Enhancing dehydrogenation kinetics of MgH2 through doping with the Nb2O5-C/Ti3C2Tx catalyst synthesized by fast Joule heating

Abstract

As a hydrogen storage material, magnesium hydride (MgH₂) has attracted global attention. Notwithstanding its high capacity, the utilization of MgH₂ is severely hampered by slow dehydrogenation rates. To accelerate hydrogen desorption of MgH₂, herein, a nanoscale Nb₂O₅-C/Ti₃C₂T_x composite catalyst has been synthesized via a fast Joule heating method. After incorporating this catalyst into MgH₂ through mechanical milling, the as-prepared MgH₂–10 wt% Nb₂O₅-C/Ti₃C₂T_x sample displays the enhanced dehydrogenation kinetics with activation energy of 62.5 kJ mol^–1 and excellent cyclic durability (99.3 % after 50 cycles). The performance improvement is attributed not only to the synergetic catalysis of multivalent Ti and Nb species but also to the hindering role of carbon nanoparticles and Ti₃C₂T_x nanosheets in powder agglomeration. The strategy reported here offers innovative solutions to developing highly efficient catalytic agents for hydrogen desorption of MgH₂-based composites.