Local- and intermediate-range atomic structures were investigated on amorphous phases of an ordinary phase-change material, Ge₂Sb₂Te₅ (GST), and an exotic one, Cu₂GeTe₃ (CGT), by using anomalous X-ray scattering close to K absorption edges of each element to find a fast amorphous-crystalline phase-change mechanism. The obtained data were analyzed by using reverse Monte Carlo modeling to obtain partial structure factors, partial pair distribution functions, and three-dimensional atomic configurations. Ring statistics were carefully examined to clarify the similarity and difference compared with the corresponding crystal structures, and it was found that amorphous GST has a number of four-membered rings indicating fragments of crystal structure, and amorphous CGT has a remarkable number of three-membered rings showing a collapse of crystal structures composed of purely six-membered rings. A persistent homology analysis was carried out and long-range ring structures of the constituent elements were observed in the amorphous phase, which may originate from fragments of crystal structures with a long-range periodicity.

Dibenzazepine-containing polymers were prepared by various polymerization methods and the effects of adding the obtained polymers to plastics were investigated. Dibenzazepine homopolymers were prepared by the oxidative polymerization of commercially available dibenzazepine derivatives and by the dehalogenative polymerization of corresponding dibromodibenzazepines. Dibenzazepine copolymers were prepared from dibromodibenzazepines. The addition of polymers to plastics afforded fluorescent function to them. The fluorescent behavior of a blend composite depended not only on the chemical structure of the polymers, but also on the plastic used as the matrix. The effects of adding dibenzazepine-containing polymer in plastic blends were investigated. When the compatibility of the plastic blend was higher, the fluorescence λ_max of the blend became shorter. This suggested that the method using a dibenzazepine-containing polymer is adaptive for estimating of the compatibility of the blend composite by the simple method.

A key requirement in developing oxygen evolution reaction (OER) electrocatalysts is increasing their surface area. Herein, we report the design of a hierarchical micro/nanostructured catalyst. Based on polystyrene colloidal template electrodeposition, an ordered microcup array surrounded by nanoflakes was fabricated. The effect of the deposition time on the formation of the catalyst and the corresponding OER performance of the catalyst were investigated using scanning electron microscopy, in situ X-ray absorption fine structure (XAFS) spectroscopy, and electrochemical analysis. The in situ XAFS measurements indicate that the structure of the hierarchical structured catalyst is similar to that of γ-FeOOH. The electrochemical analysis indicates that the hierarchical catalyst has a large surface area and a low charge transfer resistance, which lead to its excellent catalytic performance for the OER. Our study provides new insights in designing high-performance OER catalysts. Moreover, the synthesized hierarchical micro/nanostructured catalyst could be used as a platform for further studies on low-cost iron-based electrocatalysts.

Electrochemical water splitting using renewable energy shows promise for the development of sustainable hydrogen production methods. The process requires a highly active electrocatalyst for oxygen evolution to improve the overall water splitting efficiency. The present study showed that oxygen evolution improved dramatically upon the addition of glycine to cobalt phosphate, when the glycine was added to the electrolyte solution during electrodeposition. The functionality of the organic molecules was investigated using in situ UV-vis absorption, in situ X-ray absorption fine structure, and in situ infrared (IR) absorption spectroscopy in the attenuated total reflection mode. The results demonstrated that the glycine molecules assembled cobalt oxide clusters composed of CoO₆ (CoOOH) octahedrons a few nanometers in diameter upon the electrodeposition of cobalt catalysts. This suggests that the cobalt-glycine catalyst can decompose water to oxygen gas efficiently, because the number of cobalt oxide clusters increased as active reaction sites upon the addition of glycine molecules.

Group 2, 3, and 13 element-doped zirconium oxide catalysts M-ZrO₂ (M = Mg, Sr, Y, La, Ce, Sm, Er, Yb, B, Al, Ga, In, and Tl; 5 mol%) were prepared by impregnation of each metal salt aqueous solution on amorphous zirconium hydroxide, followed by calcination at 773 K. The M-ZrO₂ samples were characterized by the catalytic performance of 2-butanol decomposition at 573 K, XRD, XANES and EXAFS spectroscopic techniques. Detailed analyses were performed herein for a series of Ga–ZrO₂ with various doping amounts in the range of 1 – 60 mol%. The addition of Group 2 and 3 elements little influenced the catalytic performance of ZrO₂ itself to promote dehydration to produce 1-butene with 90% selectivity. Ga–ZrO₂ and In–ZrO₂ gave methyl ethyl ketone as the main product via dehydrogenation. The doped Ga ion mainly existed inside the bulk of zirconia by forming the Ga_xZr_1–xO₂ solid solution up to 5 mol%. Highly doped species more than 10 mol% aggregated to form ε-Ga₂O₃. Each fraction forming the solid solution and Ga₂O₃-like species was evaluated by XANES analysis.

