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

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.