Synergistic Role of Eg Filling and Anion-Cation Hybridization in Enhancing the Oxygen Evolution Reaction Activity in Nickelates

Transition-metal perovskite oxides (ABO(3)) 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 A(n+1)B(n)O(3n+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.

Automated summary

Transition-metal perovskite oxides have been shown to exhibit excellent catalytic activity in the oxygen evolution reaction (OER). The layered perovskite Ruddlesden-Popper series A(n+1)B(n)O(3n+1) is an ideal material system with high tunability, providing insights into optimizing OER activity. Catalytic performance is significantly enhanced in layered nickelate compounds with n >= 3, peaking at the n = 5 member, indicating the importance of modulating electronic properties for improved catalytic performance in transition-metal oxides.