scholarly journals Bifunctional Electrocatalyst of Low-Symmetry Mesoporous Titanium Dioxide Modified with Cobalt Oxide for Oxygen Evolution and Reduction Reactions

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 836
Author(s):  
Mabrook S. Amer ◽  
Mohamed A. Ghanem ◽  
Prabhakarn Arunachalam ◽  
Abdullah M. Al-Mayouf ◽  
Sultan M. Hadadi
Keyword(s):  
Titanium Dioxide ◽  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Synergetic Effect ◽  
Oxide Nanoparticles ◽  
Charge Carrier Density ◽  
X Ray ◽  
Cobalt Oxide Nanoparticles ◽  
Mesoporous Titanium Dioxide ◽  
Low Symmetry

Hybrids of low-symmetry (disordered) mesoporous titanium dioxide modified with different weight ratios of cobalt oxide nanoparticles (Co3O4(x)/lsm-TiO2) are prepared using a one-pot self-assembly surfactant template. The physicochemical characterization of Co3O4(x)/lsm-TiO2 hybrids by scanning and transmission electron microscopy, X-ray diffraction, N2 adsorption–desorption isotherms, and X-ray photoelectron spectroscopy confirm the successful incorporation of cobalt oxide nanoparticles (2–3 nm in diameter) with preservation of the highly mesoporous structure of titanium dioxide substrate. Among these mesoporous hybrids, the ~3.0 wt.% Co3O4/lsm-TiO2 exhibits the best performance toward both the oxygen evolution (OER) and reduction (ORR) reactions in alkaline solution. For the OER, the hybrid shows oxidation overpotential of 348 mV at 10 mA cm−2, a turnover frequency (TOF) of 0.034 s−1, a Tafel slope of 54 mV dec−1, and mass activity of 42.0 A g−1 at 370 mV. While for ORR, an onset potential of 0.84 V vs. RHE and OER/ORR overpotential gap (ΔE) of 0.92 V are achieved which is significantly lower than that of commercial Pt/C, hexagonal mesoporous, and bulk titanium dioxide analogous. The Co3O4/lsm-TiO2 hybrid demonstrates significantly higher long-term durability than IrO2. Apparently, such catalytic activity performance originates from the synergetic effect between Co3O4 and TiO2 substrate, in addition to higher charge carrier density and the presence of disordered mesopores which provide short ions diffusion path during the electrocatalytic process.

scholarly journals Synthesis, Characterization, and Antimicrobial Activity of CoO Nanoparticles from a Co (II) Complex Derived from Polyvinyl Alcohol and Aminobenzoic Acid Derivative

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Maged S. Al-Fakeh ◽  
Roaa O. Alsaedi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cobalt Oxide ◽  
Oxide Nanoparticles ◽  
Aminobenzoic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cobalt Oxide Nanoparticles ◽  
Coo Nanoparticles ◽  
Scanning Electron

Cobalt oxide nanoparticles (CoO NPs) were synthesized by the calcination method from the Co (II) complex which has the formula [Co(PVA)(P-ABA)(H2O)3], PVA = polyvinyl alcohol, and P-ABA = para-aminobenzoic acid. The calcination temperature was 550°C, and the products were characterized by element analysis, thermal analyses (TGA and DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-Vis spectra, and scanning electron microscopy (SEM) techniques. The kinetic and thermodynamic parameters (∆H   ∗ , ∆G   ∗ , and ∆S   ∗ ) for the cobalt (II) complex are calculated. The charges been carried by the atoms cause dipole moment 10.53 and 3.84 debye and total energy 11.04 × 102 and 24.80 × 102k Cal mol−1 for the Co (II) complex and cobalt oxide, respectively. X-ray diffraction confirmed that the resulting oxide was pure single-crystalline CoO nanoparticles. Scanning electron microscopy indicating that the crystallite size of cobalt oxide nanocrystals was in the range of 36–54 nm. Finally, the antimicrobial activity of cobalt oxide nanoparticles was evaluated using four bacterial strains and one fungal strain. Two strains of Gram-positive cocci (Staphylococcus aureus and Enterococcus faecalis), two strains of Gram-negative bacilli (Escherichia coli and Pseudomonas aeruginosa), and one strain of yeast such as fungi (Candida albicans) were used in this study.

