Critical comparison of methods for surface coverage by extractives and lignin in pulps by X-ray photoelectron spectroscopy (XPS)

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Pedro Fardim ◽  
Anette Heijnesson Hultén ◽  
Jean-Phillippe Boisvert ◽  
Leena-Sisko Johansson ◽  
Marie Ernstsson ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
Component Analysis ◽  
X Ray ◽  
Chemical Pulp ◽  
Mercury Acetate ◽  
Set Up ◽  
Relative Comparisons ◽  
True Values ◽  
Selection Of

Abstract Different methods for estimation of the surface coverage by extractives and lignin were critically compared. For data collection, four state-of-the-art X-ray photoelectron spectroscopy (XPS) instruments located in four different laboratories were used. Hand sheets of one mechanical and two chemical pulp samples were prepared in one laboratory and distributed among the other participants. The XPS results based on O/C ratios and curve fitting of the C 1s peak had very good intra- and interlaboratory variation for extracted and non-extracted pulp samples. The estimations of surface coverage by extractives and lignin also had acceptable intra- and interlaboratory variation. However, significant differences were observed between the results for the various methods. Estimation of surface coverage by extractives based on O/C ratios was much higher than that based on the C1 component analysis in the case of mechanical and unbleached chemical pulp. The surface coverage by lignin of mechanical pulp was reproducibly detected based on O/C ratios, C1 component analysis and by labelling with mercury acetate. The same data were, however, rather scattered if they were collected with these three methods for bleached and unbleached chemical pulp. In spite of the differences, similar trends regarding the pulp type could be observed. We interpret the results as indicating that the surface coverage for both extractives and lignin should not be considered as absolute “true” values, but rather as relative values, which are reliable only for comparison of samples for the same instrument. Even for relative comparisons, we recommend the selection of a strict experimental set-up for spectral acquisition and data treatment when applying any of the instruments and calculation models currently available.

scholarly journals Yttrium Doped TiO2 Thin Film for Gas Sensing Application Prepared by Spin Coating Method

2020 ◽  
Author(s):  
M Abdul Kaiyum ◽  
Naim Ahmed ◽  
Arif Alam ◽  
M Shamimur Rahman
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Low Cost ◽  
Pure Titanium ◽  
X Ray ◽  
Sensing Applications ◽  
Coating Method ◽  
Set Up ◽  
Spin Coater

Abstract Yttrium (Y) doped and pure Titanium Di-oxide (TiO2) thin films were prepared by using spin coater. The coater was set up in laboratory with low cost investment. The films were calcined at 450 °C for 1 hour. For characterization, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) were carried out. LCR Bridge - GW Instek LCR-821 was used for gas sensing applications. XPS showed that the change of electronic structure due to Y doping. SEM and AFM analysis were carried out to determine the surface morphology of the films. Yttrium (Y) decreased the crystallite size of the films and increased the surface roughness and porosity value, which was very good for many sensing applications. Gas sensing property of the deposited films were improved by the incorporation of yttrium impurities and the sensing property improved almost two times than pure TiO2 thin film. Different researches have been done their research related to this topic but no one researchers provide a precise explanation of their results, authors of this research have tried to do that. Moreover the films were prepared by a simple spin coater to reduce the production cost also.

Limitations to the use of Sb as a Surfactant During SiGe MBE

1998 ◽  
Vol 533 ◽  
Author(s):  
Glenn G. Jernigan ◽  
Conrad L. Silvestre ◽  
Mohammad Fatemi ◽  
Mark E. Twigg ◽  
Phillip E. Thompson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Quantum Well ◽  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Alloy Concentration

AbstractThe use of Sb as a surfactant in suppressing Ge segregation during SiGe alloy growth was investigated as a function of Sb surface coverage, Ge alloy concentration, and alloy thickness using xray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy. Unlike previous studies where Sb was found to completely quench Ge segregation into a Si capping layer, we find that Sb can not completely prevent Ge segregation while Si and Ge are being co-deposited. This results in the production of a non-square quantum well with missing Ge at the beginning and extra Ge at the end of the alloy. We also found that Sb does not relieve strain in thin films but does result in compositional or strain variations within thick alloy layers.

scholarly journals Alumina-based Coating for Coke Reduction in Steam Crackers

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2025
Author(s):  
Stamatis A. Sarris ◽  
Steffen H. Symoens ◽  
Natalia Olahova ◽  
Marie-Françoise Reyniers ◽  
Guy B. Marin ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Base Alloy ◽  
Product Distribution ◽  
X Ray ◽  
Barrier Coating ◽  
Sulfur Addition ◽  
Steam Cracking ◽  
On Line ◽  
Set Up ◽  
Section Analysis

