N and Fe doped NiO nanoparticles for enhanced photocatalytic degradation of azo dye methylene blue in the presence of visible light

Abstract

Pure NiO, N-doped, Fe-doped, N and Fe codoped NiO NPs were fabricated via a precipitation process. The powder X-ray diffraction (XRD) revealed the face centered cubic phase of NiO products. The full width at half maximum (FWHM) of the XRD peak was steadily enlarged with the order of elements N, Fe, N/Fe doped to NiO, and shifted towards a greater angle due to decrease in grain size, as shown by XRD. The average crystallite size of NiO products was calculated, ranging from 6.67 to 3.76 nm, according to the Debye Scherrer formula. The scanning electron microscopy (SEM) demonstrated considerable morphological changes in the produced nanoparticles, including those directed to rock-like geometries (NiO and Fe/NiO nanoparticles) while gas covered-nanocrystals (N/NiO and N/Fe/NiO nanoparticles) were formed using precipitation method. The particle size range of 10–50 nm was estimated using the bar scale in transmission electron microscopy (TEM) pictures. The elemental composition of Ni, O, Fe and N atoms in the respected samples was analyzed by Energy Dispersive X-Ray Analysis (EDX). Photoluminescence (PL) showed band edge emission at 370 nm. The band edge-absorption peak, which is caused by electronic transitions between energy levels, is determined to be in the range 314–325 nm. A UV–Vis analysis found an energy gap amid 3.2 eV and 2.5 eV. The chemical condition of the Fe and N doped NiO composites were validated using XPS. Using visible photo application of undoped and doped NiO NPs, the degradation of an azo dye termed methylene blue was examined. It was N/Fe/NiO (79.8%), Fe/NiO (76%), N/NiO (73%), and NiO (62%) throughout the 6 h irradiation duration. Increased production of OH• radicals was detected in fluorescence tests using terephthalic acid (TA) for N/Fe/NiO NPs, indicating the higher photo-degradation described. Furthermore, the degradation trends of both undoped and doped NiO NPs closely matched the pseudo first order kinetics, according to the kinetic analysis. There was also a suggestion for a thorough MB breakdown mechanism.

Photocatalytic activity of polyaniline‐potassium doped nickel oxide nanocomposites: A comprehensive investigation on multifaceted properties

“…The KNO (Figure 2b) 2θ angles of 37.24 , 43.28 , 62.88 , 75.42 , and 79.40 for (hkl) planes (111), (200), (220), (311), and (222), respectively. 36,[55][56][57] PANI (Figure 2a) broad peaks (characteristics peaks) were observed at 15.05 , 20.59 , and 25.25 (2θ angles) in accordance with already reported results. 37,38,40,58,59 The XRD micrograph of composites revealed the increased intensities of KNO peaks with an increased amount of KNO in PANI.…”

Synthesis and Investigation of Pure and Cu-Doped NiO Nanofilms for Future Applications in Wastewater Treatment Rejected by Textile Industry

“…We can split the transmittance spectra into two ranges: the first one at a wavelength lower than 400 nm for which transmittance is almost inexistent and where it exhibits the beginning of absorption owing to the direct transition between the valence and conduction bands. The second is at a wavelength greater than 400 nm showing the transparency of NiO films whose transmittance yield depends on Cu-doping concentration, in agreement with the literature where Mn, Zn, and Fe doping were used [44,45]. It is observed that with increasing Cu-doping, there is a decrease in transmittance and an increase in the absorbance attributed to changes in the crystalline structure due probably to the increase in NiO film thickness as indicated in XRD results.…”