Large-scale Synthesis of Low-dimension Un-doped Iron Oxide Nanoparticles by a Wet-Chemical Method: Efficient Photo-catalyst & Sensitive Chemi-sensor Applications

Iron oxide nanoparticles (NPs) have been prepared in large-scale by wet-chemical method (150.0 oC and pH 8.33) using ferric chloride and urea as a starting materials in aqueous-alkaline medium. The structural, physical, and optical properties are characterized using FT-IR, UV–vis spectroscopy, Raman spectroscopy, powder X-ray diffraction, Fieldemission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and Electron diffraction system (EDS). The NPs size (average dia. 45 ± 5 nm) was measured by FE-SEM while the single phase of NPs were exemplified using powder X-ray diffraction technique. As-grown nanoparticles were applied for the photocatalytic degradation using acridine orange (ACR) and chemical sensing of aqueous ammonia. Almost 58.38% degradation with ACR was observed in presence of nanoparticles under UV sources (250 W). The silver electrode (AgE, surface area, 0.0216 cm2) was immobilized with NPs which enhanced ammonia-sensing performances in their electrical response (I-V characterization) for detecting and quantifying the ammonia in aqueous system. The analytical performances of NPs sensor were investigated that the sensitivity and stability of the sensor improved extensively using NPs thin-film on active silver surface. The calibration plot was linear (R =0.9337) over the large range of 5.0 μM to 0.5 M. The sensitivity was calculated as 4.6154 μAcm-2mM-1 with detection limit (2.5±0.2 μM), based on a signal/noise ratio (3N/S). This study has introduced a novel way for efficient chemical sensor development as well as active photo-catalyst using low-dimensional NPs for the detection of environmental carcinogenic and hazardous compounds. Keywords: Iron oxide nanoparicles, Chemi-sensors, Sensitivity, Solution method, Optical properties