Cobalt-modified graphitic carbon nitride nanosheets for the photocatalytic degradation of diclofenac.

Diclofenac (DCF), as a challenging new type of pollutant, is resistant to removal by photocatalysis due to the poor visible-light utilization and sluggish charge separation. In this study, cobalt (Co) modified graphitic carbon nitride (3Co/CCN) was successfully synthesized using a cyanuric acid (CA)-induced dispersion of cobalt phthalocyanine (CoPc) within urea through mechanochemical method and the subsequent thermal polymerization route. Under visible-light irradiation, the 3Co/CCN displayed 2.8 times higher DCF photodegradation than that of CCN, accompanied by a 21.4-fold enhancement in reaction kinetics rate. It also demonstrated excellent photocatalytic performance in complex environmental conditions with notable photocatalytic stability. The incorporation of Co species (Co2+/Co3+) was found to improve the separation of electron-hole pairs, as confirmed by photoluminescence spectroscopy and photoelectrochemical characterization. This study introduces an efficient and cost-effective strategy for the effective removal of DCF from wastewater.