Boosting photocatalytic property of graphitic carbon nitride with metal complex fabrication for efficient degradation of organic pollutants

Abstract

The development of efficient and stable photocatalysts for degradation of refractory pollutants using minimal amounts of metal remains a major challenge. Herein, we synthesize a novel catalyst by fabrication of manganese (III) acetylacetonate complex [Mn (acac)₃] over graphitic carbon nitride (GCN) denoted as 2-Mn/GCN by facile ultra-sonication method. The fabrication of the metal complex enables the migration of electrons from the conduction band of graphitic carbon nitride to Mn (acac)₃, and migration of holes from valence band of Mn (acac)₃ to GCN upon irradiation. Exploiting the improved surface properties, light absorption, and charge separation ensure generation of superoxide and hydroxyl radicals resulting in the rapid degradation of a variety of pollutants. The designed 2-Mn/GCN catalyst realized 99.59% rhodamine b (RhB) degradation in 55 min and 97.6% metronidazole (MTZ) degradation in 40 min with 0.7% Mn content. The influence of catalyst amount, different pH and presence of anions on the degradation kinetics was also explored to offer insights into photoactive material design.

Keywords: Antibiotics; Degradation; Dyes; Graphitic carbon nitride; Metal complex grafting; Radical trapping.