Hydroxyl-facilitated efficient propane dehydrogenation over bare Ga₂O₃ via altering reaction pathway

Designing suitable catalysts for catalytic processes involving alkanes and efficiently activating C−H bond in light alkanes are both theoretically and practically significant. The present study shows that bare Ga₂O₃ without any supported species or dopants can effectively catalyze the PDH reaction. A clear structure–activity relationship based on crystallite size, acid density, and hydroxyl group density is established, the smaller the crystallite size, the higher the activity. Ga₂O₃ with a smaller crystallite size owns a higher concentration of hydroxyl species and oxygen vacancies. Comprehensive experimental investigations and DFT calculations indicate that the presence of oxygen vacancy in Ga₂O₃ decreases the apparent activation energy of PDH compared with the pristine Ga₂O₃ surface. Importantly, the existence of hydroxyl groups on the Ga₂O₃ surface can significantly improve the ability to activate C−H bond by altering the PDH reaction from a non-oxidative to the oxidative pathway at the initial stage. It is expected that these findings offer fundamental insights into regulating the physicochemical properties of metal oxides for efficient C−H bond activation and hydrogenation reactions.