Electrodeposition of metal/hydeoxide nano-composite material

锌镍的异常共沉积可能是由于氢氧化锌在阴极上优先沉淀，而根据阴极产氢量和pH值的增加，镍的沉积受到抑制。然而，本文作者报道，当溶液中同时存在Zn^<2+>和Ni^<2+>时，没有氢氧化锌析出，而两种金属的双氢氧化锌析出。研究了锌镍合金沉积过程中阴极处双氢氧化物的形成及其电解还原。通过EQCM法结合电化学测量，明确了氢的生成先于合金沉积，双氢氧化物附着在电极表面。SEM/EDX分析证实，石英表面粘附材料的电解还原产物为Zn:Ni比约为9:1的锌/镍合金。认为吸附在阴极表面的双氢氧化物是合金沉积反应的前驱体。

The anomalous codeposition of Zn-Ni may be due to the preferential precipitation of zinc hydroxide on the cathode and the inhibition of nickel deposition according to the hydrogen production at the cathode and the pH increase. However, the author reports here that when both Zn^<2+> and Ni^<2+> coexist in the solution, the zinc hydroxide does not precipitate while the double hydroxide of both metals does.The formation of the double hydroxide and its electrolytic reduction at the cathode in zinc-nickel alloy deposition were investigated. By using an EQCM method combined with the electrochemical measurement, it was clarified that the hydrogen generation occurs prior to the alloy deposition and the double hydroxide adheres to the electrode surface. It was confirmed that the electrolytic reduction product of the adhered material on the quartz surface, was the zinc/nickel alloy with the Zn:Ni ratio of about 9:1, from the analysis by using SEM/EDX. It is considered that the double hydroxide adsorbed on the cathode surface acts as a precursor of the alloy deposition reaction.