Synthesis and Characterization of Silica-Supported Boron Oxide Catalysts for the Oxidative Dehydrogenation of Propane

We report on the oxidative dehydrogenation (ODH) activity of silica-supported boron oxide prepared via incipient wetness impregnation. Characterization of pristine and spent catalysts with infrared, Raman, and solid-state NMR spectroscopy reveals the presence of both isolated and aggregated oxidized boron sites. The results of these investigations, in combination with our earlier work on bulk boron-containing ODH catalysts (e.g., h-BN, metal borides, and elemental boron), give direct evidence that oxidized boron species formed in situ on the surface of these materials are responsible for the exceptional catalytic behavior. We anticipate that investigation of supported boron materials can provide insight into the structural characteristics required for selective boron-containing ODH catalysts.