Vermiform Ni@CNT derived from one-pot calcination of Ni-MOF precursor for improving hydrogen storage of MgH2
Zi-yin DAI, Bing Zhang, Hideo Kimura, Li-rong XIAO, Rong-han LIU, Chenkang Ni, Chuan-xin HOU, Xue-qin SUN, Yuping Zhang, Xiaoyang Yang, Rong-hai YU, Wei Du, Xiu-bo XIE
Abstract
The Ni-coated carbon nanotubes (Ni@CNT) composite was synthesized by the facile “filtration + calcination” of Ni-based metal−organic framework (MOF) precursor and the obtained composite was used as a catalyst for MgH 2 . MgH 2 was mixed evenly with different amounts of Ni@CNT (2.5, 5.0 and 7.5, wt.%) through ball milling. The MgH 2 −5wt.%Ni@CNT can absorb 5.2 wt.% H 2 at 423 K in 200 s and release about 3.75 wt.% H 2 at 573 K in 1000 s. And its dehydrogenation and rehydrogenation activation energies are reduced to 87.63 and 45.28 kJ/mol (H 2 ). The in-situ generated Mg 2 Ni/Mg 2 NiH 4 exhibits a good catalytic effect due to the provided more diffusion channels that can be used as “hydrogen pump”. And the presence of carbon nanotubes improves the properties of MgH 2 to some extent.