Dynamic Study of the Oxidation State of Copper in the Course of Carbon Monoxide Oxidation over Powdered CuO and Cu2O

Nagase, Kenzo; Zheng, Yanyan; Kodama, Yasuyuki; Kakuta, J.

doi:10.1006/jcat.1999.2611

Cited by 136 publications

(74 citation statements)

References 17 publications

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“…Recently, copper-based nanomaterials have received attention because of their potential application in optoelectronic devices, catalysis and superconductors. CuO is a p-type semiconductor (E g ¼ 1.2 eV) with excellent photovoltaic, electrochemical, and catalytic properties [21][22][23][24]. Also, it is inexpensive, non-toxic, and readily available.…”

Section: Preparation and Characterization Of Cuo Nanoparticles Startimentioning

confidence: 99%

Emergent methods to synthesize and characterize semiconductor CuO nanoparticles with various morphologies – an overview

Anandan

Yang

2007

Journal of Experimental Nanoscience

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Nanotechnology can be defined as the science and engineering involved in the design, synthesis and application of materials and devices on the nanometer scale. It is not in itself a single emerging discipline, but rather a meeting of several traditional sciences such as chemistry, physics, materials science, biology and engineering to bring together the required expertise needed to develop these new technologies. The unique properties of nanoscale materials provide benefits in remediation, pollution prevention, and efficient use of resources; however, the greatest contribution to green chemistry is likely to be the new manufacturing strategies available through nanoscience. So, the present review mainly focuses on the synthesis of semiconductor CuO nanomaterials from different starting materials by adopting various routes such as vapor-solid, vapor-liquid-solid, solid-liquid, etc. to reveal the morphological features of the precursor.

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Section: Preparation and Characterization Of Cuo Nanoparticles Startimentioning

confidence: 99%

Emergent methods to synthesize and characterize semiconductor CuO nanoparticles with various morphologies – an overview

Anandan

Yang

2007

Journal of Experimental Nanoscience

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“…Other known applications of CuO are in catalysts [23,24], field emission devices [25], gas sensors [26][27][28][29], photovoltaic device [30][31][32][33][34][35], superconductors [36][37][38]. Several techniques have been used to synthesis CuO.…”

Section: Introductionmentioning

confidence: 99%

Annealing effect on the optical and solid state properties of cupric oxide thin films deposited using the Aqueous Chemical Growth (ACG) method

Mammah¹,

Opara²,

Omubo-Pepple³

et al. 2013

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Thin films of CuO having an average thickness of 720 nm were deposited on clean glass substrates using the Aqueous Chemical Growth (ACG) method with Cu(NO 3 ) 2 and C 6 H 12 N 4 as precursors and annealed at different temperatures in order to determine the effect of annealing temperature on their optical and solid state properties. The study was carried out using Rutherford Backscattering (RBS) spectroscopy for t thickness and chemical composition, X-Ray Diffraction (XRD) for crystallographic structure and a UV-VIS spectrophotometer for spectral analysis. The results indicate that the absorbance and absorption/extinction coefficient of the films vary inversely with annealing temperature while the transmittance, reflectance, direct band gap, real/imaginary dielectric constants and refractive index vary directly with annealing temperature. The results further indicate an improvement in crystallinity as annealing temperature increases. The as-deposited and annealed ACG CuO thin films were found to be suitable for use as window layer in solar cells among other electronic and optoelectronic applications.

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“…With regards to its catalytic properties, the O/Cu system ͑i.e., oxidic nanostructures of Cu͒ is known to facilitate oxidation reactions, suggesting that it has potential as an economical alternative for the rare and high-cost noble metals in various catalytic systems. [3][4][5][9][10][11][12] Our recent study on the O/Cu͑111͒ system 13 has predicted that, under technical catalytic conditions of gas pressures and temperatures, the thermodynamically favored phase is that of the bulk oxide. Hence the oxide Cu 2 O should be considered as one of the key active catalytic phases in technologically relevant reactions.…”

Section: Introductionmentioning

confidence: 99%

Native defect-induced multifarious magnetism in nonstoichiometric cuprous oxide: First-principles study of bulk and surface properties ofCu2−δO

et al. 2009

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Native defects in cuprous oxide Cu 2 O are investigated by using first-principles calculations based on density-functional theory. Considering the formation of copper and oxygen vacancies, antisites and interstitials, and a copper split-vacancy complex defect, we analyze the electronic structure and calculate their respective formation energies as a function of the change in Fermi level under both copper-rich and oxygen-rich conditions. We find that, under both growth conditions, the defect with the lowest formation energy is the simple copper vacancy, followed by the copper split-vacancy complex. Both low-energy copper defects produce hole states at the top of the valence band, largely accounting for the p-type conductivity in this material. In spite of the creation of dangling bonds at the nearest-neighbor O atoms, these copper defects are found to be spin neutral. Under oxygen-rich conditions, oxygen interstitials have low formation energies and are found to exhibit a ferromagnetic ordering with a total magnetic moment of 1.38 B and 1.36 B at the octahedral and tetrahedral sites, respectively. Considering the possibility of native defect formation at the surface of this material, we investigate the relative stability of both low-and high-index copper-oxide surfaces by comparing their surface free energies as a function of the change in oxygen chemical potential. Using the technique of ab initio atomistic thermodynamics, we then correlate the dependence of the calculated Gibbs free-surface energy as a function of oxygen pressure and temperature via the oxygen chemical potential. We identify two lowenergy surface structures, namely, Cu 2 O͑110͒ : CuO and Cu 2 O͑111͒-Cu CUS , with the former marginally more stable for oxygen-rich conditions and the latter more stable for oxygen-lean ͑or copper-rich͒ conditions. Cu 2 O͑110͒ : CuO is calculated to be nonmagnetic and Cu 2 O͑111͒-Cu CUS is calculated to be a ferromagnetic ordering, with a total magnetic moment of 0.91 B per defect. With the results for both bulk and surface native defects, we find that under oxygen-lean conditions, a ferromagnetic behavior could be attributed mainly to copper vacancy formation in the ͑111͒ surface of Cu 2 O while under oxygen-rich conditions, low-energy bulk oxygen interstitial defects induce a ferromagnetic character in the same material. This highlights the complementary role of bulk and surface native magnetic defects under different pressure and temperature conditions, especially at the nanoparticle scale where surface properties dominate.

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Dynamic Study of the Oxidation State of Copper in the Course of Carbon Monoxide Oxidation over Powdered CuO and Cu2O

Cited by 136 publications

References 17 publications

Emergent methods to synthesize and characterize semiconductor CuO nanoparticles with various morphologies – an overview

Emergent methods to synthesize and characterize semiconductor CuO nanoparticles with various morphologies – an overview

Annealing effect on the optical and solid state properties of cupric oxide thin films deposited using the Aqueous Chemical Growth (ACG) method

Native defect-induced multifarious magnetism in nonstoichiometric cuprous oxide: First-principles study of bulk and surface properties ofCu2−δO

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