Enhanced visible-light photocatalytic H-generation activity of carbon/g-CN nanocomposites prepared by two-step thermal treatment.

Photocatalytic hydrogen (H) production from water by using solar energy and a photocatalyst is a green and sustainable route to tackle the energy issues. Herein, carbon/g-CN nanocomposites were successfully synthesized via a two-step thermal treatment of urea and glucose with different ratios. As confirmed by X-ray photoelectron spectroscopy, a C-O-C bond was formed between carbon and g-CN, which leads to a strong interaction between carbon and g-CN. The prepared samples were evaluated for photocatalytic H generation under visible light irradiation. The experimental results indicate that the carbon/g-CN nanocomposites show great photocatalytic H evolution activity, as high as 410.1 μmol g h, which is 13.6-fold of pure g-CN. The enhanced photocatalytic performance not only originates from the enlarged surface area and extended visible light response range, but also from the effectively separated photo-generated charge carriers. This spatial charge separation greatly suppresses the recombination of photo-generated hole-electron pairs and facilitates efficient H production. This work provides a facile way to design highly efficient carbon nitride-based photocatalysts for potential application in photocatalytic reaction by using solar energy.