A novel S-scheme g-C3N4/Mn(VO3)2 heterojunction photocatalyst for its superior photocatalytic degradation of broad-spectrum antibiotics

For addressing the problem of the polluted water by organic matters, it is urgent to develop stable and efficient photocatalysts to degrade antibiotics in the environment. Herein, a novel layered structure g-C3N4/Mn(VO3)2 heterojunction photocatalyst is synthesized by using the microwave hydrothermal method and it is firstly applied to remove pharmaceutical pollutants. Compared with Mn(VO3)2 and g-C3N4, the outcomes illustrate that the 1/2.75-g-C3N4/Mn(VO3)2 photocatalyst displays the optimum photocatalytic capability and excellent stability in the degradation of Sulfamethoxazole (SMX). It shows a degradation efficiency of 87.3% in 110 min, which is 11 and 14 times as high as Mn(VO3)2 and g-C3N4, respectively. Moreover, the constructed heterojunction potently promotes carriers transfer and restrains the rebinding of photogenerated electron-hole pairs. Based on density functional theory, the photogenerated electron transfer pathway and photocatalytic degradation mechanism are deeply analyzed. Meanwhile, the S-scheme heterojunction model is proposed, which could improve the utilization of sunlight, and has efficient charge space separation and strong redox ability. Therefore, this work constructs an innovative photocatalyst enabling efficient degradation of pharmaceutical antibiotics, and it also presents a new outlook for strengthening the removal of antibiotics and constructing a novel S-scheme heterojunction photocatalyst.