Enhanced Hydrogen Storage Properties of MgH2 Using a Ni and TiO2 Co-Doped Reduced Graphene Oxide Nanocomposite as a Catalyst

• Published in: Frontiers in chemistry Vol. 8; p. 207
• Main Authors: Zeng, Liang, Qing, Peilin, Cai, Fangfang, Huang, Xiantun, Liu, Haizhen, Lan, Zhiqiang, Guo, Jin
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 24.03.2020
• Subjects: apparent activation energy; Chemistry; hydrogen storage properties; magnesium; nanocomposites; reduced graphene oxide
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2020.00207

To improve the hydrogen storage properties of Mg/MgH 2 , a Ni and TiO 2 co-doped reduced graphene oxide [(Ni-TiO 2 )@rGO] nanocomposite is synthesized by a facile impregnation method and introduced into Mg via ball milling. The results demonstrated that the dispersive distribution of Ni and TiO 2 with a particle size of 20–200 nm in the reduced graphene oxide matrix led to superior catalytic effects on the hydrogen storage properties of Mg-(Ni-TiO 2 )@rGO. The initial hydrogenation/dehydrogenation temperature for Mg-(Ni-TiO 2 )@rGO decreased to 323/479 K, 75/84 K lower than that of the additive-free sample. The hydrogen desorption capacity of the Mg-(Ni-TiO 2 )@rGO composite released 1.47 wt.% within 120 min at 498 K. When the temperature was increased to 523 K, the hydrogen desorption capacity increased to 4.30 wt.% within 30 min. A hydrogenation/dehydrogenation apparent activation energy of 47.0/99.3 kJ·mol −1 was obtained for the Mg-(Ni-TiO 2 )@rGO composite. The improvement in hydrogenation and dehydrogenation for the Mg-(Ni-TiO 2 )@rGO composite was due to the reduction of the apparent activation energy by the catalytic action of (Ni-TiO 2 )@rGO.