<p>Photocatalytic reduction of CO₂ to CH₄ on TiO₂ remains a major challenge due to the complex multiple electron-proton coupling process. Notably, photothermal catalysis by synergistically promoting photogenerated charge separation and thermodynamic modulation has emerged as a promising strategy to promote the selective CH₄ production, while the special influence of photo-to-thermal effect on such process is still indistinct. In this work, TiO₂ exhibits an outstanding CH₄ production rate of 29.79 µmol·g^− 1·h^− 1 with hugely increased CH₄ selectivity of 87.0% only rely on the optimization of reaction conditions (light intensity dominated photo-to-thermal effects). Combined in situ DRIFTS, electrochemical characterization, and DFT theoretical simulations indicate that photothermal heating not only accelerate the charge transfer but also lowers the energy barrier for CO₂ protonation, promoting formation of the multiple electron-proton coupling CH₄. This work demonstrates that photothermal synergy not only enhances catalytic activity but also enables precise control of CH₄ product selectivity through heat-mediated modulation of intermediate transformations. These findings provide a novel strategy for the highly efficient and selective photocatalytic conversion of CO₂ to CH₄ and have positive implications for advancing sustainable carbon utilization.</p> Graphical Abstract <p></p>