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考察了Ni/Al_2O_3,Ce和Pr改性Ni/Al_2O_3催化剂在甲醇水蒸气重整制氢过程中的性能。研究结果表明:稀土的添加可增加H2的选择性并降低CO的选择性。Pr改性Ni/Al_2O_3催化剂表现出最好的催化性能,Ni的最佳负载量为10%(质量分数)。在相同的反应条件下(反应温度为350℃和水醇摩尔比=3∶1),Ni/Al_2O_3与Pr改性的Ni/Al_2O_3催化剂的甲醇转化率相当,但Pr改性的Ni/Al_2O_3催化剂H_2的选择性从64.5%提高到了75.6%,相应的CO选择性则从31.4%降低到了4.5%。H2选择性随着水醇摩尔比的增加而升高,当水醇摩尔比为6∶1时,几乎没有CO产生。XRD和TPR表征结果表明:Pr的添加不仅促进了Ni在载体上的分散而且促进了Ni的还原,从而有利于催化性能的改善。
The performance of Ni / Al_2O_3, Ce and Pr modified Ni / Al_2O_3 catalysts for steam reforming of methanol was investigated. The results show that the addition of rare earth can increase the selectivity of H2 and reduce the selectivity of CO. Pr modified Ni / Al 2 O 3 catalyst showed the best catalytic performance, and the optimal loading of Ni was 10% (mass fraction). Under the same reaction conditions (reaction temperature is 350 ℃ and molar ratio of water to alcohol = 3: 1), the methanol conversion rate of Ni / Al_2O_3 and Pr modified Ni / Al_2O_3 catalyst is equivalent, but Pr modified Ni / Al_2O_3 catalyst The selectivity of H 2 increased from 64.5% to 75.6%, while the corresponding CO selectivity decreased from 31.4% to 4.5%. H2 selectivity increases with increasing molar ratio of hydroalcoholic to almost no CO at a molar ratio of 6: 1. XRD and TPR characterization results show that the addition of Pr not only promotes the dispersion of Ni on the support but also promotes the reduction of Ni, which is beneficial to the improvement of the catalytic performance.