Amorphous Metallic RuS₂-Enabled Solar Heating for Enhanced Photothermal Catalytic Oxidation of Halide Perovskite

Solar-driven photothermal catalysis is among the most promising routes for efficient solar energy utilization. However, conventional solar heaters of carbon materials and plasmonic metals generally suffer from either insufficient surface reactivity or narrow absorption spectra confined to the visible region, greatly limiting photothermal catalytic efficiency. Here, amorphous metallic RuS₂ (RuS₂-A) is demonstrated to function as an excellent solar heater, outperforming its crystalline semiconductor counterparts. It dramatically enhances solar energy conversion efficiency of MAPbBr₃ halide perovskite for benzylic C(sp³)-H bonds oxidation by a factor of 33-fold. Experimental characterization and theoretical calculations reveal that the hybrid RuS₂-A/MAPbBr₃ composite enables synergistic utilization of the solar spectrum, in which MAPbBr₃ primarily absorbs low-wavelength UV-vis light to generate charge carriers, while RuS₂-A efficiently converts long-wavelength visible-NIR light into thermal energy. Crucially, an Ohmic junction is formed between the photoactive MAPbBr₃ semiconductor and the RuS₂-A solar heater, enabling swift electron transfer to RuS₂-A, which also exhibits strong O₂ activation capability. Together with thermal effect, photoelectrons are accumulated, locally heated, and finally consumed at the active RuS₂-A sites, thereby greatly boosting the efficiency of photothermal catalytic toluene oxidation.