A 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 temperature s between ambient and 70 degrees C is described. The cell is based on a con ventional design with temperature sensing and heating functions built into the working electrode. The cell was applied to study the isothermal desorpt ion of carbon monoxide from a polycrystalline platinum electrode. The measu rements indicate CO desorption can be activated by the solvent. In acetonit rile containing 0.1 M tetrabutyl ammonium tetrafluoroborate (TBAF), the lif etime 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 2 5-45 degrees C and potentials between 0.0-0.2 V (vs. a Ag\AgCl\KCl (sat) re ference electrode). In contrast, CO was stable on platinum electrodes in 0. 1 M HClO4 at temperatures between ambient and 40 degrees C, as long as the electrode was maintained at double layer potentials. In acetonitrile soluti ons, the addition of chloride, oxygen or one of several organic impurities had little effect on the CO desorption behavior. (C) 1999 Elsevier Science S.A. All rights reserved.