Surface Defect Engineering on Perovskite Oxides as Efficient Bifunctional Electrocatalysts for Water Splitting.

The design of high-performance and cost-effective electrocatalysts for water splitting is of prime importance for efficient and sustainable hydrogen production. In this work, a surface defect engineering method is developed for optimizing the electrocatalytic activity of perovskite oxides for water electrolysis. A typical ferrite-based perovskite oxide material La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) is used and regulated by selective acid etching. The optimal parameters for the surface treatment are identified. An efficient bifunctional perovskite oxide, denoted LSCF-30, is prepared by selectively corroding the A-site Sr element in the surface region, which is found to not only increase the exposure and decrease the coordination of B-site metals but also effectively modulate the electronic structure of these metals. The crystal lattice of the perovskite bulk is kept constant during surface engineering, which ensures the structural stability of the perovskite catalyst. The findings demonstrate an effective strategy of surface defect engineering in enhancing the performance of perovskite oxide electrocatalysts for water splitting.