Mesoporous TiO2 nanostructures: a route to minimize Pt loading on titania photocatalysts for hydrogen production

Mesostructured TiO2 nanocrystals have been prepared using Pluronic F127 as the structure-directing agent. Platinum nanoparticles at different contents (0.1-1.0 wt%) have been photochemically deposited onto the mesoporous TiO2. TEM investigation of 0.2 wt% Pt/TiO2 calcined at 450 degrees C reveals that the TiO2 particles are quite uniform in size and shape with the particle sizes of TiO2 and Pt being 10 and 3 nm, respectively. The photocatalytic activities of the Pt loaded TiO2 have been assessed and compared with those of nonporous commercial Pt/TiO2-P25 by determining the rates and the photonic efficiencies of molecular hydrogen production from aqueous methanol solutions. The results show that the amount of hydrogen evolved on Pt/TiO2-450 at low Pt loading (0.2 wt%) is three times higher than that evolved on Pt/TiO2-P25 and twelve times higher than that evolved on Pt/TiO2-350. Despite the BET surface area of the TiO2-450 photocatalyst being 3.5 times higher than that of TiO2-P25, a 60% smaller amount of the Pt co-catalyst is required to obtain the optimum photocatalytic hydrogen production activity. The reduced Pt loading on the mesoporous TiO2 will be important both from a commercial and an ecological point of view.