Spectrally-Resolved Synergy in Photothermal Catalysis: A Temperature-regulated Transition of Hot-electron Transfer for Methanol Steam Reforming.

Photothermal catalysis promises to convert solar energy into fuels with the assistance of thermal energy, yet the synergy between light and heat remains poorly understood. Here, this work deconstructs this synergy in methanol steam reforming over Pt/TiO2. The catalyst achieves an H2 production rate of 688 mmol g-1 h-1 under UV/visible coupled illumination, driven by a nonlinear Arrhenius behavior. Spectral decoupling reveals a distinct wavelength-dependent thermal response under different temperatures. The UV band gap excitation of TiO2, although accelerating the generation of formaldehyde, remains kinetically limited by its accumulation; in contrast, visible metal interband excitation on Pt induces hot-electron injection to generate sufficient driving force to accelerate formaldehyde dissociation (>170 °C). Strong excitation (405 nm) generates sufficient driving force, whereas weak excitation (450 nm) fails to fully overcome the energy threshold required to overcome this kinetic trap. These findings propose a thermodynamic regulation model that selectively amplifies hot-electron channels, establishing a strategy to rationally harness the solar spectrum.