Beyond Fossil Fuels: The Role of V-Doped Hydrotalcites in n-Butane Oxidative Dehydrogenation for a Circular Economy

This study explores the catalytic performance of V3+-modified Mg/Al hydrotalcite-derived materials in the oxidative dehydrogenation (ODH) of n-butane, compared with catalysts derived from pyrovanadate and decavanadate precursors. Different methods for preparing hydrotalcite-like materials were applied to obtain vanadium-containing Mg-Al mixed oxide catalysts for n-butane ODH. The hydrotalcite-like precursors were doped with vanadates (V5+) via ion exchange or co-precipitation or with V3+ cations incorporated into brucite-like layers. During calcination in air or argon flow, different vanadium-containing phases were obtained. Our findings demonstrate that V3+-doped hydrotalcites exhibit superior activity and selectivity toward the total C4H8 products, with enhanced selectivity for 1,3-butadiene. The highest n-butane conversion was observed for catalysts with an MgO structure and vanadium dispersed in the oxide matrix. A similar conversion level (~44%) was obtained for a spinel-like Mg2VO4 catalyst, but only a 15% level was found for the highly crystalline α-Mg2V2O7 catalyst. In contrast, the highest selectivities toward dehydrogenated products were observed for V3+-containing and α-Mg2V2O7 catalysts. NH3- and CO2-temperature programmed desorption (TPD) analyses showed that high basicity combined with low acidity favors the formation of butene isomers and 1,3-butadiene. This work highlights the strategic potential of tailoring vanadium speciation and hydrotalcite-based catalyst design for low-carbon chemical manufacturing, supporting the transition toward a circular economy.