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 synthesizi...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 photooxidation 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 cyclohexenederived 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.展开更多
基金supported by the National Natural Science Foundation of China(No.22302001)Key Projects of the Department of Education of Anhui Province of China(No.2022AH050314)Key Program for International S&T Cooperation Projects of China(No.2017YFE0124300).
文摘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 photooxidation 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 cyclohexenederived 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.
