Synthesis And Properties Of Hollow CeO₂ Supported Catalysts

It has been unprecedented concerned that how to prevent the water pollution and air pollution in these decades years.The development of nano-science has showed some new methods.Moreover,the varies of the species and priority of nano materials make it essential to solve the specific problem.The key to control its properties is the accuracy of nano materials' surface and construction designing.An approach of simultaneous coordinating etching and Pd nano coating technology is employed to prepare hollow Pd/CeO2 nanocubes.In the experiments,the as-prepared Cu2O nanocube is hired as the template,and then S2O32-is used to self-gather around and coordinating etching of Cu2O coating with Ce4+,the prepared hydroxide formed.Thermal treatment facilitates the products of hollow CeO2 nanocubes.Finally,Pd nano covered in it,then we get the end products.The properties of hollow Pd/CeO2 nanocubes were studied with the CO oxidation reaction using temperature-programmed mode.It's T90 decrease to-5.6?.Because of it's hollow structure,the BET surface area is much larger and it has lower density.It is found that as-synthesized Pd/CeO2 with hollow nanocube structure catalysts exhibit superior catalytic activity for CO.In a similar way,an approach of simultaneous coordinating etching and precipitation reactions is employed to prepare hierarchical hollow TiO2@CeO2 nanocube heterostructures.The as-prepared Cu2O nanocube is hired as the template,and then S2O32-is used to self-gather around and coordinating etching of Cu2O,and then S2O32-is used to self-gather around and coordinating etching of Cu2O.Subsequently,OH-originated from hydrolysis of S2O32-results of the precipitation of Ti and Ce ions,and thus(TiCex)O(OH)nanoparticals formed.Finally,thermal treatment facilitates the products of TiO2/CeO2 nanocubes.It used to catalyze cyanide oxidation under visible light.The concentration of cyanide ion decreased sharply from the initial 4.70 mM to 0.18 mM corresponding to the removal rate of 96.17%with the exposure tim 90 min.The hollow cubic structures make multiple reactions of light within the chamber,allowing more efficient use of the light source.Moreover,the heterojunction effect can lead to enhanced charge separation and interfacial charge transfer efficiency.All the factors contribute greatly to the improved visible light catalytic activity.In the solvothermal alcoholysis-hydrolysis process,accompanying the two simultaneous reactions(hydrolysis of Ce3+ and carbonization of sucrose),the Ostwald ripening process is promoted by the small amount of water added in the solvothermal process.Finally,Pd nano covered in it,then we get the cage-bell Pd@CeO2 structured nanoparticle,the properties of Pd@CeO2 were studied with the CO oxidation reaction using temperature-programmed mode.It's T90 decrease to 2 ?.Because of the gap between the core and shell,the BET surface area is much larger.Then it can provide much more oxidation activity sites and exhibit excellent catalytic activity.