Co-electrodeposited rGO/MnO2 nanohybrid for arsenite detection in water by stripping voltammetry

• Noble metal free co-electrodeposited rGO/MnO2 Nanohybrid/GCE for As(III) detection in water.
• Astonishing structures observed for fabricated electrodes by SEM & TEM.
• The observed comparable sensitivity of 0.175 μA/ppb to expensive Au based electrode.
• The obtained detection limit, 0.05 ppb, is well below the WHO guidelines.

Herein, we report noble metal free, cathodically co-electroreduced rGO/MnO2 nanohybrid (NH) on glassy carbon electrodes for arsenite (As (III)) detection in water by square wave anodic stripping voltammetry (SWASV). Cyclic voltammetry, scaning electron microscopy, X-ray diffraction, trasnsmission electron microsocpy and Fourier transform infra-red (FT-IR) spectroscopy were used to probe the rGO/MnO2/GCE surface, revealing the formation of NHs. The arsenite sensing parameters such as deposition potential and time was optimized allowing a detection range of 0.1 ppb to 50 ppb in 0.1 M acetate buffer. This in-situ fabricated NHs electrodes exhibit favourable sensitivity of 0.175 μA/ppb with a theoritical limit of detection of 0.05 ppb for arsenite, which is well below the levels set by World Health Organization. Moreover, the fabricated electrode exhibited good selectivity, stability and reproducibility, in near alkaline condition without using any noble metal as sensing electrode component, desirable for practical application. These findings suggest the possibility of a cost effective electrochemical sensing electrode for a portable embedded system to determine As (III) in water.

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