| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1276804 | International Journal of Hydrogen Energy | 2016 | 9 Pages |
•A Tri-component catalyst Ni-CeOx/GNS is synthesized by impregnation-reduction method.•Ni-CeOx/GNS catalyst exhibits enhanced catalytic effect on dehydrogenation of MgH2.•The excellent kinetics is due to the synergistic effect of nanosize Ni, CeOx and GNS.•JMA model shows random nucleation of Mg is the rate limiting step of dehydrogenation.
A new hybrid nanocatalyst Ni-CeOx/GNS (graphene nanosheets supported nanoscale Ni and CeOx, x = 1.69) of high surface area and porosity is synthesized by impregnation-reduction method. It is demonstrated that the Ni-CeOx/GNS nanocatalyst exhibits improved catalytic effect on the dehydrogenation performances of MgH2 compares to individual Ni/GNS, CeOx/GNS, or GNS. Differential scanning calorimetry (DSC) measurement proved that both the onset and peak desorption temperature of MgH2-5 wt% Ni-CeOx/GNS (abbreviated as MgNCG) nanocomposites can be decreased by 90.2 and 60.1 °C, respectively. Isothermal desorption kinetic test confirmed that the dehydrogenation kinetics of MgNCG nanocomposites is dozens of times higher than the pure milled MgH2, e.g. MgNCG nanocomposites can release 6.50 wt% H2 within 10 min at 300 °C with an initial hydrogen pressure of 5 KPa, superior to 0.16 wt% H2 desorbed by MgH2 under the same condition. Additionally, the activation energy (Ea) of MgNCG decreases significantly contrast with pure milled MgH2, it is proposed that the tri-component of Ni-CeOx/GNS nanocatalyst has a synergistic effect on the highly efficient dehydrogenation of MgH2.
Graphical abstractA tri-component nanocatalyst of Ni-CeOx/GNS has a synergistic enhanced effect on the dehydrogenation of MgH2 than those of bi-component of Ni/GNS or CeOx/GNS. Figure optionsDownload full-size imageDownload as PowerPoint slide
