Theoretical investigation on structural effects of Pt-Mn catalyst on activity and selectivity for methylcyclohexane dehydrogenation

The structure of Pt-Mn/Al2O3 catalyst which shows high performance for dehydrogenation of methylcyclohexane, a prospective hydrogen carrier, was investigated by XAFS and DFT calculations. Mn addition on Pt/Al2O3 brings higher activity, selectivity, and stability for dehydrogenation of MCH than with Pt/Al2O3 alone. Results of XAFS and DFT calculations revealed that MnOx selectively covered the unsaturated coordination of Pt. On the unsaturated step facets such as Pt (1 1 0) and Pt (3 1 1), demethylation proceeds easily. Addition of Mn on Pt/Al2O3 catalyst brought selective dehydrogenation of MCH by coverage of such step sites with MnOx.