Understanding the mechanism of hydrogen (H2) formation from the conversion of water (H2O) and renewables on TiO2 surfaces with cocatalysts via either photocatalysis or other catalytic processes is of significant importance to the successful design of efficient catalysts. Herein, we have investigated H2 production from H2O, CH3OH, and C2H5OH on a Pt cluster covered rutile (R)-TiO2(110) surface (Ptclut/R-TiO2(110)) to address the mechanism of H2 production. Experimental results demonstrate that surface adsorbates not only help H atom diffusion on Ptclut/R-TiO2(110) but also take part in H2 production directly. Further density functional theory (DFT) calculations suggest that H2 production on Ptclut/R-TiO2(110) occurs via a synergistic catalysis process between Pt clusters and interfacial adsorbates rather than a recombination reaction of H atoms on Pt clusters. This work provides new insight into H2 production from H2O and renewables with Pt/TiO2 catalysts, which may be applicable to H2 production on other Pt cluster deposited metal oxide catalysts.