Surface reconstruction and enhanced catalytic performance of MAX phase V2AlC for oxidative dehydrogenation of propane

Abstract

This study investigates the surface reconstruction and catalytic performance of MAX phase V₂AlC under oxidative dehydrogenation (ODH) conditions for propane to propylene conversion. During the progression of the ODH reaction, the MAX phase V₂AlC underwent mild oxidation and surface restructuring, forming a top-coated metastable structure; the MAX phase was preserved but coated with octahedral vanadium species rich in V–O–Al bonds, which cannot be obtained by preheating V₂AlC at 550 °C in an air atmosphere. The solid with octahedral vanadium species demonstrated comparable propane conversion and 14% greater propylene selectivity compared to V₂O₅, a reference catalyst, and was stable over a continuous 24-hour reaction period. Further enhancements in performance were realized through the incorporation of MgO as a dopant. In contrast, pre-heated V₂AlC exhibited relatively poor selectivity for propylene at equivalent conversion levels. The evidence indicates a novel strategy for designing catalysts with metastable structures via surface reconstruction from ordered solids.