Solar photocatalytic degradation of sulfanilamide by BiOCl/reduced graphene oxide nanocomposites: Mechanism and degradation pathways

Abstract

Flower-like bismuth oxychloride (BiOCl) catalysts were synthesized with a facile hydrolysis reaction, where the synthesized BiOCl products were further decorated with the prepared graphene oxide (GO) to form novel BiOCl/reduced graphene oxide (BiOCl/RGO) composites. The as-synthesized materials were well characterized with the aid of various techniques, before they were used as photocatalysts for the degradation of sulfanilamide (SN) aqueous solution. The BiOCl/RGO composites contained 1 wt% RGO exhibited superior photocatalytic response, where the degradation rate of SN at 82.7% stayed 30% higher than that of pure BiOCl. The enhanced photocatalytic performances of BiOCl/RGO composites were neither related to the surface area values nor the bandgap of the fabricated photocatalysts, but associated with the enhanced visible light absorption and advanced electron transfer ability. On a basis of the analysis on the SN intermediate products by HPLC, IC, FTIR, 1H NMR, 13C NMR and MS, the degradation pathway of SN was speculated, where it was confirmed that the main intermediate product of SN was sulfanilic acid.