应用开路 电位 测 量和 循 环 伏 安 法研 究 碱 性 介 质中 Ｈ２ Ｐ Ｏ－２ 在 镍电 极 上 的 电 氧化 过程，并 对镍氧化 膜的去活 化机理 进行了探 讨．结果 表明，镍 电极在 碱性 介质 中由 于氧 化膜 的快 速形成而显示 出明显 的非 催化 活 性． Ｈ２ Ｐ Ｏ－２ 的 氧 化发 生 在 较负 的 电位 范 围， Ｈ Ｐ Ｏ２ －３ 为 氧 化 的 最终 产物． Ｈ２ Ｐ Ｏ－２ 的 氧化过程 分为 Ｈ２ Ｐ Ｏ－２ 吸附 、 Ｐ－ Ｈ 键断 裂、活性 中间 物形 成及 其氧 化等 步骤 ． Ｈ２ Ｐ Ｏ－２与活性 镍充分 的相互作 用是形成 活性基 团及随后 氧化的 必要条件 ．
Electrooxidation of hypophosphite anions on polycrystalline nickel in alkaline solutions has been investigated by cyclic voltammetry and open circuit potential measurements.The results are explained based on the mechanism that the first step of hypophosphite oxidation is the adsorption of hypophosphite ions on nickel,followed by the homolysis of its hydrogen bond with the formation of radicals.The oxidation of hypophosphite on nickel in alkaline medium occurs at lower potentials between ca.-0.8 V—-1.1 V(SCE)and phosphite ion is the only oxidation product.There is no indication of hypophosphite oxidation at higher potentials.Severe deactivation of the surface occurs when the nickel surface is covered with surface oxide/hydroxide films which separates the hypophosphite ion from nickel substrate.The results show that the rate of the anodic oxidation of hypophosphite depends strongly on the nature of the nickel substrate,operation temperature,hypophosphite concentration and sweep rate.
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