Formation of Ptδ+/Pt0 active sites on Ni-Cr composites supported on carbon carrier in bicyclohexyl dehydrogenation.

The activity of Pt/C, Pt/Ni/C, Pt/Cr/C, and Pt-Ni-Cr/C catalysts in the dehydrogenation reaction of bicyclohexyl, a step of hydrogen release in chemical hydrogen storage systems, was studied. The catalyst surface structure was investigated by transmission electron microscopy. The charge state of platinum was assessed by XPS. The role of nickel and chromium promoters in the formation of electron-deficient (Pt^δ+) and zero-valent (Pt⁰) platinum was analyzed. The activity of catalysts in the dehydrogenation reaction of bicyclohexyl was affected by the Pt^δ+/Pt⁰ ratio. The highest conversion and yield of biphenyl, the product of the complete dehydrogenation of bicyclohexyl, were achieved at aPt^δ+/Pt⁰ ratio close to 1–2. [ABSTRACT FROM AUTHOR]