Steering spatially separated dual sites on nano-TiO2 through SMSI and lattice matching for robust photocatalytic hydrogen evolution

Spatial isolation of different functional sites at the nanoscale in multifunctional catalysts for steering reaction sequence and paths remains a major challenge. Herein, we reported the spatial separation of dual-site Au and RuO₂ on the nanosurface of TiO₂ (Au/TiO₂/RuO₂) through the strong metal-support interaction (SMSI) and the lattice matching (LM) for robust photocatalytic hydrogen evolution. The SMSI between Au and TiO₂ induced the encapsulation of Au nanoparticles by an impermeable TiO_x overlayer, which can function as a physical separation barrier to the permeation of the second precursor. The LM between RuO₂ and rutile-TiO₂ can increase the stability of RuO₂/TiO₂ interface and thus prevent the aggregation of dual-site Au and RuO₂ in the calcination process of removing TiO_x overlayer of Au. The photocatalytic hydrogen production is used as a model reaction to evaluate the performance of spatially separated dual-site Au/TiO₂/RuO₂ catalysts. The rate of hydrogen production of the Au/TiO₂/RuO₂ is as high as 84 μmol h⁻¹ g⁻¹ under solar light irradiation without sacrificial agents, which is 2.5 times higher than the reference Au/TiO₂ and non-separated Au/RuO₂/TiO₂ samples. Systematic characterizations verify that the spatially separated dual-site Au and RuO₂ on the nanosurface of TiO₂ can effectively separate the photo-generated carriers and lower the height of the Schottky barrier, respectively, under UV and visible light irradiation. This study provides new inspiration for the precise construction of different sites in multifunctional catalysts.