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首页> 外文期刊>Nanotechnology >Synthesis of nanostructured Pt/CeO2-ZrO2-Al2O3 catalysts by a two-step sol-gel method
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Synthesis of nanostructured Pt/CeO2-ZrO2-Al2O3 catalysts by a two-step sol-gel method

机译：两步溶胶-凝胶法合成纳米结构的Pt / CeO2-ZrO2-Al2O3催化剂

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摘要

Porous Pt/CeO2-ZrO2-Al2O3 catalysts were synthesized by a two-step sol-gel method in which noble metal nanoparticles were first prepared as a dispersed colloid in an aqueous medium, then mixed with aluminum isopropoxide ( AIP), Ce(NO3)(4) and Zr(NO3)(4), and condensed into a gel. After calcination at 800 degrees C for 3 h, these composite catalysts showed large specific surface areas ( 150-160 m(2) g(-1)) and a narrow pore size distribution of 10-12 nm as determined from the nitrogen adsorption/desorption isotherms. XPS and TEM scans showed that the active component of the catalyst was well dispersed, with the Pt nanoparticles ( particle size 3 -5 nm) confined to the pores. It was found that changing the template surfactants from ionic cetyltrimethylammonium bromide ( CTAB) to non-ionic polyethylene glycol P-1,1,3,3-tetramethylbutylphenyl ether ( TritonX-100) did not change either the specific surface area or the pore structure, but lowered the CO-to-CO2 reaction temperature by nearly 60 degrees C. Measurements of CO conversion proved that the catalyst prepared with TritonX-100 as the template had the highest catalytic activity: the onset of the conversion of CO to CO2 began at 158 degrees C and was complete at 192 degrees C. The possible mechanism of the anti-aggregation of nanoparticles and high catalyst activity has been discussed.
机译：通过两步溶胶-凝胶法合成了多孔Pt / CeO2-ZrO2-Al2O3催化剂，在该方法中，首先将贵金属纳米颗粒作为胶体分散在水性介质中制备，然后与异丙醇铝（AIP），Ce（NO3）混合（4）和Zr（NO3）（4），并浓缩成凝胶。在800摄氏度下煅烧3小时后，这些复合催化剂显示出较大的比表面积（150-160 m（2）g（-1））和10-12 nm的窄孔径分布（根据氮吸附/解吸等温线。 XPS和TEM扫描表明，催化剂的活性成分分散良好，Pt纳米颗粒（粒径3 -5 nm）被限制在孔中。发现将模板表面活性剂从离子型十六烷基三甲基溴化铵（CTAB）更改为非离子型聚乙二醇P-1,1,3,3-四甲基丁基苯基醚（TritonX-100）不会改变比表面积或孔结构，但将CO转化为CO2的反应温度降低了近60摄氏度。CO转化率的测量证明，以TritonX-100为模板制备的催化剂具有最高的催化活性：从CO转化为CO2的反应开始于在158摄氏度下完成，并在192摄氏度下完成。已经讨论了纳米粒子抗聚集和高催化剂活性的可能机理。

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