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 catalysts were prepared via the impregnation method, using the organic gold compounds Au(PPh3)(NO3) and the inorganic gold compounds HAuCl4 as the precursors, respectively. N2 adsorp- tion/desertion, SEM-EDS, XRD, and XPS were used to characterize the catalysts. The results of N2 adsorp- tion/desertion, SEM-EDS and XRD showed that the Au particles uniformly distributed on the surface of Au/13X-Org, while the Au particles clustered on that for Au/13X-Ino. It was observed by XRD and SEM that the mean diameter of the Au particles on Au/13X-Ino was ca. 26.6 nm, which was a lot bigger than that on Au/13X-Org (5 nm). The CO oxidations have been studied to elucidate the catalytic activity of the samples. It was found that Au/13X-Org exhibited 30% CO conversion at 25 ℃. While, for Au/13X-Ino, there was no conversion at low temperature. The temperature of the complete oxidation of CO over the Au/13X-Org was 150 ℃, which was lower than that over the Au/13X-Ino (400 ℃). The different activ- ity of Au/13X-Org and Au/13X-Ino maybe attribute to two reasons, one was the size of the Au particles, andthe other was the existence of chlorine. XPS techniques verified that the Au species of the samples was only metal Au0.