Autocatalytic reduction of Cu(II) to copper by Co(II) studied by electrochemical quartz crystal microgravimetry in a wall jet cell

Electrochemical Quartz Crystal Microgravimetry (EQCM) studies were carried out in a new type of electroless copper plating solution containing Co(II)-ethylenediamine species as a reducing agent for Cu(II)-ethylenediamine complex. The rates of partial reactions of Cu(II) reduction and Co(II) oxidation were studied as a function of the electrode potential(-0.3 V to 0.05 V vs. SHE) under stopped-flow and wall jet conditions. The increase in the rate of partial reactions and the overall process under wall jet conditions suggests diffusion limitations occur in the transport of reacting species (Cu(II) and Co(II)) to the electrode and/or inhibiting products of reaction (Co(III) and ethylenediamine) to the bulk of the solution. Anodic dissolution of copper starts at 0.0 V. (C) 1997 Elsevier Science S.A.