H 2 O 2 -assisted vanadium catalysts on siliceous materials: support impact and V structure dynamics in CO 2 -promoted propane dehydrogenation

V-containing catalysts supported on purely siliceous materials are widely investigated for CO 2 -assisted propane dehydrogenation (CO 2 -PDH); however, the role of support properties in controlling the complex VOx speciation and its dynamic evolution under reaction conditions remains poorly understood. Here, we report a simple yet unconventional H 2 O 2 -assisted synthesis using V 2 O 5 to prepare V catalysts supported on fumed silica, MCM-41, and Silicalite-1. Repeated H 2 O 2 treatments progressively shifted V speciation toward lower-nuclearity VOx 2 species, with the extent of this restructuring strongly governed by the textural and structural properties of the support. V-Silicalite-1 catalysts achieved TOFs above 12 h-1, outperforming their counterparts by a factor of 2.0–2.6. Comprehensive characterization combining TPR, UV–vis DR, DSC, solid-state NMR, FT-IR spectroscopy, and in situ XAS revealed that high activity and stability arise from an optimal distribution of low-nuclearity and partially oligomerized VOx species, stabilized by the defective, hydroxyl-rich environment of Silicalite-1. Under in situ CO 2 -PDH conditions, these species undergo a highly reproducible redox cycle involving CO 2 and propane, providing a dynamic V environment that sustains propylene productivity with time on stream.