Hierarchical hollow TiO2/In2S3 heterojunction photocatalyst decorated with spatially separated dual co-catalysts for enhanced photocatalytic H-2 evolution

Achieving enhanced charge separation efficiency and accelerated surface reaction kinetics are crucial for high-performance photocatalytic hydrogen evolution. Herein, a spatially separated, dual co-catalyst-modified photocatalytic system Pt/TiO2/In2S3/PdS (Pt/TO/IS/PdS) was successfully built by the step-by-step decoration of Pt and PdS nanoparticles (NPs) on the inner and outer shells of a hierarchical hollow TiO2/In2S3 (TO/IS) heterojunction, respectively. Experimental results demonstrate that the spatial separation of reduction and oxidation co-catalysts accelerates the surface redox reaction and, more importantly, promotes photo-induced charges to flow in opposite directions. By combining the virtues of TiO2/In2S3 heterojunction shell, spatially separated dual co-catalyst and extended light absorption, the Pt/TO/IS/PdS catalyst exhibits a remarkable photocatalytic H2 production performance under visible light irradiation, which is 36.0 times enhancement than that of the TiO2/In2S3 heterojunction. This study demonstrates that the strategy of combining heterojunctions and spatially separated co-catalysts has great reference significance for developing a highly efficient photocatalytic system.