Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia.
Langmuir. 2012 Mar 20;28(11):5286-94. doi: 10.1021/la205097p. Epub 2012 Mar 9.
The first part of this report studies the electrochemical properties of single-crystal platinum electrodes in acetonitrile electrolytes by means of cyclic voltammetry. Potential difference infrared spectroscopy in conjunction with linear voltammetry was used to obtain a molecular-level picture of this interface. The second part of this report studies the hydrogen evolution and the hydrogen oxidation reactions on the three low-index faces of Pt electrodes in acetonitrile electrolytes. The data (CVs and IR spectra) strongly suggest that acetonitrile and CN(-) molecules are adsorbed on single-crystal platinum electrodes in the range of -1.5 to 0.3 V versus Ag/AgCl. Those species block part of the adsorption sites for hydrogen adatoms, and they decompose on the surface in the presence of water. The nature of the cation and the presence of water strongly affect the onset of acetonitrile electrolysis and the kinetics and stability of the adsorbed species on the electrode. Finally, the hydrogen evolution and the hydrogen oxidation reactions on platinum single-crystal surfaces in acetonitrile electrolytes are strongly affected by the surface-energy state of Pt electrodes.
本报告的第一部分通过循环伏安法研究了单晶铂电极在乙腈电解液中的电化学性质。通过电位差红外光谱结合线性伏安法，我们获得了该界面的分子水平图像。本报告的第二部分研究了在乙腈电解液中 Pt 电极的三个低指数面上的析氢和氢氧化反应。数据（CV 和 IR 光谱）强烈表明，在相对于 Ag/AgCl 为-1.5 至 0.3 V 的范围内，乙腈和 CN(-)分子被吸附在单晶铂电极上。这些物种部分阻塞了氢原子吸附位，并且在存在水的情况下在表面上分解。阳离子的性质和水的存在强烈影响乙腈电解的起始以及电极上吸附物种的动力学和稳定性。最后，在乙腈电解液中，Pt 单晶表面上的析氢和氢氧化反应强烈受到 Pt 电极表面能状态的影响。
