Transition-metals　have　emerged　as　promising　catalyst　candidates　for　improving　the　hydrogen　storage　properties　of　MgH2.　However,　the　preparation　of　uniformly　dispersed　and　extra-fine　transition-metals　catalysts　with　high　catalytic　activity　still　remains　a　challenge.　In　this　paper,　an　electrospinning-based　reduction　approach　is　presented　to　generate　nanostructured　nickel　catalyst,　which　is　protected　from　irreversible　fusion　and　aggregation　in　subsequent　high-temperature　pyrolysis,　in　carbon　nanofibers　(Ni@C)　in　situ.　The　obtained　Ni@C　reveals　remarkable　catalytic　effect　on　improving　the　hydrogen　storage　properties　of　MgH2.　For　example,　the　MgH2-10　wt%Ni@C　composite　delivers　dehydrogenation　capacities　of　5.79　wt%　and　6.12　wt%　at　280　degrees　C　and　300　degrees　C,　respectively,　whereas　the　as-milled　MgH2　hardly　decomposes　at　the　same　temperature.　By　Arrhenius　plots,　the　calculated　Ea　of　the　dehydrogenation　of　MgH2-10　wt%Ni@C　is　93.08　kJ　mol-1,　which　is　94.33　kJ　mol-1　lower　than　that　of　the　as-milled　MgH2.　Furthermore,　the　microstructure　of　Ni@C　is　remained　during　the　re/dehydrogenation　process　and　the　Ni　nanoparticles　are　still　distributed　homogeneously　in　the　composite,　accounting　for　the　excellent　cycling　performance.　This　study　could　render　combinations　of　ultrafine　metal　nanoparticles　with　carbon　accessible,　thereby,　extending　opportunities　in　catalytic　applications　for　hydrogen　storage.　(C)　2020　Elsevier　B.V.　All　rights　reserved.