Investigation on the reaction mechanism and stability of Ruddlesden-Popper structure Srn+1BnO3n+1 (B=Ru, Ir, n=1, 2) as an oxygen evolution reaction electrocatalyst in acidic medium

Abstract

R–P structured catalysts have attracted attention due to their low noble metal content and long-term stability. In this paper, we calculated the synthesis difficulty, Sr segregation, and OER catalytic activity of SrBO3, Srn+1BnO3n+1 (BRu, Ir, n = 1, 2), taking into account the effects of perovskite layer numbers and strain. The synthesis difficulty was calculated: SrBO3 < Sr2BO4 < Sr3B2O7. The perovskite layer numbers of R–P catalysts were also found to affect the OER process, from n = 1 to 2, the rate-controlling step changes from O*→OOH* to OOH*→O2. Sr2IrO4 was calculated to have the best catalytic activity but is very prone to Sr segregation. Due to the unique layered nature, Sr2IrO4 is still considered the most promising OER catalyst. Furthermore, we also concluded that applying strain impairs the OER catalytic performance of R–P oxides. Our work investigated the OER catalytic mechanisms of R–P oxides, which is significant for the development of water electrolysis.