Synthesis Of Co3O4 Nanoparticles Research Articles

Improved SnO2 nanowire acetone sensor with uniform Co3O4 nanoparticle decoration

In this study, the synthesis of Co3O4 nanoparticles (NPs) decorated onto SnO2 nanowires (NWs) was achieved through a meticulous vapor-liquid-solid (VLS) process coupled with a hydrothermal approach. The paramount objective was to amplify the gas sensing efficacy and refine the detection threshold of the acetone gas sensor. This endeavor encompassed a twofold enhancement strategy: the optimization of Co3O4 NP dimensions and their uniform dispersion across the SnO2 NW surface. This orchestrated approach yielded a remarkable 17-fold augmentation in the sensor's responsiveness towards 50 ppm acetone gas, as compared to sensors employing solely synthesized pure SnO2 NWs. Moreover, discernible sensor responses were adeptly elicited even at a minute concentration of 0.1 ppm acetone gas. A discernible advancement was discerned in contrast to antecedent research, reflecting substantial refinement in both response characteristics and the sensor's capacity to detect trace acetone gas levels. This heightened sensing proficiency can be attributed to the aptly tailored dimensions of Co3O4 NPs, harmoniously dispersed onto the SnO2 NW surface. This precise distribution engenders a pivotal p-n heterojunction, thereby eliciting the observed enhancement in sensing performance.

Determining factors for the nano-biocompatibility of cobalt oxide nanoparticles: proximal discrepancy in intrinsic atomic interactions at differential vicinage

In vivo and in vitro Intrinsic atomic interaction of Cobalt oxide nanoparticles (Co3O4) describe the differential nano-biocompatibility.

Evaluation of the photocatalytic efficiency of cobalt oxide nanoparticles towards the degradation of crystal violet and methylene violet dyes

The present work deals with the synthesis, characterization, and testing towards the photochemical degradation efficiency of cobalt oxide (Co3O4) nanoparticles (NPs). Following the synthesis of Co3O4 NPs by the hydrothermal method, the NPs are confirmed to be formed in their cubic lattice structure with the spherical shape morphology. The testing studies revealed that the Co3O4 NPs degraded the Methylene violet (MV) and Crystal violet (CV) dyes very efficiently under the UV light irradiation. A Langmuir–Hinshelwood (L–H) model has been effectively used to display the adsorption of CV and MV dye molecules taking place using surface monolayer exposure to the UV light. The kinetics and reaction mechanism behind the elimination of CV and MV dyes shows for a pseudo-second-order kinetics model. With these Co3O4 NPs as photocatalysts, the maximum photodegradation rate was observed to be 92 % and 64 % for the MV and CV (respectively) within the same period of 45 min and this enhanced photocatalytic performance is due to the effective reduction of electron-hole recombination process by the Co3O4 NPs.

Synthesis of Co3O4 nanoparticles from amino acids mixed ligands and its adsorption properties

The metal precursor derived from the reaction of Co(II) acetate with the mixed ligands of lysine(Lys) and glutamine(Glu) was used to synthesize Co3O4 nanoparticles. The precursor was characterized by (C, H, N, M), IR, electronic spectra, TGA and effective magnetic moments. Co3O4 nanoparticles were prepared from calcinations of the synthesized precursor at 800 oC. The obtained nanoparticles were characterized by X-ray powder diffraction and transmittance electron microscope. The average particle size is 50 nm. Co3O4 nanoparticles. Adsorption of Methylene Blue on the surface of the Co3O4 was studied. The synthesized metal oxide has 27.2 (mg/g) adsorption capacity of methylene blue (MB) from aquoues solution and removed 95 % of it. This method can be used to remove dyes from wastewater. Langmuir isotherm was the best model represent the adsorption of MB. Pseudo-second-order model with determination coefficient (R2) close to the unity was the best model for adsorption kinetic of MB.

Room-temperature synthesis of Co3O4 nanoparticles self-assembled into meso/nanoporous microstructures and their application

Nano/mesoporous transition metal oxides have attracted extensive attention because of their distinctive morphology and properties, along with exhibiting better performance in many applications. We employed a simple modified version of the one-pot co-precipitation method at room temperature to synthesize three-dimensional mesoporous microstructures obtained by the self-aggregation of Co3O4 nanoparticles, which is sparse in the literature. The obtained structures were used as electrode materials for electrochemical capacitors or supercapacitors. The as-obtained Co3O4 electrode exhibited acceptable specific capacitances of 400 and 165 F·g−1 at applied current densities of 1 and 10 A·g−1, respectively, with over 99% of capacity retention after 4000 cycles.

Synthesis of Co3O4 nanoparticles and their performance towards methyl orange dye removal: Characterisation, adsorption and response surface methodology

This research article describes the synthesis of cobalt-oxide nanoparticles by simple precipitation technique and their environmental application. The prepared Co3O4 nanoparticles were characterised by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, selected area diffraction, and energy-dispersive X-ray spectroscopy, along with elemental mapping analysis. The characterisation images revealed that as-synthesised nanomaterial had a hexagonal sheet-like morphology with average particle size 10–20 nm and was crystalline in nature. The nano-adsorbent displayed its efficiency in methyl orange adsorption from aqueous solution. Several adsorption factors such as pH, initial concentration, time, and temperature were examined, and isotherm, kinetic, and thermodynamic data were observed. The adsorption rate was fast and followed a pseudo–second-order kinetic model. The adsorption isotherm could be suited with both Langmuir and Freundlich isotherms. The adsorption process turned out to be spontaneous and exothermic. The effects of the various factors for methyl orange removal were analysed using the Box–Behnken design. A second-order quadratic model was used to project the response. Analysis of variance analysed the significance of the factors and their interactions. Three-dimensional response surface plots were used to determine the interactive effects of the independent factors on methyl orange adsorption capacity. The successful regeneration of Co3O4 nanoparticles suggested their usefulness in wastewater treatment and various other industrial settings. The reusability and efficient adsorptive capacity of nano-adsorbent for environmental management represent the importance of this work.

