Confirmation of X-ray Photoelectron Spectroscopy Peak Attributions of Nanoparticulate Iron Oxides, Using Symmetric Peak Component Line Shapes

2010 ◽  
Vol 114 (24) ◽  
pp. 10711-10718 ◽  
Author(s):  
S. Poulin ◽  
R. França ◽  
L. Moreau-Bélanger ◽  
E. Sacher
Keyword(s):  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Line Shapes ◽  
Component Line

Charge properties of red Argentine soils as an indicator of iron oxide/clay associations

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 423 ◽  
Author(s):  
R. M. Torres Sánchez ◽  
M. Okumura ◽  
R. C. Mercader
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
Electron Probe ◽  
Surface Coverage ◽  
Oxide Coating ◽  
Point Of Zero Charge ◽  
X Ray Diffraction ◽  
X Ray ◽  
North Eastern

The order of the relative degree of iron oxide coating of 4 samples of red soils from north-eastern Argentina was established using the point of zero charge (PZC), yielded by potentiometric titration, and the isoelectric point (IEP), obtained from the diffusion potential. When PZC is different from IEP, the relative fraction of apparent surface coverage could be assessed from the IEP. The results obtained by the application of X-ray diffraction, scanning electron microscopy, electron probe microanalysis, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, and specif ic surface area, although essential to characterise the samples, did not allow us to determine the degree of iron oxide coating. Our findings show that the order of this degree is opposite to the order of the ratio of the amount of free iron oxides to that of clay in iron oxides/clay mixtures.

scholarly journals Differentiating Nanomaghemite and Nanomagnetite and Discussing Their Importance in Arsenic and Lead Removal from Contaminated Effluents: A Critical Review

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2310
Author(s):  
Juan A. Ramos-Guivar ◽  
Diego A. Flores-Cano ◽  
Edson Caetano Passamani
Keyword(s):  
Heavy Metal ◽  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Magnetic Circular Dichroism ◽  
Cost Evaluation ◽  
Precipitation Method ◽  
Lead Removal ◽  
X Ray ◽  
Co Precipitation

Arsenic and lead heavy metals are polluting agents still present in water bodies, including surface (lake, river) and underground waters; consequently, the development of new adsorbents is necessary to uptake these metals with high efficiency, quick and clean removal procedures. Magnetic nanoparticles, prepared with iron-oxides, are excellent candidates to achieve this goal due to their ecofriendly features, high catalytic response, specific surface area, and pulling magnetic response that favors an easy removal. In particular, nanomagnetite and maghemite are often found as the core and primary materials regarding magnetic nanoadsorbents. However, these phases show interesting distinct physical properties (especially in their surface magnetic properties) but are not often studied regarding correlations between the surface properties and adsorption applications, for instance. Thus, in this review, we summarize the main characteristics of the co-precipitation and thermal decomposition methods used to prepare the nano-iron-oxides, being the co-precipitation method most promising for scaling up processes. We specifically highlight the main differences between both nano-oxide species based on conventional techniques, such as X-ray diffraction, zero and in-field Mössbauer spectroscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism, the latter two techniques performed with synchrotron light. Therefore, we classify the most recent magnetic nanoadsorbents found in the literature for arsenic and lead removal, discussing in detail their advantages and limitations based on various physicochemical parameters, such as temperature, competitive and coexisting ion effects, i.e., considering the simultaneous adsorption removal (heavy metal–heavy metal competition and heavy metal–organic removal), initial concentration, magnetic adsorbent dose, adsorption mechanism based on pH and zeta potential, and real water adsorption experiments. We also discuss the regeneration/recycling properties, after-adsorption physicochemical properties, and the cost evaluation of these magnetic nanoadsorbents, which are important issues, but less discussed in the literature.

scholarly journals Eco-Friendly Cavity-Containing Iron Oxides Prepared by Mild Routes as Very Efficient Catalysts for the Total Oxidation of VOCs

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1387 ◽  
Author(s):  
Rut Sanchis ◽  
Daniel Alonso-Domínguez ◽  
Ana Dejoz ◽  
María Pico ◽  
Inmaculada Álvarez-Serrano ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
Specific Activity ◽  
High Surface ◽  
Superior Performance ◽  
Porous Iron ◽  
Total Oxidation ◽  
X Ray

