Photocatalytic degradation of 2,4,6-trichlorophenol over g-C3N4 under visible light irradiation

Graphitic carbon nitride (g-C 3 N 4 ) was synthesized by directly thermal condensation of dicyandiamide and characterized by XRD, XPS, SEM, TEM and FT-IR. Then the as-prepared catalyst was employed to degrade priority pollutant 2,4,6-trichlorophenol (2,4,6-TCP) under visible light irradiation ( λ   >   420   nm). The 2,4,6-TCP could be completely mineralized over g-C 3 N 4 , and the pseudo-first-order rate constant for 10 −4   M 2,4,6-TCP degradation was 0.70   h −1 in the presence of 1   g/L catalyst. O 2 - / OOH ${}^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}}{\text{O}}_2^{-}/{}^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}}\text{OOH}$ was identified as the most important reactive species contributing to 2,4,6-TCP degradation in air. Meanwhile, valence band holes (VB holes) of g-C 3 N 4 was observed to play important roles for the degradation of 2,4,6-TCP at N 2 gas ambient when metal ions were added as electron acceptors. The possible degradation pathway of 2,4,6-TCP was proposed.