In-situ synthesis of Mg2Ni-Ce6O11 catalyst for improvement of hydrogen storage in magnesium

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 385; p. 123448
• Main Authors: Liu, Pei, Lian, Jiajia, Chen, Haipeng, Liu, Xiaojing, Chen, Yuanli, Zhang, Tonghuan, Yu, Hao, Lu, Guojian, Zhou, Shixue
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2020
• Subjects: Hydrogen storage; In-situ synthesis; Magnesium; Synergistic catalysis; Vacancy defect; Synergistic catalysis; Hydrogen storage; Magnesium; In-situ synthesis; Vacancy defect
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2019.123448

[Display omitted] •Mg2Ni–Ce6O11 binary nanocatalyst with oxygen vacancies can be in-situ synthesized.•The peak temperature for hydrogen desorption is reduced by 115.8 °C.•The apparent activation energy for hydrogen desorption is reduced to 72.7 kJ/mol.•Synergistic catalysis of Mg2Ni–Ce6O11 improves hydrogen sorption properties of Mg. To decrease the hydrogen sorption temperature and increase the hydrogen sorption rate is important for the practical application of magnesium for hydrogen storage. The binary nano-catalysts Mg2Ni and Ce6O11 with oxygen vacancy defects was in-situ synthesized on Mg surface via the hydrogen activation of Mg-Ni-CeO2. The hydrogen storage material Mg-20Ni-CeO2 can release 4.19 wt% H2 in 5 min at 320 °C, which is significantly higher than that of Mg with 10 wt% Ni (3.44 wt% H2) or 10 wt% CeO2 (0.34 wt% H2). The peak temperature and apparent activation energy for hydrogen desorption of Mg-20Ni-CeO2 are reduced by 115.8 °C and 63.89 kJ/mol respectively comparing with that without catalyst. Structural analysis suggests that Mg2Ni and Ce6O11 can be in-situ synthesized on Mg surface, which shows a synergistic catalysis for hydrogen storage. During H2 absorption, the oxygen vacancy defects on Ce6O11 surface can trap H2 molecules, while the Mg2Ni on Mg/Mg2Ni interface can promote H2 dissociation. For H2 desorption, the Mg2Ni can weaken the Mg-H bond and act as “hydrogen pump” to transfer H for H2 formation with the assistance of Ce3+/Ce4+ transformation in Ce6O11. The results of this study provide a new horizon for a novel binary catalyst design for hydrogen storage.