The Stable Core-shell Gold@carbon Nanosphere Catalyst Is Used For The Study Of Benzyl Alcohol Oxidation

During the past few decades,there have been comprehensive studies on nanocatalysts.Especially,gold nanoparticles with small size have high catalytic activity to selective oxidation reaction.However,the catalytic activity of 15 nm gold nanoparticles is rarely reported.Based on organic-organic self-assembly method,we control the hydrothermal synthesis conditions to synthesis Au@MCN.The prepared Au@MCN catalyst is reacted with selective catalytic oxidation of benzyl alcohol in the aqueous phase.It presents high catalytic activity and selective for the oxidation of benzyl alcohol using oxygen as the oxidant.The full text is divided into five chapters,the first chapter is literature review,mainly including research progress of order mesorous materials and application prospects of supported nanogold catalysts.In chapter 2,the synthesis of ordered mesoporous core-shell gold@carbon nanospheres catalysts are introduced.Based on organic-organic self-assembly method,we control the hydrothermal synthesis conditions to synthesis Au@MCN,using AuNPs as a gold core,phenolic resin as a carbon shell precursor.After carbonization,the spherical morphology with a size of approximately 90 nm posess high surface area（⁶40 m²/g）,large pore volume（⁰.55 cm³/g）,uniform mesopore size（².6 nm）and the size of the gold nucleus remains at 15 nm.The gold core with a size of 15 nm is confined to the carbon shell.There is no aggregation,even if it is calcined at a high temperature of 700°C,showing a high thermal stability of the catalyst.In the third chapter,the catalytic performance of ordered mesoporous core-shell gold@carbon nanospheres catalysts are studied.The prepared Au@MCN catalyst is reacted with selective catalytic oxidation of benzyl alcohol in the aqueous phase.It presents high catalytic activity and selective for the oxidation of benzyl alcohol using oxygen as the oxidant.At atmospheric pressure and 60°C,the TOF value can reach5463 h^-1.No significant reduction in TOF and loss of Au is observed after 5repetitions,indicating that the catalyst has high stability and reproducibility.The hot infiltration test,together with the trapping test using mercapto-functionalized SBA-15solids,shows that the soluble gold species are undetected during successive catalytic runs and the active center is a heterogeneous nano-gold catalyst.Then,we synthesize the ordered mesoporous core-shell gold@silicon nanospheres catalysts（Au@MSN）,using in the selective oxidation of benzyl alcohol.The catalytic activity sources of the two catalysts are studied by various means of characterization.The last chapter is summary of the whole work.