Affiliation:
1. Key Laboratory of Marine Chemistry Theory and Technology (Ministry of Education) College of Chemistry & Chemical Engineering Ocean University of China Qingdao Shandong 266100 China
2. Department of Chemical and Biological Engineering Faculty of Engineering University of Ottawa Ottawa ON K1N6N5 Canada
Abstract
AbstractOptimizing the electronic structure of electrocatalysts is of particular importance to enhance the intrinsic activity of active sites in water/seawater. Herein, a series of medium‐entropy metal oxides of X(NiMo)O2/NF (X = Mn, Fe, Co, Cu and Zn) is designed via a rapid carbothermal shocking method. Among them, the optimized medium‐entropy metal oxide (FeNiMo)O2/NF delivered remarkable HER performance, where the overpotentials as low as 110 and 141 mV are realized at 1000 mA cm−2 (@60 °C) in water and seawater. Meanwhile, medium‐entropy metal oxide (FeNiMo)O2/NF only required overpotentials of as low as 330 and 380 mV to drive 1000 mA cm−2 for OER in water and seawater (@60 °C). Theoretical calculations showed that the multiple‐metal synergistic effect in medium‐entropy metal oxides can effectively enhance the d–p orbital hybridization of Mo─O bond, reduce the energy barrier of H* adsorbed at the Mo sites. Meanwhile, Fe sites in medium‐entropy metal oxide can act as the real OER active center, resulting in a good bifunctional activity. In all, this work provides a feasible strategy for the development of highly active and stable medium‐entropy metal oxide electrocatalysts for ampere‐level water/seawater splitting.