Reduction of carbon monoxide on a mediated and partially immersed electrode

Abstract

The reduction of carbon monoxide into methanol has been performed using Everitt's salt {K₂Fe^II[Fe^II(CN)₆]} as a mediator in the presence of homogeneous catalysts at a three-phase (electrode/solution/gas) interface. These conditions enhance the reduction of CO owing to the rapid transport of CO to the active zone of the electrode. The logarithm of the reduction current is linearly related to log (time) with a slope of –1/2 and reaches a constant value after an extensive period of polarization. A theoretical equation for the current against time curve is derived based on a surface-diffusion model in which CO from the gas phase is first adsorbed on the electrode surface and then diffuses along the surface toward the intersection of the three phases; the computed plot of current against time fits the experimental one well.