Crystal Facet and Electronic Structure Modulation of Perovskite Oxides for Water Oxidation

In water-splitting catalysts, exposing high-activity crystal facets with optimal electronic structures can significantly enhance the oxygen evolution reaction (OER) kinetics. In this work, we demonstrate a facile strategy for simultaneously modulating the preferential crystal facet and electronic structure of perovskite oxides for their use as water-electrolysis catalysts using a template-mediated growth approach. Experimental and computational analyses revealed that the preferred crystal facet of La0.5Sr0.5CoO3 (LSC) grown on MoReS2 was effectively modulated to the (110) plane, and the free energy barrier of the rate-determining step was lowered by such crystal facet engineering. Furthermore, the interfacial charge transfer between LSC and MoReS2 enabled the optimal electronic structure of the B-site cation in LSC. Consequently, LSC grown on MoReS2 exhibited an OER activity of 210 mV at 10 mA cm–2, surpassing the performance of state-of-the-art perovskite oxide-based catalysts. Our findings provide new insights into the design of efficient perovskite oxide-based electrocatalysts for water electrolysis.