In-situ construction of tubular core–shell noble-metal-free CMT@TiO2/ZnIn2S4 S-scheme heterojunction for superior photothermal-photocatalytic hydrogen evolution

Developing efficient and stable photocatalysts for hydrogen generation still remains a huge challenge. Herein, we adopted Cynanchum fibers as a carbon source and substrate to construct a ternary hollow core–shell carbon microtubes@TiO₂/ZnIn₂S₄ (denoted as CMT@TiO₂/ZnIn₂S₄) for photothermal-assisted photocatalytic hydrogen evolution (PHE). For the catalyst system, ZnIn₂S₄ is the main visible light absorber, TiO₂ is introduced to form a heterojunction with ZnIn₂S₄ to facilitate the separation of photogenerated carriers, and hollow CMT derived from Cynanchum fibers serves as a conductive scaffold and a photothermal core to elevate the surface temperature of the localized reaction system. Benefiting from the rationally designed multicomponents and microstructures, the photocatalyst proposed enhanced PHE activity of 9.71 mmol·g⁻¹·h⁻¹, which was 30.3, 2.7 and 1.5 times higher than those of binary CMT@TiO₂, pristine ZnIn₂S₄ and TiO₂/ZnIn₂S₄ composite, respectively. The outperformed PHE activity of CMT@TiO₂/ZnIn₂S₄ could be ascribed to the synergy of the formation of intimate heterointerface, the CMT-induced photothermal effect and the hierarchical core–shell architecture. This work provides a promising approach for constructing efficient and durable photocatalysts for H₂ evolution.

Graphical abstract