Visible light promoted aerobic selective photo-oxidation of cyclohexene on LaCoxCu1−xO3 catalyst

Heterogeneously catalyzed liquid oxidation of olefins with O 2 provides an alternative way for synthesizing high-value added chemicals. Herein, we report a straightforward urea-redox and sol-gel process for synthesizing LaCo x Cu 1− x O 3 for aerobic photo-oxidation of cyclohexene. Our research highlights a marked increase in the proportions of Co 2+ and Cu + species in a low chemical state, as well as enhanced visible light absorption through this method. Mechanistic investigations suggest that the catalytic process, particularly with LaCo 0.7 Cu 0.3 O 3 , involves a radical pathway mediated by reactive oxygen species. The presence of Cu + /Co 2+ species and surface oxygen vacancies is proposed to boost O 2 adsorption and activation on the catalyst, facilitating the formation of 2-cyclohexene-1-hydroperoxides. Furthermore, Cu 2+ /Co 3+ species are thought to aid in generating cyclohexene-derived radical species. The efficient aerobic oxidation of cyclohexene on LaCo 0.7 Cu 0.3 O 3 catalyst relies on the formation of reactive oxygen species and carbon radicals, facilitated by its strong visible light illumination. It achieves a cyclohexene conversion of 89.4% and selectivity to cyclohex-2-ene-1-one of 72.2%, along with stable recyclability after six reuses. The creation of nano-structured LaCo x Cu 1− x O 3 through the urea-redox and sol-gel process offers a promising avenue for the development of highly efficient catalysts for the aerobic photo-oxidation of cyclohexene to cyclohex-2-ene-1-one in the future.