Cobalt boride catalysts for small-scale energy application

Abstract The objects of investigation were cobalt boride catalysts for a one-step production of hydrogen from NaBH 4 . Cobalt oxides prepared by calcination of cobalt salts at 500 °C were used as precursors of the catalyst active phase. It was shown that the nature of the cobalt oxide precursor has a substantial influence on the rate of formation of active component in the reaction medium of sodium borohydride and, hence, on its activity in NaBH 4 hydrolysis. The length of the activation period and catalytic activity do not correlate with the dispersion and the specific surface area of the synthesized Co 3 O 4 samples but depend on their inhomogeneity and the defect structure of the oxide due to the distribution of cobalt ions in the crystal lattice. The more defects are present in of Co 3 O 4 the faster the rate of its reduction and, hence, the higher its catalytic activity in NaBH 4 hydrolysis. On the basis of active oxide prepared from cobalt chloride, solid state NaBH 4 pellets have been prepared. For the first time, NaBH 4 pellets were used as a source of H 2 source for a thermo-electrical energy conversion device based on combustion technologies.