O1s Binding Energy Research Articles

All-electron first-principles GWΓ simulations for accurately predicting core-electron binding energies considering first-order three-point vertex corrections.

In the conventional GW method, the three-point vertex function (Γ) is approximated to unity (Γ ∼ 1). Here, we developed an all-electron first-principles GWΓ method beyond a conventional GW method by considering a first-order three-point vertex function (Γ(1) = 1 + iGGW) in a one-electron self-energy operator. We applied the GWΓ method to simulate the binding energies (BEs) of B1s, C1s, N1s, O1s, and F1s for 19 small-sized molecules. Contrary to the one-shot GW method [or G0W0(LDA)], which underestimates the experimentally determined absolute BEs by about 3.7eV for B1s, 5.1eV for C1s, 6.9eV for N1s, 7.8eV for O1s, and 5.8eV for F1s, the GWΓ method successfully reduces these errors by approximately 1-2eV for all the elements studied here. Notably, the first-order three-point vertex corrections are more significant for heavier elements, following the order of F > O > N > C > B1s. Finally, the computational cost analysis revealed that one term in the GWΓ one-electron self-energy operator, despite being computationally intensive, contributes negligibly (<0.1eV) to the C1s, N1s, O1s, and F1s.

Research on reactivity evaluation and micro-mechanism of various solid waste powders for alkali-activated cementitious materials

Alkali-activated cementitious material (AACM) based on the utilization of solid waste is a new type of environmentally friendly inorganic material, which has the advantages of early strength, fast hardening, high strength, and better durability. The reactivity of solid waste powder is a key factor for its appropriate utilization in alkali-activated cementitious materials, necessitating a rational evaluation of its reactivity. The reactivity evaluation was conducted on various solid waste powders, including fly ash (FA), red mud (RM), recycled micro-powder (RMP), red brick powder (RBP), coal gangue powder (CGP), and cement kiln dust (CKD). The effects of NaOH concentration, weight ratio of water to solid waste powder (W/P) and curing humidity on the compressive strength were investigated，then the compressive strength under optimal conditions was determined based on response surface analysis. The compressive strength under optimal conditions was used to evaluate the reactivity of solid waste powders. Moreover, microscopic tests (e.g., XPS test, ICP test, and NMR test) were carried to evaluate the reactivity of the solid waste. The relative number of bridging oxygen (RBO) measured by the NMR method in conjunction with chemical composition analysis serves as an effective method for evaluating the reactivity of solid waste powders. The leaching rate of Silicon (Si) and Aluminum (Al) ions in the ICP method depended mainly on the NaOH concentration and the elemental content in the raw material. In addition, the binding energies of O1s, Si 2p, and Al 2p tested by the XPS method had no particular correlation with the compressive strength.

Factors Affecting Microscopic Basicity of Silicate Glasses from the Perspective of O1s Binding Energy

The factor affecting the microscopic basicity of oxygen in the SiOSi bond are investigated on the basis of the O1s binding energy measured by X‐ray photoelectron spectroscopy (XPS). The samples used are SiO2, Na2OSiO2, CaOSiO2, CaOMgOSiO2, and CaOAl2O3SiO2. For analysis on clean surfaces, samples are finally prepared by fracturing in a vacuum in an XPS system. From the O1s spectra, derived are the centers of gravity of the O1s spectra and the binding energies of O1s in the SiOSi, SiOAl, AlOAl, SiONa, SiOCa, and SiOMg bonds. A good linear relationship is found between the center of gravity of the O1s spectra and the optical basicity, suggesting that the center of gravity of the O1s spectra is a reasonable basicity index of silicate glasses used in this work. It is also found that there is a linear relationship between the binding energy of O1s in the SiOSi bond and the optical basicity, irrespective of the glass systems. This indicates that the experimental microscopic basicity of oxygen in SiOSi bond is affected not only by the first neighboring ions of oxygen but also by the composition of the sample.

