Sol–gel synthesis of α-Fe₂O₃ nanoparticles and its photocatalytic application

α-Fe₂O₃ nanoparticles was synthesized through a simple and efficient sol–gel process using citric acid and triethanolamine. The phase structure, morphology, and optical properties of the as-prepared products were extensively characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and ultraviolet spectroscopy. The chemical compositions of the as-synthesized α-Fe₂O₃ nanoparticles have been analyzed by Fourier transform infrared spectroscopy. X-ray diffraction pattern indicated that the as-synthesized products were α-Fe₂O₃ with well-crystallized rhombohedral structure. The crystallite size of the α-Fe₂O₃ nanoparticles synthesized through citric acid and triethanolamine was 5 and 6 nm, respectively. SEM observation showed that the α-Fe₂O₃ products consist of spherical-like shape with uniform size distribution. The absorption edge of the α-Fe₂O₃ nanoparticles were measured at 558 and 563 nm. Optical measurement revealed that the band gap value of α-Fe₂O₃ nanoparticles was 2.22 and 2.20 eV. The photocatalytic activity of the α-Fe₂O₃ nanoparticles was analyzed by degradation of methylene orange, and the α-Fe₂O₃ nanoparticles showed excellent photocatalytic performance.