There is growing interest in the reforming of methanol and other bio-oxygenates as high-density, CO₂-neutral, renewable sources of H₂. Photocatalysis is worthy of investigation as a potentially economic means to drive such endothermic processes. In this study, in-situ DRIFTS, adapted for optical pumping and coupled to on-line MS, was used to observe the surface of TiO₂ (Degussa P25) during photo-metallization from pre-sorbed hexachloroplatinate, at a nominal Pt loading of 1 wt%, and to evaluate photo-reforming of methanol over the resulting Pt/TiO₂ composite. The irreversible growth of a quasi-continuum absorption, characteristic of the surface plasmon resonance of zerovalent Pt nanoparticles, along with bands at 2050 and 1830 cm⁻¹ typical of metal-adsorbed CO, indicated that photo-metallization was complete typically within 2 hours. Methanol reforming was photocatalyzed at room temperature but in low quantum efficiency, ϕ ≈ 0.01. However, this was raised substantially, to ϕ ≈ 0.07, simply by the application of mild heating (T ≤ 70 °C). Photo-reforming proceeded at a fixed rate but the H₂/CO₂ ratio generally exceeded that of the reforming stoichiometry, suggesting some retention of CO₂. The photo/thermal synergy was rationalized by model DRIFTS studies, starting from formalin (hydrated formaldehyde), which revealed key features of the mechanism. TiO₂ promoted the Cannizzaro disproportionation in the dark, yielding formate and methoxy species already at 40 °C. While methoxy was effectively cycled back to the initial photo-dehydrogenation stage, the slow step was identified as formate decomposition to H₂ and CO₂. The low value measured for the apparent activation energy (∼40 kJ mol⁻¹) was taken as supporting evidence for ‘water-assisted destabilization’ of formate, as originally reported by Shido and Iwasawa. No evidence was found for an alternative thermal- or photo-reforming mechanism involving the Pt–CO_ad species.