NiO Products Research Articles

Comparative study between oxide/soft ferrite, oxide/hard ferrite, and soft/hard ferrite nanocomposites: structural, electrical, and magnetic properties

Three binary nanocomposites (NCs): (0.5NiO/0.5Ni0.5Zn0.5Fe2O4), (0.5NiO/0.5BaFe12O19), and (0.5Ni0.5Zn0.5Fe2O4/0.5BaFe12O19) were prepared using the co-precipitation method followed by the wet ball-milling technique. X-ray diffraction analysis showed the production of NiO and Ni0.5Zn0.5Fe2O4 single phases, while the α-Fe2O3 secondary phase appeared in the BaFe12O19 and the 0.5Ni0.5Zn0.5Fe2O4/0.5BaFe12O19 nanocomposite. The transmission electron microscopy investigation and the selected area electron diffraction demonstrated the presence of the nanocomposites’ constituent phases. x-ray photoelectron spectroscopy identified the oxidation states found in the prepared samples (Ba2+, Ni2+, Ni3+, Zn2+, Fe3+, and O2−). The bandgap values (Eg) of the nanocomposites are in the range between 2.79 and 3.66 eV, which indicates their semiconductor nature. The DC conductivity experiment confirmed the semiconducting nature of all samples, and the activation energies ( EaH ) and ( EaL ) at high and low-temperature regions, respectively, were calculated from the Arrhenius equation. According to the vibrating sample magnetometer, the NCs exhibited ferromagnetic (FM) as showed by the M-H loops. In the oxide/soft ferrite NC, the dM/dH curve indicated strong exchange coupling interactions, while the hard and the soft magnetic phases in the oxide/hard ferrite and the soft/hard ferrite NCs were weakly exchanged coupled. Significant uses had been found for each of the three nanocomposites according to their constituent phases and properties.

Phase Transformation of Zr-Modified LaNiO3 Perovskite Materials: Effect of CO2 Reforming of Methane to Syngas

Zr-modified LaNiO3 catalysts (LaNixZr1−xO3; 0 ≤ x ≤ 1) are synthesized by the sol–gel method. The physio-chemical properties of materials are investigated using different characterization techniques and evaluated for the CO2 reforming of methane to syngas. Interestingly, the characterization studies revealed the phase transformation from La-Zr pyrochlore to La-Ni perovskite depending on the Ni:Zr ratio in the material. The formation of the pyrochlore phase is observed for high-Zr-containing catalysts, thus leading to the production of bulk NiO. The formation of La-Ni perovskite is observed for high-Ni-containing catalysts and the ZrO2 acted as a support. The formation of La-Ni perovskite supported on ZrO2 enhanced the Ni dispersion of the catalysts. The high dispersion of Ni enhanced the catalytic activity, and LaNi0.8Zr0.2O3 showed the best performance among all of the studied catalysts in terms of conversions and the H2/CO ratio.

Effect of molar concentration on optoelectronic properties of NiO nanoparticles for p-n junction diode application

In this work, fine nickel oxide nanoparticles (NiO NPs) were successfully made utilizing a straightforward co-precipitation approach at low temperature. The effects of precursor concentration on the structural, optical, and electrical characteristics of NiO nanoparticles were investigated. All indexed diffraction peaks in XRD demonstrate the production of NiO with cubic structure. An increase in NiO crystallite size above 16.8 nm was observed when the precursor concentration exceeds 2 M, suggesting the presence of nanostructure in the final product. In FT-Raman spectra, the band centered at ∼ 500 cm–1 is due to Ni-O stretching (LO) mode, and two-magnon (2 M) scattering mode causes the band at 1514 cm–1. The synthesized product is composed of almost rod-shaped particles with a size range of 10–20 nm, according to FESEM pictures. The UV absorption studies showed a high absorption at the fundamental absorption edges originating at 332 nm, which gradually shifted to a lower energy region up to 400 nm with increasing precursor concentration, which means a reduction in bandgap values. The effect of precursor concentration associated with the electrical characteristics of the produced NiO nanoparticles has been investigated for the temperature range 30 to 130 °C. The I-V characterization was used to compute the different photo-diode parameters including n, ФB, Io, PS, R, QE, and D* . The remarkable high photosensitivity of 1100% and specific detectivity of 4.324 × 10−10 Jones for the diode evaluated at 120 mW/cm2 was observed in a 2 M fabricated diode. These findings imply that all the fabricated diodes are exceptionally light-sensitive and are well-suited for upcoming UV photodetector applications.

