Scanning electrochemical microscopy investigation of nitrate reduction at activated copper cathodes in acidic medium

The cathodic reduction of nitrate at copper electrodes was investigated by using scanning electrochemical microscopy (SECM) in the stripping-mode SECM (SM-SECM). This electrochemical process is facilitated at surfaces activated by a potential protocol involving anodic dissolution and subsequent reduction of copper cations, which causes an increase in the surface area. In the presence of chloride, a much more significant current enhancement was noticed, and a mechanism based on the formation of CuCl was proposed to explain the increased rate of nitrate reduction at this experimental condition.

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► Scanning electrochemical microscopy was used to monitor Cu(I) species formed at a copper substrate.
► The formation of CuCl provides a rougher copper surface.
► The kinetic for nitrate reduction is enhanced at the rougher copper surface.