Crystal‐amorphous interface synergy in Ni/CrV‐mixed metal oxide: A strategy for rapid hydrogen uptake/release in magnesium hydride

Optimizing the kinetics and lowering the ab/dehydrogenation temperature of magnesium hydride (MgH₂) are crucial for hydrogen storage applications. The synergy among multi-metals (such as Ni, Cr, Fe, Cu, etc.) can reduce the ab/dehydrogenation activation energy of magnesium hydride by leveraging the characteristics of transition metals. Herein, Crystal-amorphous interfaces were regulated via changing the reducing atmosphere through precise design to form the semi-crystalline Ni/CrV-MMO catalysts. After the tests, the 10 wt%Ni/CrV-MMO-doped MgH₂ initial hydrogen release at 190 ℃ and desorbed 5.6 wt% H₂ at a relatively low temperature of 275 ℃ within 10 min. Moreover, this composite material absorbed 5.7 wt% H₂ within 2 min at 150 ℃, achieving a remarkably low hydrogen absorption activation energy of only 28.35 kJ·mol⁻¹, which is far below pure MgH₂ (68.42 kJ·mol⁻¹). Mechanistic studies and density functional theory (DFT) reveal that the amorphous CrV-MMO elevates the D-band center of Ni by contacting with the Ni interface, which weakens the Mg–H bond strength and consequently lowers the dehydrogenation barrier. The existence of crystal-amorphous interfaces effectively optimizes the transport of interfacial charges. This crystal-amorphous interface synergy strategy offers a general blueprint for low-temperature, high-rate MgH₂ storage systems.