International Journal of Hydrogen Energy, Vol.45, No.38, 19516-19530, 2020
Multiple improvements of hydrogen sorption and their mechanism for MgH2 catalyzed through TiH2@Gr
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 similar to 204 degrees C, which is 31 degrees C and 36 degrees 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@Cr on MgH2 has been put forward. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.