Effect of in-situ formation of CeH2.73/CeO2-x and V2O3 on hydrogen storage performance of MgH2

Abstract

MgH2, one of the most promising lightweight hydrogen storage mediums, has aroused intensive attention due to its outstanding reversible hydrogen storage capacity. However, it suffers from the intrinsic high operating temperature and sluggish kinetics from de-/hydrogenation, hindering its further industrial application. Herein, we successfully synthesized a novel rare earth Ce co-doping with V element forming bimetallic oxide additive, CeVO4 nanoparticles, which exhibits an excellent catalytic effect for enhancing the hydrogen storage performance in MgH2. With an optimization addition of 10 wt% CeVO4, the initial dehydrogenation temperature of the composite decreased from 286 °C to 212 °C. The composite can desorb 6.03 wt% H2 within 6 min at 300 °C and absorb 1.9 wt% H2 within 20 min even at a low temperature of 50 °C. The apparent dehydrogenated activation energy of the composite was obtained as 61.38 ± 3.9 kJ mol−1. The catalyst mechanism analysis revealed that the “hydrogen pumping” effect of the in-situ formed CeH2·73/CeO2-x and V2O3 play a crucial role in boosting the de-/hydrogenation properties of CeVO4-catalyzed MgH2. This work is helpful for further rational designs of novel catalysts in promoting the commercialization of MgH2.