High-performance photocatalytic degradation of NiO nanoparticles embedded on a-Fe2O3 nanoporous layers under visible light irradiation

Thin layers of pure Fe2O3 and modified by polyvinyl alcohol (PVA) were synthesized by sol gel route. The morphology of Fe2O3 was modified by the creation of pores by evaporating the Polyvinyl alcohol at 550 ?. This modified structure improved the removal rate of methylene blue (MB) dye aqueous solution under visible irradiation in 10%. The effect of sensitization ratio of NiO nanoparticles onto Fe2O3/PVA (porous) showed very good degradation efficiency up to 100%. Characterization of Fe2O3, Fe2O3 modified by PVA (Fe2O3/ PVA), Fe2O3/PVA/NiO have been used such as X-ray diffraction (XRD), FT-IR, scanning electron microscopy (SEM), UV-Vis ... etc. The kinetic parameters of MB elimination by Fe2O3, Fe2O3/PVA and Fe2O3/PVA/NiO were calculated using linear models such as pseudo first order (PFO), pseudo-second order (PSO) and Elovich. Four error functions were used namely, correlation coefficients (R2), Root Mean Square Error (RMSE), Mean Square Error (MSE) and Sum Squares Error (SSE), to better fit the kinetic equation. The MB elimination mechanism has been studied based on the intra-particle diffusion equation. The effect of pH on the MB removal rate by the two most active catalysts, Fe2O3/PVA and Fe2O3/PVA/ with 1%wt. NiO nanoparticles, as well as the pHPZC point were evaluated. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).