Pt-based bimetals are promising catalysts for propane dehydrogenation.The microscopic reaction mechanism and dominant energy pathway of CO2-assisted propane dehydrogenation on Pt-based catalyst are still unclear.Therefore,the density functional theory(DFT)was used to study the reaction networks and key steps of direct dehydrogenation of propane(PDH)and CO2-assisted propane dehydrogenation(CO2-ODH)on Pt(111)and Pt3Mn(111)surfaces.The calculation results show that the addition of CO2 can reduce the energy barrier of rate-limiting step of PDH,which is beneficial to the consumption of surface H species,thus promoting the forward reaction of propane dehydrogenation.This is conducive to the formation of propylene,and further changes the reaction pathway and reaction kinetics.The energy barrier of CO2 in elimination of carbon deposition is high,and the introduction of Mn is conducive to the elimination of carbon deposition by CO2.In addition,the introduction of the second metal component Mn not only reduces the desorption energy of propylene product,but also increases its C—C cracking barrier,thus improving the selectivity to propylene product.
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