自组装技术制备Au/SiO2催化剂及其催化空气氧化环己烷的性能研究

通过自组装方法制备了Au/SiO2纳米复合催化剂，并采用透射电镜、X-射线衍射、原子吸收光谱、紫外-可见光谱和氮吸附脱附（比表面积及孔结构分析）对其进行表征。以空气氧化环己烷制备环己酮和环己醇为探针反应，在不加入任何溶剂或助催化剂的条件下考察了金含量、反应温度、压力、时间及焙烧温度对催化剂活性的影响。结果发现，金负载量为1%的Au/SiO2催化剂经500 ℃焙烧，在最佳温度、压力和反应时间下，表现出良好的催化活性，环己烷转化率最高可达10.1%, 环己酮和环己醇的总选择性约为92%。

PREPARATION OF Au/SiO2 CATALYSTS BY SELF-ASSEMBLY TECHNIQUE AND ITS CATALYTIC PERFORMANCE OF OXIDATING CYCLOHEXANE WITH AIR

Nanocomposite catalysts of Au/SiO2 were prepared by self-assembly method. X-ray diffraction (XRD), transmission election microscopy (TEM), atom absorption spectrometry (AAS), ultraviolet-visible spectroscopy (UV-Vis) and nitrogen adsorption/desorption technique were used to characterize these samples. The oxidation of cyclohexane with air to produce cyclohexanol and cyclohexanone without using any organic solvent or co-catalyst was investigated over the as-prepared Au/SiO2 catalysts. The influences of gold content, reaction temperature, reaction pressure, reaction time and calcination temperature on the catalytic performance of catalysts prepared were studied. It was found that catalyst prepared with a gold loading of 1% and calcined at 500℃ exhibited good catalytic performance, when it was continuous reacted under an air pressure of 3.0 MPa for 4 h ,the conversion of cyclohexane and the total selectivity to cyclohexanol and cyclohexanone were about 10% and 92%, respectively.