Xu Guang, Zhang Wei, Zhang Ying, Zhao Xiaoxia, Wen Ping, Ma Di
Department of Materials Science and Engineering, College of Science, China University of Petroleum (Beijing) Changping District Beijing 102249 PR China
Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University Qinhuangdao 066004 PR China.
RSC Adv. 2018 May 25;8(35):19353-19361. doi: 10.1039/c8ra02762e.
FeO nanoclusters anchored on porous reduced graphene oxide (FeO@rGO) have been synthesized by a one-step hydrothermal route, and then ball milled with LiBH to prepare a hydrogen storage composite with a low onset dehydrogenation temperature, and improved dehydrogenation kinetics and rehydrogenation reversibility. The LiBH-20 wt% FeO@rGO composite begins to release hydrogen at 74 °C, which is 250 °C lower than for ball-milled pure LiBH. Moreover, the composite can release 3.36 wt% hydrogen at 400 °C within 1000 s, which is 2.52 times as high as that of pure LiBH. Importantly, it can uptake 5.74 wt% hydrogen at 400 °C under 5 MPa H, and its hydrogen absorption capacity still reaches 3.73 wt% after 5 de/rehydrogenation cycles. The activation energy ( ) of the hydrogen desorption of the composite is decreased by 79.78 kJ mol when 20 wt% FeO@rGO is introduced into LiBH as a destabilizer and catalyst precursor, showing enhanced thermodynamic properties. It could be claimed that not only the destabilization of FeO, but also the active LiBO species formed , as well as the wrapping effect of the graphene, synergistically improve the hydrogen storage properties of LiBH. This work provides insight into developing non-noble metals supported on functional graphene as additives to improve the hydrogen storage properties of LiBH.
通过一步水热法合成了锚定在多孔还原氧化石墨烯上的FeO纳米团簇（FeO@rGO），然后将其与LiBH进行球磨，以制备具有低起始脱氢温度、改善脱氢动力学和再氢化可逆性的储氢复合材料。LiBH-20 wt% FeO@rGO复合材料在74℃开始释放氢气，这比球磨纯LiBH的起始温度低250℃。此外，该复合材料在400℃下1000 s内可释放3.36 wt%的氢气，是纯LiBH的2.52倍。重要的是，它在400℃、5 MPa氢气压力下可吸收5.74 wt%的氢气，经过5次脱氢/再氢化循环后其吸氢容量仍达到3.73 wt%。当引入20 wt% FeO@rGO作为LiBH的去稳定剂和催化剂前驱体时，复合材料的氢解吸活化能降低了79.78 kJ/mol，显示出增强的热力学性能。可以认为，不仅FeO的去稳定化作用，而且形成的活性LiBO物种以及石墨烯的包裹效应，协同改善了LiBH的储氢性能。这项工作为开发负载在功能化石墨烯上的非贵金属作为添加剂来改善LiBH的储氢性能提供了思路。
