Simple method for preparing of sulfur–doped graphitic carbon nitride with superior activity in CO2 photoreduction

S-doped porous carbon nitride was obtained by a simple method using melamine and sulfuric acid. The synthesized material exhibits high BET specific surface area (75 m²/g) compared to non-doped C₃N₄ (25 m₂/g). According to X-ray photoelectron spectroscopy sulfur atoms substitute nitrogen forming C−S bonds in the structure of carbon nitride. Incorporation of sulfur into C₃N₄ results in a significant increase of the light absorbance intensity especially in the UV region compared to undoped sample. Synthesized S-doped carbon nitride was found to be p-type semiconductor with high catalytic activity towards photoreduction of carbon dioxide with water vapour. Doping C₃N₄ with sulfur increases the catalytic activity in this reaction almost tenfold.