The influence of different concentrations of cyclohexanone (i.e. 10 mM, 25 mM, 50 mM, 100 mM; NO3 -concentration was kept constant at 100 mM) added to the electrolyte was investigated through 2.5 h electrolysis experiments at 100 mA/cm 2 (Figure ). Low concentrations of cyclohexanone (e.g. 10 mM) were found to produce cyclohexanone oxime with high yields (99±1%), while the FE for cyclohexanone oxime was quite low (17±0.3%). In contrast, high concentrations of cyclohexanone (e.g. 100 mM) led to high FE for cyclohexanone oxime (40±2%), but the yield was lower (32±2%). Therefore, a medium concentration of cyclohexanone (25 mM) was chosen to balance the yield and FE for cyclohexanone oxime.