Multilayered TNAs/SnO2/PPy/β-PbO2 anode achieving boosted electrocatalytic oxidation of As(III)

Dealing with arsenic pollution has been of great concern owing to inherent toxicity of As(III) to environments and human health. Herein, a novel multilayered SnO 2 /PPy/ β -PbO 2 structure on TiO 2 nanotube arrays (TNAs/SnO 2 /PPy/ β -PbO 2 ) was synthesized by a multi-step electrodeposition process as an efficient electrocatalyst for As(III) oxidation in aqueous solution. Such TNAs/SnO 2 /PPy/ β -PbO 2 electrode exhibited a higher charge transfer, tolerable stability, and high oxygen evolution potential (OEP). The intriguing structure with a SnO 2 , PPy , and β -PbO 2 active layers provided a larger electrochemical active area for electrocatalytic As(III) oxidation. The as-synthesized TNAs/SnO 2 /PPy/ β -PbO 2 anode achieved drastically enhanced As(Ⅲ) conversion efficiency of 90.72% compared to that of TNAs/ β -PbO 2 at circa 45.4%. The active species involved in the electrocatalytic oxidation process included superoxide radical (•O 2 − ), sulfuric acid root radicals (•SO 4 − ), and hydroxyl radicals (•OH). This work offers a new strategy to construct a high-efficiency electrode to meet the requirements of favorable electrocatalytic oxidation properties, good stability, and high electrocatalytic activity for As(III) transformation to As(V).