Hydrogen production using zinc-doped carbon nitride catalyst irradiated with visible light

Recently, graphitic carbon nitride (g-C₃N₄) has been investigated as a photocatalyst for water splitting and organic dye degradation. In this study, we have developed a simple soft-chemical method of doping Zn into g-C₃N₄ to prepare a metal-containing carbon nitride. The doping was confirmed by x-ray photoelectron spectroscopy, and diffusion reflectance spectra revealed a significant red shift in the absorption edge of Zn/g-C₃N₄. This hybrid material shows high photocatalytic activity and good stability for hydrogen evolution from an aqueous methanol solution under visible light irradiation (λ≥420 nm). The hydrogen evolution rate was more than 10 times higher for a 10%-Zn/g-C₃N₄ sample (59.5 μmol h^-1) than for pure g-C₃N₄. The maximum quantum yield was 3.2% at 420 nm.