Hydrogen generation from the hydrolysis of sodium borohydride with new pyridinium dicationic salts containing transition metal complexes

Pyridinium based dicationic ionic salts [C6(mpy)2] containing transition metal halide anions [NiCl4]2− and [CoCl4]2− were synthesized and characterized by 1H NMR, 13C NMR, LRMS-MS & TGA. The catalytic activities of dicationic ionic liquids were studied for the first time in the hydrolysis reaction of sodium borohydride. The reported work includes the full experimental details for the collection of a wealth of kinetic data to determine the activation energy (Ea = 56.36 kJ/mol) and effects of the amount of catalyst, amount of substrate and temperature on the rate for the catalytic hydrolysis of NaBH4. The activation energy of the catalyst dicationic tetrachloronickelate (II) anion for hydrogen production is comparable to that of other metal halide catalysts.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Pyridinium dicationic ionic liquids containing transition metal complexes were synthesized. ► Dicationic ILs were tested for the hydrogen generation from sodium borohydride. ► [C6(mpy)2][NiCl4]2− was found to be active catalyst than [C6(mpy)2][CoCl4]2−. ► [C6(mpy)2][NiCl4]2− catalyst provides 5048 ml hydrogen generation over 23 h.