Magnetic Assembled Anode Combining PbO2 and Sb-SnO2 Organically as An Effective and Sustainable Electrocatalyst for Wastewater Treatment with Adjustable Attribution and Construction.

A new electrode consisting of a Ti/PbO2 shell as main electrode (ME) and numerous Fe3O4/Sb-SnO2 granules as auxiliary electrodes (AEs) was developed for flexible electrochemical oxidation (EO) treatment of wastewater. Material and electrochemical characterizations were carried out to study the impacts of the loading amount of the AEs on the attribution and construction of the electrode. Lignin, a complex group of polymeric macromolecules, was selected as the representative actual contaminant to test the real EO capability of the assembled electrodes with different AE loading amounts. The stability and recyclability of the electrodes were also investigated. Results showed that the roughness and the surface area of the electrode were increased with the increased loading amount of AEs, while improvement of the electrode properties was achieved only with the appropriate amounts of AEs. The optimum AE loading (such as 0.25 and 0.5 g on 6 cm2 ME) boosted the EO performance of the anode toward lignin by ∼20%, making the electrode more capable in benzene ring opening. Excessive AEs were found to be unavailing, which only increased the percentage of the less accessible catalytic active sites. Moreover, a preliminary operating mechanism of this 2.5D electrode was proposed to evaluate the effect of AEs and further reveal the relationships of structure and activity of the 2.5D electrode. Finally, the electrode's lifetime was lengthened and further boosted via loading AEs and the subsequent recycling of AEs.