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Methodologies and Advanced Characterizations of Photoelectrochemical Processes
Published in Anirban Das, Gyandshwar Kumar Rao, Kasinath Ojha, Photoelectrochemical Generation of Fuels, 2023
Camilla Tossi, Ornella Laouadi, Ilkka Tittonen, Aadesh P. Singh
X-ray photoelectron spectroscopy (XPS) is a technique for chemical analysis that exploits the energy emitted by electrons which, after being excited by X-ray photons, are ejected from the sample. The kinetic energy of the emitted electrons provides information on the chemical species present on the surface of the analyzed sample, with a depth of a few nanometers: this technique is of interest for analyzing the chemical and structural properties of the electrode. In particular, it can determine if there are dangling bonds on the surface of a metal oxide, which can easily attract solvated ions in the electrolyte, or if the material formed a native oxide that can protect the layer from corrosion, or if there is a space charge layer that favors the separation of photogenerated charge carriers of opposite sign. XPS is usually performed exsitu, to evaluate the chemical state of the working material both before use and after use: before use, it helps in predicting the behavior of the material at the interface with the electrolyte, while immediately after use it provides information on how the water and the dissolved ions have interacted with the WE: intermediate products may deposit on the surface, corrosion sites may reveal recrystallization or recomposition of the material, and the results can be invested immediately toward the improvement of the fabrication techniques and the engineering of the working materials [54].
Properties and characterization of conductive polymers
Published in Ze Zhang, Mahmoud Rouabhia, Simon E. Moulton, Conductive Polymers, 2018
David L. Officer, Klaudia Wagner, Pawel Wagner
X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique that can be used to determine elemental composition, empirical formula, and the chemical and electronic states of the elements that exist within a material. XPS has been used to determine the degree of doping in PPy (Naudin et al. 2002) and PEDOT (Massonnet et al. 2015). However, because of the surface sensitiveness of this technique, the results from the bulk of the film can be obscured by the surface information (Neoh et al. 1997).
Density, surface properties and neutron diffraction
Published in D. Campbell, R.A. Pethrick, J.R. White, Polymer Characterization, 2017
D. Campbell, R.A. Pethrick, J.R. White
This technique which is often known as X-ray photoelectron spectroscopy (XPS) is based on the observation that electrons are emitted by atoms under X-ray bombardment. If the target is a solid the energy of the emitted electrons is measured and this enables the binding energy to be determined. The exciting radiation is a monoenergetic beam of soft X-rays, usually the Kα radiation of aluminium or magnesium. A related technique, ultraviolet photoelectron spectroscopy, uses UV radiation and provides information on valence electron structure but is more difficult to use and interpret and is not used extensively for polymer analysis. Since the electrons are emitted with low energy they are easily recaptured and only those produced very close to the surface have a significant chance of escape. Only these can contribute to the signal and the information comes from a very small depth of the order of nanometres.
Bayesian estimation for XPS spectral analysis at multiple core levels
Published in Science and Technology of Advanced Materials: Methods, 2021
Atsushi Machida, Kenji Nagata, Ryo Murakami, Hiroshi Shinotsuka, Hayaru Shouno, Hideki Yoshikawa, Masato Okada
X-ray photoelectron spectroscopy (XPS) is a technique to measure the kinetic energy distribution of photoelectrons emitted by X-ray irradiation and to obtain information on the type, amount and chemical bonding state of elements present on the surface of a sample, which is used in various surface analyses of materials. In the field of spectroscopy, reference spectrum databases are being rapidly constructed, and it is necessary to develop automated spectrum analysis methods using reference spectrum data. Previous studies developed a method to estimate parameters such as composition ratios, peak position adjustments and peak width adjustments of samples using genetic algorithms [1]. Additionally, this method makes it possible to identify the combinations of compounds in samples using Bayesian information criterion. The genetic algorithms, however, do not allow us to make statistical reliability assessments about the results of the estimation.
Effects of Gamma Irradiation on the Morphological, Physical, and Thermal Properties of B4C/CF/PI/AA6061 Hybrid Composite Laminates
Published in Nuclear Science and Engineering, 2020
Xuelong Fu, Jie Tao, Dunwen Zuo
X-ray photoelectron spectroscopy (XPS) is a powerful technique for analyzing the surface chemistry, primarily analyzing the chemical composition of materials with depths less than 10 nm. When an electron beam penetrates the specimens, the carrier will be released by a specific group owing to the presence of ionizing radiation and transported as a substance between the strands or groups. For the BCPAs, the influence of gamma irradiation on the polyimide resin group is analyzed; carbon as a main element in the polyimide chain is an important functional group; and the group includes a C-O band, C = O band, C-N band, and C-C band.30Figure 8 shows a full XPS spectrum of the BCPAs gamma-irradiated with different doses. It can be seen that the main elements in the full spectrum were C, O, and N. The peak intensity of C1s and O1s exhibited a slight difference with the irradiation dose, while the parameters of C1s and the corresponding state changes can be deduced. The irradiation defects and relative evolution mechanism are described. Therefore, the C1s spectra of the BCPAs after gamma irradiation are analyzed in this section.
Effect and mechanism of microemulsion on low-rank coal flotation by mixing AEO-3 and diesel oil
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Zhonghua Xue, Lianping Dong, Bo Hao, Minqiang Fan, Weiwang Chen, Chongyi Yang, Haipeng Li, Sijie Li, Hongli Yang
X-ray photoelectron spectroscopy (XPS) is based on the principle that because different elements have different electron binding energies, the elements contained in a sample can be identified based on the photoelectron absorption peaks. Samples were tested using a Thermo Fischer ESCALAB 250Xi X-ray photoelectron spectrometer (USA), and the types and contents of the oxygen-containing functional groups could be determined via C1s peak fitting. The binding energy was corrected based on the 284.8 eV carbon-carbon bond in the carbon element.