Fabrication of heterostructural Ru-SrTiO₃ fibers through in-situ exsolution for visible-light-induced photocatalysis

A hybrid metal-semiconductor can be utilized as an attractive photocatalyst which demonstrates unique synergistic properties stemming from the materials combination. One of the essential advancements is precisely controllable for each geometrical factor in metal and its semiconductive support. Herein, we synthesized Sr_0.9Ti_0.9Ru_0.1O_3-δ (STRO) fibers by the electrospinning method and tailored the morphology by in-situ exsolved Ru nanoparticles (NPs). Thus, a metal-semiconductor heterostructure is formed. The hierarchical Ru-STRO catalyst manifested a remarkable enhancement of solar-assisted photocatalytic activity with a 5-fold increase in hydrogen evolution rate, attributed to enhanced charge separation, reaction sites, and light absorption. Theoretical simulations and Kelvin probe force microscopy (KPFM) explained the reaction pathways of photogenerated carriers and how their partitioning and transportation are tuned by Ru NPs. Our work provides a novel method to easily fabricate metal-semiconductor heterostructure via an in-situ growth method for the development of high-performance photocatalysts.