A novel silver-loaded graphitic carbon nitride with structural defect assisted by ascorbic acid for the fast and efficient degradation of sulfamethoxazole

The heterojunction construction and structural defect engineering both can effectively improve the catalytic performance of semiconductor photocatalysts. In this work, a novel composite photocatalyst consisted of the porous graphitic carbon nitride with two structural defects of oxygen atom and cyano group (COCN) and silver nanoparticles (AgNPs) decorated to COCN plane has been successfully prepared. And the morphology, structure, chemical composition and photoelectrical properties of this composite photocatalyst (Ag/COCN) were further characterized. Due to the synergistic effect of the heterojunction, surface plasmon resonance effect of AgNP and structural defects, Ag/COCN showed the narrow bandgap, high light absorption and fast charge separation so as to achieve a fast and efficient degradation of sulfamethoxazole (SMX). Through further optimization of AgNPsloaded content, Ag/COCN presented the excellent photocatalytic activity on SMX degradation under simulated solar irradiation that more than 99.9% of SMX was removed within 20 min, which is among the best results reported thus far for SMX degradation rate via photocatalysis.