SiO2-Modified Pt/Al2O3for Oxidative Dehydrogenation of Ethane: A Preparation Method for Improved Catalytic Stability, Ethylene Selectivity, and Coking Resistance

Abstract

A SiO2-modified Pt/Al2O3 catalyst (SiO2/Pt/Al2O3) was synthesized with a solution-based method using Pt/Al2O3 as the starting catalytic material and tetraethoxysilane (TEOS) as the Si precursor. The modification process can be conducted with several cycles. Each of the modification cycles included sequentially an evacuation step at an elevated temperature and an impregnation step followed by a solution-treatment step. The introduced SiO2 layer showed an obvious sintering-resisting effect for the Pt nanoparticles at a high temperature of 600 °C. When used for catalytic oxidative dehydrogenation of ethane (ODHE), SiO2/Pt/Al2O3 presented a significantly improved catalytic stability and coking depression compared to the unmodified Pt/Al2O3. Furthermore, the introduced SiO2 layer helped improve the ethane conversion slightly and the selectivity to ethylene mildly. The improved selectivity to ethylene could be associable with the Bronsted acid sites brought by the SiO2 layer as well as site distribution of the ...