Large enhancements in the current response of primary alcohols caused by the interactions of unlike anions

A trend is revealed for the electrochemical oxidation of methanol and primary alcohols. The percent increase in current, which is achieved by replacing some of the supporting electrolyte with a more inhibiting one, becomes larger with respect to the number of carbon atoms in the alcohol. This trend is correlated to increases in the ratio of the amount of aldehydes and carboxylic acids produced to the amount of CO intermediates formed. Localized interactions of unlike anions substantially enhance the rate of production of aldehydes and carboxylic acids. Because of the requirement of a larger number of sites and the adsorption of large surface intermediates, comparable rate increases are not achieved for the formation and removal of CO intermediates.