Preparation and Characterization of NiO Nanoparticles via Solid-State Thermal Decomposition of Ni(II) Complex

Nickel(II) complex, Ni(Brsalph)(NO₃) was synthesized and characterized by elemental analyses and Fourier-transformed infrared (FT-IR) spectroscopy. Heating of Ni(Brsalph)(NO₃) at 550 °C for 3.5 h have resulted NiO nanoparticles. Fourier-transformed infrared spectrum confirmed the composition of products. The crystalline structures and morphology of NiO nanoparticles were studied by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy.     

Preparation and characterization of NiO nanoparticles from thermal decomposition of the [Ni(en)3](NO3)2 complex: A facile and low-temperature route

NiO nanoparticles with an average size of 15 nm were easily prepared via the thermal decomposition of the tris(ethylenediamine)Ni(II) nitrate complex [Ni(en)₃](NO₃)₂ as a new precursor at low temperature, and the nanoparticles were characterized by thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), UV-Vis spectroscopy, BET specific surface area measurement, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and magnetic measurements. The magnetic measurements confirm that the product shows a ferromagnetic behavior at room temperature, which may be ascribed to a size confinement effect. The NiO nanoparticles prepared by this method could be an appropriate photocatalytic material due to a strong absorption band at 325 nm. This method is simple, fast, safe, low-cost and also suitable for industrial production of high purity NiO nanoparticles for applied purposes.     

Simple and low-temperature synthesis of NiO nanoparticles through solid-state thermal decomposition of the hexa(ammine)Ni(II) nitrate, [Ni(NH3)6](NO3)2, complex

NiO nanoparticles with an average size of about 12 nm were easily prepared via the thermal decomposition of hexa(ammine)Ni(II) nitrate complex, [Ni(NH₃)₆](NO₃)₂, at low temperature of 250 °C. The product was characterized by thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), UV-Vis spectroscopy, BET specific surface area measurement, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and magnetic measurement. The magnetic measurement revealed a small hysteresis loop at room temperature, confirming a superparamagnetic (weak ferromagnetic) nature of the synthesized NiO nanoparticles. Indeed, the NiO nanoparticles prepared by this method could be an appropriate semiconductor material due to the optical band gap of 3.35 eV which shows a red shift in comparison with the previous reports. This method is simple, fast, safe, low-cost and also suitable for industrial production of high purity NiO nanoparticles for applied purposes.     

Synthesis and characterization of NiO nanoclusters via thermal decomposition

Thermal decomposition process has been developed to synthesize nickel oxide (NiO) nanoclusters via the reaction between a new precursor, nickel oxalate [Ni(O₄C₂)(H₂O)₄] and oleylamine (C₁₈H₃₇N). The combination of triphenylphosphine (C₁₈H₁₅P) and C₁₈H₃₇N were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and ultraviolet–visible (UV–Vis) spectroscopy. The synthesized NiO nanoclusters have a cubic structure with average size 2–10 nm.     

Synthesis of cobalt nanoparticles from [bis(2-hydroxyacetophenato)cobalt(II)] by thermal decomposition

[Bis(2-hydroxyacetophenato)cobalt(II)] was used as a new precursor to prepare cobalt (Co) and tricobalt tetraoxide (Co₃O₄) nanoparticles of 15–25 nm in average diameter by thermal decomposition. The different combinations of triphenylphosphine, and oleylamine were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared (FT-IR) spectroscopy. Time-dependent FT-IR studies indicate that oxidation of the as-synthesized cobalt nanoparticles in air is slow. The valence change of cobalt from the nanoparticle sample is not observed after it is kept in hexane under air for 30 days. The magnetic property was studied with vibrating sample magnetometer (VSM). The hysteresis loops of the obtained samples reveal the soft magnet behaviors the enhanced coercivity (H_c) and decreased saturation magnetization (M_s) in contrast to their respective bulk materials.     

Synthesis and Characterization of Nickel Oxide Nanoparticles from Ni(salen) as Precursor

Nickel oxide nanoparticles have been synthesized by thermal treatment of N,N′-(bis(salicylidene)-ethylene-1,2-diamine)Nickel(II); [Ni(salen)]; as precursor which has been synthesized via two methods: [Ni(salen)] were obtained by solid state reaction in absence solvent and co-precipitation reaction in presence of propanol as solvent, respectively. Nickel oxide nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy.     