Alumina-based coatings have been claimed as being an advantageous modification in industrial ethylene furnaces. In this work, on-line experimentally measured coking rates of a commercial coating (CoatAlloy™) have pointed out its superiority compared to an uncoated reference material in an electrobalance set-up. Additionally, the effects of presulfiding with 500 ppmw DMDS per H2O, continuous addition of 41 ppmw S per HC of DMDS, and a combination thereof were evaluated during ethane steam cracking under industrially relevant conditions (Tgasphase = 1173 K, Ptot = 0.1 MPa, XC2H6 = 70%, dilution δ = 0.33 kgH2O/kgHC). The examined samples were further evaluated using online thermogravimetry, scanning electron microscopy and energy diffractive X-ray for surface and cross-section analysis together with X-ray photoelectron spectroscopy and wavelength-dispersive X-ray spectroscopy for surface analysis. The passivating coating illustrated a better performance than the reference Ni-Cr Fe-base alloy after application of an improved pretreatment, followed by piddling changes on the product distribution. Presulfiding of the coating affected negatively the observed coking rates in comparison with the reference alloy, so alternative presulfiding and sulfur addition strategies are recommended when using this barrier coating.

X-Ray Photoelectron Spectroscopic Studies of Palladium Dispersed on Carbon Surfaces Modified by Ion Beams and Plasmatic Oxidation

1995 ◽  
Vol 60 (3) ◽  
pp. 383-392 ◽  
Author(s):  
Zdeněk Bastl
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
Spectroscopic Studies ◽  
Core Level ◽  
Graphite Surface ◽  
Photoelectron Spectra ◽  
Surface Layers ◽  
X Ray ◽  
Core Level Binding Energy

The effects of ion bombardment and r.f. plasma oxidation of graphite surfaces on subsequent growth and electronic properties of vacuum deposited palladium clusters have been investigated by methods of X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy with X-ray excitation (XAES). Due to the significantly increased density of surface defects on which the nucleation process occurs the bulk value of the Pd 3d core level binding energy is achieved at higher surface coverage by palladium on bombarded surfaces than on ordered graphite. Angle resolved photoelectron spectra of oxidized graphite surfaces reveal significant embedding of oxygen in graphite surface layers. The C 1s and O 1s photoelectron spectra are consistent with presence of two major oxygen species involving C-O and C=O type linkages which are not homogeneously distributed within the graphite surface layers. Two effects were observed on oxidized surfaces: an increase of palladium dispersion and interaction of the metal clusters with surface oxygen groups. Using the simple interpretation of the modified Auger parameter the relaxation and chemical shift contributions to the measured Pd core level shifts are estimated. In the region of low surface coverage by palladium the effect of palladium-oxygen interaction on Pd core level binding energy exceeds the effects of increased dispersity.

scholarly journals Background Estimation in X-ray Photoelectron Spectroscopy Data Using an Active Shirley Method with Automated Selection of the Analytical Range

2019 ◽  
Vol 17 (0) ◽  
pp. 61-68 ◽  
Author(s):  
Ryo Murakami ◽  
Hironori Kageyama ◽  
Kazuki Nakamura ◽  
Hiromi Tanaka ◽  
Hiroshi Shinotsuka ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spectroscopy Data ◽  
X Ray ◽  
Background Estimation ◽  
Analytical Range ◽  
Selection Of

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.

Lead Corrosion and Formation of Lead Oxides from a Lead-air Cell in Methanesulfonic Acid

2017 ◽  
Vol 19 (4) ◽  
pp. 217-222
Author(s):  
Wan Jeffrey Basirun ◽  
Idris Mohamed Saeed ◽  
Hanieh Ghadimi ◽  
Magaji Ladan ◽  
Mohammad Reza Mahmoudian ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
Methanesulfonic Acid ◽  
X Ray Diffraction ◽  
Air Cathode ◽  
X Ray ◽  
Lead Corrosion ◽  
Microscopy Image ◽  
Lead Oxides ◽  
Discharge Field

The corrosion of lead in methanesulfonic acid solution in the presence of a MnO2 air cathode in a primary lead-air cell is in-vestigated. The highest power density of the lead-air cell is 2.8 mW cm-2. X-ray photoelectron spectroscopy and powder X-ray diffraction results demonstrate the formation of lead (II) oxide and lead (IV) dioxide on the air cathode after continuous discharge. Field emission scanning electron microscopy image shows that the surface coverage of lead (II) oxide and lead (IV) dioxide on the air cathode is only partial and will allow oxygen reduction.

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