Characterization and applications of as-grown β-Fe2O3 nanoparticles prepared by hydrothermal method

The production of low-dimensional nanoparticles (NPs) with appropriate surface modification has attracted increasing attention in biological, biochemical, and environmental applications including chemical sensing, photocatalytic degradation, separation, and purification of toxic molecules from the matrices. In this study, iron oxide NPs have been prepared by hydrothermal method using ferric chloride and urea in aqueous medium under alkaline condition (pH 9 similar to 10). As-grown low-dimensional NPs have been characterized by UV-vis spectroscopy, FT-IR, X-ray diffraction, Field emission scanning electron microscopy, Raman spectroscopy, High-resolution Transmission electron microscopy, and Electron Diffraction System. The uniformity of the NPs size was measured by the scanning electron microscopy, while the single phase of the nanocrystalline beta-Fe2O3 was characterized using powder X-ray diffraction technique. As-grown NPs were extensively applied for the photocatalytic degradation of acridine orange (AO) and electrochemical sensing of ammonia in liquid phase. Almost 50% photo-catalytic degradation with AO was observed in the presence of UV sources (250 W) with NPs. beta-Fe2O3 NP-coated gold electrodes (GE, surface area 0.0216 cm(2)) have enhanced ammonia-sensing performances in their electrical response (I-V characterization) for detecting ammonia in liquid phase. The performances of chemical sensor were investigated, and the results exhibited that the sensitivity, stability, and reproducibility of the sensor improved significantly using beta-Fe2O3 NPs on GE surface. The sensitivity was approximately 0.5305 +/- A 0.02 mu Acm(-2)mM(-1), with a detection limit of 21.8 +/- A 0.1 mu M, based on a signal/noise ratio of 3 with short response time.