Urchinlike Carbon-Coated TiO₂ Microspheres with Enhanced Photothermal-Photocatalytic Hydrogen Evolution Performance for Full-Spectrum Solar Energy Conversion

Although carbon-based nanocomposites exhibit excellent photocatalytic properties, the role played by the photothermal effect of carbon-based nanocomposites is frequently underestimated. Herein, we report the preparation of carbon coated urchinlike TiO₂ microspheres (TiO₂@CS) via a facile one-step solvothermal method for photothermal and photocatalytic hydrogen evolution. Carbon microspheres as the substrate, coated with TiO₂ nanorods, can absorb near-infrared energy and increase the surface temperature of TiO₂@CS, enhancing the photothermal effect. The photothermal catalytic hydrogen generation activity of the optimized catalyst is 5.1 times higher than that of the sum of the photocatalytic and thermocatalytic reactions. The excellent hydrogen production rate is attributed to the synergistic effect of electron mobility and surface temperature. The presence of carbon microspheres expands the light absorption and effectively transfers and separates photogenerated carriers, hence significantly improving the photocatalytic efficiency. We demonstrate that the design of carbon-based nanocomposites with better photothermal properties is a promising approach to obtain significantly enhanced photocatalytic activity.