Computational study of oxygen evolution reaction on flat and stepped surfaces of strontium titanate

Oxygen evolution reaction (OER) is reconciled with the bottleneck in hydrogen production via photo- or electrocatalytic water splitting. One of the remedies to overcome this shortcoming is to develop catalytically efficient anode materials. Strontium titanate (STO) is a potential candidate for the OER by referring to recent experimental reports on enhanced photocatalytic activity of faceted nanoparticles. In this paper, we perform electronic structure calculations in the density functional theory approximation to study the OER on flat and stepped surfaces, such as encountered in nano-sized STO. We demonstrate that stepped surfaces reveal higher OER activity than flat surfaces, which is consistent with experimental data. We also observe partial breaking of OER scaling relation on stepped surfaces, albeit this does not necessarily cause higher catalytic activity. Finally, we propose recommendations for thorough implementation of zero-point energy calculations as the calculation method may impact the free-energy landscape of the OER.