Photoelectrocatalytic degradation of deoxynivalenol on CuO-Cu2O/WO3 ternary film: Mechanism and reaction pathways

Abstract

A ternary film of CuO-Cu2O/WO3 possessing high visible-light photoelectrocatalytic (PEC) performance was prepared for degradation of deoxynivalenol (DON). In such a ternary film, the introduction of CuO-Cu2O significantly promoted the absorption of WO3 in the visible region and reduced the recombination of photogenerated charge carriers. As a result, the CuO-Cu2O/WO3 film exhibited high photoelectrochemical activity under visible light illumination. The PEC performance of CuO-Cu2O/WO3 film was evaluated by the decoloration of Rhodamine B. The result indicated that the CuO-Cu2O/WO3 film exhibited higher PEC activity than WO3 or CuO-Cu2O film. When the CuO-Cu2O/WO3 film was applied to study the removal of DON, the degradation efficiency reached 87.6% after 180-min PEC treatment. According to reactive oxygen species detected by electron spin resonance analysis, a Z-scheme and type-II PEC mechanism was proposed for this ternary film. Furthermore, the intermediates formed during the PEC degradation process of DON were separated by high-performance liquid chromatography and identified with liquid chromatography-mass spectrometry. On the basis of sixteen intermediate products identified, we proposed a degradation pathway for DON in such a PEC system.