Synthesis and dehydriding process of crystalline Ce(BH4)3

The synthesis of a new borohydride with a theoretical hydrogen capacity of 6.5 wt% is reported. Both XRD and FTIR studies demonstrate that Ce(BH4)3 is obtained from mechanochemical reaction between CeCl3 and LiBH4. Dehydriding properties of Ce(BH4)3 were investigated using XRD, DSC and volumetry using a Sievert-type device. Thermal decomposition of Ce(BH4)3 led to 3.5 wt% hydrogen release in a multi-step process, involving an unknown intermediate compound and CeH2. It was observed that Ce(BH4)3 is partially reversible under 6 MPa of H2 at 350 °C and absorbs 28% of the total hydrogen capacity obtained experimentally. The activation energy of Ce(BH4)3 decomposition is 136 kJ mol−1.