Novel carbon and defects co-modified g-C3N4 for highly efficient photocatalytic degradation of bisphenol A under visible light

Graphite carbon nitride ( g -C 3 N 4 , CN) is considered as a promising semiconductor for environmental catalysis. However, pure CN can not meet the requirements for actual applications due to its high recombination rate of photogenerated electron-hole pairs and a relatively large band gap preventing full utilization of solar energy. In this work, we report synthesis of a novel carbon and defects co-modified g -C 3 N 4 (C x CN) by calcination of melamine activated by oxalic. This new catalyst C x CN has porous structure with much higher surface areas compared with pristine CN. UV–vis analysis and DFT calculations show that C x CN has a lower bandgap for enhancing visible light adsorption compared with CN. Photoluminescence (PL) and photoelectrochemical analyses show that C x CN has a low recombination rate of photogenerated electron-hole pairs, which improves the utilization of solar energy. As a result, C x CN samples show high efficiency for the degradation of bisphenol A (BPA) under visible light irradiation, where the best catalyst of C x CN (C 1.0 CN) samples shows about 22 times higher photocatalytic degradation rate than that of CN. Moreover, C 1.0 CN shows high mineralization rate and can degrade BPA into CO 2 and H 2 O by the generated active species, like superoxide radicals ( O 2 − ) and holes (h + ).