Magnetically separable tea leaf mediated nickel oxide nanoparticles for excellent photocatalytic activity

Synthesis of nanoparticles having low chemical toxicity has been interest of researchers for decades. Utilization of plant phytochemicals as reducing agent is now a globally recognized alternative technique for environmental friendly and low-cost production of nanoparticles. This work reports a facile green synthesis protocol of Nickel Oxide nanoparticles (NiO NPs) using fresh tea leaf extract. The synthesized nanoparticles have been characterized through various analytical techniques like Powder XRD (P-XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The XRD results reveal the formation of crystalline nickel oxide nanoparticles. FTIR spectrum displays the existence of different polyphenolic groups over NiO NPs surface. TEM and SEM images indicate the formation of slightly agglomerated spherical nanoparticles with particle size 3–5 ​nm. The nanoparticles were used towards the photocatalytic degradation of both cationic, anionic dyes and their mixtures under optimum conditions in the presence of UV light irradiation. More than 95% degradation was observed for all the dye solutions with 30 ​mg ​L^-1 catalytic dose. Moreover, the degradation efficiency of the nanoparticle was studied by altering various parameters like pH, initial dye concentration and amount of catalytic dose. Pseudo first order kinetic model was employed in all the reactions. A detailed mechanism and kinetics of the all the reactions were studied. Interestingly, the catalyst showed excellent recyclability up-to 4th cycles with very low catalytic activity loss.     

微波辅助合成石墨烯/氧化镍复合材料及其表征

本文通过微波辅助的方法,快速而有效地在热膨胀石墨烯(RG)的缺陷上原位合成氧化镍纳米颗粒,形成石墨烯/氧化镍复合材料(RG/NiO)。利用X-射线衍射(XRD),拉曼光谱(Raman),傅里叶变换红外(FTIR),扫描电镜(SEM),透射电镜(TEM),热重-差热(TGA-DSC)对所制备样品的结构、形貌和NiO在复合材料中的含量进行表征。结果表明,热膨胀石墨烯层数约7~8层,层间距约为0.35 nm,缺陷多,在水热和微波处理后抗氧化性明显变差。复合材料中氧化镍颗粒平均粒径为25 nm,均匀而密集地分散在石墨烯平面上,同时在复合材料中的含量为19.8%。     

微波辅助合成石墨烯/氧化镍复合材料及其表征

本文通过微波辅助的方法,快速而有效地在热膨胀石墨烯(RG)的缺陷上原位合成氧化镍纳米颗粒,形成石墨烯/氧化镍复合材料(RG/NiO)。利用X-射线衍射(XRD),拉曼光谱(Raman),傅里叶变换红外(FTIR),扫描电镜(SEM),透射电镜(TEM),热重-差热(TGA-DSC)对所制备样品的结构、形貌和NiO含量在复合材料中的含量进行表征。结果表明,热膨胀石墨烯层数约7~8层,层间距约为0.35nm,缺陷多,在水热和微波处理后抗氧化性明显变差。复合材料中氧化镍颗粒平均粒径为25nm,均匀而密集地分散在石墨烯平面上,同时在复合材料中的含量为19.8%。     

Spectroelectrochemical characterisation of poly[Ni(saltMe)]-modified electrodes

Electrogenerated polymers based on the nickel(II) complex 2,3-dimethyl-N,N'-bis(salicylidene)butane-2,3-diaminatonickel(II), poly[Ni(saltMe)], were characterised by in situ FTIR and UV/Vis spectroscopy and ex-situ EPR spectroscopy in order to gain insights into film structure, electronic states and charge conduction. The role of the nickel ions during film oxidation was probed by using EPR to study naturally abundant Ni and 61Ni-enriched polymers. The data from all the spectroscopic techniques are consistent, and clearly indicate that polymerisation and redox switching are associated with oxidative ligand based processes; coulometry suggests that one positive charge was delocalised through each monomer unit. EPR provided evidence for the non-direct involvement of the metal in polymer oxidation: the polymer is best described as a polyphenylene-type compound (conducting polymer), rather than an aggregation of nickel complexes (redox polymer), and the main charge carriers are identified as polarons. An explanation for the high electrochemical stability and conductivity of poly[Ni(saltMe)] with respect to that of poly[Ni(salen)] is proposed. based on stereochemical repulsion between monomeric units; this can impose a less compact supramolecular structure on polymers with bulkier substituents.     

Thermal decomposition of [bis(salicylaldehydato)cadmium(II)] to CdS nanocrystals

The present investigation reports, the novel synthesis of nanocrystals CdS using thermal decomposition of [bis(salicylaldehydato)cadmium(II)], as a new precursor, and elemental sulfur in oleylamine. The as-synthesized CdS crystals have diameters about 10 nm. The products were characterized by X-ray diffraction (XRD) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) spectroscopy and Fourier transformed infrared (FT-IR) spectra. The results of this paper show that the shape and size of cadmium sulfide nanocrystals can be controlled systematically by adjusting certain reaction parameters, such as the reactant concentration, the reaction temperature and the reaction time. Cadmium sulfide nanoparticles and nanorods with different lengths have been successfully prepared.     

