Enhanced visible light photocatalytic performance of crystalline g-C3N4 nanosheets by one-step molten salt method

Abstract

The crystalline g-C3N4 nanosheets have been successfully prepared by one-step molten salts method. The microstructures and optical properties of as-prepared samples were characterized by different techniques, such as XRD, EDS, XPS, SEM, TEM, BET, PL and Uv–vis DRS. The results showed that the unit of the crystalline g-C3N4 nanosheets was composed of triazine ring, which was different from heptazine-based g-C3N4. The crystalline g-C3N4 nanosheets were thin and transparent, which were similar to graphene. The crystalline g-C3N4 nanosheets exhibits the excellent photocatalytic activity, which can degrade 98% RhB within 120 min under visible light irradiation. However, the degradation efficiency of bulk g-C3N4 is only 40% within 120 min. The enhanced photocatalytic activity of g-C3N4 nanosheets can be attributed to 2D nanosheet morphology, which inhibits the electron-hole recombination. In addition, the high specific surface area of g-C3N4 nanosheets positively increases the contact area with pollutants, making the degradation reaction more efficiently. A plausible photocatalytic mechanism was proposed for the degradation of RhB under visible light irradiation.