Synthesis of g-C3N4/TiO2-based photocatalysts for hydrogen production from organic substrates.

Here, for the first time, a study of composite graphitic carbon nitride photocatalysts based on laboratory synthesized TiO2 (g-C3N4/TiO2) for the hydrogen evolution reaction (HER) from aqueous solutions of organic substrates under visible light irradiation is presented. The methods to synthesize TiO2 and g-C3N4/TiO2 include precipitation and hydrothermal routes, followed by calcination. A comparison of the synthetic approaches was carried out using a variety of electron donor systems (glucose, ethanol and triethanolamine). The highest HER activity is achieved with a photocatalyst containing 10 wt% g-C3N4 on TiO2, obtained by precipitation. Pt- and Cu-modified photocatalysts exhibit hydrogen evolution rates of 161 and 34 µmol h-1 g-1, respectively, in aqueous glucose solution. This enhanced performance originates from the successful formation of effective heterojunctions between g-C3N4 and the different phases of TiO2, as well as the material sensitivity to both visible and UV light.