Electrochemical Sensing of H 2 O 2 by Employing a Flexible Fe 3 O 4 /Graphene/Carbon Cloth as Working Electrode.

We report the synthesis of Fe 3 O 4 /graphene (Fe 3 O 4 /Gr) nanocomposite for highly selective and highly sensitive peroxide sensor application. The nanocomposites were produced by a modified co-precipitation method. Further, structural, chemical, and morphological characterization of the Fe 3 O 4 /Gr was investigated by standard characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and high-resolution TEM (HRTEM), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The average crystal size of Fe 3 O 4 nanoparticles was calculated as 14.5 nm. Moreover, nanocomposite (Fe 3 O 4 /Gr) was employed to fabricate the flexible electrode using polymeric carbon fiber cloth or carbon cloth (pCFC or CC) as support. The electrochemical performance of as-fabricated Fe 3 O 4 /Gr/CC was evaluated toward H 2 O 2 with excellent electrocatalytic activity. It was found that Fe 3 O 4 /Gr/CC-based electrodes show a good linear range, high sensitivity, and a low detection limit for H 2 O 2 detection. The linear range for the optimized sensor was found to be in the range of 10-110 μM and limit of detection was calculated as 4.79 μM with a sensitivity of 0.037 µA μM -1 cm -2 . The cost-effective materials used in this work as compared to noble metals provide satisfactory results. As well as showing high stability, the proposed biosensor is also highly reproducible.