Effect of Reduction Atmosphere on Structure and Catalytic Performance of PtIn/Mg(Al)O/ZnO for Propane Dehydrogenation

Abstract

The effect of reduction atmospheres, H2/N2, C3H8/H2/N2, C3H8 and CO, on the structure and propane direct dehydrogenation performance of PtIn/Mg(Al)O/ZnO catalyst derived from ZnO-supported PtIn-hydrotalcite was studied. The physicochemical properties of the as-prepared and used catalytic system were characterized by various characterization methods. The results show that the dehydrogenation performance, especially the stability of the PtIn/Mg(Al)O/ZnO catalyst, was significantly improved along with the change in reduction atmosphere. The highest catalytic activity (51% of propane conversion and 97% propylene selectivity), resistance toward coke deposition, and stability for more than 30 h were achieved with the H2/N2-reduced catalyst. The optimal dehydrogenation performance and coke resistance are mainly related to the high Pt dispersion and In0/In3+ molar ratio, strong Pt–In interaction and small metal particle size, depending on the nature of the reduction atmospheres. The reconstruction of meixnerite favors the stability and coke resistance to some extent.

Design Strategies of Stable Catalysts for Propane Dehydrogenation to Propylene

“…Currently, adding metal promoters to form alloys or intermetallic compounds is one of the most effective methods to ameliorate central active components and inhibit catalytic deactivation in Pt-based catalytic systems. As is generally acknowledged, these promoters are believed to exert geometric and electronic effects pivotally to active components. − Metal promoters can inhibit the aggregation of active sites and reduce the number of neighboring Pt atoms within the assembles, and the electron transfer they provide can tune the electronic properties of central sites, increasing the energy barriers of deep dehydrogenation and adjusting the ability to adsorb propylene.…”

Recent progress in catalytic dehydrogenation of propane over Pt-based catalysts

“…Some researchers have studied the preparation conditions of magnesium aluminum oxide support, such as Mg/Al molar ratio, pH value, and calcination temperature of the precursor. 83,84 Zhang et al 85 found that the formation of highly crystalline meixnerite can redisperse the metal active sites and adjust the acid-base properties of the catalyst, improving stability and coke resistance.…”

MgF2-Modified Hydrotalcite-Derived Composites Supported Pt-In Catalysts for Isobutane Direct Dehydrogenation

“…Now, the focus has been switched to calcined hydrotalcite or hydrotalcitelike (HT) composites, which have been used in direct dehydrogenation of propane and have good performance compared to other supports [10][11][12]. Calcined hydrotalcite or hydrotalcite-like (HT) materials are the typical composite metal oxides [35][36][37]. These have suitable surface acidic characteristics and high specific surface area, which is conducive to the adsorption of alkanes and the desorption of alkenes and enhances Pt particle dispersion.…”