Precipitation of Nickel Hydroxides from Nickel Dodecylsulphate

摘要

Classical precipitation techniques applied to a nickel di-dodecylsulphate Ni(DS)_2 precursor were developed. In the range of concentrations studied this precursor forms direct micelles in water. In pH-controlled double jet precipitation with soda at 60°C, the pure α, poorly crystallised β_(bc) and well crystallised β phases are successively obtained by pH shifts from 8 to 11, whereas the platelet morphology remains similar. In the same conditions, classical salts never lead to α phase and the particle size and morphology is pH dependent. Hydroxide precipitation by ammonia decomplexation, via heating at 60°C, Ni(DS)_2 leads to well-calibrated stacks of (β-Ni(OH)_2 nanopancakes (300 nm in diameter and 200 nm stacking length) whereas classical salts lead to micrometric particles characterised by thin interconnected walls.