Constructing S-scheme Au/g-C3N4/BiVO4 heterojunction with peroxymonosulfate-enhanced photocatalytic activity and mechanism insight

Dissolved organic matter (DOM) in black-odorous water can cause excessive growth of plants and algae, leading to deterioration of water quality. Herein, an S-scheme Au/g-C3N4/BiVO4 heterojunction was constructed using a three-step method for DOM degradation in real black-odorous water in the presence of peroxymonosulfate (PMS). 4Au/g-C3N4/BiVO4/PMS exhibited highly efficient photocatalytic performance, and the DOM removal rate could reach 92.9 %, which was 19.1 and 9.9 times higher than that of g-C3N4/PMS and BiVO4/PMS, respectively. The changes of fluorescence components in DOM were detected using synchronous fluorescence spectra and two-dimensional correlated spectroscopy analysis, and the toxicity of catalytically treated black odorous water was evaluated by growth inhibition of Escherichia coli . A reasonable S -scheme mechanism was suggested by theoretical calculations and photoelectrochemical tests. The S -scheme mechanism and the syner- gistic effect of photocatalysis and hybrid advanced oxidation process (HAOP) increased the catalytic activity of Au/g-C 3 N 4 /BiVO 4 /PMS.