In2O3/TiO2 nano photocatalysts for solar hydrogen production from methanol:water mixtures

In2O3/nano TiO2 and In2O3/TiO2 (P-25) photocatalysts with different In2O3 loadings have been prepared by solid state dispersion method. These catalysts are characterized by XRD, surface area, TEM, UV-vis DRS and XPS techniques. XRD analysis shows the fine dispersion of In2O3 on the surface of TiO2. The photocombinates of In2O3 prepared using the lab-made TiO2 are nano sized with an average size of 8-10 nm compared to the particle size of In2O3/TiO2 (P-25) combinates. The In2O3/nano TiO2 photocatalysts show higher surface area as compared to In2O3/TiO2 (P-25) photocatalysts due to nanosize of the particles. UV-vis DRS results show the visible light absorption of the catalysts in both the series. XPS analysis shows the interaction between In2O3 and TiO2, although the extent of interaction is low. Photocatalytic hydrogen evolution studies have been conducted over these catalysts from water and methanol:water mixtures under solar light irradiation. The 2 wt% In2O3 loaded nano TiO2 and P-25 catalysts show maximum hydrogen production activity from pure water splitting. A very good improvement in the activity is seen when the reaction is carried out in methanol:water mixtures. Maximum hydrogen production of 4080 mu moles/hour is observed on 5 wt% In2O3/nano TiO2 catalyst, which is almost double the activity observed on In2O3/TiO2 (P-25) catalyst.