Low-Symmetry Mesoporous Titanium Dioxide (lsm-TiO2) Electrocatalyst for Efficient and Durable Oxygen Evolution in Aqueous Alkali

2018 ◽  
Vol 165 (7) ◽  
pp. H300-H309 ◽  
Author(s):  
Mabrook S. Amer ◽  
Mohamed A. Ghanem ◽  
Abdullah M. Al-Mayouf ◽  
Prabhakarn Arunachalam
Keyword(s):  
Titanium Dioxide ◽  
Oxygen Evolution ◽  
Aqueous Alkali ◽  
Mesoporous Titanium Dioxide ◽  
Low Symmetry

Superior performance and stability of anion exchange membrane water electrolysis: pH-controlled copper cobalt oxide nanoparticles for the oxygen evolution reaction

2020 ◽  
Vol 8 (8) ◽  
pp. 4290-4299 ◽  
Author(s):  
Myeong Je Jang ◽  
Juchan Yang ◽  
Jongmin Lee ◽  
Yoo Sei Park ◽  
Jaehoon Jeong ◽  
...  
Keyword(s):  
Cobalt Oxide ◽  
Anion Exchange ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Electrolysis ◽  
Anion Exchange Membrane ◽  
Superior Performance ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles ◽  
Exchange Membrane

Cu0.5Co2.5O4 nanoparticles are obtained by changes in the pH and applied as the anode in anion exchange membrane water electrolysis.

Morphologically controlled cobalt oxide nanoparticles for efficient oxygen evolution reaction

2021 ◽  
Vol 582 ◽  
pp. 322-332
Author(s):  
Bappi Paul ◽  
Piyali Bhanja ◽  
Sachin Sharma ◽  
Yusuke Yamauchi ◽  
Zeid A. Alothman ◽  
...  
Keyword(s):  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles

Titanium dioxide modification with cobalt oxide nanoparticles for photocatalysis

2015 ◽  
Vol 32 ◽  
pp. 259-263 ◽  
Author(s):  
Heon Lee ◽  
Young-Kwon Park ◽  
Sun-Jae Kim ◽  
Byung-Hoon Kim ◽  
Sang-Chul Jung
Keyword(s):  
Titanium Dioxide ◽  
Cobalt Oxide ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles

Synthesis and characterization of nano sized cobalt oxide by precipitation method

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Pavithra D ◽  
Sujatha K ◽  
Sudha A P
Keyword(s):  
Cobalt Oxide ◽  
Ammonium Oxalate ◽  
Cobalt Nitrate ◽  
Morphological Properties ◽  
Precipitation Method ◽  
Oxide Nanoparticles ◽  
Average Crystalline Size ◽  
Co3o4 Nanoparticles ◽  
X Ray ◽  
Cobalt Oxide Nanoparticles

In the present work, cobalt oxide nanoparticles were prepared by using precipitation method. The cobalt nitrate [Co (No3)2] and ammonium oxalate [C2H8N2O4] were used as precursors for the synthesis of cobalt oxide nanoparticles and the resultant product was Calcinated at 400˚C for 2 hrs. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDAX) to analyze the structural and morphological properties. The XRD pattern of the synthesized cobalt oxide nanoparticles exhibits cubic structure with the average crystalline size of 8.06 nm. The functional groups of the synthesized nanoparticles were confirmed by using FTIR spectrum (400 to 4000 cm-1). In the synthesized sample and its purity were confirmed from EDAX spectrum. The surface morphology of the synthesized Co3O4 nanoparticles shows spherical morphology. The optical properties of the synthesized cobalt oxide nanoparticles were investigated by photoluminescence spectrum which shows a minor emission at around 440 nm.

scholarly journals Synthesis and Structural, Optical Properties of Cadmium Doped Cobalt Oxide Nanoparticles

2021 ◽  
pp. 32-37
Author(s):  
Mayakannan M ◽  
Vinoth E ◽  
Prabakar S
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Cobalt Oxide ◽  
Fourier Transform Infrared ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cobalt Oxide Nanoparticles ◽  
Vis Spectroscopy

The nanostructure cadmium doped cobalt oxide nanoparticles were prepared by microwave irradiation techniques. The prepared nanoparticles were further characterized using Powder X-ray diffraction, Fourier transform infrared spectroscopy and UV-Vis spectroscopy. The Powder X ray diffraction results shows good crystalline nature. The Fourier transform infrared spectroscopy conforms stretching and bending vibration of metal oxygen groups. UV-Vis spectroscopy results show absorption edges are 204 nm, 220nm prepared nanoparticles additionally optical parameter skin depth, extinction co-efficient, reflectance, refractive index is calculated.

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