Spontaneous formation of hollow cobalt oxide nanoparticles by the Kirkendall effect at room temperature at the water–air interface

Nanoscale ◽  
2013 ◽  
Vol 5 (6) ◽  
pp. 2429 ◽  
Author(s):  
Miriam Varón ◽  
Isaac Ojea-Jimenez ◽  
Jordi Arbiol ◽  
Lluis Balcells ◽  
Benjamín Martínez ◽  
...  
Keyword(s):  
Cobalt Oxide ◽  
Room Temperature ◽  
Kirkendall Effect ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles ◽  
Spontaneous Formation ◽  
Air Interface

scholarly journals Histidine-Assisted Synthesis and Cellular Compatibility of Magnetic Cobalt Oxide Nanoparticles at Room Temperature

2011 ◽  
Vol 22 (2) ◽  
pp. 492-499 ◽  
Author(s):  
Junjie Zhao ◽  
Zhongbing Huang ◽  
Jingwen Zeng ◽  
Min Deng ◽  
Guangfu Yin ◽  
...  
Keyword(s):  
Cobalt Oxide ◽  
Room Temperature ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles

scholarly journals Oxidative Treatment of Rhodamine B Solution on CoOx/sepiolite Catalysts

2020 ◽  
pp. 37-46
Author(s):  
Thao Nguyen Tien ◽  
Dang Van Long ◽  
Nguyen Bich Ngoc ◽  
Nguyen Thi Nhu
Keyword(s):  
Hydrogen Peroxide ◽  
Cobalt Oxide ◽  
Rhodamine B ◽  
Room Temperature ◽  
Specific Area ◽  
Precipitation Method ◽  
Oxide Nanoparticles ◽  
Physical Methods ◽  
Cobalt Oxide Nanoparticles ◽  
Oxidative Treatment

Sepiolite loaded with different cobalt oxide contents has been prepared by the precipitation method followed by calcination at 410ºC. The synthesized Co-loaded samples were characterized by physical methods using XRD, SEM, BET, and H2-TPR. The obtained solids have a large specific area and good distribution of cobalt oxide nanoparticles on sepiolite carrier. The catalysts were tested for the oxidative removal of rhodamine B solution and found that 1.0 – 3.0 wt.% cobalt ion/sepiolite samples exhibited the highest decoloration efficiency of rhodamine B (88-90%) in the presence of hydrogen peroxide at room temperature after the treatment of 30 mg/L of RhB solution in 210 minutes.

Synthesis of some Novel Imidazoles Catalyzed by Co3O4 Nanoparticles and Evaluation of their Antibacterial Activities

2018 ◽  
Vol 21 (4) ◽  
pp. 271-280 ◽  
Author(s):  
Mohammad A. Ghasemzadeh ◽  
Mohammad H. Abdollahi-Basir ◽  
Zahra Elyasi
Keyword(s):  
Cobalt Oxide ◽  
Ammonium Acetate ◽  
Reaction Times ◽  
Antibacterial Activities ◽  
Primary Amines ◽  
Oxide Nanoparticles ◽  
Co3o4 Nanoparticles ◽  
Cobalt Oxide Nanoparticles ◽  
Ft Ir ◽  
Tetrasubstituted Imidazoles

