Enhanced hydrogen desorption from the Co-catalyzed LiBH4–Mg(BH4)2 eutectic composite

Co-based catalyst can significantly improve the dehydrogenation kinetics of the eutectic composite of LiBH4–Mg(BH4)2 (1/1 M ratio). The onset hydrogen desorption temperature of the composite is at about 155 °C, which is ca. 245, 110 or 27 °C lower than that of LiBH4, Mg(BH4)2 or pristine LiBH4–Mg(BH4)2, respectively. Upon holding the samples at 270 °C, the Co catalyzed composite can release hydrogen at a rate 1.6 times faster than that of the pristine one. Electron Paramagnetic Resonance (EPR) characterization evidenced that Co was in a reduced state of Co+ which may serve as the functional species in catalyzing the dehydrogenation of the composite.

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► The LiBH4–Mg(BH4)2 composite was modified by Co catalyst for the first time.
► The Co-doped sample can release H2 1.6 times faster than that of the pristine one.
► Co+ species may serve as the functional species and help the decomposition of [BH4]−.