Photocatalytic evaluation of self-assembled porous network structure of ferric oxide film fabricated by dry deposition process

Abstract

Ferric oxide powder in the alpha phase (alpha-Fe2O3) was deposited on an aluminum oxide (Al2O3) substrate by a nanoparticle deposition system using the dry deposition method. X-ray diffraction (XRD) images confirmed that the phase of the deposited alpha-Fe2O3 did not change. The deposited alpha-Fe2O3 was characterized in terms of its microstructure using scanning electron microscopy (SEM). A porous network microstructure formed when small agglomerates of Fe2O3 (SAF) were deposited. The deposition and formation mechanism of the microstructure were investigated using SEM and three-dimensional (3D) profile analysis. First, a dense coating layer formed when the film was thinner than the particle size. After that, as the film thickness increased to over 5 mu m, the porous network structure formed by excavating the surface of the coating layer as it was bombarded by particles. Rhodamine B (RhB) was degraded after 6 h of exposure to the Fe2O3 coating layer with SAF, which has good photocatalytic activity and a high porous network structure. The kinetic rate constants of the SAF and large agglomerates of Fe2O3 (LAF) were calculated to be 0.197(h(-1)) and 0.128(h(-1)), respectively, based on the absorbance results. Using linear sweep voltammetry, we confirmed that the photoelectric effect occurred in the coating layer by measuring the resulting current under illuminated and dark conditions. (C) 2016 Elsevier B.V. All rights reserved.