ELECTROCATALYTIC REDUCTION OF NO3- AND NO2- ON COMPOSITE COPPER-THALLIUM ELECTRODE IN ALKALINE SOLUTIONS.

The electrochemical behaviour of the copper-thallium composite film has been investigated in 10 mM NaOH solutions towards the electroreduction of nitrate and nitrite ions in the range of potentials between 0.0 and -1.4 V vs. SCE. The Cu45Tl55 binary films exhibited a higher electrocatalytic activity for the reduction of NO3- and NO2- than pure copper and thallium electrodeposited films. The presence of thallium species in the composite film causes a marked increase of the roughness factor with subsequent increase of the catalytic response due to the nitrate and nitrite reduction. Alternatively, thallium particles act as promoters of NO3- and NO2- adsorption on the electrode surface with their subsequent accumulation on the surface catalytic centres and increase of the cathodic currents.