MgH2 is a promising hydrogen storage material due to its high capacity (7.6 wt %), low cost, and environmental benignity, but its application is hindered by sluggish kinetics and high thermodynamic stability. Constructing catalytic systems has proven effective in addressing these limitations. Herein, we report a two-dimensional NiTi-layered double hydroxide (NiTi-LDH) catalyst that achieves atomic-level dispersion of bimetallic Ni-Ti active sites. The MgH2-6 wt % NiTi-LDH composite exhibits significantly enhanced dehydrogenation performance, with the onset desorption temperature reduced from 290.1 °C (pristine MgH2) to 230.1 °C. The composite also demonstrates exceptional cycling stability, retaining 96.53% of its initial capacity after 100 cycles at 300 °C. Microstructural analysis reveals that NiTi-LDH nanosheets are uniformly dispersed in the MgH2 matrix, providing abundant bimetallic active sites. During cycling, in situ formation of Mg2Ni/Mg2NiH4 and Ti/TiHx species facilitates hydrogen diffusion and provides favorable nucleation sites for the reversible Mg/MgH2 phase transformation, collectively enhancing hydrogen storage kinetics and reversibility.
Qiu et al. (Thu,) studied this question.