Hou Quanhui, Zhang Jiaqi, Zheng Zhu'An, Yang Xinglin, Ding Zhao
School of Automotive Engineering, Yancheng Institute of Technology, Yancheng, 224051, China.
School of Energy and Power, Jiangsu University of Science and Technology, Zhenjiang, 212003, China.
Dalton Trans. 2022 Oct 11;51(39):14960-14969. doi: 10.1039/d2dt02425j.
Bimetallic catalysts offer unique advantages for improving the hydrogen storage performance of MgH. Herein, NiFe/BC nanocatalysts were prepared a simple solid phase reduction method using a low-cost biomass charcoal (BC) material as the carrier. The onset temperature of hydrogen release for the MgH + 10 wt% NiFe/BC composite was 184.5 °C, which is 155.5 °C lower than that of pure MgH. The dehydrogenated composite starts to absorb hydrogen at as low as 30 °C and is able to absorb 5.35 wt% of H within 10 min under 3 MPa hydrogen pressure at 150 °C. In comparison to pure MgH, the apparent activation energies of dehydrogenation and rehydrogenation of MgH + 10 wt% NiFe/BC were reduced by 52.89 kJ mol and 23.28 kJ mol, respectively. The hydrogen storage capacity of the composite was maintained in 20 de/rehydrogenation cycles, indicating a good cycling stability. X-Ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray energy dispersive spectroscopy (EDS) characterization reveal that the formation of multiphases MgNi and Fe catalysts during the hydrogen uptake and release reaction and the transformation of MgNi/MgNiH together contribute to the superior hydrogen adsorption and desorption performance of MgH.
双金属催化剂在提高MgH的储氢性能方面具有独特优势。在此，采用简单的固相还原法，以低成本生物质炭（BC）材料为载体，制备了NiFe/BC纳米催化剂。MgH + 10 wt% NiFe/BC复合材料的氢释放起始温度为184.5℃，比纯MgH低155.5℃。脱氢后的复合材料在低至30℃时开始吸氢，在150℃、3 MPa氢气压力下10分钟内能够吸收5.35 wt%的H。与纯MgH相比，MgH + 10 wt% NiFe/BC的脱氢和再氢化表观活化能分别降低了52.89 kJ/mol和23.28 kJ/mol。复合材料的储氢容量在20次脱氢/再氢化循环中得以保持，表明具有良好的循环稳定性。X射线衍射（XRD）、透射电子显微镜（TEM）和X射线能谱（EDS）表征表明，在吸氢和释氢反应过程中多相MgNi和Fe催化剂的形成以及MgNi/MgNiH的转变共同促成了MgH优异的氢吸附和解吸性能。
