Transforming Gold Halide perovskite@CuS Nanocomposite into Smart Dual-Functional Platforms for Sustainable Electrochemical Detection of Food Dyes and Green Hydrogen Production, with DFT Insights

In the quest for next-generation technologies, the development of functional nanomaterials has become a game-changer, unlocking new possibilities in sensing and energy applications. Among these, halide perovskites have risen to prominence, offering unparalleled versatility with their exceptional electronic properties, making them ideal for innovative solutions in both environmental monitoring and energy conversion. In this report, a functional nanocomposite consisting of Cs2AuCoCl6 halide perovskites and CuS nanosheets has been synthesized by a simple solvothermal method. The material is extensively characterized using various techniques, which confirms its structural integrity and composition. Electrochemical evaluation through Electrochemical Impedance Spectroscopy (EIS) and Linear Sweep Voltammetry (LSV) reveals exceptional performance for both individual and simultaneous electrochemical detection of Acid Yellow 23 (AY) and Sunset Yellow FCF (SY) dyes. The limit of detection for the simultaneous determination of AY and SY is found to be 59.21 nM and 68.43 nM, respectively. The LSV curves also show linearity over a wide range of dye concentration levels, ranging from 10 to 180 nM. Real sample analysis in alcoholic and non-alcoholic beverages demonstrates the practical applicability of the sensor in real-world scenarios. Density Functional Theory (DFT) calculations are utilized to study the redox mechanisms of the dye molecules, providing valuable theoretical insights into the redox mechanisms. Additionally, the nanocomposite proves to be an outstanding electrode catalyst for the Hydrogen Evolution Reaction (HER) with a low potential of -69 mV at 10 mA cm⁻², a small Tafel slope of 60 mV dec⁻¹ as demonstrated by LSV analysis. This work highlights the broad potential of the nanocomposite, bridging the fields of dye sensing, electrochemical catalysis, and theoretical modeling, offering innovative solutions for environmental and energy-related challenges.