Facile construction of Mxene‐supported niobium hydride nanoparticles toward reversible hydrogen storage in magnesium borohydride
Ao Xia, Jiaguang Zheng, Qingbo Zhang, Yugang Shu, Chengguo Yan, Liuting Zhang, Zhanliang Tao, Lixin Chen
Abstract
Abstract The facile construction of nanoscale NbH x supported by Ti 3 C 2 (NbH x @Ti 3 C 2 ) was achieved using facile ball milling strategy to improve the hydrogen desorption kinetics and reversibility of magnesium borohydride (Mg(BH 4 ) 2 ). The doping of 30 wt% NbH x @Ti 3 C 2 catalyst reduced the onset dehydrogenation temperature of Mg(BH 4 ) 2 to 71.2 °C. Additionally, the Mg(BH 4 ) 2 + 30NbH x @Ti 3 C 2 composite achieved remarkable hydrogen release of over 9.2 wt% at a temperature as low as 230 °C, indicating unexpected dehydrogenation kinetics. Moreover, the reversibility of NbH x @Ti 3 C 2 doped Mg(BH 4 ) 2 was retained to more than 4.2 wt% after four cycles, which was increased by 68% compared to that of undoped Mg(BH 4 ) 2 . The strong catalysis of NbH x @Ti 3 C 2 catalyst could be attributed to the synergistic effect of NbH x and Ti 3 C 2 in hydrogen spillover and diffusion. NbH x acted as a “hydrogen pump” for effective hydrogen spillover, while Ti 3 C 2 created numerous diffusion channels for hydrogen dissolution and provided the active catalytic site to facilitate the re/dehydrogenation of Mg(BH 4 ) 2 .