Role of alcohol solvents on physico-chemical characteristics and photocatalytic performance of titania

Abstract

The recent research on semiconductor photocatalysis reveals that the uni/multi nano heterojunction composites shows superior photocatalytic performance compared to the pristine one. Moreover, it has been reported that the use of alcoholic solvents has significant influence in the phase formation and thereby on the photocatalytic performance. The present work reports the synthesis of titania using sol gel technique employing different alcohol solvents. The samples were analysed using structural, surface and optical characterisation techniques. The structural analysis confirms the high crystalline nature of the samples along with its nanoscale size distribution. The titania samples synthesised with ethanol and propanol solvents exhibit mixed phase and the sample synthesized with butanol solvent showed pure anatase phase which agrees with the earlier reports revealing the role of length of the carbon chain of the solvent on phase transformation. The surface characterization reveals the formation of nano agglomerates in all the cases. Photoluminescence analyses of the samples were also carried out to identify the trap levels in the samples. The photocatalytic activities of the samples were performed under U-V irradiation with the probe pollutant methylene blue. All the three samples showed good photocatalytic performance compared to the commercial photocatalyst Degussa P25. The titania sample synthesized using ethanol solvent showed superior photocatalytic activity compared to other samples. The superior photocatalytic performance of the ethanol based titania sample maybe attributed to the efficient separation of the charge carrier at the anatase-rutile nano heterojunction of the mixed phase titania along with high surface area. This study reveals that the nature of the solvent for the sol gel synthesis have a substantial influence in the physico-chemical and photocatalytic performance of titania.