Adsorption of Pb(II) and Cu(II) by succinic anhydride-modified apple pomace

To address the environmental issues arising from the substantial accumulation of apple pomace (AP), a succinic anhydride-modified AP, denoted as SAMAP, was synthesized through succinylation for the treatment of heavy metal ions. The structural characteristics and the thermal stability of SAMAP were characterized by FTIR, CP/MAS 13C NMR and thermogravimetry. The batch adsorption with a dosage of 35 g L−1 at pH 5.0 and ambient temperature indicated that adsorption rates of Cu(II), Zn(II), and Pb(II) by AP were 53.85%, 60.44%, and 82.24%, respectively, while those by SAMAP were 90.54%, 50.73%, and 89.83%, respectively. P-value analysis further confirms the significant difference in metal ion adsorption between AP and SAMAP. The maximum adsorption capacity of SAMAP for Pb(II) is 121.43 mg g−1. Column adsorption further verified the durability and applicability of SAMAP for treating Cu(II) and Pb(II). The adsorption mechanism of SAMAP for Cu(II), and Pb(II) primarily involves electrostatic interactions and the coordination via carboxylic groups on SAMAP, as supported by enhanced binding energies of C1s and O1s and a weakening vibration of C-O in carboxylic groups shown in XPS and FTIR spectra after adsorption. This study provides a promising potential for using AP to remove Cu(II) and Pb(II) in effluents.

Understanding surface structures of In2O3 catalysts during CO2 hydrogenation reaction using time-resolved IR, XPS with in situ treatment, and DFT calculations

The In2O3 catalyst has been shown to have a high activity for CO2 hydrogenation to methanol. For this high pressure process, reliable spectral assignment of surface species formed by interaction with CO2, H2O, and other major reaction ingredients, is the key step to achieve mechanistic understanding. In this study, in situ IR and XPS are performed to investigate the O1s binding energies of the adsorbates induced by CO2 and H2O treatments along with density functional theory (DFT) simulations to further correlate the calibrated assignments with surface structures. Time resolved IR indicates that carbonates formation induced by CO2 exposure replaces the original hydroxyl on In2O3, and XPS further reveals that these two oxygen species have very similar binding energies (532.0 ± 0.2 eV). Computational results using the In2O3(110) and (111) slab models give good agreement with the XPS experiments, further suggesting that the amount of oxygen vacancy concentration does not induce new lattice oxygen O1s binding energy, but resulting in a slight shift to a higher binding energy instead. Our results provide useful structure information for the In2O3 catalyst surface and shed light for further investigations into its kinetic behavior under methanol synthesis condition.

Electrochemical characteristic of non-stoichiometric SmBa0.45Sr0.5Co2O5+d layered perovskite oxide system for IT-SOFC cathode

In this study, the composition of the layered perovskite SmBa0.5Sr0.5Co2O5+d was changed to different non-stoichiometric compositions by changing the substitution amount of Ba and Sr.SmBa0.45Sr0.5Co2O5+d (SBSCO-0.45/0.5) showed the lowest area specific resistance (ASR) because the area % caused by high binding energy (HBE) of O1s in the X-ray photoelectron spectroscopy (XPS) analysis was the largest compared to all other tested compositions and also the unit cell volume was smaller than that of other samples.The dense SmBa0.5Sr0.48Co2O5+d (SBSCO-0.5/0.48) showed the highest electrical conductivity. This is because SBSCO-0.5/0.48 has the smallest decrease in oxygen contents compared to other samples when subject to temperature increase. Also, through XPS analysis, it was found that the area % of the Co3+ and Co4+ coexistence regions of Co2p of SBSCO-0.5/0.48 was the largest. The electrical conductivity values and behaviors of the porous SBSCO-0.45/0.5 and SBSCO-0.5/0.48 were not significantly different.Comparing the single-cell performance with composite cathodes comprised of SBSCO-0.45/0.5 and SBSCO-0.5/0.48 with CGO91, the results show that the single-cell with the SBSCO-0.45/0.5 and CGO91 cathode showed higher maximum power density.

