Cu and CuPb electrodes prepared via potentiostatic electrodeposition from metal oxides in hydrophobic protic amide-type ionic liquid/water mixture under ambient air for nonenzymatic nitrate reduction

摘要

Cu and CuPb electrodes were prepared via electrodeposition from a hydrophobic protic amide-type ionic liquid, the protonated betaine bis((trifluoromethyl)sulfonyl)amide ([Hbet][TFSA]), and water mixture containing CuO/PbO as the metal sources under ambient air rather than inert atmosphere. The possible coordination structure and the voltammetric behavior of the metal ions were carefully studied. The electrodeposited Cu electrodes showed steady activity towards nitrate reduction, and the activity depended on the electrodeposition potential. The dependence might be due to the change of surface morphologies of Cu with the electrodepositing potentials. The activity was markedly enhanced once Pb was doped into the electrodeposits (CuPb). The bulk electrolysis of nitrate indicated that the key step nitrite formation occurred during the electrocatalytic reduction, and nitrite could be further reduced to other nitrogen species. The electrodeposited CuPb electrodes exhibited the potential to be used as the electrocatalysts of nitrate reduction and/or nitrate sensor. (C) 2019 Elsevier Ltd. All rights reserved.