Iron oxides (FeOx) are non-toxic, non-expensive and environmentally friendly compounds, which makes them good candidates for many industrial applications, among them catalysis. In the present article five catalysts based on FeOx were synthesized by mild routes: hydrothermal in subcritical and supercritical conditions (Fe-HT, Few200, Few450) and solvothermal (Fe-ST1 and Fe-ST2). The catalytic activity of these catalysts was studied for the total oxidation of toluene using very demanding conditions with high space velocities and including water and CO2 in the feed. The samples were characterized by X-ray diffraction (XRD), scanning and high-resolution transmission electron microscopy (SEM and HRTEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption isotherms. It was observed that the most active catalyst was a cavity-containing porous sample prepared by a solvothermal method with a relatively high surface area (55 m2 g−1) and constituted by flower-like aggregates with open cavities at the catalyst surface. This catalyst displayed superior performance (100% of toluene conversion at 325 °C using highly demanding conditions) and this performance can be maintained for several catalytic cycles. Interestingly, the porous iron oxides present not only a higher catalytic activity than the non-porous but also a higher specific activity per surface area. The high activity of this catalyst has been related to the possible synergistic effect of compositional, structural and microstructural features emphasizing the role of the surface area, the crystalline phase present, and the properties of the surface.

scholarly journals Nanomateriais à base de óxidos de ferro suportados com resíduos ricos em sílica

2019 ◽  
Vol 40 ◽  
pp. 225
Author(s):  
Marcela Trojahn Nunes ◽  
Fabiele Schaefer Rodrigues ◽  
Jocenir Boita
Keyword(s):  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
Structural Investigation ◽  
Rice Husk Ash ◽  
Low Cost ◽  
Chemical Components ◽  
X Ray ◽  
Low Toxicity ◽  
Synchrotron Light ◽  
Red Ceramics

Nanoparticles can be obtained through different chemical components, such as iron oxides that have the advantages of easy synthesis, low toxicity, biocompatibility, high adsorption capacity and low cost. Since, the NPs have quite peculiar characteristics differing significantly from other materials mainly by the increase of the surface area and also by the quantum effects. The objective of this work is to obtain Nanomaterials based on iron oxides supported by different residues (rice husk ash, red ceramics and agate), composed mostly of SiO2, using the polyol method, and to evaluate the possibility of using them in different applications, for example, in the field of catalysis and in various engineering processes. The Nanomaterials were characterized with experimental techniques existing in the National Synchrotron Light Laboratory (LNLS), which allow the electronic and structural investigation of Nanomaterials such as X-ray Induced Photoelectron Spectroscopy (XPS). The study allowed to identify that it was possible to use residues with SiO2 in the obtaining of NPs, as well as, confirmed that there is differentiation in their structure. Enabling the expansion of studies in relation to the application of these Nanomaterials.

Interaction of Niobium with Polycrystalline Palladium Surface. X-ray Photoemission Study

2008 ◽  
Vol 73 (10) ◽  
pp. 1314-1326
Author(s):  
Ivan Jirka ◽  
Zdeněk Bastl
Keyword(s):  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
Binding Energies ◽  
Growth Mode ◽  
X Ray ◽  
Line Shapes ◽  
Level Lines ◽  
Pd Alloy ◽  
Palladium Surface ◽  
Photoemission Study

Evolution of niobium-palladium (Nb-Pd) interface alloy prepared by in situ Nb deposition on highly defect polycrystalline Pd surface at room temperature has been investigated using X-ray photoelectron spectroscopy. The binding energies of the Nb 3d5/2 and Pd 3d5/2 core-level lines and their line shapes and the kinetic energies and shapes of Pd M4,5N4,5N4,5 Auger spectrum have been used to characterize the Nb-Pd system. A two-step growth mode of the Nb adlayer has been observed: a two-dimensional (2D)-like growth in a submonolayer Nb concentration region and three-dimensional (3D) intermixing of Nb and Pd atoms at Nb loadings above the monolayer coverage. The latter growth mode resulted in appearance of rather homogeneous Nb-Pd alloy phase.

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