Lead-free perovskite Cs3Bi2Br9/FeS2 hollow core-shell Z-scheme heterojunctions toward optimized photothermal-photocatalytic H2 production

Photothermal catalysis is a promising technology primarily utilized the solar energy to produce photogenerated e^-/h⁺ pairs together with the production of heat energy. However, the inefficient separation of charge carriers and inadequate response to near-infrared (NIR) light usually leads to the unsatisfactory photocatalytic efficiency, hindering their application potentials. In this work, a significantly enhanced photothermal catalytic hydrogen evolution reaction over the lead-free perovskite Cs₃Bi₂Br₉/FeS₂ (CBB/FS) heterostructure is simultaneously verified, where the CBB/FS Z-scheme heterojunctions display the strong stability and superb photothermal catalytic activity. Under the simulated solar irradiation (AM 1.5G), the optimized CBB/FS-5 achieves a photocatalytic hydrogen evolution rate of 31.5 mmol g^-1 h^-1, which is 112.6 and 77.1 times higher than that of FS and CBB, respectively, together with an apparent quantum yield of 29.5 % at 420 nm. This significantly improved photocatalytic H₂ evolution can be mainly attributed to the Z-scheme charge transfer and photothermal-assisted synergistically enhanced photocatalytic H₂ production, and the potential mechanism of the enhanced photocatalytic H₂ evolution is also proposed by photoelectrochemical characterizations, in situ XPS, EPR spectra, and the DFT calculations. This work provides new insights to the design of high-efficient photothermal catalysts, leading to the sustainable and efficient solutions towards the energy and environmental challenges.