Effect of Mg content on isobutane dehydrogenation properties over nanosheets supported Pt-In catalysts

A series of hydrotalcite nanosheets with different Mg content were in-situ constructed on the surface of Al2O3 support by one-step synthesis method. And promoter In and active component Pt were introduced in the nanosheets by consecutive impregnation-reconstruction method. Furthermore, the supported Pt-In bimetallic catalysts PtIn/HTR-x (x = 0.05, 0.1, 0.15, 0.2 mol·L-1) were prepared by calcination and reduction. The relationship between the structure, physical and chemical properties of the catalyst and its precursor and the direct dehydrogenation performance of isobutane was explored. The results show that the Mg2+ concentrations determine the nanosheets thickness, which affects the structure, reducibility, surface chemical states, and surface acidity and dehydrogenation properties of these catalysts. The catalyst with Mg2+ concentration of 0.15 mol·L-1exhibits the optimum dehydrogenation performance, of which the isobutene yield reaches 58%. The excellent activity, selectivity and stability of PtIn/HTR-0.15 are attributed to the maximum specific surface area, strong metal-support interaction and high surface In3+/In0 atomic ratio, and the good anti-carbon deposition performance is related to the low concentration and weak strength of surface strong acid sites. © 2023 Chemical Industry Press. All rights reserved.