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 SnO2/PPy/beta-PbO2 structure on TiO2 nanotube arrays (TNAs/SnO2/PPy/beta-PbO2) was synthesized by a multi-step electrodeposition process as an efficient electrocatalyst for As (III) oxidation in aqueous solution. Such TNAs/SnO2/PPy/beta-PbO2 electrode exhibited a higher charge transfer, tolerable stability, and high oxygen evolution potential (OEP). The intriguing structure with a SnO2, PPy, and beta-PbO2 active layers provided a larger electrochemical active area for electrocatalytic As(III) oxidation. The assynthesized TNAs/SnO2/PPy/beta-PbO2 anode achieved drastically enhanced As(III) conversion efficiency of 90.72% compared to that of TNAs/beta-PbO2 at circa 45.4%. The active species involved in the electrocatalytic oxidation process included superoxide radical (center dot O-2(-)), sulfuric acid root radicals (center dot SO4-), and hydroxyl radicals (center dot 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).

Automated summary

In this study, a novel multilayered electrocatalyst was synthesized to achieve efficient conversion of As(III) to As(V). The electrode exhibited higher charge transfer, tolerable stability, and high oxygen evolution potential, providing a larger electrochemical active area for As(III) oxidation.