Short-Distance Hydrogen Spillover on an Isolated Amorphous RuTe_x Cocatalyst for Superior Photocatalytic H₂ Evolution

Hydrogen spillover has been extensively demonstrated as an effective strategy to promote hydrogen evolution; however, in conventional binary-component catalysts, this process is often hindered by long spillover pathways and high interfacial resistance. Herein, we report an efficient short-distance hydrogen-spillover pathway achieved on an isolated amorphous RuTe_x cocatalyst, which obviously enhances the photocatalytic H₂-evolution activity of TiO₂. Upon loading RuTe_x nanoparticles onto the TiO₂ surface (RuTe_x/TiO₂), distance-dependent electron transfer from the RuTe_x cocatalyst to TiO₂ induces a gradual change in the electronic structure of the Ru and Te active sites, resulting in a gradual increase in electron density from the bottom to the top of the RuTe_x nanoparticles. This gradient establishes two distinct functional regions within each nanoparticle: a strong H-adsorption region near the RuTe_x/TiO₂ heterointerface (RuTe_x/TiO₂(bottom)) and a strong H-desorption region away from the interface (RuTe_x/TiO₂(top)), thereby enabling an efficient hydrogen spillover process within the isolated cocatalyst. As a result, the RuTe_x/TiO₂ composite achieves a photocatalytic H₂-production rate of 3.47 mmol·g^-1·h^-1 under alkaline conditions, which is 81.6 times higher than that of pure TiO₂. This study opens an avenue for the design of catalysts with enhanced hydrogen spillover, paving the way for advanced H₂ generation.