Multiple improvements of hydrogen sorption and their mechanism for MgH2 catalyzed through TiH2@Gr. (31st July 2020)

• Record Type: Journal Article
• Authors: Verma, Satish Kumar; Bhatnagar, Ashish; Shukla, Vivek; Soni, Pawan Kumar; Pandey, Anant Prakash; Yadav, Thakur Prasad; Srivastava, Onkar Nath
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 38(2020)
• Page Start: 19516
• Page End: 19530
• Publication Date: 2020-07-31
• Subjects: Hydrogen storage -- Magnesium hydride -- Graphene templated Ti-based catalyst -- Mechanism; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.05.031
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The present investigation reports the effect of TiH2 templated over graphene (TiH2 @Gr) on the hydrogen sorption characteristics of MgH2 /Mg. The as synthesized TiH2 @Gr leads to significant effect on sorption in MgH2 by the following effects: the first is dehydrogenation of MgH2 –TiH2 @Gr, which leads to the conversion of some part of TiH2 into TiH1.924 . TiH2 together with TiH1.924 works as a better catalyst than TiH2 alone. The second is ball-milling of TiH2 @Gr, which produces defective graphene, which also works as co-catalyst. The third is anchoring of TiH2 on graphene, which does not allow the catalyst to agglomerate. The catalytic effect of TiH2 @Gr on MgH2 is found to be better than Ti@Gr and TiO2 @Gr. The onset desorption temperature for MgH2 –TiH2 @Gr is ~204 °C, which is 31 °C and 36 °C lower than MgH2 –Ti@Gr, MgH2 –TiO2 @Gr respectively. The better catalytic behavior of TiH2 @Gr also persists during de/re-hydrogenation kinetics and cycling study of MgH2 . The feasible mechanism for superior catalytic for TiH2 @Gr on MgH2 has been put forward. Graphical abstract: Image 1 Highlights: Onset dehydrogenation temperature of 204 °C for MgH2 catalyzed by TiH2 @Gr. Good cyclic stability and improved thermodynamics for MgH2 catalyzed by TiH2 @Gr. Mechanism for catalytic action of TiH2 @Gr on MgH2 . Comparison of catalytic effect of Ti@Gr, TiO2 @Gr and TiH2 @Gr on MgH2 .