Gold electrode modified with ultrathin SnO₂ nanosheets with high reactive exposed surface for electrochemical sensing of As(III)

Here we report a system using ultrathin SnO₂ nanosheets with high reactive exposed (110) surface modified gold electrode for sensitive detection of As(III) by Square wave anodic stripping voltammetry (SWASV) with a mild acid condition (pH 5.0). Ultrathin SnO₂ nanosheets have been synthesized via a hydrothermal process successfully with the thickness of about 0.52 nm (four atomic layers thick). This oxide is used as electrode modifier, and the modified electrode exhibits good performance in stripping determination of As(III). The LOD actually measured is 5 μg L⁻¹ and below the guideline value given by the World Health Organization (WHO). As compared with SnO₂ bulks, ultrathin SnO₂ nanosheets are found to exhibit stronger adsorption capability and better detection performance toward As(III), it may be due to the atomic thickness and extremely huge percentage of (110) facet ultrathin nanosheets materials exposed. Finally, this system is successfully applied for the analysis of a real sample collected from Inner Mongolia, China. Most importantly, we pose a potential for the use of ultrathin materials to improve the electrochemical performance of bare gold electrode in mild acid condition.