Towards easy reversible dehydrogenation of LiBH4 by catalyzing hierarchic nanostructured CoB

The nanostructured CoB of morphologies, being rod-like, flake-like, chain-like, waxberry-like and mulberry-like, was synthesized, and then doped into LiBH4 by ball milling. CoB played as pure catalyst facilitating de/rehydrogenation of LiBH4, and its morphology greatly influenced the catalytic activity. The catalytic effect of CoB is approximately in the order of mulberry-like>waxberry-like>chain-like>flake-like>rod-like, in accordance with their specific surface area from high to low. For dehydrogenation at 200 degrees C, mulberry-like and waxberry-like CoB dramatically enhanced the dehydrogenation of LiBH4, but not other CoB catalysts. 4.6 and 4.8 wt% hydrogen was released from LiBH4 catalyzed by those two CoB, respectively, and the later showed reversibility of >2 wt%. For dehydrogenation at 350 degrees C, mulberry-like CoB showed the best catalytic effect. 10.4 wt% hydrogen was liberated from LiBH4 with almost full reversibility under 400 degrees C and 10 MPa rehydrogenation conditions, remaining 9.6 wt% at the fourth cycle. (C) 2014 Elsevier Ltd. All rights reserved.