Melting-splashing-quenching mechanism enabled by n-heptane-assisted plasma ball milling for efficient construction of high-performance Mg–TiO2 hydrogen storage systems

Addressing the bottlenecks of cold-welding, oxidation, and low refining efficiency of ductile magnesium powder in conventional ball milling, this study develops a novel heptane-assisted dielectric barrier discharge (DBD) wall-attached plasma ball milling (NPBM) process. High-purity 50–200 nm spherical Mg–TiO 2 composites were synthesized within only 1 h. Our findings reveal that the “Melting-Sputtering-Quenching (MSQ)” mechanism induced by NPBM is the primary driver for the rapid 100 nm-level spheroidization of Mg, while heptane serves as both a quenching medium and a chemical barrier to suppress thermal welding and side reactions. Kinetic investigations demonstrate that the composite achieves a hydrogen absorption capacity of 4.50 wt% at 175 °C, with a JMAK dehydrogenation activation energy as low as 92.6 kJ mol −1 . This work provides a promising strategy for the rapid synthesis of metastable light-metal hydrogen storage materials.