摘要
氢化镁(MgH_(2))因其高储氢容量和低成本被视为极具潜力的固态储氢材料,但其热力学稳定性高与动力学性能差的问题限制了实际应用。通过一步溶剂热法成功制备了石墨片负载的镍硫化物催化剂(NiS_(2)@xC),系统探究了不同石墨片添加量(0%、3%、5%、10%(质量分数))对MgH_(2)储氢性能的影响。结果表明,石墨片的引入显著抑制了NiS_(2)颗粒的团聚,使其均匀分散并原位生长于石墨片表面,平均粒径由1.60μm降至200~500 nm,比表面积和活性位点数量显著增加。当石墨片添加量为3%(质量分数)时,MgH_(2)-NiS_(2)@3C复合材料展现出最优性能:起始放氢温度降为240℃,在300℃下10 min内释放6.50%(质量分数)的氢气,总放氢容量达6.70%(质量分数);吸氢性能方面,5 min内吸氢量为5.50%(质量分数)。过量石墨片(10%(质量分数))则会因物理屏蔽效应阻碍氢扩散,导致性能下降。通过SEM、XRD等表征手段揭示了石墨片负载对材料微观结构及催化机理的影响,证实适量石墨片通过抑制颗粒团聚、增加活性位点暴露和优化氢扩散通道,显著提升MgH_(2)的吸/放氢动力学,为高活性复合催化剂的理性设计提供了重要参考。
Magnesium hydride(MgH_(2))has emerged as a promising solid-state hydrogen storage material due to its high hydrogen storage capacity and low cost.However,its practical application has been restricted by high thermodynamic stability and poor kinetic properties.In this study,a nickel sulfide catalyst supported on graphite flakes(NiS_(2)@x C)was successfully synthesized via a one-step solvothermal method,with systematic investigation into the effects of graphite flake loading(0,3,5,10 wt%)on the hydrogen storage performance of MgH_(2).Results demonstrated that the introduction of graphite flakes effectively suppressed the agglomeration of NiS_(2)particles,enabling their uniform dispersion and in-situ growth on the graphite surface.The average particle size was reduced from 1.60μm to 200-500 nm,accompanied by a significant increase in specific surface area and active site exposure.The MgH_(2)-NiS_(2)@3C composite with 3 wt%graphite loading exhibited optimal performance.When the initial hydrogen desorption temperature decreased to 240℃,6.50 wt%hydrogen release was achieved within 10 min at 300℃with a total desorption capacity of 6.70 wt%.Regarding hydrogen absorption,5.50 wt%hydrogen uptake was accomplished within 5 min.Excessive graphite loading(10 wt%)conversely degraded performance due to physical shielding effects that impeded hydrogen diffusion.Comprehensive characterizations via SEM and XRD elucidated the microstructure evolution and catalytic mechanism,confirming that appropriate graphite loading enhanced hydrogen sorption kinetics through three synergistic effects:(1)preventing particle aggregation,(2)increasing accessible active sites,and(3)optimizing hydrogen diffusion pathways.This work provides critical insights for the rational design of high-performance composite catalysts in hydrogen storage applications.
作者
马瑜飞
吴成章
罗雯雯
徐畅
MA Yufei;WU Chengzhang;LUO Wenwen;XU Chang(Sino-European School of Engineering Technology,Shanghai University,Shanghai 200444,China;School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)
出处
《功能材料》
北大核心
2026年第1期20-27,共8页
Journal of Functional Materials
基金
国家重点研发项目(2023YFB3809103)。
关键词
储氢材料
氢化镁
石墨片负载
二硫化镍
储氢性能
hydrogen storage materials
magnesium hydride
nickel disulfide
graphite flake-supported
hydrogen storage performance
