Developing efficient catalysts is of great significance in improving the sluggish kinetics and high desorption temperature of MgH₂ hydrogen storage material. Here, ultrathin NiTi-layered double hydroxide (NiTi-LDH) nanosheets are used as precursors to prepare Mg₂Ni/TiH_1.5 composite catalysts to improve the hydrogen storage properties of MgH₂. The variation of Ni/Ti ratio in LDH plays an important role in regulating the composition, morphology and distribution of Mg₂Ni/TiH_1.5 catalysts, which significantly affect their synergistic catalytic effect. Mg₂Ni/TiH_1.5 composite catalyst exhibits significantly improved catalytic performance compared with conventional Ni-, Ti- and Ni/Ti-based catalysts. The optimal MgH₂/Mg₂Ni/TiH_1.5 system shows a significantly reduced desorption temperature of 212 ℃ which is 133 ℃ lower than that of pure MgH₂ (345 ℃), and can release 5.97 wt% hydrogen within 300s at 300 ℃. Further mechanism analysis reveals that the unique flaky morphology and suitable composition of Ni/Ti LDH can significantly enhance the synergistic effect of Mg₂Ni and TiH_1.5, which promotes the fracture of the HH and Mg-H bonds.

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 ^oC, 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.

Design and synthesis of highly efficient and cost-effective bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remain a big challenge. Herein, a quaternary amorphous nanocompound Ni-Fe-P-B has been synthesized by a facile, scalable co-reduction method. The Ni-Fe-P-B exhibits high electrocatalytic activity and outstanding durability for both HER and OER, delivering a current density of 10 mA·cm^-2 at overpotentials of 220 and 269 mV, respectively. When loaded on carbon fiber paper (CFP) as a bifunctional catalyst, the Ni-Fe-P-B@CFP electrode requires a low cell voltage of 1.58 V to obtain 10 mA·cm^-2 for overall water splitting with negligible recession over 60 h. The excellent catalytic performances of Ni-Fe-P-B mainly benefit from the metal-metalloid combined composition modulation and the unique amorphous structure. This work provides new insights into the design of robust bifunctional catalysts for water splitting, and may promote the development of multicomponent amorphous catalysts.