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采用十六胺和不同铈前驱体(硝酸铈铵或硝酸亚铈)分别合成了纳米CeO2(H4和H3),考察了纳米CeO2载体的织构性质对Au-Pd催化剂甲醇部分氧化制氢(POM)性能的影响,用HRTEM、N2吸附、XRD和TPR等对样品进行了表征。结果表明,铈前驱体对载体的性能有较大的影响,以硝酸铈铵为前驱体所制H4载体具有较小的粒径(约5 nm)和平均孔径(5.3 nm)、较大的比表面积(243 m2/g),而硝酸亚铈所制H3载体具有较大的平均孔径(7.9 nm)。POM结果表明,纳米CeO2负载的Au-Pd催化剂具有较好的催化性能,300℃时,Au-Pd/H3的活性和H2选择性分别达100%和59.7%。低温时催化剂的活性和H2选择性为:Au-Pd/H3>Au-Pd/H4,而高温时顺序相反,这是由于低温时催化剂的孔径对反应物和产物的扩散影响较大,高温时催化剂的比表面积和活性组分分散度起主要作用。
Nano-CeO2 (H4 and H3) were synthesized by using hexadecylamine and different cerium precursors (ceric ammonium nitrate or cerous nitrate) respectively. The effects of the texture properties of nano-CeO2 support on partial oxidation of methanol by Au-Pd catalyst ) Performance. The samples were characterized by HRTEM, N2 adsorption, XRD and TPR. The results show that the cerium precursor has a great influence on the performance of the catalyst. The H4 carrier with ceric ammonium nitrate as the precursor has the smaller particle size (about 5 nm) and the average pore size (5.3 nm), and the larger ratio Surface area (243 m2 / g), whereas cerium nitrate H3 carriers have a larger average pore size (7.9 nm). POM results show that the Au-Pd catalyst supported on nano-CeO2 has good catalytic performance, and the activity and H2 selectivity of Au-Pd / H3 reach 100% and 59.7% respectively at 300 ℃. The catalyst activity and H2 selectivity at low temperature are: Au-Pd / H3> Au-Pd / H4, while the reverse order at high temperature is due to the large influence of the pore size of the catalyst on the diffusion of reactants and products at low temperatures. The specific surface area of the catalyst and the degree of dispersion of the active ingredient play a major role.