Electron‐Deficient Destabilization Coupled With Mg‐philic Catalysis: A Dual‐Modulation Strategy for Low‐Temperature Dehydrogenation of Mg(BH 4 ) 2

Mg(BH 4 ) 2 stands out as a promising high‐capacity hydrogen storage material, yet its application is hindered by sluggish dehydrogenation kinetics and high operation temperatures. To break the bottleneck, we propose a novel coupling strategy of electron‐deficient destabilization and Mg‐philic catalysis. Specifically, an electron‐deficient boron‐doped graphene host is fabricated to induce charge redistribution and structural destabilization of Mg(BH 4 ) 2 and thereby weaken B─H bonds. Meanwhile, Nb‐based catalysts with moderate Mg affinity are incorporated to drive the full dehydrogenation of Mg(BH 4 ) 2 , during which multifunctional Nb‐based active sites are in situ evolved that facilitate B─H bond cleavage, hydrogen diffusion and Mg nucleation. Benefiting from such coupling effect, the optimized nanocomposite features record‑low temperatures for two‐step dehydrogenation from Mg(BH 4 ) 2 via MgH 2 to Mg, initiating at 50°C and peaking at 81/144°C, with substantially reduced dehydrogenation activation energy of 38.74/58.86 kJ mol −1 . Moreover, the stable Nb‐based Mg‐philic sites enable the durable catalysis for the reversible conversion of MgH 2 /Mg and suppress the accumulation of MgB 12 H 12 intermediate byproducts, enhancing the cyclic stability. This work offers instructive insights into the performance modulation of Mg(BH 4 ) 2 and other complex metal hydrides for advanced hydrogen storage.