Pt/Al2O3 catalyst with Pt particle size of 6 nrn was prepared by ethylene glycol reduction method and the kinetics of propane dehydrogenation was then studied under atmospheric pressure and at 450-490 'C. The apparent reaction orders for propane and hydrogen were the first and minus half, respectively, and the apparent reaction activation energy was about 80 kJ/mol. Based on Density Functional Theory(DFT) calculation, a microkinetic model was established on Pt(lll) facet, where the kinetic simulation was carried out. The simulation indicated that the adsorbed hydrogen atom was the most abundant surface intermediate and that the reaction rate was limited by the second hydrogen elimination. A Langmuir-Hinshelwood Hougen-Watson (LHHW) model was subsequently obtained based on the information provided by microkinetics. Compared with conventional kinetic model, the models established in this study were superior in the reliability of the mechanism indicated by DFT calculation and the convenience of the acquisition of the kinetic parameters. The simulation also indicated that the models could well predict the experiments.%采用乙二醇还原法制备了Pt颗粒粒径为6 nm的Pt/Al2O3催化剂,借助密度泛函理论(DFT)计算的动力学参数,建立了Pt(111)面上的微观反应动力学模型,并在此基础上建立了Pt(111)面上的Langmuir-Hinshelwood Hougen-Watson(LHHW)模型.结果表明:丙烷脱氢对丙烷的反应级数是1.00级,对氢气的反应级数是-0.51级:反应的表观活化能约为80 kJ/mol:在Pt(111)面上,氢原子是最丰富的表面吸附物种,丙烷脱氢速率受第二步脱氢控制.
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