A modular functionalized anode for efficient electrochemical oxidation of wastewater: Inseparable synergy between OER anode and its magnetic auxiliary electrodes.

Abstract

Oxygen evolution reaction (OER) anodes, (e.g., IrO) are well-known inefficient catalysts for electrochemical oxidation (EO) of refractory organics in wastewater due to the high energy consumption via OER. However, in this study this kind of anode participated in a very effective EO process via a specific modular anode architecture. Traces of magnetic FeO/Sb-SnO particles as auxiliary electrodes (AEs) were attracted on the surface of the two-dimensional (2D) Ti/IrO-TaO by a NdFeB magnet, and thereby constituted a new magnetically assembled electrode (MAE). MAE could be renewed by recycling its AEs. The electrochemical properties as well as the EO performances of the MAE could be regulated by adjusting the loading amount of AEs. Results showed that even a small amount of AEs could increase surface roughness and offer massive effective active sites. When removing color of azo dye Acid Red G, the optimal MAE exhibited ∼1100 % and ∼500 % higher efficiencies than 2D Ti/IrO-TaO and 2D Ti/Sb-SnO, respectively. The superiority of the MAE was also applicable in degrading phenol. The synergy between Ti/IrO-TaO and magnetic Sb-SnO particles was therefore discussed.