Temperature controlled cell for in situ infrared spectroelectrochemical measurements and its use in the study of CO isothermal desorption

An infrared spectroelectrochemical cell capable of operation at temperatures between ambient and 70 °C is described. The cell is based on a conventional design with temperature sensing and heating functions built into the working electrode. The cell was applied to study the isothermal desorption of carbon monoxide from a polycrystalline platinum electrode. The measurements indicate CO desorption can be activated by the solvent. In acetonitrile containing 0.1 M tetrabutyl ammonium tetrafluoroborate (TBAF), the lifetime of a CO adlayer decreased progressively from about 6 h to less than 2 h when CO desorption was monitored at constant temperatures in the range 25-45 °C and potentials between 0.0-0.2 V (vs. a Ag|AgCl|KCl (sat) reference electrode). In contrast, CO was stable on platinum electrodes in 0.1 M HClO₄ at temperatures between ambient and 40 °C, as long as the electrode was maintained at double layer potentials. In acetonitrile solutions, the addition of chloride, oxygen or one of several organic impurities had little eflect on the CO desorption behavior.