Zhichao Yu,Wei Zhang,Yongxi Zhang,Yaokun Fu,Ying Cheng,Sanyang Guo,Yuan Li,Shumin Han
Magnesium hydroxide (MgH 2 ) has excellent reversibility and high capacity, and is one of the most promising materials for hydrogen storage in practical applications. However, it suffers from high dehydrogenation temperature and slow sorption kinetics. Rare earth hydrides and transition metals can both significantly improve the de/hydrogenation kinetics of MgH 2 . In this work, MgH 2 –Mg 2 NiH 4 –CeH 2.73 is in-situ synthesized by introducing Ni@CeO 2 into MgH 2 . The unique coating structure of Ni@CeO 2 facilitates homogeneous distribution of synergetic CeH 2.73 and Mg 2 NiH 4 catalytic sites in subsequent ball milling process. The as-fabricated composite MgH 2 -10 wt% Ni@CeO 2 powders possess superior hydrogenation/dehydrogenation characteristics, absorbing 4.1 wt% hydrogen within 60 min at 100 °C and releasing 5.44 wt% H 2 within 10 min at 350 °C. The apparent activation energy of MgH 2 -10 wt% Ni@CeO 2 is determined to be 84.8 kJ/mol and it has favorable hydrogen cycling stability with almost no decay in capacity after 10 cycles.
Sodium phenoxide is considered as one of the potentially promising hydrogen storage materials due to its high hydrogen capacity and enhanced thermodynamic properties. However, efficient catalysts are needed to overcome kinetic barriers of the hydrogenation and dehydrogenation processes. In the present work, an ultrafine amorphous Ru–B alloy catalyst was synthesized by a solid-phase ball milling of RuCl 3 with NaBH 4 and subsequently tested for the hydrogenation of sodium phenoxide in an aqueous solution at room temperature . The conversion of phenoxide is significantly improved by 48.9 % on the Ru 3.9 B alloy catalyst compared with pristine Ru nanoparticles . Kinetic studies revealed that the hydrogenation of sodium phenoxide is of first-order with respect to H 2 pressure and zero-order to the concentration of sodium phenoxide over the Ru 3.9 B catalyst. Characterizations showed that the electronic structure of Ru is well modulated by B, leading to an electron-rich state of Ru. The highly active catalysis may be due to the fine dispersion, amorphous state, and electron-rich state of Ru in the ultrafine alloy.
Chengguo Yan,Jiaguang Zheng,Ao Xia,Qingbo Zhang,Meiling Lv,Zhenxuan Ma,Chao Su,Zhendong Yao
Among conventional hydrogen storage materials , LiBH 4 has been regarded as one of the best hydrogen transporters due to its relatively large hydrogen capacities. However, because of its extraordinarily high dehydrogenation temperatures, LiBH 4 was not suitable for hydrogen storage due to its stable thermodynamic features. Herein, we present a novel approach to LiBH 4 that uses solid-state multi-hydroxyl mannitol as a reactant, regulating hydrogen release below 69.9 °C. More than 7 wt% H 2 could be released with ultra-fast rates at 140 °C from the LiBH 4 -mannitol composite. XRD , FTIR , and SEM tests revealed that the reaction between mannitol (H δ+ ) and LiBH 4 (H δ− ) to produce hydrogen was accompanied by the generation of large amounts of heat in situ, which further promoted the decomposition of LiBH 4 for hydrogen production , exceeding the theoretical dehydrogenation amount of H δ+ - H δ− reaction. This work indicates possibilities for the development of fast and easy high-capacity hydrogen generation systems based on complex hydrides.
危险品化学品经营许可证（带存储）