Photochemical Studies of In₂O₃ Admixed Nanostructured TiO₂ in Regard to Hydrogen Production Through Photoelectrolysis

Abstract

In the present investigation, PEC solar cell based on nanostructured (ns) TiO₂ photoelectrode prepared by the hydrolysis of Titanium-tetraisopropoxide followed by deposition of thin film by spin-on method, has been developed. It has been shown that TiO₂(ns) photoelectrode bearing PEC cell exhibits higher PEC output due to improved quantum yield. Yet another improvment in TiO₂(ns) photoelectrode carried out in the present work corresponds to admixing In₂O₃ for improving the spectral response of TiO₂(ns). The PEC cell based on TiO₂(ns)-In₂O₃ photoelectrode shows PEC response (V_oc = 720 mV, I_sc = 11 mA/cm²) under illumination of a 1000 W Xe-Hg lamp. The hydrogen gas evolution under photoelectrolysis employing TiO₂(ns) photoanode was found to be 1.4 ml h^-1 on the other hand the In₂O₃ admixed TiO₂(ns) electrode exhibited a higher hydrogen gas evolution rate of 1.9 ml h^-1. Evidence and arguments have been put forward to show that the presence of In₂O₃ over TiO₂(ns) makes the system possess the advantage of a colloidal photochemical system. Better performance of the new photoelectrode is thought to be due to nanostructural nature of TiO₂ photoelectrode improved spectral response and catalytic activity of In₂O₃ in regard to the gas evolution kinetics.