Evaluation of Photocatalytic Activity and Electrochemical Properties of Hematite Nanoparticles

Abstract

The symmetric nano morphologies, asymmetric electronic structures, and as well as the heterojunctions of the developed photocatalytic systems perform a vital role in promoting light absorption, separation of electron and hole pairs and charge carrier transport to the surface when exposed to near-infrared (NIR) light. In this present work, we synthesized hematite (α-Fe2O3) nanoparticles (NPs) by a facile hydrothermal method and studied their structural, optical, and photocatalytic properties. Powder X-ray diffraction (XRD) confirmed the rhombohedral phase of the α-Fe2O3 NPs, and Fourier transform infrared spectroscopy (FT-IR) was used to investigate symmetric and asymmetric stretching vibrations of the functional groups on the surface of the catalysts. The optical bandgap energy was estimated to be 2.25 eV using UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and scanning electron microscopy (SEM) images indicated sphere like morphology. The oxidation and reduction properties of α-Fe2O3 NPs were analyzed by cyclic voltammetry (CV). The α-Fe2O3 NPs were utilized for the degradation of methylene blue (MB) dye under natural sunlight. The experimental results demonstrate that the degradation efficiency was achieved at 33% in 2 h, and the pseudo-first-order rate constant was calculated to be 0.0033 min−1.

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“…38 Evidence for Fe–O–Fe stretching and Fe–OH stretching of surface iron bound hydroxy groups is seen around 953 cm −1 and 1043 cm −1 , respectively. 39 The broad band in the region 1300–1400 cm −1 could be due to the vibrational mode of γ-Fe 2 O 3 36 or O–H in plane deformation of the Fe–OH bonds at the surface. 39 The weak peak at 2338 cm −1 is due to trapped water molecules, those at 2845 cm −1 and 2925 cm −1 are characteristics of C–H peaks of contaminants and the strong band at 3410 cm −1 is due to water and surface hydroxyl groups.…”

“…39 The broad band in the region 1300–1400 cm −1 could be due to the vibrational mode of γ-Fe 2 O 3 36 or O–H in plane deformation of the Fe–OH bonds at the surface. 39 The weak peak at 2338 cm −1 is due to trapped water molecules, those at 2845 cm −1 and 2925 cm −1 are characteristics of C–H peaks of contaminants and the strong band at 3410 cm −1 is due to water and surface hydroxyl groups. 40 pH ZPC of MNPs was found to be 7.27 (Fig.…”