Studies on the enhanced photocatalytic hydrogen evolution over Pt/PEG-modified TiO2 photocatalysts

Polyethylene glycol (PEG) with different average molecular weight (400, 2000, 6000, 20 000) was used as a templating reagent to synthesize PEG-modified TiO 2 photocatalyst by sol–gel method. This study revealed that PEG molecules of appropriate size acted significantly in well-controlled crystal growth and the enlargement of surface area via the pore-forming function. The Pt cocatalyst was loaded by the photochemical deposition method to investigate its photocatalytic activity for H 2 evolution from an aqueous ethanol solution. The Pt/PEG-modified TiO 2 photocatalyst showed higher photocatalytic activity than Pt/unmodified TiO 2 and Pt/Degussa P25- TiO 2 , among which Pt/PEG6000- TiO 2 demonstrated the highest activity with an average H 2 evolution rate of 1615 μ mol h - 1 . Therefore, the utilization of PEG to modify the microstructure of TiO 2 was proved to be an efficient way to acquire improved photocatalytic performance. The extended studies of the reaction at different temperatures and from a series of hydrocarbon sacrificial reagents were also performed over Pt/PEG6000- TiO 2 . The results were helpful to obtain further understanding of the photocatalytic reaction.