Visible light assisted photodegradation of 2,4-dinitrophenol using Ag2CO3 loaded phosphorus and sulphur co-doped graphitic carbon nitride nanosheets in simulated wastewater

Abstract

Nowadays, hybrid photocatalysts are gaining importance due to their improved photocatalytic activity. In the present work, Ag2CO3 was integrated phosphorous and sulphur co-doped g-C3N4 (PSGCN) photocatalyst (Ag2CO3/PSGCN) to minimize the recombination of photogenerated electron-hole pair. The co-doping resulted in band gap lowering in GCN leading to more visible light activity. Successful formation of well dispersed Ag2CO3/PSGCN suspension in water was established by zeta potential and Tyndall effect experiments. Phosphorous and sulphur co-doping in g-C3N4 resulted lowering of optical band gap that enhanced its photodegradation ability under visible light. The reduction in photogenerated electron-hole pair recombination was confirmed by photoluminescence and electrochemical impedance analysis. The photodegradation of 2, 4, dinitrophenol (DNP) followed pseudo first order kinetics and enhanced photocatalytic activity was due to semiconductor heterojunction for effective separation of electron–hole pair. Holes and hydroxyl radicals were two main oxidative species responsible for photodegradation of DNP into non-toxic products. COD, HPLC and LC-MS investigations were used to investigate the degradation fragment during DNP mineralization. Ag2CO3/PSGCN nanocomposite revealed high stability and recycle efficiency substantial for ten catalytic cycles. Keywords: Co-doped graphitic carbon nitride, Ag2CO3, Heterojunction formation, Enhanced photocatalysis, 2,4-dinitrophenol degradation