Tuned d-band states over lanthanum doped nickel oxide for efficient oxygen evolution reaction

The d-band state of materials is an important descriptor for activity of oxygen evolution reaction (OER). For NiO materials, there is rarely concern about tuning their d-band states to tailor the OER behaviors. Herein, NiO nanocrystals with doping small amount of La3+ were used to regulate d-band states for promoting OER activity. Density of states calculations based on density functional theory revealed that La3+ doping produced upper shift of d-band center, which would induce stronger electronic interaction between surface Ni atoms and species of oxygen evolution reaction intermediates. Further density functional theory calculation illustrated that La3+ doped NiO possessed reduced Gibbs free energy in adsorbing species of OER intermediate. Predicted by theoretical calculations, trace La3+ was introduced into crystal lattice of NiO nanoparticles. The La3+ doped NiO nanocrystal showed much promoted OER activity than corresponding pristine NiO product. Further electrochemical analysis revealed that La3+ doping into NiO increased the intrinsic activity such as improved active sites and reduced charge transfer resistance. The in-situ Raman spectra suggested that NiO phase in La3+ doped NiO could be better maintained than pristine NiO during the OER. This work provides an effective strategy to tune the d-band center of NiO for efficient electrocatalytic OER.

Effects of Ta and Y additions on the high temperature oxidation mechanisms of Ni–10Al alloy at 1100 °C

Ni–10Al-xTa (x = 0, 0.4, 1, 3 wt%) and Ni–10Al-0.4Ta-xY (x = 0.2, 0.4, 0.6 wt%) alloys were prepared by powder metallurgy technology. The effect of Ta and Y on the oxidation resistance mechanism of Ni–10Al alloy at 1100 °C was investigated. The results show that Ta forms Ta-rich regions (including Ni3Ta and Ta oxides) in the alloy matrix. Ta-rich regions on the surface become preferential sites to produce poorly protected NiTa2O6. However, the Ni3Ta in the matrix beneath the oxide film hinders the outward diffusion of Al, reducing the consumption of Al and enhancing the stability of Al2O3 layer. The conflicting effect of Ta allows for a range of Ta additions. The oxidation resistance of Ni–10Al alloy is improved with minor Ta (0.4 wt%) and excess Ta destroys the oxide film. The minor Y addition (0.2 wt%) promotes the adhesion of oxide film, while excessive Y accelerates the production of NiO and the internal oxidation of Al2O3, resulting in an increased oxidation rate. In addition, Y impedes the outward diffusion of Ta, which inhibits the production of NiTa2O6 and Ta oxides in the oxide film.

Novel construction of the catalyst from red mud by the pyrolysis reduction of glucose for the peroxymonosulfate-induced degradation of m-cresol.

Red mud of low cost is regarded as a promising alternative to heterogeneous catalysts for activating peroxymonosulfate (PMS) to degrade m-cresol. Improper valence states of metal oxides and coated active substances in red mud greatly hampered its wide application. To solve this problem, the modified red mud (WRMG/700) was prepared by the pyrolysis reduction of glucose in N2 atmosphere. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectrum (XPS) analysis confirmed the production of Fe3O4, MnO and NiO in red mud and their gathering on the surface of particles. WRMG/700 exhibited the excellent performance toward PMS activation for the m-cresol degradation with 99.02% degradation efficiency and a pH-independent catalytic activity between initial pH 3-8. The removal efficiency of COD increased with the reaction time under the optimized degradation conditions. The free radical scavenging experiments and electron paramagnetic resonance (EPR) test confirmed 1O2 played a dominant role during m-cresol degradation in the WRMG/700/PMS system, implying m-cresol degradation was a non-radical oxidation process. Accordingly, the possible reaction mechanism was proposed. WRMG/700 retained its activation performance even after five recycles. This study showed a low cost and simple operation process for m-cresol elimination.

