Unraveling the Propene Selectivity in Isopropanol Conversion on Graphene-Enhanced WO3 Superacids: An Integrated Experimental and DFT Study

The catalytic dehydration and dehydrogenation of isopropanol serve as model reactions for evaluating the acid-base properties of catalysts. In this study, tungsten oxide-based superacid catalysts modified with graphene oxide (GO) were synthesized using environmentally friendly methods. Characterization techniques such as TGA, XRD, SEM, FTIR, and BET surface analysis were employed to assess the structural and textural properties of the catalysts. The catalytic performance was evaluated through isopropanol conversion. The incorporation of GO enhances the dispersion of active sites and improves the catalyst's surface properties, promoting higher catalytic efficiency. The performance of isopropanol conversion, revealing that the presence of strong Brønsted and Lewis acid sites favored dehydration to propene, while redox-active sites facilitated dehydrogenation to acetone. Complementing the experimental findings, Density Functional Theory (DFT) calculations elucidate the reaction mechanisms, revealing that the dehydration pathway to propene is kinetically favored over dehydrogenation by a significant ~ 19 kcal/mol lower activation barrier for the rate-determining step.