Efficient catalytic effect of the page-like MnCo2O4.5 catalyst on the hydrogen storage performance of MgH2†
Abstract
Binary transition metal oxides have exhibited highly excellent de/hydrogenation kinetic catalytic properties on magnesium hydride (MgH2). Thence, page-like MnCo2O4.5 nanoparticles have been synthesized to enhance the de/hydrogenation performance of MgH2. The initial dehydrogenation temperature of the MgH2-6 wt% MnCo2O4.5 composite decreases to 285 °C. Interestingly, MgH2 doped with 6 wt% MnCo2O4.5 can fully release 6.4 wt% H2 in 4 min at 325 °C. On the contrary, only 0.58 wt% of H2 is released from the undoped as-milled MgH2 in 4 min at 325 °C. Moreover, the dehydrogenated MnCo2O4.5 doped composite can absorb 4.43 wt% H2 in 30 min at 150 °C. Moreover, we found that the desorption activation energy of the composite decreases by 50.18% compared with that of the undoped as-milled MgH2. The evolution process and catalytic mechanism of MnCo2O4.5 on MgH2 were explored through the evidence of X-ray diffraction and transmission electron microscopy. It is believed that Mn-containing phases and Co-containing phases formed in situ during the dehydrogenation process can synergistically catalyze MgH2 to achieve better kinetic performance.