Solar-driven reversible hydrogen storage in metal oxides-catalyzed MgH2

Solid-state hydrogen storage technologies exhibit significant potential for practical applications. A major challenge impeding the deployment of hydrogen storage materials is their reliance on elevated temperatures. Achieving reversible hydrogen absorption and desorption under mild conditions is crucial for advancing this technology. To address the limitations associated with conventional electrical heating, a photoelectric driving strategy is proposed by introducing TiO 2 /Fe 2 O 3 heterojunction photocatalyst and utilizing light as the sole energy source. Under the light intensity of 1.78 W cm −2 , MgH 2 +7TiO 2 /3Fe 2 O 3 composite is able to release 3.11 wt% H 2 within 45 min, with a remarkably low dehydrogenation activation energy of 77.32 kJ mol −1 . The composite also exhibits desirable reversibility in hydrogen storage and performs well under natural light conditions. Solar-driven reversible hydrogen storage of MgH 2 proposes an alternative to electrical heating and realizes the operation under milder conditions, offering a promising approach to address energy and environmental challenges.