Synthesis of Co3O4 nanoparticles with controllable size and their catalytic properity

Co3O4 nanoparticles of controllable size were synthesized via a variant microemulsion method combined with hydrothermal treatment. With this improved method, Co3O4 nanoparticles with uniform shape and narrow size distribution were controllably synthesized. By varying the surfactant and water ratio, particles of around 27.97 nm, 42.88 nm and 48.99 nm were synthesized. These nanoparticle catalysts behaved differently at low and high temperature. These samples showed high activity for CO oxidation and 100% CO conversion was achieved at 30 °C. However, the catalysts gradually lost their activity after about 100 min. Our research found that CO2 had a huge influence on the stability of catalysts at low temperature. The relationship between stability at 30 °C and ratio of Co3+/Co2+, as well as particle size and desorption rate of CO2, was also thoroughly investigated in this work.

Synthesis of Co3O4 nanoparticles with block and sphere morphology, and investigation into the influence of morphology on biological toxicity.

In the present study, cobalt oxide (Co3O4) magnetic nanoparticles with block and sphere morphologies were synthesized using various surfactants, and the toxicity of the particles was analyzed by monitoring biomarkers of nanoparticle toxicity in zebrafish. The use of tartarate as a surfactant produced highly crystalline blocks of Co3O4 nanoparticles with pores on the sides, whereas citrate lead to the formation of nanoparticles with a spherical morphology. Co3O4 structure, crystallinity, size and morphology were studied using X-ray diffractogram and field emission scanning electron microscopy. Following an increase in nanoparticle concentration from 1 to 200 ppm, there was a corresponding increase in nitric oxide (NO) generation, induced by both types of nanoparticles [Co3O4-NP-B (block), r=0.953; Co3O4-NP-S (sphere), r=1.140]. Comparative analyses indicated that both types of nanoparticle produced significant stimulation at ≥5 ppm (P<0.05) compared with a control. Upon analyzing the effect of nanoparticle morphology on NO generation, it was observed that Co3O4-NP-S was more effective compared with Co3O4-NP-B (5 and 100 ppm, P<0.05; 200 ppm, P<0.01). Exposure to both types of nanoparticles produced reduction in liver glutathione (GSH) activity with corresponding increase in dose (Co3O4-NP-B, r=-0.359; Co3O4-NP-S, r=-0.429). However, subsequent analyses indicated that Co3O4-NP-B was more potent in inhibiting liver GSH activity compared with Co3O4-NP-S. Co3O4-NP-B proved to be toxic at 5 ppm (P<0.05) and GSH activity was almost completely inhibited at 200 ppm. A similar toxicity was observed with both types of Co3O4-NPs against brain levels of acetylcholinesterase (AChE; Co3O4-NP-B, r=-0.180; Co3O4-NP-S, r=-0.230), indicating the ability of synthesized Co3O4-NPs to cross the blood-brain barrier and produce neuronal toxicity. Co3O4-NP-B showed increased inhibition of brain AChE activity compared with Co3O4-NP-S (1,5, and 10 ppm, P<0.05; 50, 100 and 200 ppm, P<0.01). These results suggested that the morphology of nanoparticle and surface area contribute to toxicity, which may have implications for their biological application.

Synthesis of Co3O4 nanoparticles by oxidation-reduction method and its magnetic characterization

Abstract Without any surfactant, antiferromagnetic Co3O4 nanoparticles were synthesized successfully for the first time by means of an oxidation-reduction method with cobalt sulfate as starting material, which was oxidized to cobalt salt by NaNO3 after alkalinizing with NaOH. Morphological, structural, spectroscopic and magnetic characterization of the product were done by SEM, TEM, XRD, and VSM, respectively. The average crystallite size (on the base of line profile fitting method), D and σ, is estimated as 30 ± 6 nm. Some anomalous magnetic properties and their enhanced effect have been observed in Co3O4 antiferromagnetic nanocrystallites, including a bias field, coercivity, permanent magnetic moments and an open loop. These phenomena are attributed to the unidirectional anisotropy which is caused by the exchange coupling between AFM and FM layers, the existence of the spin glass like surface spins of Co3O4 nanoparticles due to size effects and surface-area effect.

A facile route to controlled synthesis ofCo3O4 nanoparticles and their environmental catalytic properties

Using ammonia and Co(CH3COO)2·4H2O as starting materials, a facile and surfactant-free route to controlled synthesis ofCo3O4 nanoparticleswas proposed. Co3O4 nanoparticles with average sizes of 3.5, 6, 11, 19 and 70 nm were obtained throughadjusting the ethanol amount in the solvent (the ratio of ethanol to water) orthe concentration of raw materials. In this process, the presence of enoughO2 was crucial for theformation of pure Co3O4 phase. The environmental catalytic properties of as-obtainedCo3O4 nanoparticles were investigated. The results indicated their remarkable catalysis forozonation degradation of phenol, which denoted a promising application as catalyst inwaste-water treatment.