Interplay of Vanadia Surface Density and Support Nature in CO ₂ ‐Assisted Propane Dehydrogenation Over V ₂ O ₅ ‐Catalysts

The influence of vanadium surface density and support nature (MoO 3 , Nb 2 O 5 , and SiO 2 ) on V 2 O 5 ‐supported catalysts was systematically investigated for the CO 2 ‐assisted oxidative dehydrogenation of propane (CO 2 ‐ODHP). Two catalyst series were prepared: one with a fixed V 2 O 5 loading (5 wt.%), leading to high vanadium surface densities, and another targeted to a theoretical density of 2 V.nm −2 , corresponding to highly dispersed species. The materials were characterized by XRD, N 2 physisorption, ED‐XRF, H 2 ‐TPR, UV‐vis, and in situ Raman spectroscopy. Structural analyses revealed that high vanadium densities favored the aggregation into polymeric domains and clusters, whereas lower densities stabilized isolated and oligomeric VO 4 species. Catalytic tests showed that these isolated/oligomeric species were the most active for CO 2 ‐ODHP, with those supported on MoO 3 and Nb 2 O 5 exhibiting the highest propylene‐specific activities due to strong VO X ‐support interactions. Notably, the highly dispersed VO x species on MoO 3 exhibited the best overall performance, owing not only to the presence of monomeric and polymeric vanadium domains but also to the intrinsic activity of MoO x sites. Indeed, in this catalyst, CO 2 can effectively reoxidize V─O v ─V and V─O v ─Mo interfaces, as well as V═O terminal oxygen sites, through the rWGS reaction, thereby improving catalytic stability and preventing coke formation.