Nanocubes phase adaptation of In2O3/TiO2 heterojunction photocatalysts for the dye degradation and tracing of adsorbed species during photo-oxidation of ethanol

Abstract

This work reports an efficient method to prepare In2O3/TiO2 heterojunction photocatalysts containing different micro-structures including nanorods (ITNR) and nanocubes (ITNC) with a coordination chemical approach followed by thermal treatments. The as-prepared materials were characterized by various physicochemical tests, to verify the structural properties and the associated photocatalytic properties. In addition, malachite green (MG) dye and ethanol were used to examine their photooxidation properties. Both experiments demonstrated the photocatalytic activity of the as-prepared samples were in the order of ITNC > ITNR > TiO2 > In2O3. This tendency implied that the formation of semiconductor-semiconductor heterojunction in ITNC and ITNR. Reduced the lower recombination rate of electron-hole pair, along with the lower electrical resistance, and higher OH adsorption sites. In addition, ITNC has a larger surface area and a wide absorption spectrum under visible light region than that of the ITNR. The scavenger study of dye degradation shows that more than 70% of the MG dye was degraded through OH radicals, which was further confirmed by the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The results illustrated the adsorbed gas-phase ethanol was converted to CO2 and H2O through different reaction pathways, which revealed that both surface-adsorbed OH radicals and the photogenerated holes were contributed to the higher photocatalytic activity.