Boosted photogenerated charge carrier separation by synergy of oxygen and phosphorus co-doping of graphitic carbon nitride for efficient 2-chlorophenol photocatalytic degradation

Abstract

Although graphitic carbon nitride (g-C3N4) has been attracted with its unique band structure, the ease of recombination of charge and the poor light-capturing capability limits its application in degradation of organic pollutants. Herein, via simple one-step thermal polymerization, oxygen and phosphorus dopants are simultaneously introduced into the heptazine unit of g-C3N4. The obtained O and P co-doped g-C3N4 could completely remove 2-chlorophenol (2-CP) in 30 min, much superior to bulk g-C3N4. The density functional theory (DFT) calculations and experimental characterization demonstrate that the synergy of O and P co-doping leads to the changes in bandgap structure, thus obviously enhancing the light-capturing capability and promoting the charge carrier separation. Moreover, the synergy of O and P co-doping facilitates the adsorption and enrichment of oxygen molecules at phosphorus sites, contributing to the generation of abundant reactive oxygen radicals. These radicals actively participate in the subsequent degradation of organic pollutants.