Interfacial Synthesis of Prussian Blue-Decorated Sulfur-Doped Reduced Graphene Oxide Nanocomposite for Electrochemical Sensing and Detoxification of As(III)

Electrochemical sensing is considered as one of the most promising approaches for quick, reliable, and on-site detection and monitoring of arsenic (As) levels in water. However, the unavailability of stable, selective, and affordable electrode materials hampers the development of portable, cost-effective, reliable, and practically applicable arsenic-sensing electrochemical devices. In this article, we describe a straightforward biphasic synthesis method for the crafting of sulfur-doped reduced graphene oxide (S-rGO)-supported Prussian blue (PB) nanodeposits (S-rGO/PB), a nanocomposite with exceptional stability and activity for selective and sensitive electrochemical sensing of As. The S-rGO/PB is demonstrated to selectively and sensitively electrocatalyze the As(0)/As(III) and As(III)/As(V) charge transfer processes via the participation of the Fe(II)/Fe(III) cycle as revealed by X-ray photoelectron spectroscopy, thereby ensuring accurate and sensitive electrochemical sensing of As in water samples. We demonstrate that with the S-rGO/PB electrode, As(III) can be sensed via differential pulse voltammetry (DPV) with sensitivity values of 1.79 (As(0)-As(III)) and 10.69 mu A ppb-1 cm-2 (As(III)-As(V)) and limits of detection as low as 0.0104 and 0.0536 ppb, respectively. Alongside real-time applicability, the S-rGO/PB is demonstrated to exhibit excellent stability and specificity toward arsenic sensing even in the presence of other interferents. Importantly, the As(III) estimates obtained for real water samples using DPV over S-rGO/PB closely match the estimates obtained with atomic absorption spectrometry, a highly expensive and sophisticated state-of-the-art technique known for its accuracy in estimation of the sub-ppb traces of heavy metals. The presented results suggest that the S-rGO/PB composite is a promising electrode material that can facilitate the design and development of portable, affordable, reliable, and practically applicable electrochemical setups for on-site sensing and electrodetoxification of As(III) in water samples. The availability and accessibility of such setups are a must for the worldwide success of arsenic mitigation initiatives, particularly in underdeveloped and impoverished nations.

Automated summary

In this article, a sulfur-doped reduced graphene oxide (S-rGO)-supported Prussian blue (PB) nanodeposits (S-rGO/PB) composite is described as a promising electrode material for the electrochemical sensing of arsenic (As). The S-rGO/PB composite demonstrates stability, sensitivity, and selectivity in detecting As in water samples, with results matching those obtained from atomic absorption spectrometry. The availability of portable and affordable electrochemical setups for As detection is crucial for successful arsenic mitigation initiatives.