Sr/Si Template Formation for the Epitaxial Growth of SrTiO3 on Silicon

2002 ◽  
Vol 716 ◽  
Author(s):  
Xiaoming Hu ◽  
Y. Liang ◽  
Yi Wei ◽  
J.L. Edwards ◽  
R. Droopad ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Epitaxial Growth ◽  
Photoelectron Spectroscopy ◽  
Oxidation Process ◽  
Oxidation Mechanism ◽  
Metal Thin Films ◽  
X Ray ◽  
In Situ Techniques ◽  
Interfacial Structures

AbstractA novel silicon cleaning process using strontium metal thin films has been described. The silicon dioxide de-oxidation process using strontium as catalysts has been studied by X-ray Photoelectron Spectroscopy (XPS) and other in-situ techniques. A Sr/Si template for the epitaxial growth of SrTiO3 single crystals on silicon can be directly formed as a result of the above Sr-de-oxidation process. The de-oxidation mechanism can be explained after solving the interfacial structures of the Sr/SiO2/Si system with in-situ XPS.

scholarly journals In Situ and In Operando Techniques to Study Li-Ion and Solid-State Batteries: Micro to Atomic Level

Inorganics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 85
Author(s):  
Maryam Golozar ◽  
Raynald Gauvin ◽  
Karim Zaghib
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Atomic Level ◽  
X Ray ◽  
In Situ Techniques ◽  
Transmission Electron ◽  
Wide Range ◽  
Li Ion

This work summarizes the most commonly used in situ techniques for the study of Li-ion batteries from the micro to the atomic level. In situ analysis has attracted a great deal of interest owing to its ability to provide a wide range of information about the cycling behavior of batteries from the beginning until the end of cycling. The in situ techniques that are covered are: X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Scanning Transmission Electron Microscopy (STEM). An optimized setup is required to be able to use any of these in situ techniques in battery applications. Depending on the type of data required, the available setup, and the type of battery, more than one of these techniques might be needed. This study organizes these techniques from the micro to the atomic level, and shows the types of data that can be obtained using these techniques, their advantages and their challenges, and possible strategies for overcoming these challenges.

scholarly journals In-situ X-ray techniques for non-noble electrocatalysts

2020 ◽  
Vol 92 (5) ◽  
pp. 733-749 ◽  
Author(s):  
Sung-Fu Hung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Mechanism ◽  
Structural Evolution ◽  
Reduction Reaction ◽  
High Price ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Techniques ◽  
State Variation

AbstractElectrocatalysis offers an alternative solution for the energy crisis because it lowers the activation energy of reaction to produce economic fuels more accessible. Non-noble electrocatalysts have shown their capabilities to practical catalytic applications as compared to noble ones, whose scarcity and high price limit the development. However, the puzzling catalytic processes in non-noble electrocatalysts hinder their advancement. In-situ techniques allow us to unveil the mystery of electrocatalysis and boost the catalytic performances. Recently, various in-situ X-ray techniques have been rapidly developed, so that the whole picture of electrocatalysis becomes clear and explicit. In this review, the in-situ X-ray techniques exploring the structural evolution and chemical-state variation during electrocatalysis are summarized for mainly oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). These approaches include X-ray Absorption Spectroscopy (XAS), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The information seized from these in-situ X-ray techniques can effectively decipher the electrocatalysis and thus provide promising strategies for advancing the electrocatalysts. It is expected that this review could be conducive to understanding these in-situ X-ray approaches and, accordingly, the catalytic mechanism to better the electrocatalysis.

Fabrication and in situ X-ray photoelectron spectroscopy of granular metal thin films

1991 ◽  
Vol 206 (1-2) ◽  
pp. 264-268 ◽  
Author(s):  
S.I. Shah ◽  
B.A. Doele ◽  
I. Weerasekera ◽  
K.M. Unruh
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Metal Thin Films ◽  
X Ray

Kinetics and mechanism of Mn2+ removal from groundwater using iron–manganese co-oxide filter film

2019 ◽  
Vol 19 (6) ◽  
pp. 1711-1717
Author(s):  
Yingming Guo ◽  
Jianmin Zhang ◽  
Xi Chen ◽  
Jing Yang ◽  
Jianxiong Huang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxidation Process ◽  
Oxidation Mechanism ◽  
X Ray ◽  
First Order ◽  
Sand Surface ◽  
First Order Kinetics ◽  
Start Up ◽  
Do Concentration ◽  
Iron Manganese

AbstractTo shorten the ripening period of filter sand, iron–manganese co-oxide filter film (MeOx) was formed quickly on the virgin quartz sand surface by oxidizing Mn2+ and Fe2+ from groundwater using KMnO4 continuously. After the start-up period, we found that Mn2+ could be removed efficiently by MeOx, even if the dissolved oxygen (DO) concentration in the influent was only about 1.0–1.5 mg/L. This means that the removal process of Mn2+ does not need to consume DO. The kinetic experiments for Mn2+ indicated that the adsorption and oxidation kinetics followed pseudo-first-order kinetics. The film (MeOx) was characterized by X-ray photoelectron spectroscopy (XPS). All manganese adsorbed on the surface of the sand was the oxidized form, and the manganese oxide coated onto the sand effectively oxidized Mn2+ to Mn3+ or Mn4+. The binding energy of the observed photoelectron peaks of O(1s) showed the existence of [≡Mn-OH] on the surface of the film by XPS, which might be a key intermediate in the mechanism of Mn2+ oxidation. Finally, a chemical catalytic oxidation mechanism for Mn2+ removal was proposed by the analysis of the oxidation process.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

scholarly journals Understanding Selectivity in CO2 Hydrogenation to Methanol for MoP Nanoparticle Catalysts Using In Situ Techniques

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 143
Author(s):  
Melis S. Duyar ◽  
Alessandro Gallo ◽  
Samuel K. Regli ◽  
Jonathan L. Snider ◽  
Joseph A. Singh ◽  
...  
Keyword(s):  
Formation Rate ◽  
Methanol Conversion ◽  
Transition Metal Catalysts ◽  
Colloidal Synthesis ◽  
X Ray ◽  
In Situ Techniques ◽  
Methanol Formation ◽  
Diffuse Reflectance Infrared ◽  
Formate Intermediate

Molybdenum phosphide (MoP) catalyzes the hydrogenation of CO, CO2, and their mixtures to methanol, and it is investigated as a high-activity catalyst that overcomes deactivation issues (e.g., formate poisoning) faced by conventional transition metal catalysts. MoP as a new catalyst for hydrogenating CO2 to methanol is particularly appealing for the use of CO2 as chemical feedstock. Herein, we use a colloidal synthesis technique that connects the presence of MoP to the formation of methanol from CO2, regardless of the support being used. By conducting a systematic support study, we see that zirconia (ZrO2) has the striking ability to shift the selectivity towards methanol by increasing the rate of methanol conversion by two orders of magnitude compared to other supports, at a CO2 conversion of 1.4% and methanol selectivity of 55.4%. In situ X-ray Absorption Spectroscopy (XAS) and in situ X-ray Diffraction (XRD) indicate that under reaction conditions the catalyst is pure MoP in a partially crystalline phase. Results from Diffuse Reflectance Infrared Fourier Transform Spectroscopy coupled with Temperature Programmed Surface Reaction (DRIFTS-TPSR) point towards a highly reactive monodentate formate intermediate stabilized by the strong interaction of MoP and ZrO2. This study definitively shows that the presence of a MoP phase leads to methanol formation from CO2, regardless of support and that the formate intermediate on MoP governs methanol formation rate.

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

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