An electrochemical process for producing nanoparticlesof cuprate hydroxychlorides

The present invention relates to an electrochemical process for producing nanoparticles of mixed copper hydroxide-chloride compounds responding to the chemical formula MxCu4-x(OH)yClz wherein M is one or more metal cations from the group comprising a divalent earth alkali metal cation, a divalent transition metal cation or a trivalent transition metal cation, and wherein 0 ≤ x ≤ 1, 5.5 ≤ y ≤ 6.5 and 1.5 ≤ z ≤ 3, the method comprising the steps of (1) supplying to a cathode compartment of an electrochemical cell, wherein the cathode compartment comprises a catholyte and is equipped with a cathode comprising a gas diffusion electrode with a porous electrochemically active material, a liquid water based mixture containing dissolved therein Cl- ions, at least one precursor salt containing the one or more metal cations M, and at least one Cu2+ precursor salt, wherein the ratio of the concentration of Cu2+ to M is smaller than 10:1, (2) adjusting the pH of the reaction mixture to a value between 2.0 and 6.0, (3) supplying an O2 containing oxidant gas to the gas diffusion electrode, (4) subjecting the cathode to an electrochemical potential which is below the thermodynamic limit of O2 reduction at the pH of the reaction mixture, (5) applying a potential to the gas diffusion electrode to cause reduction of the O2 contained in the oxidant gas to one or more of the corresponding peroxide, OH-, ionic and/or radical reactive O containing species, and isolating nanoparticles of MxCu4-x(OH)yClz.