Aim and Objective: The multi-component condensation of benzil, primary amines, ammonium acetate and various aldehydes was efficiently catalyzed using cobalt oxide nanoparticles under ultrasonic irradiation. This approach describes an effective and facile method for the synthesis of some novel 1,2,4,5-tetrasubstituted imidazole derivatives with several advantages such as high yields and short reaction times and reusability of the catalyst. Moreover, the prepared heterocyclic compounds showed high antibacterial activity against some pathogenic strains. Materials and Method: The facile and efficient approaches for the preparation of Co3O4 nanoparticles were carried out by one step method. The synthesized heterogeneous nanocatalyst was characterized by spectroscopic analysis including EDX, FE-SEM, VSM, XRD and FT-IR analysis. The as-synthesized cobalt oxide nanoparticles showed paramagnetic behaviour in magnetic field. In addition, the catalytic influence of the nanocatalyst was examined in the one-pot reaction of primary amines, benzil, ammonium acetate and diverse aromatic aldehydes under ultrasonic irradiation. All of the 1,2,4,5-tetrasubstituted imidazoles were investigated and checked with m.p., 1H NMR, 13C NMR and FT-IR spectroscopy techniques. The antibacterial properties of the heterocycles were evaluated in vitro by the disk diffusion against pathogenic strains such as Escherichia coli (EC), Bacillus subtillis (BS), Staphylococcus aureus (SA), Salmonellatyphi (ST) and Shigella dysentrae (SD) species. Results: In this research cobalt oxide nanostructure was used as a robust and green catalyst in the some novel imidazoles. The average particle size measured from the FE-SEM image is found to be 20-30 nm which confirmed to the obtained results from XRD pattern. Various electron-donating and electron-withdrawing aryl aldehydes were efficiently reacted in the presence of Co3O4 nanoparticles. The role of the catalyst as a Lewis acid is promoting the reactions with the increase in the electrophilicity of the carbonyl and double band groups. To investigate the reusability of the catalyst, the model study was repeated using recovered cobalt oxide nanoparticles. The results showed that the nanocatalyst could be reused for five times with a minimal loss of its activity. Conclusion: We have developed an efficient and environmentally friendly method for the synthesis of some tetrasubstituted imidazoles via three-component reaction of benzil, primary amines, ammonium acetate and various aldehydes using Co3O4 NPs. The present approach suggests different benefits such as: excellent yields, short reaction times, simple workup procedure and recyclability of the magnetic nanocatalyst. The prepared 1,2,4,5-tetrasubstituted imidazoles revealed high antibacterial activities and can be useful in many biomedical applications.

Green Synthesis of Cobalt Oxide Nanoparticles by a Starch-Assisted Method

2019 ◽  
Vol 9 (3) ◽  
pp. 362-370 ◽  
Author(s):  
D. Vaya ◽  
Meena ◽  
B.K. Das
Keyword(s):  
Photocatalytic Activity ◽  
Cobalt Oxide ◽  
Sol Gel ◽  
Complex Nature ◽  
Oxide Nanoparticles ◽  
Capping Agent ◽  
Chemical Route ◽  
Gel Method ◽  
Sol Gel Method ◽  
Cobalt Oxide Nanoparticles

Background: The properties of the material are altered when material size shifted towards nano-regime. This feature could be used for wastewater treatment process using model pollutant such as dyes. Recently, nanoparticles are synthesized by a green chemical route using different capping agents. This is the reason we adopt starch as green capping agent along with sol-gel method. Objective: To synthesize cobalt oxide nanoparticles by green chemical route and utilized it in degradation of dyes. Methods: Synthesis of cobalt oxide nanoparticles by sol-gel method using starch as a capping agent. The characteristics of surface modifications were investigated by UV-VIS, TEM, SEM, XRD and FTIR techniques. Results: Cobalt oxide nanoparticles synthesized and inhibited photocatalytic activity. Conclusion: Deactivation of photocatalytic activity due to complex nature of starch. This property can be used elsewhere as in light shielding applications to coat and protect surfaces in order to keep them cool and safe from damage as in the painting of vehicles, roofs, buildings, water tanks, etc.

scholarly journals Correction: An anionic and cationic surfactant-assisted hydrothermal synthesis of cobalt oxide nanoparticles as the active electrode material for supercapacitors

2021 ◽  
Author(s):  
R. R. Samal ◽  
Aneeya K. Samantara ◽  
S. Mahalik ◽  
J. N. Behera ◽  
B. Dash ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Cobalt Oxide ◽  
Cationic Surfactant ◽  
Electrode Material ◽  
Oxide Nanoparticles ◽  
Active Electrode ◽  
Cobalt Oxide Nanoparticles ◽  
Surfactant Assisted

Correction for ‘An anionic and cationic surfactant-assisted hydrothermal synthesis of cobalt oxide nanoparticles as the active electrode material for supercapacitors’ by R. R. Samal et al., New J. Chem., 2021, 45, 2795–2803; DOI: 10.1039/D0NJ05088A.

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