Synthesis, spectroscopic, structural and electrochemical studies of nickel(II) and copper(II) complexes derived from 2-hydroxy-4-methacryloyloxybenzaldehyde

The free Schiff bases H₂MABCE, H₂MABCP, and H₂MABCT and their complexes [Ni(MABCE)], [Ni(MABCP)], [Ni(MABCT)], [Cu(MABCE)], [Cu(MABCP)], and [Cu(MABCT)] have been synthesized and characterized by spectroscopic, cyclic voltammetric, and thermal studies. The geometry around nickel is square planar with N₂O₂ donor atoms. Cyclic voltammetric studies of the Ni(II) complexes show one-electron quasi-reversible waves corresponding to Ni(II)/Ni(I) and Ni(II)/Ni(III) processes. The Cu(II) complexes exhibit an irreversible well defined one electron transfer reduction peak in the range of ?0.34 to ?1.08 V. The electronic spectra of the complexes suggest a four-coordinate geometry. The crystal structure of the ligand H₂MABCT and the complex [Ni(MABCP)] have also been reported. The mean Ni–N and Ni–O bond distances are Ni–N = 1.849(4) and Ni–O = 1.837(4) Å.     

Solid State Synthesis and Characterization of Zinc Oxide (ZnO) Microflakes by [Bis(acetylacetonato)zinc(II)] and Sodium Hydroxide at Room Temperature

A novel and simple one-step solid state reaction in the presence of a suitable surfactant, sodium dodecyl sulfate (SDS), and a novel precursor, [bis(acetylacetonato)zinc(II)]; [Zn(acac)₂]; has been developed to synthesize uniform zinc oxide microflakes with an average thickness of 0.3–2.4 μm. In the absence of SDS the product samples contained microrods. The formation of zinc oxide microflakes depends on the molar ratio of Zn(II)/SDS and the experimental procedure. The products were characterized by X-ray diffraction, photoluminescence spectroscopy, FT-IR spectroscopy, surface area, scanning electron microscopy and transmission electron microscopy to depict the phase and morphology. The synthesized ZnO microflakes have a hexagonal zincite structure.     

Synthesis, characterization and optical band gap of NiO nanoparticles derived from anthranilic acid precursors via a thermal decomposition route

This study focuses on the preparation and characterization of single phase NiO nano particles. Four nickel anthranilic acid complexes were synthesized by the semi-solid phase reaction method as precursors for the preparation of NiO nanoparticles via a solid-state decomposition procedure at 700 °C. Thermogravimetric analysis (TGA) was applied to determine the thermal behavior of the precursors and the temperature at which the precursors decompose leaving the oxide. The crystalline structures of the products were investigated by X-ray diffraction (XRD), the morphology of particles by SEM and TEM. The particles size was determined by STM, and the average particle size was found to be 8 nm. Electronic spectra were used to clarify qualitatively the change in absorption band positions on changing the particle size of NiO. The optical band gap of the NiO nanoparticles was calculated and indicated a direct transition. The values of the optical band gap of NiO nanoparticles increase as the particle size decreases.     

NiO亚微米球的制备及其光催化性质

在混合溶剂体系中,通过简单的二步方法成功合成了NiO亚微米球。第一步,以Ni(CH3COO)2和精氨酸为主要反应物,160℃溶剂热反应8 h制备出前驱体;第二步,煅烧前驱体成功合成了NiO产物。利用X射线粉末衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),热重分析(TGA)等手段对产物进行了表征。在紫外光照射下,研究不同光催化剂对甲基橙溶液降解效果。结果表明,NiO亚微米球在紫外光照射条件下对甲基橙溶液有光降解作用。     

Planting of bis(1,5‐cyclooctadiene) nickel upon silica to harvest NiO (<5 nm) nanoparticles in a silica matrix

Bis(1,5‐cyclooctadiene) nickel [Ni(COD)₂] was employed as a nickel precursor to prepare nickel oxide nanoparticles upon high‐surface‐area mesoporous silica. Under protection of argon, Ni(COD)₂ was dissolved in tetrahydrofuran (THF) to react with surface silanols of mesoporous silica SBA‐15, which formed a black powder after completion of the surface reaction. Calcination of the powder produced ultrafine NiO inside the mesoporous silica matrix, which was evidenced by X‐ray diffraction, N₂ adsorption–desorption, transmission electron microscopy and thermogravimetric analysis. The thermogravimetric analysis suggests that NiO formation is a result of surface nickel species calcination, whereas structural characterization clearly show that NiO nanoparticles of <5 nm are evenly distributed inside the silica SBA‐15 matrix and mesoporosity is well preserved upon calcinations and NiO formation. The surface reaction between Ni(COD)₂ and surface silanols was found for the first time, and the method used here may be extended conveniently to prepare other metal oxide nanoparticles upon high‐surface‐area supports as well. Copyright © 2005 John Wiley & Sons, Ltd.     

