Catalytic effects of V- and O-species derived from PrF3/V2C for efficient hydrogen storage in MgH2
Zhenluo Yuan, Yuhang Wang, Xiuxiu Zhang, Shuyan Guan, Xiaojiao Wang, Liqiang Ji, Qiuming Peng, Shumin Han, Yanping Fan, Baozhong Liu
Abstract
Magnesium hydride (MgH 2 ) is considered as an ideal hydrogen storage material with excellent hydrogen capacity, but the slow kinetics impedes its application. Herein, an efficient additive of V 2 C MXene-anchored PrF 3 nanoparticles (PrF 3 /V 2 C) was synthesized, which presents excellent catalytic effect in improving the reversibility and stability of hydrogen storage in MgH 2 . The initial dehydrogenation temperature of the 5 wt.% PrF 3 /V 2 C-containing MgH 2 (182 °C) is 105 °C lower than that of pure MgH 2 , and 6.5 wt.% hydrogen is rapidly released from 5 wt.% PrF 3 /V 2 C-added MgH 2 sample in 6 min at 240 °C. In addition, 5 wt.% PrF 3 /V 2 C-containing MgH 2 sample possesses outstanding reversible hydrogen storage capability of 6.5 wt.% after 10 cycles of dehydrogenation and hydrogenation. Microstructure analysis shows that the introduction of Pr improves the stability of V-species (V 0 and V 2+ ) and O-species (lattice oxygen (O L ) and vacancy oxygen (O V )) formed during ball milling, promotes the interaction between V-species and O-species, and enhances their reversibility, which contributes to the significant improvement in re/dehydrogenation reversibility and cycling stability of MgH 2 . This study provides effective ideas and strategies for the purpose of designing and fabricating high-efficient catalysts for solid-state hydrogen storage materials.