Organic-inorganic composite of g-C3N4-SrTiO3:Rh photocatalyst for improved H-2 evolution under visible light irradiation

Abstract

The organic-inorganic composite g-C3N4-SrTiO3:Rh was prepared for the first time as a photocatalyst for hydrogen production and the resulting hydrogen evolution rate under visible light irradiation from aqueous methanol solution was measured. A high hydrogen evolution rate of 223.3 mu mol h(-1) was achieved by using 0.1 g of as-prepared photocatalyst powder comprised of 20 wt.% g-C3N4 80 wt.% SrTiO3:Rh (0.3 mol%). The hydrogen evolution rate was greater than that obtained by SrTiO3:Rh (0.3 mol%) by a factor of 3.24. The quantum efficiency of as-prepared composite photocatalyst was 5.5% at 410 nm for hydrogen evolution. The high activity of the composite photocatalyst for hydrogen evolution stemmed from its electron hole separation and transportation capabilities due to the hetero-junctions of the organic-inorganic composite materials. The proposed mechanism for the electron hole separation and hydrogen evolution of the g-C3N4 SrTiO3:Rh composite under visible light irradiation featured the reduced recombination of the photo-generated charge carriers. The doping of Rh ions into the SrTiO3 has contributed to the high photocatalytic activity by forming a donor level from the valance band to the conduction band. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.