PRELIMINARY INVESTIGATIONS ON THE MIXED-OXIDE MATERIAL TIO2-IN2O3 WITH REGARD TO PHOTOELECTROLYTIC HYDROGEN-PRODUCTION

The present communication describes a new photoelectrode system, TiO2-In2O3 for hydrogen production through photoassisted electrolysis of water. The mixed oxide electrodes have been synthesized by solid state sintering. These sintered disc electrodes exhibit enhanced photovoltage and photocurrent of 0.70 V and 11 mAcm-2 respectively, whereas for TiO2 they were 0.8 V and 5 mAcm-2 respectively. X-Ray diffraction and scanning electron microscopic investigations of the mixed oxide electrodes have been carried out to monitor their gross and surface structural characteristics. EDAX analysis has been carried out to explore the chemical stoichiometry. These studies indicate microcrystalline like surface characteristics and a cation doping (In approximately 2%) for the TiO2-In2O3 electrodes. The relative enhancement in hydrogen evolution under photoassisted mode of electrolysis of TiO2 and mixed oxide electrodes (TiO2-In2O3) has been found to be from 1.0 to 1.5 ml h-1. The probable causes of enhancements in photoactivity and hydrogen evolution have been suggested as (1) In cation doping in TiO2 lattice; (2) an increase surface area with In2O3 inclusion and (3) a decrease in the band gap and enhanced range of absorption of mixed oxide electrode and (4) the catalytic activity of In2O3.