The Mechanism and Kinetics of Cyanide-Assisted Carbon Monoxide Desorption from Pt Electrodes: An Infrared Spectroscopic Study

Using a thin layer flow cell, we examined the dynamic process Of COad desorption at a Pt film electrode in contact with cyanide (CN-) containing solution by time-resolved electrochemical in situ infrared spectroscopy with attenuated total reflection configuration under well-defined mass transport. The time-resolved IR spectral features reveal that starting with a COad saturated layer (i) there is an inverse linear relationship between the band intensities of COL and CN- stretching; (ii) the CN-/COad displacement transient exhibits a "volcano" shape with three distinct kinetic regions including a slow ignition period, fast increase, and subsequent decay in the rate; (iii) the CN-/COad displacement rate decreases with electrode potential. The results suggest that COad desorption is directly related to the nucleation of CNad- islands on the surface. The mechanism of cyanide-assisted COad desorption is discussed.