Strain effect on oxygen evolution reaction of the SrTiO₃ (0 0 1) surface

Strontium titanate (SrTiO₃) is one of the most promising photocatalysts for overall water splitting (OWS). Strains can be commonly introduced in SrTiO₃ during the synthetic processes, for example, in pulsed laser deposition. However, the effect of the strains on the catalytic performance of OWS is still unclear to date. Herein, first-principles calculations were performed to evaluate the impact of biaxial strains applied in SrTiO₃ (001) surface on the oxygen evolution reaction (OER), the bottleneck of OWS. It was found that the applied strains, especially the compressive strains, significantly affect the free energy changes for H₂O dissociation and *OOH deprotonation of OER on SrTiO₃ (001). More interestingly, the tensile strains reduce the surface energy and lower the OER overpotential through reducing the free energy change for the rate-determining step, i.e., the second step of OER (*OH deprotonation), while the compressive strains increase the surface energy and the OER overpotential. Consequently, it is probable to introduce the tensile strains in the synthetic process to enhance the OER performance on SrTiO₃ (001) surface.