Hydrothermal Synthesis of Co Substituted MnWO 4 Nanostructure for Fluorometric Sensing and Determination of 4-Nitrophenol

Abstract

The detection of 4-Nitrophenol (4-NP) is extremely important due to its toxic nature and harmful impact on the environment. In this work, we have developed a simple cost-effective fluorescence platform based on Co-MnWO4 nanostructure synthesized via a hydrothermal method. The successful incorporation of cobalt into the MnWO4 lattice was confirmed through various characterization techniques, which also revealed improved structural and optical properties. Compared to pristine material, Co-MnWO4 showed reduced photoluminescence intensity, indicating better charge separation. When applied as a sensor, the material exhibited excellent sensitivity towards 4-NP with a high Stern-Volmer constant (K SV ) (1.89×10 4 M -1 ) along with low detection limit of 9.8 nM. The fluorescence mechanism was mainly governed by a combination of electron transfer, inner filter effect, and strong interaction between the probe and analyte as supported by Time resolve photoluminescence (TRPL) studies. In addition, the probe demonstrated fast response, high selectivity, good stability over a wide pH range, and excellent reusability. Real sample analysis further confirmed its practical applicability making Co-MnWO4 a promising material for environmental monitoring of toxic pollutants.