Electrochemical oxidation of cinnamic acid with Mo modified PbO2 electrode: Electrode characterization, kinetics and degradation pathway

• Typical transition metal Mo doped PbO2 electrode was prepared.
• Mo-doped PbO2 electrode showed an obvious enhancement for the removal of pollutants.
• The enhanced mechanism was discussed with the help of SEM and XRD analysis.
• The degradation pathway of cinnamic acid was proposed.

A novel molybdenum modified PbO2 electrode was successfully prepared with the method of electrodeposition. The SEM and XRD were employed to study the surface morphology of electrodes, which indicated that the modified PbO2 electrode had a larger effective area and more compact film. Electrochemical degradation of cinnamic acid (CA) in aqueous solution with Mo–PbO2 electrode and PbO2 electrode were investigated. The results showed that the Mo–PbO2 electrode had a better effect of CA removal. The operational parameters influencing the electrochemical degradation of CA with Mo–PbO2 electrode were optimized and the results revealed that the electrochemical degradation of CA followed the pseudo-first-order kinetics and the optimal removal of CA and COD were 85.51% and 25.79% after 120 min on condition of the electrolyte concentration, initial concentration of CA, current density and initial value of pH were 0.1 mol/L, 300 mg/L, 10 mA/cm2 and 3.4, respectively. The degradation mechanism of CA in electrochemical oxidation with Mo–PbO2 electrode was analyzed and the main degradation pathway of CA was proposed based on the intermediates identified by IC and GC–MS.