Layered double hydroxide-derived Mg2Ni/TiH1.5 composite catalysts for enhancing hydrogen storage performance of MgH2

Abstract

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/TiH1.5 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/TiH1.5 catalysts, which significantly affect their synergistic catalytic effect. Mg2Ni/TiH1.5 composite catalyst exhibits significantly improved catalytic performance compared with conventional Ni-, Ti- and Ni/Ti-based catalysts. The optimal MgH2/Mg2Ni/TiH1.5 system shows a significantly reduced desorption temperature of 212 °C which is 133 °C lower than that of pure MgH2 (345 °C), and can release 5.97 wt% hydrogen within 300s at 300 °C. 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 TiH1.5, which promotes the fracture of the HH and Mg-H bonds.

Keywords

• Hydrogen storage materials
• MgH2
• Layered double hydroxides
• Nanocatalysts