Cerium dioxide has a comparatively lower Ce4+/Ce3+redox pair,which leaves abundant oxygen vacancies on oxide lattice,also making incorporation of foreign ion and subsequent applications feasible and convenient.In this...Cerium dioxide has a comparatively lower Ce4+/Ce3+redox pair,which leaves abundant oxygen vacancies on oxide lattice,also making incorporation of foreign ion and subsequent applications feasible and convenient.In this work,a series of cerium-yttrium mixed oxides were prepared by using polyvinylpyrrolidone as major template through sol-gel,which were further employed as catalyst for dehydration of aniline with formic acid into N-phenylformamide.Characterizations reveal that synthetic samples have a variety of morphologies including nanoparticle,microflower,and uniform microrods.The monitoring of particle size,zeta potential,and ultravioletvisible(UV-Vis)of preparative solution indicate that selfassembly of polyvinylpyrrolidone and its subsequent reaction with metal ion determines sample morphology.In catalytic dehydration,all samples show high dehydration efficiencies that are comparable to those from anhydrous Na2SO4 and combination of dicyclohexylcarbodiimide with 4-dimethylaminopyridine and dichloromethane shows better outputs than water.In association with structural analysis,cerium looks more active than yttrium,while yttrium mainly plays as a structure-directing and poreformingagent.Thisstudymaycontributeto micro-/nanofabrication of rare earth composites and their catalytic applications.展开更多
基金the Natural Science Foundation of Shaanxi Province(No.2017JM2016)the Fundamental Research Funds for the Central Universities(No.xjj2014005)。
文摘Cerium dioxide has a comparatively lower Ce4+/Ce3+redox pair,which leaves abundant oxygen vacancies on oxide lattice,also making incorporation of foreign ion and subsequent applications feasible and convenient.In this work,a series of cerium-yttrium mixed oxides were prepared by using polyvinylpyrrolidone as major template through sol-gel,which were further employed as catalyst for dehydration of aniline with formic acid into N-phenylformamide.Characterizations reveal that synthetic samples have a variety of morphologies including nanoparticle,microflower,and uniform microrods.The monitoring of particle size,zeta potential,and ultravioletvisible(UV-Vis)of preparative solution indicate that selfassembly of polyvinylpyrrolidone and its subsequent reaction with metal ion determines sample morphology.In catalytic dehydration,all samples show high dehydration efficiencies that are comparable to those from anhydrous Na2SO4 and combination of dicyclohexylcarbodiimide with 4-dimethylaminopyridine and dichloromethane shows better outputs than water.In association with structural analysis,cerium looks more active than yttrium,while yttrium mainly plays as a structure-directing and poreformingagent.Thisstudymaycontributeto micro-/nanofabrication of rare earth composites and their catalytic applications.
