Interaction between Hydrogen and Magnesium Films: From Hydrogenochromism to Applications

Hydrogen, as a promising clean energy carrier, underscores the critical need for reliable detection technologies to ensure its safe and efficient use. Magnesium (Mg) thin films, with their hydrogenochromic properties, are particularly well-suited for hydrogen sensing applications due to their dramatic optical transitions. However, practical implementation faces challenges in achieving both rapid response and durability under cyclic conditions. To overcome these limitations, advanced interfacial tuning techniques have been developed to optimize hydrogen diffusion pathways and reinforce structural resilience. This review focuses on the scientific mechanism governing the interaction between Mg-based thin films and hydrogen, highlighting their suitability as hydrogen sensors with superior hydrogenochromic characteristics. Controllable manufacturing methods allow precise control over the alloy composition and microstructure of Mg-based thin films, facilitating the construction of phases and interfaces conducive to support efficient hydride formation, ultimately improving hydrogen response performance. Recent advancements in microstructure engineering, refined in situ characterization techniques, and promising optical applications drive the rapid development of Mg-based thin films.