Chitosan Stabilised Iron Containing Nanoparticles For Photocatalytic Hydrogen Generation

Metal nonoparticles stabilized by polymers is emerging as a new class of materials having entirely new physico-chemical properties as that of bulk and atom both. Stabilizers play important role in protecting the nanoparticles and also contributes in improvising the overall surface area. Chitosan, a natural polymer is selected as a stabilizer for the synthesis of iron containing nanoparticles. These nonoparticles are thoroughly characterized by using BETsurface area, FTIR, TEM and XPS. TEM image is showing well dispersed nanofibers with average size of 13nm. XPS data supports the formation of Fe2O3 type structure with O1s binding energy at 534.5 eV and Fe 2P3/2 and Fe 2P1/2 binding energies at 712eV and 723.2 eV. BET Surface area value is 36.72m2 /g with pore size of 145.16 and pore volume of 0.1332 cm3 /g. This synthesized nanomaterial was evaluated for photocatalytic hydrogen generation via water splitting reaction. Iron containing nanoparticles are showing excellent photocatalytic activity with hydrogen generation yield of 55.5 mmoles h-1g -1 of photocatalyst. The nanoparticles are magnetically retrievable and hence can be separated effectively from heterogeneous system.

X-Ray Photoelectron Spectroscopy of Polystyrene Composite Films

In this paper, X-ray Photoelectron Spectroscopy (XPS) measurements were obtained to determine the chemical structure of these polystyrene (PS) doped and undoped thin films. The purpose is to analyze the graphs and binding energies of each element to determine. The XPS analysis of these pure PS compared doped PS thin film does show a tunable potential for optimum properties. PS has a relative basic host matrix, and it is our hypothesis that first, we can show that XPS can be a useful and resourceful tool in characterizing these thin films for chemical structure and binding information. Secondly, we intend to show that through the addition of dopants, we can affect the binding energies. The results show the impact on O1s binding energies ± 4.43-5.57 eV and for C1s ± 1.45 -9.37 eV. These analyses have been performed in several studies on polymer nanocomposite materials. Here, we introduce the use of the XPS analysis in recent notable polymer nanocomposite studies for various target applications.

Study on the Synthesis and Structural Properties of Zeolite A-MgO Composite for Defluoridation of Water

Zeolite A-MgO composite was synthesized in presence of zeolite A particles, MgCl2 and urea solution under hydrothermal reaction at 150oC for 5 h followed by calcination at 600°C/2 h. XRD and FTIR results showed the crystallization of MgO along with NaA zeolite crystals. Nano-sheet like MgO particles (50-70 nm) were grown onto the surface of NaA zeolite crystals (1 μm). BET surface area and pore size of the sample were found to be 69 m2.g−1 and 3.9 nm, respectively. XPS analysis showed the binding energies of O1s, Si2p, Na1s, Al2p and Mg2p as 531.6, 102.4, 1072.2, 74.2 and 49.9 eV, respectively. The synthesized product (1 g.L−1 dose) showed 72% adsorption of fluoride (7.24 mg.L−1) within 5 min and reached up to 94% for 90 min at pH 6.8. The adsorption capacity of the sample was calculated as 107.64 mg.g−1 from Langmuir isotherm. The sample could be regenerated up to 5th cycle. A tentative mechanism for the adsorption of fluoride from aqueous solution by the synthesized zeolite A-MgO composite was proposed.

An Extrinsic Faradaic Layer on CuSn for High-Performance Electrocatalytic CO 2 Reduction

An Extrinsic Faradaic Layer on CuSn for High-Performance Electrocatalytic CO ₂ Reduction

On the signatures of oxygen vacancies in O1s core level shifts

Density functional theory calculations are used to investigate O1s surface core level shifts for MgO(100), ZnO(101¯0), In2O3(111) and CeO2(111). Shifts are calculated for the pristine surfaces together with surfaces containing oxygen vacancies and dissociated H2. Pristine surfaces show small negative shifts with respect to the bulk components and vacancies are found to have a minor effect on the O1s binding energies of neighboring oxygen atoms. OH-groups formed by H2 dissociation yield binding energies shifted to higher energies as compared to the oxygen atoms in the bulk. The results stress the difficulties in assigning core-level shifts and suggest that assignments of shifts in O1s binding energies to neighboring oxygen vacancies for the explored oxides should be reconsidered.

