铁和钼掺杂到氢氧化钴中，在三金属羟基氧化物中引入了丰富的氧空位和活性金属中心，使催化剂在10 mA cm时具有223 mV的低过电位、43.6 mV dec的低塔菲尔斜率，并且在碱性介质中具有较长的稳定运行时间（>50 h），与目前最佳的OER催化剂相当。此外，研究表明铁的掺杂有利于氧空位的产生。在这项工作中还发现，使用一定量（5 mg）的铁掺杂剂可以通过调节金属离子周围的电子密度来改变催化剂的电子结构，从而优化中间体的结合能。本工作揭示了铁和钼对三金属羟基氧化物催化剂结构的掺杂效应，并阐明了OER催化剂组分与催化性能之间的关系。
