Investigation of the adsorption of phosphoric acid on platinum at elevated temperature by means of IR spectroscopy combined to electrochemical methods

该项目的目的是详细了解高温下磷酸和其他磷酸盐物种在铂表面上的吸附。这些光谱电化学调查应提供有关吸附物种的状态的信息。这意味着例如在不同温度和电势下的吸附几何形状或质子化程度。该信息对于理解高温聚合物电解质燃料电池的阴极上的铂催化剂处的氧还原反应是相关的。该反应受到磷酸在电化学活性表面位点上的吸附的阻碍。计划建立一种方法，该方法使用非破坏性的表面敏感的红外反射吸收光谱法，用于根据施加的电势和温度调查吸附的磷酸。为此，电位调制技术，减法归一化界面傅立叶变换红外光谱（SNIFTIRS），将用于监测两个电位之间的差异。因此，将不存在磷酸吸附的电势用作参考，以显示吸附后的差异。使用这些数据将导致更好地理解取决于温度的氧还原反应的阻碍。

The aim of this project is the detailed understanding of the adsorption of phosphoric acid and other phosphate species on platinum surfaces at elevated temperature. These spectroelectrochemical investigations should give information about the state of the adsorbed species. That means for example the adsorption geometry or the degree of protonation at various temperatures and potentials. This information is relevant for understanding the oxygen reduction reaction at platinum catalyst on the cathode of a high temperature polymer electrolyte fuel cell. This reaction is hindered by adsorption of phosphoric acid on electrochemically active surface sites.The establishment of a method, which uses the non-destructive surface sensitive infrared reflection absorption spectroscopy for investigation of the adsorbed phosphoric acid depending on the applied potential and temperature, is planned. For this purpose a potential modulation technique, the subtractively normalized interfacial fourier transform infrared spectroscopy (SNIFTIRS), will be used for monitoring the difference between two potentials. Thus, the potential, where no adsorption of phosphoric acid is present, is used as reference, to show the differences after adsorption. Using this data will lead to a better understanding of the hindrance of the oxygen reduction reaction depending on the temperature.