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

Graphitic carbon nitride (g-C3N4) 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-C3N4, 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. O2-/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-C3N4 was observed to play important roles for the degradation of 2,4,6-TCP at N2 gas ambient when metal ions were added as electron acceptors. The possible degradation pathway of 2,4,6-TCP was proposed.

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• g-C3N4 was synthesized by directly thermal condensation of dicyandiamide.
• 2,4,6-TCP could be degraded over g-C3N4 under visible irradiation.
• O2-/OOH was the most important reactive species in the presence of O2.
• 2,4,6-TCP was oxidized by hole at N2 gas ambient in the presence of metal ions.
• The possible degradation pathway of 2,4,6-TCP was proposed.