The structural characterization and H(2) sorption properties of carbon-supported Mg(1-x)Nix nanocrystallites.
Magnesium (hydride) is a promising system for the reversible on-board storage of hydrogen, but suffers from slow sorption kinetics and a high thermodynamic stability of the hydride. We explored a combined approach to tackle these problems: nanosizing and carbon-supporting the magnesium, and doping it with nickel. Samples were prepared by melt infiltration with magnesium of nanoporous carbon onto which 1-12 wt% nickel nanoparticles had been predeposited. For loadings up to 15 wt% MgH2, 10-30 nm crystallites with different compositions were formed inside the porous carbon, each giving a specific H2 desorption signature. Surprisingly, higher Mg loadings resulted in more homogeneously mixed samples, which was due to the facilitated wetting of the carbon with the magnesium due to the presence of nickel. Hydrogen release temperatures close to that of Mg2NiH4 were observed for high MgH2 loadings (50 wt%) and small amounts of Ni (Mg(0.95)Ni(0.05)). The favourable H2 desorption properties could mainly be attributed to excellent kinetics due to the efficient mixing of magnesium, nickel and carbon on the nanoscale.
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands.
René
R
Bogerd
Philipp
P
Adelhelm
Johannes H
JH
Meeldijk
Krijn P
KP
de Jong
Petra E
PE
de Jongh
D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D006859:Hydrogen / Q000737:chemistry* / Q000302:isolation & purification; D046911:Macromolecular Substances / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry*; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D009532:Nickel / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
D046911:Macromolecular Substances; D002244:Carbon; D009532:Nickel; D006859:Hydrogen; D008274:Magnesium