Synergistic Role of E<sub>g</sub> Filling and Anion–Cation Hybridization in Enhancing the Oxygen Evolution Reaction Activity in Nickelates
Jianhui Song, Xin Jin, Shuo Zhang, Xingyu Jiang, Jiangfeng Yang, Zi Li, Jian Zhou, Huigang Zhang, Yuefeng Nie
Abstract
Transition-metal perovskite oxides (ABO3) have been demonstrated to exhibit the excellent catalytic activity of the oxygen evolution reaction (OER). Here, we show that the layered perovskite Ruddlesden–Popper (RP) series An+1BnO3n+1 is an ideal material system with high tunability of the electronic structure and orbital occupancy, providing a clean system to reveal the important factors in optimizing the OER activity in transition-metal oxides. We show that the catalysis performance is significantly enhanced in the layered nickelate (Lan+1NinO3n+1) compounds with n ≥ 3 and peaked at the n = 5 member, which is about 4 times higher than that in the corresponding perovskite compound (LaNiO3). Our work suggests that the variation of the n value can effectively modulate the NiO2 electronic properties, and the proper combination of Op-Nid hybridization and eg occupancy can result in substantially enhanced catalytic performance in transition-metal oxides.