Achieve high-efficiency hydrogen storage of MgH2 catalyzed by nanosheets CoMoO4 and rGO

The development of high-efficiency carbon-based multifunctional catalysts is of great significance for improving solid-state hydrogen storage materials. Herein, it was confirmed that CoMoO4 sheet-like nanocatalysts uniformly supported on the surface of reduced graphene oxide (CoMoO4/rGO) were successfully prepared by a simple hydrothermal reaction. The novel CoMoO4/rGO catalyst was subsequently doped into MgH2 to improve its hydrogen storage performance. MgH2-10 wt% CoMoO4/rGO starts to release hydrogen at around 204 ?, which is about 36 ? and 156 ? lower than that of MgH2 -10 wt%CoMoO4 and pure MgH2, respectively. In addition, 6.25 wt% H2 can be released within 10 min at 300 ? After complete dehydrogenation, H2 can be absorbed below 80 ?. Meanwhile, it can absorb 4.2 wt% H2 in 20 min under the condition of 150 ? and 3 MPa. Moreover, the activation energy of hydrogen absorption and dehydrogenation of MgH(2-)10 wt%CoMoO4/rGO composites are reduced by 31.44 kJ mol(-1) and 33.78 kJ mol(-1), respectively, compared with pure MgH2. Cycling experiment shows that the MgH2-10 wt%CoMoO4/rGO composite system can still maintain about 98% of the hydrogen storage capacity after 10 cycles. Furthermore, studies on the catalytic mechanism show that the synergistic effect between the in-situ generated MgO, Co7Mo6 and Mo may help to promote the diffusion of H2, thereby improving the MgH2 Hydrogen storage properties. (C) 2022 Elsevier B.V. All rights reserved.