Influence of Photodeposition Parameters on the Hydrogen Production Activity of Semiconductor-Supported Platinum Photocatalyst

Photocatalytic water splitting represents a sustainable approach for solar-driven hydrogen (H 2 ) production. Platinum/titanium dioxide (Pt/TiO 2 ) systems are highly efficient, with Pt enhancing charge separation and serving as active sites for reduction reactions. In this work, Pt was photodeposited onto TiO 2 under controlled conditions, aiming for a Pt loading of 1 wt %, to examine the effects of three key synthesis parameters: methanol (MeOH) concentration as a sacrificial agent, TiO 2 pretreatment via calcination, and Pt precursor addition strategy (single-step vs stepwise). The resulting Pt/TiO 2 catalysts were then employed for photocatalytic H 2 production under ultraviolet (UV) illumination. Varying MeOH content (0, 5, and 16.7 v/v %) during deposition showed that, in the absence of MeOH, Pt loading and photocatalytic stability were poor, with rapid performance decay over time. In contrast, the presence of MeOH significantly enhanced Pt loading and photocatalytic activity. Thermal treatment of TiO 2, despite lowering Pt loading (0.66 wt %), enhanced activity through improved crystallinity, Pt dispersion, and oxygen vacancy formation, as confirmed by XRD and XPS analyses. Similarly, stepwise Pt precursor addition, while yielding a slightly lower Pt loading (0.68 wt %) compared to the single-step method, produced well-dispersed Pt nanoparticles that significantly improved operational stability during photocatalytic H 2 production. Moreover, compared to bare TiO 2, introducing Pt slightly reduces the band gap due to Pt-induced intermediate energy states, enhancing light absorption and photocatalytic efficiency. These findings demonstrate that careful control of sacrificial agent concentration, thermal treatment, and deposition strategy are essential for optimizing Pt/TiO 2 photocatalysts toward efficient and stable solar H 2 production.