铂电极电催化过程中的阳离子效应研究

Studies on Cationic Effect in Electrocatalytic Process of Platinum Electrode

金属阳离子在铂电极的电催化过程中起着重要作用。采用循环伏安法和线性伏安法研究了Na^(+)、K^(+)和Rb^(+)阳离子在多晶铂电极表面对氢的吸脱附以及羟基吸附中的作用。在稀硫酸溶液中,多晶铂电极表面两个氢的脱附电流氧化峰是由于氢在(100)和(110)面上脱附造成的,氢的脱附峰电流随着稀硫酸溶液中所含金属离子半径的增大而增大。此外,金属阳离子浓度对Pt(100)面的氢的脱附峰影响更大。在0.90 V附近,铂电极表面氧化物的生成电流随着阳离子半径的增加而增加,其电流顺序为:I(Rb^(+))>I(K^(+))>I(Na^(+))。最后以相应的碱金属碘化物为研究对象,在0~1.00 V范围内,其氧化峰电流大小顺序为:I(RbI)>I(KI)>I(NaI)。

Metal cations play an important role in the electrocatalytic process of platinum electrodes.In this paper,electrochemical methods of cyclic and linear sweep voltammetry were used to study the role of Na^(+),K^(+)and Rb^(+)in the absorption and desorption of hydrogen and adsorption of hydroxyl on the surface of polycrystalline platinum electrode.Both hydrogen desorption peaks on the surface of polycrystalline platinum electrode correspond to the desorption of hydrogen on the single crystal surface of Pt(100)and Pt(110),respectively.The current of desorption of hydrogen increases with the radius of metal ions containing in the dilute sulfuric acid solution.The concentration change in alkali metal cations has a larger effect on the desorption peak of hydrogen on the Pt(100)surface.The generating current of surface oxide of platinum electrode near 0.90 V increases with the cation radius and the current order is:I(Rb^(+))>I(K^(+))>I(Na^(+)).Finally,the corresponding alkali metal iodide were studied in the range of 0~1.00 V and the oxidation peak current order was:I(RbI)>I(KI)>I(NaI).