Nb2O5 based photocatalysts for efficient generation of H2 by Photoreforming of aqueous solutions of ethanol

Abstract

A series of Nb2O5 semiconductors and their composites with TiO2 have been prepared following a hydrothermal treatment at varied synthetic conditions, and tested for the photoreforming of aqueous solutions of ethanol. The photo-reforming activity has been tested under UV and natural solar light irradiation, both in the absence and in the presence of Pt as co-catalyst. Our data has shown that the Nb2O5-TiO2 composite prepared by a hydrothermal treatment of three days displayed the highest photocatalytic activity, with a hydrogen production of 138 mmolH2h−1g−1 under UV light (apparent quantum yield of ca. 44 %) and 40 mmolH2kJ−1g−1 under natural solar light (apparent quantum yield of ca. 85 % considering only the UV fraction of sunlight). The exalted photocatalytic activity of this material was attributed to the concomitance of two favorable events, namely the possible formation of a heterojunction between the two semiconductors and the optimal ratio of them in this composite.