论文部分内容阅读
分别以金的有机配合物Au(PPh3)(NO3)和无机化合物HAuCl4为前驱体,采用常规浸渍法分别制备了Au/13X-Org和Au/13X-Ino,并以后者作为对照.采用N2-吸附/脱附、SEM-EDS、XRD和XPS等技术对所制样品的织构、晶体结构和价态进行了表征,并研究了所制样品对CO的催化氧化性能.N2-吸附/脱附、SEM-EDS和XRD结果表明,对于Au/13X-Org样品,Au较均匀地分布在13X载体上,而Au/13X-Ino样品,Au聚集地分布在13X载体上.通过XRD和SEM测定表明Au/13X-Ino上金粒子(平均粒径≈26.6nm)明显大于Au/13X-Org上金粒子(平均粒径<5nm).CO催化氧化结果表明,Au/13X-Org催化性能明显优于Au/13X-Ino,Au/13X-Org在低温25℃时CO转化30%,150℃完全转化;而Au/13X-Ino在低温无活性,CO完全转化温度高于400℃.对于这种“惰性”13X载体负载Au活性的差别可能归因于金粒子的大小和前驱体中有无氯物种两方面的原因.XPS结果表明,在Au/13X-Org和Au/13X-Ino催化剂上催化氧化的活性中心为金属态Au0.
Au / 13X-Org and Au / 13X-Ino were prepared by conventional impregnation method using Au (PPh3) (NO3) and HAuCl4 as precursors, respectively. Adsorption / desorption, SEM-EDS, XRD and XPS were used to characterize the texture, crystal structure and valence of the prepared samples, and the catalytic oxidation of the prepared samples was studied .N2-adsorption / desorption The results of SEM-EDS and XRD show that Au is more uniformly distributed on the 13X support for the Au / 13X-Org sample and Au is concentratedly distributed on the 13X support for the Au / 13X-Ino sample. The results of XRD and SEM Au / 13X-Ino gold particles (average diameter ≈26.6nm) were significantly larger than the Au / 13X-Org gold particles (average particle size <5nm) .CO catalytic oxidation results show that the catalytic performance of Au / 13X- Au / 13X-Ino, Au / 13X-Org converted 30% of CO at low temperature and completely transformed at 150 ℃, while Au / 13X-Ino was inactive at low temperature and CO completely transformed at temperature above 400 ℃. The difference in the Au activity of the “inert” 13X carriers was probably attributed to the size of gold particles and the presence of chlorine-free species in the precursors.XPS results showed that the difference between Au / 13X-Org and Au / 13X-Ino catalysts Catalytic oxidation of the active center of metal Au0.