Development of ionic-sensor based on sono-chemically prepared low-dimensional β-Fe2O3 nanoparticles onto flat-gold electrodes by an electrochemical approach

Iron oxide nanoparticles (NPs) was prepared sono-chemically in presence of ultrasonic irradiation in aqueous alkaline medium at room conditions, where ferric chloride and urea were used as starting materials. NPs were characterized using powder X-ray diffraction, field-emission scanning electron microscopy, UV/vis. X-ray photoelectron, Fourier-transform infra-red spectroscopy (FT-IR), and Raman spectroscopy, etc. They were deposited on a flat polycrystalline gold electrode (AuE, surface area, 0.0216 cm2) to give a sensor with a fast response towards selective ion (i.e., fluoride ion, F−) in phosphate buffer system. The fabricated chemi-sensor also exhibits good sensitivity, lower detection limit, and long-term stability as well as enhanced electrochemical responses towards the target analyte. The calibration plot is linear (r2: 0.9598) over the 0.1 nM to 1.0 mM fluoride concentration ranges. The sensitivity and detection limit is ∼1.8718 μA cm−2 mM−1 and ∼0.092 ± 0.02 nM (at a Signal-to-Noise-Ratio of 3) respectively in short response time (10.0 s). Finally it was confirmed that the nanostructures and the optical features of iron oxide can be extended to a large range in un-doped semiconductor nanomaterials for proficient chemical sensor applications.