|Cite this article as:|
|Zhiyu Lu, Jiahuan He, Mengchen Song, Yan Zhang, Fuying Wu, Jiaguang Zheng, Liuting Zhang, and Lixin Chen, Bullet-like vanadium-based MOFs as a highly active catalyst for promoting the hydrogen storage property in MgH2, Int. J. Miner. Metall. Mater.,(2021). https://doi.org/10.1007/s12613-021-2372-5|
The practical application of magnesium hydride (MgH2) was seriously limited by its high desorption temperature and slow desorption kinetics. In this study, a bullet-like catalyst based on vanadium related MOFs (MOFs-V) was successfully synthesized and doped with MgH2 by ball milling to improve its hydrogen storage performance. Microstructure analysis demonstrated that the as-synthesized MOFs was consisted of V2O3 with a bullet-like structure. After adding 7wt% MOFs-V, the initial desorption temperature of MgH2 was reduced from 340.0°C to 190.6°C. Besides, the MgH2+7wt% MOFs-V composite released 6.4wt% H2 within 5 min at 300°C. Hydrogen uptake was started at 60°C under 32 bar hydrogen pressure for the 7wt% MOFs-V containing sample. The desorption and absorption apparent activity energy of the MgH2+7wt% MOFs-V composite was calculated to be 99.6±12.6 kJ mol-1 and 32.8±3.9 kJ mol-1, much lower than154.5±16.3 kJ mol-1 and 81.1±2.4 kJ mol-1 for the as-prepared MgH2. The MgH2+7wt% MOFs-V composite exhibited superior cyclic property. During the 20 cycles isothermal dehydrogenation and hydrogenation experiments, the hydrogen storage capacity stayed almost unchanged. X-ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS) measurements confirmed the presence of metallic vanadium in the MgH2+ 7wt% MOFs-V composite, which served as catalytic unit to markedly improve the hydrogen storage properties of Mg/MgH2 system.