Synthesis of g-C ₃ N ₄ /TiO ₂ -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.