Degradation of catechol on BiOCl: charge transfer complex formation and photoactivity

Abstract: BiOCl photocatalysts were successfully synthesized using Bi(NO3)3·5H2O and KCl as raw materials. The physical properties and optical absorption performances of as-prepared samples were characterized through XRD, SEM, TEM, XPS and DRS. Contrary to common expectations, catechol could be degraded with visible light on as-synthesized BiOCl. The observed visible-light induced activity could be due to the formation of charge transfer complex, confirmed by DRS, FTIR, Raman, and XPS. About 65.0 % of catechol was degraded after 120 min light irradiation, and the rate constant, k, is 9.04×10–3 min–1. The addition of L-ascorbic acid inhibited the degradation of catechol, indicating •O2– being the main active species in catechol redox reaction. Finally, the degradation mechanism of catechol under visible light irradiation with BiOCl was proposed.