Development of novel nanocomposites based on SrSnO3-conjugated coconut-shell activated carbon with conducting polymers towards 4-nitrophenol detection by electrochemical approach

Abstract

To simplify the synthesis process for developing a sensor for 4-nitrophenol (4-NP), an in-situ chemical oxidation method was applied by composite of coconut shell-activated carbon (CSAC) and SrSnO3 coated with conducting polymers (CPs) such as Polypyrrole (PPy), Polyindole (PIn), and Polycarbazole (PCz), resulting in the formation of ternary nanocomposites (NCs) consisting of CSAC/SrSnO3/PPy, CSAC/SrSnO3/PIn, and CSAC/SrSnO3/PCz. To facilitate their application as a sensing platform, the synthesized NCs were successfully modified onto a glassy carbon electrode (GCE), enabling their effective use in the detection of 4-NP. Despite utilizing the same fillers, the composites displayed distinct thermal and structural characteristics, suggesting the formation of fundamentally different composites that interact with the 4-NP analyte in unique ways. Furthermore, the detection effectiveness of all the NCs was compared in this study. It was found that the ternary CSAC/SrSnO3/PPy NCs exhibited higher sensitivity compared to sensors composed of either CSAC/SrSnO3/PIn or CSAC/SrSnO3/PCz NCs. These findings highlight the potential of CSAC/SrSnO3/PPy ternary NCs as promising sensors for 4-NP detection, attributed to their high sensitivity (6.329 µAmM−1cm−2), exceptionally lower detection limit (LOD; 0.15 nM), and limit of quantity (LOQ; 0.45 nM) with a linear dynamic range (LDR) from 1.0 nM to 10.0 mM for 4-NP concentrations. Additionally, the proposed 4-NP sensor improved electrical interactions and demonstrated rapid response times and satisfactory reproducibility in its performance. The proposed sensor was employed for the environmental samples analysis and highly satisfactory results were obtained. Thus, the study presents a novel approach for the detection of hazardous chemicals in the environment by utilizing newly developed NCs based on an electrochemical method.