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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., 30(2023), No. 1, pp.44-53. https://dx.doi.org/10.1007/s12613-021-2372-5
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., 30(2023), No. 1, pp.44-53. https://dx.doi.org/10.1007/s12613-021-2372-5
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子弹状钒基MOFs作为高活性催化剂促进MgH2的储氢性能

摘要: 氢化镁(MgH2)具备较高的脱氢温度和缓慢的脱氢动力学性能,这严重限制了其在储氢领域的实际应用。本研究成功合成了一种基于金属钒的有机框架材料(MOFs-V),并通过球磨技术掺杂到MgH2来提高其储氢性能。微结构分析表明煅烧后的MOFs-V具有子弹状结构。当加入7wt% MOFs-V后,升温放氢测试表明MgH2的初始放氢温度由340.0降低至190.6°C。在300°C的恒温测试中,MgH2+7wt%MOFs-V复合材料在5 min内释放了6.4wt%的H2。对于升温吸氢测试,在3.2 MPa氢气压力下,含7wt% MOFs-V的样品60°C便开始吸氢。MgH2+7wt%MOFs-V的放/吸氢表观活化能分别为(98.4 ± 2.9)和(30.3 ± 2.1) kJ·mol−1,远低于MgH2的(157.5 ± 3.3)和(78.2 ± 3.4) kJ·mol−1。此外,MgH2+7wt%MOFs-V复合材料具有良好的循环性能,储氢容量经过20个恒温循环后基本保持不变。X射线衍射(XRD)和X射线光电子能谱(XPS)分析证实吸放氢过程中生成了具有高催化活性的金属钒,从而显著改善了Mg/MgH2体系的储氢性能。

 

Bullet-like vanadium-based MOFs as a highly active catalyst for promoting the hydrogen storage property in MgH2

Abstract: 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 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 3200 kPa hydrogen pressure for the 7wt% MOFs-V containing sample. The desorption and absorption apparent activity energies of the MgH2+7wt%MOFs-V composite were calculated to be (98.4 ± 2.9) and (30.3 ± 2.1) kJ·mol−1, much lower than (157.5 ± 3.3) and (78.2 ± 3.4) 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.

 

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