Evaluation of potential reaction between BaZr0.8Y0.2O3-δ ceramics and Pt at high temperatures

BaZr0.8Y0.2O3-δ (BZY20) is found to react with Pt at high temperatures, although Pt is generally regarded as an inert material that prevents its reaction with many materials even at high temperatures. The reaction between BZY20 with Pt is difficult to be confirmed by X-ray diffraction (XRD) analysis as no observable secondary phase can be detected even after high-temperature treatment. However, the obvious color change of the fired BZY20 powder implies the potential reaction. Therefore, transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS) and X-ray photoelectron spectroscopy (XPS) techniques are used to have an insightful analysis of the material. TEM-EDS result indicates that there is an existence of Pt element in the BZY20 powder after firing, suggesting a Pt diffusion into the BZY20 lattice. XPS analysis results further confirm the content of Pt4+ and Pt2+ in the BZY20 powder after firing and the content of Pt4+ increases with the increase of firing temperatures, and the increase of Pt4+ content lowers the O1s binding energy, which might be beneficial for the proton migration.

Insights into the Osteogenic Differentiation of Mesenchymal Stem Cells on Crystalline and Vitreous Silica.

Cell responses to oxide biomaterials depend on the protein adsorption behavior of the biomaterial surface. Thus, the inherent properties of oxide biomaterial surfaces play a key role in this process. However, commonly used biomaterials, such as calcium phosphate and titanium dioxide, have surfaces with strong mineralization, which may interfere with the ability to clarify the key aspects of the oxide biomaterial regarding protein adsorption and cellular processes. Here, nonmineralized crystalline and vitreous silica were selected as model oxide biomaterials to explore the inherent properties of these materials on the absorption behavior of the functional protein fibronectin (Fn) and on the osteogenic differentiation of mesenchymal stem cells (MSCs). We demonstrated that due to the smaller O1s binding energy, the weaker polarization of oxygen atoms in vitreous silica produced a greater amount of acidic hydroxyls after hydration compared to crystalline silica. These distinct features significantly upregulated the exposure of arginylglycylaspartic acid (RGD) and synergy sites (PHSRN) of Fn and eventually enhanced the osteogenic differentiation of MSCs on vitreous silica surfaces through activation of the integrin-linked kinase (ILK) signaling pathway. Our results highlight the key role of inherent oxide biomaterial crystallinity in protein adsorption and cell behavior.

Local structure, connectivity and physical properties of glasses in the B2O3-Bi2O3-La2O3-WO3 system

Glasses of (100 - (x + y))·(0.6B2O3·0.4Bi2O3)·xLa2O3·yWO3, x = 0, 10; y = 0 ÷ 40 mol% were prepared by melt quenching. Density measurements, thermal analysis, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and theoretical modeling using Density Functional Theory were employed to identify the effect of WO3 content on the structural and physicochemical properties of these glasses. The glass transition temperature and density increase steadily with increasing WO3 content, most probably because of the formation of mixed Bi–O–W and La–O–W crosslinks. The lower band gap energy values show that the introduction of WO3 or La2O3 to 60B2O3·40Bi2O3 glass increases the number of non-bridging oxygen species in the glass structure. The photoelectron analysis aided by theoretical calculations discover that additionally to the tetrahedrally coordinated W ions, most of the existing WO6 octahedral units in glasses with nominal WO3 content below 20 mol% are distorted, leaving practically the tungsten ions in a quasi-tetrahedral coordination. At higher WO3 content (30–40 mol%) the concentration of octahedrally coordinated tungsten atoms dominate strongly over those of tetra- and quasi-tetra-coordinated W ions. Moreover, the comparison with appropriate crystal standards allows offering a complete description of the existing bridging and non-bridging linkages and their most likely O1s binding energies.

Arsenic vitrification by copper slag based glass: Mechanism and stability studies

