Synthesis Of CeO₂ And Its Composites Toward Enhanced Photocatalytic Performance

Solar energy is a kind of clean energy widespread on Earth.How to efficiently convert low-density solar energy into storable chemical energy has been a continuous pursuit of scientsts.Semiconductor-based photocatalytic organic synthesis is considered to be a consummate means to convert solar energy.Since benzaldehyde is an important intermediate in pharmaceutical and perfumery industries,selective photo-oxidation of benzyl alcohol to benzaldehyde is of great value.However,the rapid recombination of the photo-generated carries usually leads to low catalytic activity.Therefore,rationally designing highly efficient photocatalyst is a frontier hot spot in the field of photocatalysis.CeO₂,with the unique f electron,is widely used in ultraviolet absorption,electronic devices,three-way catalysts,etc.The ability of ceria to exhibit facile redox properties(Ce³⁺???Ce⁴⁺),as well as forming and annihilating oxygen vacancies while maintaining structural integrity,is the key of its widespread application in heterogeneous catalysis.In the field of photocatalysis,cerium dioxide has been studied for pollutant degradation,oxygen production and organic synthesis.However,the poor absorption of sunlight limits its photocatalytic performance.Hence,how to modify cerium dioxide with its unique advantages to improve its photocatalytic performance is of great value.In this thesis,we construct the cerium dioxide nanorod/benzyl alcohol surface complex and CeO₂/Cd_0.5Zn_0.5S nanocomposite successfully,and investigate their photocatalytic performance toward selective oxidation benzyl alcohol to benzaldehyde under visible light irradiation.The primary contents show below:?1?The effects of calcination temperature and reaction temperature on the photocatalytic performance of CeO₂ toward selective oxidation benzyl alcohol to benzaldehyde under visible light irradiation were studied.The research results indicate that,benzyl alcohol adsorbed on cerium nanorods can form surface complex,which can successfully expend its visible light response;the introduction of thermal field can effectively improve the catalytic performance toward oxidation of benzyl alcohol under visible light irradiation.?2?CeO₂/Cd_0.5Zn_0.5S nanocomposites were synthesized successfully,and the photocatalytic performance toward selective oxidation benzyl alcohol under visible light was studied.The results prove that,the intimate contact and the matching band position between CeO₂ and Cd_0.5Zn_0.5S accelerates the charge separation and promotes the photocatalytic activity.The innovation points derived from present research:?1?Studied the interaction between CeO₂ and benzyl alcohol from the point of surface-complex for the first time and investigated the effects of thermal field toward photo-oxidation of benzyl alcohol under visible light irradiation.?2?Prepared the CeO₂/Cd_0.5Zn_0.5S nanocomposite photocatalyst for the first time,and proved that the intimate contact,the matching band position and the rich surface reaction sites are the key of enhangced performance toward photo-oxidation of benzyl alcohol under visible light,which provides a new insight for rational design photocatalyst with super activity under visible light.