Mesoporous black TiO2/MoS2/Cu2S hierarchical tandem heterojunctions toward optimized photothermal-photocatalytic fuel production.

[Display omitted] • Mesoporous black TiO 2 /MoS 2 /Cu 2 S hierarchical tandem heterojunction photocatalysts are fabricated. • MoS 2 acts as a bridge between black TiO 2 and Cu 2 S to form tandem heterojunctions. • MoS 2 and Cu 2 S extend photoresponse to NIR region and exhibit an obvious photothermal effect. • It shows excellent visible-light-driven photocatalytic H 2 production performance. • It is ascribed to the hierarchical tandem heterojunction favoring charge transfer and separation efficiency. Mesoporous black TiO 2 /MoS 2 /Cu 2 S (b-TiO 2 /MoS 2 /Cu 2 S) hierarchical tandem heterojunctions visible-light photocatalysts are fabricated through evaporation-induced self-assembly, high-temperature hydrogenation, and solvothermal strategies. Mesoporous black TiO 2 (b-TiO 2) serves as the host to assemble MoS 2 and Cu 2 S, which could absorb near-infrared energy to enhance photothermal effect. MoS 2 nanosheets with vertical growth on b-TiO 2 not only act as co-catalyst but also serve as a bridge to integrate mesoporous black TiO 2 microspheres and Cu 2 S nanoparticles in tandem systems, thereby can effectively transfer and separate photogenerated charge carriers. The visible-light photocatalytic hydrogen production rate of the b-TiO 2 /MoS 2 /Cu 2 S without any precious metals cocatalysts is as high as 3376.7 μmol h−1 g−1, which is about 16 times higher than that of b-TiO 2. The excellent photocatalytic performance could be ascribed to the formation of hierarchical tandem heterojunctions with suitable band gap alignment favoring charge transfer and separation, and the introduction of MoS 2 and Cu 2 S extending photoresponse to NIR region. In addition, both MoS 2 and Cu 2 S with narrow band gap could convert solar light into heat energy, which further promotes photocatalytic performance. The designed strategy could provide new insights for fabricating other tandem heterojunctions with high-performance for solar energy conversion. [ABSTRACT FROM AUTHOR]