Computational screening of doped αMnO2 catalystsfor the oxygen evolution reaction

Minimizing energy and materials costs for driving the oxygen evolution reaction (OER) is paramount for the commercialization of water electrolysis cells and rechargeable metal-air batteries. Using density functional theory calculations, we analyze the structural stability, catalytic activity and electronic conductivity of pure and doped αMnO2 for the OER.

As a model surface, we investigate the (110) and (100) facets, on which we identify three possible active sites: a coordination unsaturated, bridge and bulk site. We evaluate the performance of pure and Cr, Fe, Co, Ni, Cu, Zn, Cd, Mg, Al, Ga, In, Sc, Ru, Rh, Ir, Pd, Pt, Ti, Zr, Nb and Sn doped αMnO2.

At each site and for each dopant, we impose the preferred valence by adding/subtracting electron donors (hydrogens) and electron acceptors (hydroxyls). From a subset of stable dopants, we identify Pd doped αMnO2 as the only catalyst that can outperform pristine aMnO2. We also discuss approaches to increase the electron conductivity as pure αMnO2 is a narrow band-gap material.