Enhanced hydrogen desorption properties of MgH2 by highly dispersed Ni: The role of in-situ hydrogenolysis of nickelocene in ball milling process

•Highly dispersed Ni in MgH2 matrix is obtained by in-situ hydrogenolysis of NiCp2.•The as-prepared MgH2–NiCp2 sample has enhanced hydrogen desorption kinetics.•The as-prepared MgH2–NiCp2 sample exhibits superior cycle stability.•Improvement of properties is attributed to highly dispersive catalytic...

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Bibliographic Details
Published inJournal of alloys and compounds Vol. 900; p. 163547
Main Authors Peng, Cong, Li, Yongtao, Zhang, Qingan
Format Journal Article
LanguageEnglish
Published Lausanne Elsevier B.V 15.04.2022
Elsevier BV
Subjects
Ball milling
Catalysis
Dehydrogenation
Desorption
Dispersion
Hydrogen
Hydrogen storage
Hydrogen storage materials
Hydrogenolysis
Kinetics
Magnesium
Magnesium hydride
Nanoparticles
Nickelocene
Nickelocene
Hydrogen storage
Magnesium hydride
Catalysis
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Summary:•Highly dispersed Ni in MgH2 matrix is obtained by in-situ hydrogenolysis of NiCp2.•The as-prepared MgH2–NiCp2 sample has enhanced hydrogen desorption kinetics.•The as-prepared MgH2–NiCp2 sample exhibits superior cycle stability.•Improvement of properties is attributed to highly dispersive catalytic phase. [Display omitted] Magnesium hydride is a promising hydrogen storage material and how to improve its sorption kinetics is one of challenges in practical applications. In this paper, a new approach is proposed to catalyze MgH2 with highly dispersed Ni nanoparticles by in-situ hydrogenolysis of nickelocene (NiCp2) in ball milling process. After ball milling under 4 MPa hydrogen atmosphere for 15 h, the MgH2–16.1 wt% NiCp2 sample exhibits a homogeneous morphology where the in-situ formed Ni nanoparticles with size of ~8 nm are highly dispersed in MgH2 matrix. During initial dehydrogenation, Ni would react with MgH2 to form Mg2Ni which inherits the configuration of its high dispersion. In the subsequent hydrogen absorption and desorption cycles, the much fine and highly dispersed Ni-based catalytic phase contributes to the superior hydrogen desorption kinetics of MgH2 with a high-capacity retention rate of ~96% after 50 cycles. This work demonstrates that the in-situ formation of highly dispersed catalytic species is beneficial for improving hydrogen storage properties of MgH2.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2021.163547