Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7719093 | International Journal of Hydrogen Energy | 2014 | 7 Pages |
Abstract
Two different Co-S compounds with enhanced hydrogen storage properties, Co9S8 and CoS2, were prepared by ball-milling mixtures of Co metal and S powder. X-ray diffractometry, scanning electron microscopy and transmission electron microscopy were used to show that specific molar ratios of Co:S and ball-milling speeds and times result in pure Co9S8 and CoS2, thus overcoming a long-standing inability to obtain pure Co-S compounds via ball-milling. A galvanostatic charge-discharge process and cyclic voltammetry measurements showed that the as-obtained Co9S8 and CoS2 nanoparticles have enhanced electrochemical hydrogen storage capacities of 1.79 and 1.57Â wt% hydrogen, respectively, which are higher than those previously reported. In addition, based on the corresponding X-ray photoelectron spectroscopy and cyclic voltammetry measurements, a new electrochemical hydrogen storage mechanism for the two Co-S compounds was proposed and discussed.
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Authors
Wei Qin, Baoguo Hu, Di Bao, Peng Gao,