Abstract
The catalytic activity of CeO(2) can be modulated by incorporating defects and inducing strong metal-support interactions. Herein, we introduce CuO into CeO(2) for generating oxygen vacancies (CeO(2-x) ) via the interaction between CuO and CeO(2). The resultant catalyst CuO/CeO(2) exhibited improved performance for the photocatalytic degradation of isoproturon (a herbicide). The improvement in catalytic performance was attributed to the oxygen vacancies and interfacial charge transfer between CuO and CeO(2). Notably, the addition of CuO increased the oxygen vacancies in CeO(2), correlating with the increase in the Ce(3+) content (31.2%). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy studies substantiated the increase in surface oxygen vacancies in CeO(2). We investigated the oxygen vacancies quantitatively and detected the chemical states of the Cu and Ce species. Photoluminescence (PL) studies validated the role of oxygen vacancies in restraining the recombination of photogenerated electron and hole pairs, thereby improving the catalytic activity of CuO/CeO(2). Trapping experiments were conducted to identify the reactive species involved in the photocatalytic degradation process. Based on a thorough evaluation of the characteristics of the catalyst and photocatalysis experimental outcomes, a potential reaction mechanism was proposed. Furthermore, high-resolution mass spectrometry (HRMS) analysis was utilized to identify degradation intermediates, enabling us to outline the possible degradation pathways of isoproturon. Isoproturon (IPU) was effectively degraded under UV light with CuO/CeO(2) compared with pristine CeO(2). A 95% degradation efficiency was achieved with CuO/CeO(2) (10 mg) for the IPU solution (10 μg L(-1)) within 120 minutes. This study provides detailed insights into the structural analysis of defective CeO(2) and an in-depth mechanism of its photocatalysis, facilitating the design of high-performance ceria-based catalysts for photocatalytic degradation of emerging contaminants in water.