以SnO2为载体,采用沉积沉淀法(DP)、共沉淀法(CP)和浸渍法(IM)制备了金负载Au/SnO2催化剂,同时采用沉积沉淀法制备了M-Au/SnO2(M=Pd,Pt)双会属负载催化剂.通过X射线衍射(XRD)、BET比表面积测定、透射电镜(TEM)和X射线光电子能谱(XPS)等技术对样品进行表征,并测定其对CO的催化活性.结果表明:与CP法和IM法相比,DP法制备的Au/SnO2-DP催化剂,Au颗粒(<5 nm)较小,分布均匀:Au/SnO2-DP中的Au是以金属态Au0存在,而Au/SnO2-CP和Au/SnO2-IM中,金以Au0和Au3+的混合价态存在,在Au/SnO2-DP和M-Au/SnO2中的Au、Pt、Pd和SnO2之间存在相互作用;Au/SnO2-DP催化性能明显优于Au/SnO2-CP和Au/SnO2-IM.Au与Pt和Pd的双金属复合催化剂催化活性明显提高.不同方法制备Au/SnO2催化活性的差别主要是由于Au颗粒大小和Au氧化态的不同而产生.而M-Au/SnO2活性提高,可能是由于Au与Pt和Pd之间的相互作用.%Au/SnO2 catalysts were prepared by deposition-precipitation (DP), co-precipitation (CP) and typical wet impregnation methods (IM).M(M=Pt, Pd)-promoted Au/SnO2 catalysts were prepared by the DP method.The samples were characterized by X-ray diffraction (XRD), Brunaner-Emmett-Teller (BET) adsorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques.The results showed that compared with CP and IM, the DP method led to a fairly uniform dispersion of gold nanoparticles with diameters less than 5 nm and larger specific surfaces for the Au/ SnO2 catalyst.The Au in Au/SnO2-DP was metallic (Au0) while in Au/SnO2-CP and Au/SnO2-IM the Au consisted of a mixture of Au0 and Au3+.The oxidation of carbon monoxide over the Au/SnO2-DP and Mpromoted Au/SnO2-DP catalysts were investigated.We observed that the Pd- or Pt-doping of Au/SnO2-DP resulted in a significant increase in performance.We conclude that the different activities of the Au/SnO2 catalysts that were prepared using different preparation methods may be attributed to the size of the Au particles and the states of gold.A remarkable improvement in catalytic activity because of Pd or Pt doping was associated with strong interactions between Pd or Pt and Au.
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