Computational Design Principles of Two-Center First-Row Transition Metal Oxide Oxygen Evolution Catalysts

Abstract

Computational screens for oxygen evolution reaction (OER) catalysts based on Sabatier analysis have seen great success in recent years; however, the concept of using chemical descriptors to form a reaction coordinate has not been put under scrutiny for complex systems. In this paper, we examine critically the use of chemical descriptors as a method for conducting catalytic screens. Applying density functional theory calculations to a two-center metal oxide model system, we show that the Sabatier analysis is quite successful for predicting activities and capturing the chemical periodic trends expected for the first-row transition metal series, independent of the proposed mechanism. We then extend this analysis to heterodimer metallic systems—metal oxide catalysts with two different catalytically active metal centers—and find signs that the Sabatier analysis may not hold for these more complex systems. By performing a principal component analysis on the computed redox potentials, we show (1) that a single chemical descriptor inadequately describes heterodimer overpotentials and (2) mixed-metal overpotentials cannot be predicted using only pure-metal redox potentials. We believe that the analysis presented in this article shows a need to move beyond the simple chemical descriptor picture when studying more complex mixed metal oxide OER catalysts.