The influences of Mg/Al molar ratio on the properties of PtIn/Mg(Al)O- x catalysts for propane dehydrogenation reaction

The Mg(Al)O-x supports with different Mg/Al molar ratios and the supported bimetallic Pt–In catalysts are synthesized, characterized by several state-of-art methods and applied to propane dehydrogenation reaction. The results verify that the Mg/Al molar ratio markedly influences the structure, properties and catalytic performances of PtIn/Mg(Al)O-x catalysts for propane dehydrogenation reaction. It is found that the PtIn/Mg(Al)O-4 catalyst (Mg/Al molar ratio is 4:1) has nanoflake-like structure, the largest specific surface area, the smallest average metal particle size (2.5 nm), the highest Pt dispersion and harmonious acid–base properties of the catalyst. Meanwhile, the PtIn/Mg(Al)O-4 catalyst exhibits good reducibility of metal species due to the moderate interactions between metals and support according to H2-TPR results. The highest propane conversion and propylene selectivity are got over PtIn/Mg(Al)O-4 catalyst, which nearly exhibits no deactivation during one 12 h once-through propane dehydrogenation reaction. Moreover, the PtIn/Mg(Al)O-4 catalyst possesses good reproducibility ability. After 8 reaction–regeneration cycles, the initial and final propane conversions still attain 66.4% and 43.5% accompanied with the propylene selectivity above 95%.