Facile fabrication of an Mxene-supported nano high-entropy hydride unlocking reversible hydrogen storage in Mg(BH4)2

Abstract

Nano-sized high-entropy hydrides (HEH) were synthesized and uniformly loaded onto Ti₃C₂via a modified mechanochemical method and were further demonstrated as an efficient catalyst for enhancing the hydrogen desorption kinetics and reversibility of Mg(BH₄)₂. The hydrogen was desorbed from Mg(BH₄)₂ + 30HEH@Ti₃C₂ at 83.5 °C, with a complete hydrogen release of 9.84 wt% achieved at 330 °C. The dehydrogenation activation energies were notably reduced to 131 kJ mol⁻¹ and 163 kJ mol⁻¹, which were identified as the primary factors responsible for the enhanced dehydrogenation kinetics. Cyclic tests revealed that HEH@Ti₃C₂ significantly enhanced the reversible ability of Mg(BH₄)₂, maintaining a reversibility of 4.6 wt% after the 10th test. This study introduced a new approach to developing high-performance catalysts through the design and fabrication of multi-component catalysts.