Showing papers by "Salah Ammar published in 2022"

A facile approach to the synthesis of bilayer hematite films for efficient photocatalytic degradation of methylene blue dye in aqueous solution

Abstract: In this study, a novel approach was used for the preparation of α-Fe2O3 films via electrodeposition followed by hydrothermal treatment for different time periods. The impacts of the time taken for hydrothermal treatment on the structure and morphology of the electrodeposited films were investigated. According to the X-ray diffraction and Raman spectroscopy results, the alpha structure type showed a unique pure phase. The α-Fe2O3 possessing two phases was revealed for the nanoparticles coated with nanorods by scanning electron microscopy. The energy dispersive X-ray microscopy displayed a remarkable decrease in the intensity of the Tin element due to the formation of nanorods on the nanoparticles. The results showed that the ascending increase in the time for hydrothermal treatment led to significant changes in film morphology and chemical composition with a direct consequence on the photocatalytic performance. The α-Fe2O3 films exhibited high efficiency towards the degradation of methylene blue, which was attributed to its structure.

Photoelectrochemical and electrochemical urea oxidation with microwave-assisted synthesized Co-Fe2O3@NiO core–shell nanocomposites

Abstract: This work reported the electrochemical and photoelectrochemical (PEC) properties of a new photoelectrode based on hematite Co-Fe2O3@NiO, a photoactive semiconductor, was prepared using a process involving a combination of the co-precipitation and microwave-assisted synthesis of Fe2O3, Co-Fe2O3 and Co-Fe2O3@NiO, respectively. The obtained products were characterized by X-Ray powder Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray analysis (EDX), Ultraviolet–Visible (UV–vis) analysis, Fourier Transform Infrared spectroscopy (FT-IR). X-ray diffraction (XRD) pattern of the sample determined the crystal structure of α-Fe2O3 nanoparticles. The SEM image shows spherical nanoparticles. FTIR spectrospy spectrum confirmed the phase purity and chemical bond for the sample. Optical studies show a variation of band gap from 2.118 to 2.07 eV. The electrochemical and photoelectrochemical (PEC) performance of the films were examined by cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The electrochemical oxidation of water achieved by Cobalt-doped Fe2O3@GCE modified electrode exhibited the current density of 21 mA/g at 0.5 V vs. SCE for 5 at% of Co and reveals enhanced specific capacitance of 352.11 F/g. The catalytic performance of urea oxidation was measured by cyclic voltammetry on Co-Fe2O3@NiO nanoparticles modified glassy carbon electrode (GCE) in alkaline medium. The electrode Co-Fe2O3@NiO without annealing showed a peak current density of 1.59 mA/cm2 at 0.1 M urea in 1.0 M NaOH, which was 3.6 fold higher than that of Co-Fe2O3@NiO with annealing. In another part, this work reported the photoelectrochemical (PEC) properties of photoanode prepared by spin coating. The highest photocurrent 0.042 mA/cm2 at 0.5 V Vs SCE was obtained for 5% Co-Fe2O3@NiO while the photocatalytic oxidation of urea.

Fe2O3 and Fe2O3/Ni(OH)2 photoanodes for highly efficient photoelectrochemical water splitting and urea oxidation

Abstract: In this manuscript, we propose to produce and characterize a photoelectrodes based on hematite Fe2O3/Ni(OH)2, without hazardous chemical substances (non-CMR substances) and no ozone emanation in handmade photocell. Fe2O3 and Fe2O3/Ni(OH)2 photoanodes were synthesis by hydrothermal method, and were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energydispersive X-ray analysis (EDX), and ultraviolet–visible (UV–Vis) analysis. The photoelectrochemical (PEC) performances of the Fe2O3 and Fe2O3/Ni(OH)2 films was examined by linear sweep voltammetry techniques, cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy analysis, which confirm that the highest photocurrent about 0.344 mA/cm2 at 0.5 V vs Hg/HgO was obtained for the Fe2O3/Ni(OH)2 photoanode in 0.1 M urea than 0.09 mA/cm2 without urea. Result provided in this work can provide an imperative guideline for the design of efficient photocatalysis application using Fe2O3/Ni(OH)2 for photoelectrochemical urea conversation.