Effect of indium doping on the PbO2 electrode for the enhanced electrochemical oxidation of aspirin: An electrode comparative study

A novel indium (In) doped PbO2 electrode featuring high electrochemical activity and electrode stability toward electrochemical degradation of refractory organic pollutants was prepared by electrodeposition technique. Based on the aspirin removal efficiency, the optimized molar ratio of In/Pb in electrodeposition solution was 1%. In contract with the undoped PbO2 electrode, the constructed In-doped PbO2 electrode displayed a more compact structure, a better oriented crystal of smaller size, an increased concentration of active oxygen species, a higher oxygen evolution potential, a lower charge transfer resistance and a higher electrode stability. The In-doped PbO2 electrode was demonstrated to have a superior electrochemical oxidation ability with higher (OH)-O-center dot generation capacity. For In-doped PbO2 electrode, the removals of aspirin and COD reached 76.45% and 52.09% after 2.5 h of electrolysis, respectively. Meanwhile, the energy saving could be up to 30.56% after In doping. This outcome was in good agreement with the results of surface characterization of PbO2 electrodes. Finally, combination with the safety evaluation, we could conclude that In-doped PbO2 electrode was a promising anode for the treatment of organic pollutants.