(673a) Electrocatalysis of Total Water Splitting On Perovskite Oxides and Oxynitrides

Perovskite oxides and oxynitrides have recently been the subject of multiple screening studies (Castelli et al, Persson et al) in order to determine which materials have a bandstructure conducive to overall water splitting.  However, such screening studies neglect the effect of kinetic overpotentials for oxygen evolution (OER) and hydrogen evolution (HER).  In the present work, we use density functional theory (DFT) calculations to describe the limiting potentials for both OER and HER on the 100 facet of various perovskite materials.  Our results are found to be compatible with previous theoretical descriptions of oxide materials for total water splitting such as those proposed by Rossmeisl et al.  More importantly, we demonstrate that perovskite photoelectrocatalysts with bandgaps well-suited for total water splitting may have kinetic limitations that make co-catalysts necessary.  We also describe the theoretical activity of a variety of perovskite compounds for water splitting in order to identify active candidate materials for electrodes in photoelectrocatalytic or electrocatalytic water splitting devices.