In the present work, the (100−x)(58SiO2-20Fe2O3-10B2O3-12Na2O)−xAs (x=0, 2, 4, 6, 8wt%) glasses, which are main constituents of the copper slag based glasses, were produced by conventional melting method to study the arsenic vitrification mechanism and stability. X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR) and X-photoelectron spectroscopy (XPS) were used to investigate the mechanism of arsenic vitrification. The XRD analysis for the x≤wt 8% samples shows that all the samples form homogeneous glasses and the arsenic is compatible with the copper slag based glass. The FTIR spectrum of the glasses have revealed that the arsenic exists in the form of AsO4 tetrahedra and the Qn structure of the copper slag based glass has been strengthened with the increase addition of arsenic. The changes of the binding energies of Si2p, O1s, As3d and Fe2p directly indicate the formation of SiOAs and FeOSi/As bonds in the glass, which strengthens the chemical stability of the glass. Lastly, USEPA toxicity characteristics leaching procedure (TCLP) and differential scanning calorimetry (DSC) tests were used to study the chemical durability and thermal stability of the glasses containing arsenic. The leaching concentrations of As, B, Fe, Na, and Si are under safety thresholds and the increase addition of arsenic into the glasses can decrease the leaching concentrations, indicating that the arsenic can improve the chemical stability of the glass. The arsenic added into the glass can improve the ΔT, which strengthens the thermal stability of the glasses.

Effect of substrate temperature and post annealing temperature on ZnO:Zn PLD thin film properties

The pulsed laser deposition (PLD) substrate temperature and post-annealing temperature are effective methods to control the film optical and structural properties. The structure, morphology and optical properties of the deposited and post-annealed PLD ZnO:Zn films were studied. The films were deposited at different substrate temperatures of 50 °C, 200 °C and 400 °C. The films deposited at the substrate temperature of 50 °C and 200 °C were post-annealed in air at 400 °C and 600 °C for two hours. The films all had a highly preferential orientation with the hexagonal c-axis perpendicular to the substrate surface. The stress was found to be compressive stress with values −3.289 GPa, −4.864 GPa and −4.425 GPa for the film deposited at 50 °C, 200 °C and 400 °C, respectively. After post-annealing treatments, the stress of the films was almost completely released and stress-free films were obtained. The crystallite sizes were 19 nm, 25 nm and 39 nm, while the average particles sizes were 95 nm, 85 nm and 129 nm for the film deposited at 50 °C, 200 °C and 400 °C respectively. The crystallite sizes and particles sizes seemed to increase with the increase in the substrate temperature. Contrary to this, the change in crystallite sizes were inversely proportional to the particles size when increasing the post-annealing temperatures. Deconvoluted X-ray photoelectron spectroscopy peaks of the O1s binding energy region revealed that the films deposited at different substrate temperatures contained oxygen-related defects. Photoluminescence studies revealed that the films all emitted ultra-violet emission around 379 nm. The film deposited at 50 °C emitted a broad green emission centered at ∼524 nm. By increasing the substrate temperature up to 200 °C and 400 °C a new orange emission around 621 nm and 634 nm as well as a weak emission around 416 nm and 500 nm were observed, respectively. After post-annealing treatments, new bands over the visible region (blue, green and orange-red) were observed, the orange-red emissions at ∼ 626 nm to 681 nm being dominant for the annealed samples. The defects-related visible emission was discussed in detail and it was in good agreement with previous studies.

Porous nano-cerium oxide wood chip biochar composites for aqueous levofloxacin removal and sorption mechanism insights.

The adsorption removal of levofloxacin (LEV), a widely used fluoroquinolone antibiotic, by using the biochars derived from the pyrolysis of pine wood chip pretreated with cerium trichloride was investigated through batch sorption experiments and multiple characterization techniques. The differences in the basic physicochemical properties between Ce-impregnated biochars and the pristine biochars were confirmed by the analysis of elemental compositions, specific surface areas, energy dispersive spectrometry, X-ray diffraction, and thermo-gravimetry. FT-IR spectra of the pre- and post-sorption biochars confirmed the chemical adsorption for LEV sorption onto the biochars. Large shifts in the binding energy of Ce3d, O1s, C1s, and N1s regions on the pre- and post-sorption biochars indicated the surface complexation of LEV molecule onto the biochars. The binding species of Ce4+ and Ce3+ identified by X-ray photoelectron spectroscopy reflect the role of Ce oxides during sorption. Batch adsorption showed the significant enhancement of adsorption capacity for LEV after the Ce modification. Batch adsorption kinetic data fitted well with the pseudo-second-order model. Both the Langmuir and the Freundlich models reproduced the isotherm data well. Findings from this work indicated that Ce-impregnated biochars can be effective for the removal of aqueous LEV.

