首页> 中文期刊> 《北京工业大学学报》 >铝柱撑蒙脱石负载Au和Pt催化剂的结构特点及其催化氧化CO性质

铝柱撑蒙脱石负载Au和Pt催化剂的结构特点及其催化氧化CO性质

         

摘要

Abstract: To increases cation exchange capacity (CEC), Ca-montmorillonite is exchanged upon Ca2+ and Mg2+ to Na+ and forms Na-montmorillonite. Al pillared montmorillonite (Al-PILCS) support is prepared by the intercalation of polymerization of aluminum hydroxyl ions (Al-agent) with Na- montmorillonite and then calcined. Platinum and gold is deposited on Al-PILCS by deposition- precipitation (DP) and impregnation. The characterization and catalytic activity of the samples are investigated by X-ray diffraction (XRD), N2-sorption analysis, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) techniques, and CO oxidation reaction. Results of XRD and N2-desorption/adsorption show that due to pillaring, Al-PILCS in microporous surface area and micropore volume increase distinctively. The influence of the preparation methods on the catalytic activity for CO oxidation is markedly large for Au/Al-PILCS and negligible for Pt/Al-PILCS catalysts. The DP method gives the most active catalysts for both Pt and Au. Pt catalysts prepared by DP show a much greater activity than Au catalysts. Different activities of Au/Al-PILCS and Pt/Al-PILCS may attribute to two reasons: the size of Au and Pt parties, and different reaction mechenismes. XPS techniques verified that the Au species of the samples is only metal Au~ over Au/Al-PILCS-IM and oxidation state Au8+ and metal Au0 coexist over Au/Al-PILCS-DP.%摘要:将钙基蒙脱石(Ca—M)钠化改性制得钠化蒙脱石(Na—M),随后用羟基铝离子柱化液对Na-M柱撑改性制得铝柱撑蒙脱石(Al-PILCS),使用沉积一沉淀法和浸渍法2种方法将Au和Pt负载在Al-PILCS上,制得Au/Al-PILCS和Pt/Al-PILCS.通过x射线衍射仪(XRD)、N2-吸附/脱附、透射电镜(TEM)和X射线光电子能谱仪(XPS)等技术对样品进行表征,并测定其对CO的催化活性.XRD和N2-吸附/脱附结果表明,铝柱撑蒙脱石Al-PILCS的比表面积、微孔面积和微孔体积较蒙脱石原矿ca—M增加较大.对于Au和Pt负载型Al-PILCS催化剂,Pt/Al-PILCS催化活性明显优于Au/Al-PILCS.制备方法对Pt/Al-PILCS的活性影响较小,而对Au/Al-PILCS的催化活性影响较大.分析表明,不同方法制备Au/Al-PILCS催化活性的差别,主要由于Au颗粒大小和Au氧化态的差别.而Au/Al-PILCS和Pt/Al。PILCS之间的活性差别,可能是由于金和铂的粒径大小和反应机理差异.

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