The Zn93Cu7 alloy (surface area = 1 cm 2 ) was used as working electrode to drive the electrochemical NO3R to produce cyclohexanone oxime in 16 mL of 0.5 M aqueous potassium phosphate (KPi) buffer solution (pH 7.0) containing 100 mM KNO3 and 25 mM cyclohexanone. Pt and Ag/AgCl electrodes were used as counter and reference electrodes, respectively, and electrochemical tests were carried out in a gas-tight H-type cell at constant current (chronopotentiometry). More details of the electrochemical cell setup can be found in Experimental methods and Figure . Electrolysis time was adjusted to keep a constant value of charges injected into the electrolyte. The potential required to achieve a certain current density was obtained from the steady-state potential of the electrolysis. A chronopotentiometry graph for electrolysis over 2.5 h at 100 mA/cm 2 can be found in Figure as an example of obtaining the steady-state potential.