Exploiting the exceptional biosynthetic potency of the endophytic Aspergillus terreus in enhancing production of Co3O4, CuO, Fe3O4, NiO, and ZnO nanoparticles using bioprocess optimization and gamma irradiation

Developing a suitable applicative process and scaling up the microbial synthesis of nanomaterials is an attractive and emerging prospect for a future sustainable industrial production. In this paper, optimization of fermentation conditions for enhanced production of Co3O4, CuO, Fe3O4, NiO, and ZnO nanoparticles by the endophytic A. terreus ORG-1 was studied. Different cultivation conditions were evaluated. Then, a response surface methodology program was used to optimize physical conditions controlling the biosynthesis of these NPs. Finally, the use of gamma irradiation for improvement of NPs’ production was adopted. Under the optimum conditions and after gamma irradiation, the final yields of the respective NPs reached 545.71, 651.67, 463.19, 954.88, 1356.42 mg L−1. To the best of our knowledge, this is the first report on the production and enhancement of different types of nanomaterials from one microbial culture that can open up the way towards the industrialization of the microbial production of nanomaterials.

N and\xa0Fe doped NiO nanoparticles for enhanced photocatalytic degradation of azo dye methylene blue in the presence of visible light

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.

Removal of Malachite Green Dye from Aqueous Solutions by an Efficient Nanosized NiO Fabricated by a Facile Sol-Gel Autocombustion

Nickel oxide nanostructures were synthesized via a sol-gel combustion method using glucose, glycine and tartaric acid fuels. The effect of the fuel type on the formed nanostructures was studied. The as-prepared products were characterized by means of FE-SEM, HR-TEM, XRD, and FT-IR analyses. The results exhibited that the used fuels gave NiO products with different morphologies, and the glucose fuel produced pure NiO nanoparticles with the smallest crystallite size (ca. 8.2 nm). The adsorption properties of the NiO products for the removal of malachite green dye (MG) was examined. Using a batch method, various parameters affecting the adsorption properties were studied. The results revealed that NiO nanostructure generated from the glucose fuel had the highest adsorption capacity

Plasma spraying of transition metal oxide coatings

ABSTRACTThe rapid increase in the world population has drastically increased the generation of organic solid waste. Currently, this is disposed of mainly in landfills, leading to environmental pollution that necessitates the development of new treatment technologies. Catalytic wet oxidation has been proven to be an effective technology for solid waste destruction and the elimination of hazardous organic compounds. The aim of this work is to explore the production of NiO, MnO2, Fe2O3 and CuO as transition metal oxide catalyst coatings using plasma spraying. Little, if any, literature has been presented on the plasma spray deposition of these materials, so this work provides the first proof of concept and benchmark for future development. The coating compositions were quantified from XRD patterns and the coating thickness measured from cross-sectional optical images. The optimal coating from each composition was analysed by scanning electron microscopy to determine the coating microstructure and phase distribution.

Solution-processed NiO x nanoparticles with a wide pH window as an efficient hole transport material for high performance tin-based perovskite solar cells

The development of tin-based perovskite solar cells (PSCs) is a promising approach to meet the demand of eco-friendly, lead-free perovskite photovoltaics. Limited to the poor chemical stability of tin perovskites, tin-based PSCs usually have to be fabricated with an inverted device structure and both the device efficiency and stability are highly dependent on the selection of hole transport materials (HTMs). Here, we report the synthesis of inorganic nickel oxide (NiO x ) nanoparticles (NPs) via a soft base precipitation method, which enables us to obtain highly dispersed NiO x NPs over a wide pH window. The as-prepared NiO x NPs are employed as the HTM for formamidinium tin iodide (FASnI3) PSCs, resulting in excellent device efficiency (∼8%) and stability (1200 h). Our study offers a facile strategy for mass production of NiO x NPs and easy access to efficient and robust inorganic HTMs that could further boost the development of high performance tin-based PSCs.

One-pot flash combustion synthesis of Fe@NiO nanocomposites for supercapacitor applications

The authors report on the synthesis of Fe–NiO nanoparticles (Fe–NiO NPs) with a spherical shape via facile flash combustion synthesis. A structural test shows cubic formations of Fe–NiO NPs in all Fe concentrations. A reduction in crystallite size was observed with increasing Fe content from 27 nm to 12 nm. A vibrational study also indicates a cubic Fe–NiO NPs structure. However, slight shifts in peak positions were observed during Fe doping in NiO. The existence of Fe in NiO product was confirmed using energy dispersive X-ray (EDX) analysis, and its homogeneity in the final products was observed in scanning electron microscopy (SEM) e-mapping images. An X‐ray photoelectron spectroscopy (XPS) study was also carried out to confirm the incorporation of Fe in NiO matrix. A field-emission scanning electron microscopy (FESEM) study showed the formation of spherical nanoparticles in all Fe–NiO NPs samples. However, it was noted that the grain size reduced with increasing Fe content, which is in agreement with the X-ray diffraction (XRD) results. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) with a selected area electron diffraction (SAED) curve indicate very low-dimension NP formation from NiO. An optical test was performed based on the Kubelka-Munk theory along with an estimation of energy gas, which showed an increase of 3.5–3.75 eV with Fe content doping in NiO. Furthermore, the possibility of applying spherical Fe–NiO NPs as an electrode material was also assessed in a three-electrode assembly cell, and the results show that the NiO doped with 5% of Fe exhibited superior capacitance performance (F4, 297.67 F g-1) compared to the other samples.

