论文部分内容阅读
γ-Al2O3,α-Al2O3和SiO2三种不同的载体制备的Pt催化剂进行了高温丙烯气氛中的选择性氢氧化实验(SHC)。在不同载体制备的催化剂上进行的反应都得到了较高的氢气转化率,反应过程中也有一定量的丙烯损失,但是在涉及的所有催化剂上丙烯被氧化为一氧化碳或二氧化碳的量都很少。为了评价催化剂在高温丙烯中选择性氧化氢气的能力,引入了A因数的概念。实验结果表明,α-Al2O3负载1.6wt.%Pt催化剂具有最高的A因数。从A因数的角度来看,传统的γ-Al2O3,并不是本实验催化剂合适的载体。通过对载体和催化剂一系列的表征如BET、NH3-TPD、热重、TPR和TEM等研究了载体对于催化效果的影响。结果显示具有较低比表面积以及较低酸性的载体有利于在载体表面生成较大的Pt颗粒,这种颗粒与载体表面的相互作用较小,有利于抑制消耗丙烯的副反应,因而氢氧化的选择性可以得到提高。
γ-Al 2 O 3, α-Al 2 O 3 and SiO 2 supported Pt catalysts were investigated by selective hydrogen oxidation (SHC) in a high-temperature propylene atmosphere. The reactions carried out on the catalysts prepared on different supports gave higher hydrogen conversions and a certain amount of propylene loss during the reaction but less on all the involved catalysts for the oxidation of propylene to carbon monoxide or carbon dioxide. In order to evaluate the catalyst’s ability to selectively hydrogenate hydrogen in high temperature propylene, the concept of A factor was introduced. The experimental results show that the α-Al2O3 loading 1.6wt.% Pt catalyst has the highest A factor. From the A factor point of view, the traditional γ-Al2O3 is not a suitable carrier for this experimental catalyst. The effect of support on the catalytic effect was investigated by a series of characterization of supports and catalysts such as BET, NH3-TPD, TG, TPR and TEM. The results show that the carrier with lower specific surface area and lower acidity is conducive to the formation of larger Pt particles on the surface of the carrier. The interaction between the particles and the carrier surface is small, which is beneficial for inhibiting the side reaction which consumes propylene, Selectivity can be improved.