Characterization and formation of bioactive hydroxyapatite coating on commercially pure zirconium by micro arc oxidation

Hydroxyapatite (HA, Ca10(PO4)6(OH)2) based coatings are used in biomaterial applications and biomedical industrial applications due to its bioactive and biocompatible properties. In this study, commercially pure zirconium was coated in the solution consisting of calcium acetate (CA, (CH3COO)2Ca)) and β-calcium glycerophosphate (β-Ca-GP, (β-C3H5(OH2)PO4Ca)) by micro arc oxidation (MAO) in a single-step process for 1, 10 and 30 min duration times to produce HA-based coatings.The phase structures, surface morphologies, functional groups of molecules, chemical composition of surface and the binding energies of atoms on the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. Zirconium (Zr), monoclinic and cubic zirconium oxide (ZrO2), cubic calcium zirconium oxide (Ca0.15Zr0.85O1.85), orthorhombic calcium zirconium oxide (CaZrO3) and HA phases on the coatings were detected by XRD analysis. The strongest intensity of crystal HA was also observed in XRD for the coating produced at 30 min. The surface morphologies of coatings produced by MAO method at 1 min have very porous structures because of the existence of micro discharge channels during the process. The surface coatings morphologically have HA microstructure owing to the crystallization of HA particles at 10 min and the existence of growing HA particles in MAO process at 30 min. The HA phase is confirmed by v3 (PO4−3) and vs (OH−) FTIR band assignments in ATR-FTIR and by the binding energies of Ca2p, P2p and O1s in XPS for coating produced at 30 min.

Oxidation of Planar and Plasmonic Ag Surfaces by Exposure to O2/Ar Plasma for Organic Optoelectronic Applications

ABSTRACTHere, we expose planar and plasmonic Ag surfaces to a low-power O2/Ar plasma to form an ultrathin surface oxide layer. We study the chemical state and morphology of the plasma-treated Ag surfaces using X-ray photoelectron spectroscopy, scanning electron microscopy, and dark-field microscopy. We observe the formation of an ultrathin layer (&lt; 10 nm) composed of both AgOx and Ag2CO3 for a plasma exposure time of 1 s by investigating shifts in the Ag3d, O1s, and C1s core level binding energies. For an exposure time of 1 s, the surface structure of the planar and plasmonic Ag surfaces remains unchanged. For exposure times of 5 - 30 s, the planar Ag surfaces become porous and exhibit increased surface roughness. We demonstrate that the plasma-treated planar and plasmonic Ag surfaces lead to improvements in the excited-state population of a polymer:fullerene coating through ultrafast pump-probe reflectometry.

The Electronic Structure of Saturated NaCl and NaI Solutions in Contact with a Gold Substrate

The near ambient pressure X-ray photoelectron spectroscopy set up installed recently at SOLEIL synchrotron facility is used to study the electronic structure of NaCl and NaI saturated solutions formed on a gold substrate. The binding energies of the solution constituents are measured with respect to the Fermi level of the gold substrate. The C1s binding energy of the aliphatic contaminant floating at the surface of the solution is an evidence that the Fermi level in the metal and in the solution are aligned. The use of the Fermi level common energy reference is an added value with respect to previous works realized with micro-jets that were calibrated in energy with respect to vacuum level. We observe that the water valence molecular levels binding energies, and hence the Fermi positioning in the gap of the liquid, the Na+ 2s binding energy and even the work function are independent of the nature of the anions. The secondary electron energy distribution curves show that the work functions of the two solutions are equal within experimental uncertainty. We discuss this point considering the different ion distributions at the surface (related to the different size and polarizability of the anions), and the possible contribution of carbon contaminants. We compare the WF values extracted from the secondary electron edges to alternative measurements using the binding energy of the gas phase O1s or 1b1 spectra (referenced to the gold Fermi level). The ionization energies (referenced to the vacuum level), that we obtain by adding the work function to the measured binding energies, are in good accord with previously published works using micro-jets, obtained, however, at much lower solute concentration. Finally we discuss the origin of the Fermi level pinning in the liquid band gap and consider the possibility that the H+/H2 redox level is aligned with the metal Fermi level.