Facile synthesis, characterization and electrochemical performance of nickel oxide nanoparticles prepared by thermal decomposition

Spherical-like NiO nanoparticles were synthesized by calcination of a new nickel precursor and characterized by FT-IR, UV–Vis, PL, XRD and TEM. Also, the electrochemical properties of the NiO products were studied. The results indicate that NiO product shows high reversible capacity of 992 mAh g−1 at current density of 100 mA g−1 and exhibits high rate performance of 675 mA h−1 at current density of 1000 mA g−1. The enhanced anode performance could be originate from the reversible redox reaction of Ni ↔ NiO and the reversible formation/decomposition reactions of the polymer/gel-like film, induced by the small size of NiO nanoparticles.

Synthesis of crystalline NiO nanorodes from a new Ni(II) nano-coordination compound and its application in sonocatalytic dye removal

Nanostructures of a new nickel(II) coordination compound of [Ni(ntaH2)2].2H2O, 1, (where ntaH3 is nitrilotriacetic acid) were synthesized, and characterized by scanning electron microscopy (SEM), x-ray powder diffraction (XRPD), and FT-IR spectroscopy. Moreover, the structure of compound 1 was determined using the single crystal x-ray diffraction technique. The asymmetric unit of 1 consists of one half of the [Ni(ntaH2)2] complex where the Ni ion is located on the center of symmetry, and one non-coordinated water molecule. The ntaH2 ligand coordinated to the metal center in a tridentate fashion provides a slightly distorted octahedral geometry around the nickel(II) ion. Non-covalent interactions i.e. hydrogen bonding extend the molecular structure into a 3D supramolecular array. Compound 1 was found to be a cost-effective precursor for nanoscale nickel oxide which was obtained in good yield. NiO nanorods were fully characterized and examined as a sonocatalyst to remove the methyl orange (MO) from the aqueous solution in the absence of any oxidants. Knowing that increasing metal concentrations endangers the aquatic ecosystems, the above treatment of the Ni(II) ion might be considered as an effective decontamination of nickel-bearing wastewaters and a facile route to converting it to a desirable NiO product.

Growth and Photocatalytic Properties of NiO Nanostructures Prepared in Acidic and Alkaline Solutions with Same Reagents

Different Ni compound nanomaterials have been prepared successfully by simple hydrothermal synthesis, in which only the dosages of the reactants and the pH values of the solutions are controlled. Under acidic conditions, NiC2O4·2H2O nanotubes are prepared, whereas under alkaline conditions, single crystalline Ni(OH)2 nanosheets can be made. For the first time, the crystalline structure of NiC2O4·2H2O is obtained based on X-ray diffraction. After annealing, the as-prepared nanostructures become NiO nanotubes and nanosheets. However, their crystalline structures are different from the original counterparts for the loss of H2O molecules. The photocatalytic properties of the final NiO products are measured. The nanotubes show a much stronger performance in the degradation of methylene blue than the nanosheets. The mechanisms for growth and photocatalysis are also discussed.

Synthesis, characterization, and biological activity of some novel Schiff bases and their Co(II) and Ni(II) complexes: A new route for Co3O4 and NiO nanoparticles for photocatalytic degradation of methylene blue dye

