Electrochemical Detection of As (III) on a Manganese Oxide‐Ceria (Mn₂O₃/CeO₂) Nanocube Modified Au Electrode

Abstract

Abstract Ceria cubes decorated with manganese oxide nanoparticles (Mn 2 O 3 /CeO 2 nanocubes) were synthesized and used to modify a Au electrode for analysis of As(III) in aqueous solution. This modified electrode displayed improved sensitivity than either oxide on their own, indicating a synergistic effect due to the effect of Mn 2 O 3 on the properties of CeO 2 . The improved sensitivity could be ascribed to the enhanced As (III) adsorption ability of Mn 2 O 3 /CeO 2 nanocube during electrochemical pre‐concentration, combined with the well known As(III) sensing qualities of the gold substrate. The Mn 2 O 3 /CeO 2 nanocube modified gold electrode behaved as a promising sensor with stable, repeatable square wave anodic stripping voltammetry (SWASV) peaks, separated from common interfering ions in natural water including Cu (II) under practical conditions. Repeatability and stability studies revealed the As (III) sensor to be robust and reliable, with a sensitivity of 0.0414 μA/ppb and a limit of detection (LoD) of 3.35 ppb under optimized conditions, indicating a possible general use of this class of heteronanostructures in electroanalytical chemistry for studies that rely upon adsorption of deposition of the analyte prior to stripping analysis.