Electrochemical oxidation of acetamiprid using Yb-doped PbO2 electrodes: Electrode characterization, influencing factors and degradation pathways

The Yb-doped PbO2 electrodes were fabricated by electrodeposition method. SEM and XRD experiments revealed that the adulteration of Yb can decrease the crystal grain size and make the electrodes more compact. Electrochemical measurements, accelerated service lifetime and bulk electrolysis experiments proved that Yb-doped PbO2 electrodes had higher oxygen evolution overpotential, stability and acetamiprid removal ratio than pure PbO2 electrodes. The effect of operating parameters, such as current density, initial acetamiprid concentration, and pH value, on the electrocatalytic degradation of acetamiprid were systematically studied. The electrocatalytic oxidation reaction of acetamiprid on Yb-doped PbO2 electrodes was highly effective, which obeyed the pseudo-first-order kinetics model. Intermediates analysis and electrocatalytic degradation mechanism of acetamiprid by Yb-doped PbO2 electrodes were implemented, and the degradation pathways were divided into three different sub-routes due to three function groups on acetamiprid initially attacked by hydroxyl radicals. Finally, all the byproducts were decontaminated into CO2 and H2O. These results proved that Yb-doped PbO2 electrodes have more promising application potential for the electrocatalytic degradation of refractory organic pollutants.