Six novel Co(II) and Ni(II)-triazole Schiff base complexes have been successfully synthesized by refluxing the prepared triazole Schiff bases with CoCl2·6H2O or NiCl2·6H2O. The Schiff base ligands were prepared through condensation of 3-R-4-amino-5-hydrazino-1,2,4-triazole with dibenzoylmethane [RH, CH3, and CH2CH3; namely, L1, L2, and L3, respectively]. The prepared Co(II) and Ni(II) complexes have been identified using elemental analysis, FT-IR, UV–Vis, magnetic moment, conductivity, and thermal analysis. On the basis of the conductance results, it was concluded that all the prepared complexes are nonelectrolytes. Interestingly, the prepared Co(II) and Ni(II) complexes were employed as precursors for producing of Co3O4 and NiO nanoparticles, respectively. The produced nanostructures have been identified by XRD, HR-TEM, FT-IR and UV–Vis spectra. The produced nanoparticles revealed good photocatalytic activity for the degradation of methylene blue dye under UV illumination in presence of hydrogen peroxide. The percent of degradation was estimated to be 55.71% in 420.0 min and 90.43% in 360.0 min for Co3O4 and NiO, respectively. Moreover, the synthesized complexes, nano-sized Co3O4, and NiO products have been examined, employing modified Bauer- Kirby method, for antifungal (Candida albicans and Aspergillus flavus) and antibacterial (Staphylococcus aureus and Escherichia coli) activities.

Solid State Process for Preparation of Nickel Oxide Nanoparticles: Characterization and Optical Study

In the present work, we report preparation of NiO nanoparticles with well-defined plate morphology by solid-state reaction of NiCl2∙6H2O and the Schiff base ligand N,N′-bis-(3-methoxysalicylidene)benzene-1,4-diamine), as a novel precursor via solid state thermal decomposition method. This method is a simple and environmentally friendly for preparing transition metal oxides. The result of TGA analysis of the precursor showed that the proper calcinations temperature is 450 oC. The NiO product was characterized by XRD, FT-IR and UV-Vis spectroscopy, SEM and TEM. The results indicated that the obtained product is face-centered cubic of nickel oxide, plate shape with average particle size of 10-20 nm. The optical absorption band gap of the nickel oxide nanoparticles was estimated to be 2.1 eV.

Effects of Co2+ doping on physicochemical behaviors of hierarchical NiO nanostructure

A series of Co2+ doped NiO materials (Ni1−xCoxO with x=0, 0.125, 0.25 and 0.5) were synthesized using a facile hydrothermal method followed by a calcination process. The effects of Co2+ doping on the structural, morphological, magnetic and catalytic properties of NiO were systematically investigated. The results indicated that Co2+ doping would bring about a series influence to the as-obtained NiO product. The XRD results indicated that within the region of 0≤x≤0.25 the doped products revealed a pure NiO phase. The elementary unit for the hierarchy NiO gradually transformed from nanosheets to nanoneedles with the increase of Co2+ doping content. As-obtained Co2+ doped NiO products showed ferromagnetism at room temperature and the magnetization value was increased with the increase of Co2+ doping content. The catalytic properties of NiO concerning the thermal decomposition of ammonium perchlorate (AP) were significantly improved via the introduction of Co2+. The Ni1−xCoxO products with x=0.25 showed the best catalytic performance to AP, which could decrease the beginning and ending decomposition temperature of AP by 44 and 108°C. The change of morphology, enhancement of electrical conductivity and the synergistic effect between Co2+ and NiO were the main factors responsible for the improvement of physicochemical behaviors.

A facile one-step route for production of CuO, NiO, and CuO–NiO nanoparticles and comparison of their catalytic activity for ammonium perchlorate decomposition

This study demonstrates a straightforward, inexpensive, high-yield, and ecofriendly route for synthesis of sphere-like CuO, NiO, and CuO–NiO (with different molar ratios) nanoparticles (NPs) through emulsion route.

Synthesis of Fe2O3, Co3O4 and NiO nanoparticles by thermal decomposition of doped polyaniline precursors

Polyaniline (PANI) was synthesized by the oxidative polymerization of aniline with potassium dichromate as an oxidant. PANI was characterized by IR, UV, and TG. The effect of inclusion of CoCl2, NiCl2, and FeCl3 on the thermal and optical properties of polyaniline has been studied. The results showed that the doped PANIs are thermally more stable than the pure PANI. The optical band gap of the doped PANIs is smaller than the pure polymer. PANI has higher corrosion inhibition of Al than the doped polymers. Doped PANIs have been used as molecular precursors for the production of Co3O4, NiO, and Fe2O3 nanoparticles by thermal decomposition route. The structures of the obtained metal oxides have been characterized by XRD and TEM. The average sizes of the prepared nanoparticles were estimated as 22, 17, and 13 nm for Co3O4, NiO, and Fe2O3 samples, respectively.