Short-Distance Hydrogen Spillover on an Isolated Amorphous RuTe _x Cocatalyst for Superior Photocatalytic H ₂ 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 H 2 -evolution activity of TiO 2 . Upon loading RuTe x nanoparticles onto the TiO 2 surface (RuTe x /TiO 2 ), distance-dependent electron transfer from the RuTe x cocatalyst to TiO 2 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 /TiO 2 heterointerface (RuTe x /TiO 2 (bottom)) and a strong H-desorption region away from the interface (RuTe x /TiO 2 (top)), thereby enabling an efficient hydrogen spillover process within the isolated cocatalyst. As a result, the RuTe x /TiO 2 composite achieves a photocatalytic H 2 -production rate of 3.47 mmol·g –1 ·h –1 under alkaline conditions, which is 81.6 times higher than that of pure TiO 2 . This study opens an avenue for the design of catalysts with enhanced hydrogen spillover, paving the way for advanced H 2 generation.