Chemically stable TMOx@Ti-MgO (TM = Mn and Cu) catalyst enhanced De/hydrogenation kinetics of Mg/MgH2

Abstract

Ti-based catalysts have been identified to be efficient in enhancing hydrogenation and dehydrogenation (de/hydrogenation) kinetics of Mg/MgH2. However, their catalytic activity is constrained by the strong Ti‒H bond and chemical instability. Herein, we demonstrate that TM O x @Ti-MgO ( TM = Mn and Cu) composite catalysts can simultaneously enhance hydrogen dissociation, diffusion and nucleation processes. MgH2 catalyzed by TM O x @Ti-MgO released 6.03−6.14 wt. % H2 within 5 min at 280 °C and 0.89−1.12 wt. % H2 within 60 min at 180 °C. The partially oxidized Ti2+ and Ti3+ states are stabilized in MgO lattice, accelerating hydrogen adsorption, dissociation and diffusion processes. The TM O x , additionally, serve as the active center for nucleation, further improving de/hydrogenation reactions. The TM O x @Ti-MgO catalysts are characterized by high chemical stability, realizing improved cycle properties. These findings suggest a new approach to achieving controllable Catalyst-Hydrogen bond strengths and optimizing performance in de/hydrogenation reactions.