BaTiO₃-MoS₂ Nanocomposite as a New Peroxidase Mimic for the Colorimetric and Smartphone-Assisted Detection of H₂O₂

Detecting and monitoring hydrogen peroxide (H₂O₂) levels is crucial across various industries due to its potential health hazards at elevated concentrations. Hence, there’s an urgent need for cost-effective, rapid, and straightforward analytical methods for H₂O₂ detection and monitoring. This study introduces a simple synthesis method for Barium Titanate (BaTiO₃) and Molybdenum disulfide (MoS₂) (BaTiO₃/MS) nanocomposite via mechanochemical means. The nanocomposite exhibits remarkable peroxidase-like activity, catalyzing the oxidation of TMB (3,3’,5,5’-tetramethylbenzidine) in the presence of H₂O₂. This catalytic reaction results in the formation of a blue-colored solution with an absorbance peak at 652 nm. The increase in absorbance, facilitated by the catalytic properties of BaTiO₃/MS enables precise detection of H₂O₂ with a detection limit of 8.0 µM. Furthermore, a modified filter paper incorporating the nanocomposite and agarose gel with TMB was developed. The change in color intensity of the filter paper upon exposure to H₂O₂ was observed and quantified in terms of RGB (Red Green Blue) values using an Android smartphone-based software Color Meter as well as Windows-based software ImageJ. Both the programs gave nearly similar RGB values. This paper-based sensor eliminates the reliance on a UV-visible spectrophotometer, making it portable and user-friendly. This study presents a novel approach for optical and colorimetric detection, with the potential to advance sensing devices for various analytes.