Turkish perlite supported nickel oxide as the heterogeneous acid catalyst for a series of Claisen–Schmidt condensation reactions

Potentially active and eco-friendly solid acid catalysts have been synthesized by loading different weight percentages (10, 15, and 50) of nickel oxide on thermally activated Turkish perlite through the deposition-precipitation method. Structural features of prepared catalysts were analyzed using BET surface area analysis, X-ray diffraction, scanning electron microscope (SEM), SEM-EDX, transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR), pyridine adsorbed FT-IR, UV-Vis diffuse reflectance spectroscopy (DRS), and thermogravimetric analysis (TGA) techniques. Pyridine adsorbed FT-IR analysis confirmed the presence of the optimum amount of Bronsted acidic sites in a catalyst having 15 wt. % loading of nickel oxide, which was tested for catalyzing a series of Claisen–Schmidt condensation of cyclohexanone and aromatic aldehydes to produce good isolated yield (90%–93%) of 2,6-bis(substituted benzylidene)cyclohexanones, significantly used in anti-tumor and cytotoxic activities. The high catalytic efficiency of the chosen catalyst remains almost intact up to six reaction cycles. On higher wt. % loading of nickel oxide, crystallite size increases along with agglomeration of larger nickel oxide particles on catalyst surface resulting in pore blockage and poor catalytic activity. Loading of NiO on the surface of thermally activated Turkish perlite was confirmed by SEM-EDX analysis, and TEM observations show that the particle size of the preferred catalyst was less than 50 nm. Based on results drawn from XRD, FT-IR, pyridine adsorbed FT-IR, UV-Vis DRS studies, model structures were proposed for Turkish perlite and all prepared catalysts. During this work, the catalytic potential of the preferred catalyst was compared with other previously reported catalysts, and it showed appreciable results. The formed products were further confirmed by their melting point and ¹H-NMR analysis.     

Synthesis,crystal structure,and electrochemical properties of Ni(II) and Cu(II) complexes with two unsymmetrical N2O2 Schiff base ligands

Nickel(II) and copper(II) complexes of two unsymmetrical tetradentate Schiff base ligands [Ni(Me-salabza)] (1), [Cu(Me-salabza)] (2) and [Ni(salabza)] (3), {H₂salabza = N,N′-bis[(salicylidene)-2-aminobenzylamine] and H₂Me-salabza = N,N′-bis[(methylsalicylidene)-2-aminobenzylamine]}, have been synthesized and characterized by elemental analysis and spectroscopic methods. The crystal structures of 2 and 3 complexes have been determined by single crystal X-ray diffraction. Both copper(II) and nickel(II) ions adopt a distorted square planar geometry in [Cu(Me-salabza)] and [Ni(salabza)] complexes. The cyclic voltammetric studies of these complexes in dichloromethane indicate the electronic effects of the methyl groups on redox potential.     

Synthesis and characterisation of Ni(II), Cu(II), and Zn(II) complexes with an acyclic Mannich base functionalised with thioglycolate moiety

New complexes ML(CNS)·nH₂O [M = Ni, n = 0.5; M = Cu, n = 4.5; M = Zn, n = 0.5, HL: 6-mercapto-(1,4,8,11-tetraazaundecanyl)-6-carboxylic acid)] have been synthesised, chemical analysed, and characterised by different spectroscopic techniques (IR, UV–Vis–NIR, ¹H NMR, EPR, ESI–MS), and magnetic measurements. Based on the IR spectra a dinuclear structure with the 1,3-CSN coordination was proposed for Ni(II) and Cu(II) complexes. The dinuclear structure of Cu(II) complex is also consistent with both magnetic behaviour and EPR spectrum. According to TG, DTG and DTA curves the thermal transformations are complex processes, including dehydration, Mannich base oxidative degradation and thiocyanate decomposition. The final product of decomposition is the most stable metallic oxide, as XRD data indicates. The new complexes were also screened for their microbicidal and antibiofilm properties.     

Controllable synthesis of NiC2O4·2H2O nanorods precursor and applications in the synthesis of nickel-based nanostructures

A controllable synthesis of NiC₂O₄·2H₂O nanorods precursor was obtained via the microemulsion-mediated solvothermal method and a further synthesis of β-Ni(OH)₂ nanorods, nickel oxide (NiO) sub-microtubes, Ni nanospheres and flower-like nickel complexes nanostructures by using the precursor. The morphologies and crystalline structures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and the X-ray powder diffraction (XRD). The morphologies and sizes of the precursors can be readily tuned by adjusting experimental parameters of the reverse microemulsion system. The synthesized β-Ni(OH)₂ nanorods composed of fine nanosheets shown excellent electrochemical performance as an electrode material in rechargeable battery systems.