High-efficiency and stable Z-scheme heterojunction of Co9S8 anchored by g-C3N4 for peroxymonosulfate activation

Photocatalytic technology and peroxymonosulfate (PMS) based advanced oxidation technology have been proven to be simple and effective strategies for recalcitrant organic pollutants degradation. In this work, we designed and prepared a coupled photocatalytic and advanced oxidation system for sulfamethazine (SMR) antibiotics degradation. Firstly, a series of Z-scheme Co 9 S 8 /g-C 3 N 4 heterojunction photocatalysts are prepared by a simple two-step method and further work as PMS activators. The prepared Co 9 S 8 /g-C 3 N 4 photocatalysts exhibit a great improvement in electron-hole pairs migration and visible-light response due to heterojunction formation. In addition, the g-C 3 N 4 acts as a substrate to anchor the Co 9 S 8 nanoparticle, which suppresses the Co 9 S 8 leaching and prevents the Co 9 S 8 oxidation. Consequently, the Co 9 S 8 /g-C 3 N 4 /PMS system displayed an improved SMR degradation ability (93 % for Co 9 S 8 /g-C 3 N 4 /PMS vs. 86 % for Co 9 S 8 /g-C 3 N 4 ). After the fourth cyclic degradation experiment, the Co 9 S 8 /g-C 3 N 4 /PMS system still maintained a comparatively high degradation rate. Considering its good properties and better degradation performance, we propose that the synergistic effect of photocatalytic technology and PMS possess a promising prospect for application in environmental treatment.