One-step metal acetylacetonates catalyst for improved hydrogen storage of MgH2

Solid-state hydrogen storage via MgH 2 offers high volumetric density, safety, and energy efficiency but is hampered by high H 2 desorption temperatures and sluggish kinetics. Although nanostructured catalysts enhance performance, their complex synthesis and instability limit viability. We present a one-step strategy that leverages metal acetylacetonates (M(acac) n ) to address these challenges. Combined V(acac) 3 with MgH 2 enables the in situ formation of a highly dispersed V-O-Mg interfacial layer, markedly enhancing H 2 sorption kinetics, achieving an onset dehydrogenation temperature of 170 °C, low temperature H 2 desorption (5.3 wt% at 184 °C) and absorption (4.3 wt% at 24 °C), and excellent cycling stability (95.6 % retention after 100 cycles). Kinetic analysis reveals that dehydrogenation initiates via two-dimensional nucleation-growth and transitions to a temperature-dependent mechanism at high conversion (α > 0.3). Density functional theory indicates that V-induced surface reconstruction and charge redistribution lower the H 2 desorption barrier. Additionally, Zr(acac)₄ and TiO(acac)₂ show similar performance improvements, suggesting a promising pathway for optimizing MgH 2 using metal acetylacetonate-based catalysts.