Exploration of eg orbital occupancy in Prussian blue analogues for enhanced oxygen evolution reaction

Abstract

A correlation between the eg orbital occupancy of metal active sites and the oxygen evolution reaction (OER) performance has been investigated for four Prussian blue analogues, specifically FeCNMA PBAs, where MA represents Fe, Co, Ni, and Cu. Density functional theory (DFT) calculations indicate that the eg orbital occupancy of Co sites in FeCNCo PBA with CN vacancies approaches unity. As a result, FeCNCo PBA demonstrates superior electrocatalytic OER performance compared to the other three PBAs. This work validates the impact of manipulating the electronic configuration of the MA site on the OER catalytic performance of Prussian blue analogues.