Synergy between metallic components of MoNi alloy for catalyzing highly efficient hydrogen storage of MgH2

Abstract

Catalysts play a critical role in improving the hydrogen storage kinetics in Mg/MgH2 system. Exploring highly efficient catalysts and catalyst design principles are hot topics but challenging. The catalytic activity of metallic elements on dehydrogenation kinetics generally follows a sequence of Ti>Nb>Ni>V>Co>Mo. Herein, we report a highly efficient alloy catalyst composed of low-active elements of Mo and Ni (i.e. MoNi alloy) for MgH2 particles. MoNi alloy nanoparticles show excellent catalytic effect, even outperforming most advanced Ti-based catalysts. The synergy between Mo and Ni elements can promote the break of Mg-H bonds and the dissociation of hydrogen molecules, thus significantly improves the kinetics of Mg/MgH2 system. The MoNi-catalyzed Mg/MgH2 system can absorb and release 6.7 wt.% hydrogen within 60 s and 10 min at 300 °C, respectively, and exhibits excellent cycling stability and low-temperature hydrogen storage performance. This study provides a strategy for designing efficient catalysts for hydrogen storage materials using the synergy of metal elements.