Dispersive X-ray absorption fine structure (DXAFS) spectroscopy is a versatile measurement technique for analyzing chemical reactions in real time. We have developed a novel time-resolved DXAFS instrument based on two polychromators and a wide-range position-sensitive detector that permits direct observation of the synergistic effects of two elements. This system enables simultaneous acquisition of the X-ray absorption spectra for two different elements without any mechanical movement of the X-ray optics. The developed system was successfully applied to monitor both the synthesis of a Ni–Cu bimetallic catalyst, which revealed that the reduction of Ni occurred at a higher temperature than that of Cu, and the charge–discharge processes of a Li_xNi_0.5Mn_1.5O₄-based lithium-ion battery, which demonstrated that the redox reactions of Ni and Mn occurred sequentially at specific electrode potentials.

The elucidation of the mechanism for steel corrosion under a coating layer has been attracting research attention. Herein, we utilized a confocal micro-X-ray fluorescence (XRF) analytical instrument to conduct non-destructive elemental analysis near the surface of a steel sheet. Using this method, elemental map images of steel sheet cross sections were obtained without sample destruction. To confirm corrosion suppression in the presence of Mg ions, we observed the corrosion behavior of hot-dip galvanized steel sheets immersed in an aqueous NaCl solution to which Mg ions were added. By using the confocal micro XRF system, the elution of the coating components and the precipitation process of the corrosion products were confirmed.

Regulating the nanostructure of composite nanoparticles is essential for making them suitable for various applications. In general, the chemical reduction method is employed for preparing metal nanoparticles in the liquid phase. However, complicated techniques are required to control the nanostructure during particle synthesis. The evaporation/condensation method is used for synthesizing nanoparticles in the vapor-phase. Although this method produces impurity-free particles without aggregation, very few studies have been carried out on the synthesis of composite particles in the vapor-phase. In this study, we synthesized composite nanoparticles in the vapor-phase by using the evaporation/condensation method. The results showed that bimetallic nanoparticles are produced by this method. Moreover, it was indicated that the nanostructure of the synthesized nanoparticles is influenced by the order of the electric furnace with different temperatures.

The electrochemical and photophysical properties of a heteroleptic Cu(I) complex bearing an aliphatic α-diimine ligand, [Cu(dab)(xantphos)]⁺ (Cu-dab; dab = N,N′-diphenyl-2,3-dimethyl-1,4-diazabutadiene, xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene), were evaluated together with those of complexes [Cu(dmp)(xantphos)]⁺ (Cu-dmp; dmp = 2,9-dimethyl-1,10-phenanthroline), [Cu(dmbpy)(xantphos)]⁺ (Cu-dmbpy; dmbpy = 5,5′-dimethyl-2,2′-bipyridine), and [Cu(bq)(xantphos)]⁺ (Cu-bq; bq = 2,2′-biquinoline), bearing aromatic diimine ligands. Cu-dab exhibited a two-step ligand-centered redox behavior, where the first wave corresponded to an electrochemically reversible one-electron reduction process. Although Cu(I)-aromatic diimine complexes Cu-dmp, Cu-dmbpy, and Cu-bq exhibited obvious luminescence from the metal-to-ligand charge transfer (MLCT) excited state, Cu-dab did not show any luminescence. Computational studies indicated that this non-luminescent property was caused by the large structural relaxation of Cu-dab during photoexcitation.

Insoluble sulfur (IS), used as a vulcanizing reagent of rubber, is prepared by the thermal ring-opening polymerization of sulfur (S₈). Enhancing its thermal stability and content ratio (yield) is important for the industrial production of IS. The post-heating process at a high temperature of 70 or 90°C of the mixture of IS and S₈ enhanced the thermal stability of IS and reduced the yield of IS. Further, the process at 30°C enhanced its thermal stability and maintained its yield. Since the thermal stability of IS is considered to be closely related to the chain length of polymer sulfur, a method for determining the chain length of IS was investigated by quantifying the amount of electron spin of radicals from sulfur, estimated from electron spin resonance (ESR) measurements. We confirmed that the long-period post-heating process at 30°C induced high thermal stability without reducing the yield of IS due to growth of the sulfur polymer chains.

A novel sulfonated cellulose-magnetite (Fe₃O₄) composite sorbent was prepared and applied for the removal of Cu²⁺ ions from an aqueous solution. It was characterized by infrared spectroscopy, X-ray fluorescence, elemental analysis, SEM, VSM and X-ray photoelectron spectroscopy. The effect of the sorbent dose, initial solution pH, and temperature on Cu²⁺ removal were studied. The removal of the Cu²⁺ was completed in 15 min, and the sorption kinetics of Cu²⁺ was found to follow a pseudo-second-order kinetic model. An equilibrium test demonstrated that sorption of Cu²⁺ onto a hybrid sorbent agreed well with the Langmuir adsorption model for a maximum adsorption capacity of 4.2 mg/g. Moreover, the optimum pH for Cu²⁺ removal was found to be ≥4. Furthermore, the thermodynamic parameters reveal the feasibility, spontaneity and endothermic nature of the sorption process. In addition, Cu²⁺ ions can be desorbed from the sorbent with a 0.5 M H₂SO₄ solution.

A preconcentration technique with a magnetite-kaolin adsorbent capable of magnetic separation was developed for the determination of rhodium in environmental samples. The magnetite-kaolin nanocomposite was prepared for the preconcentration of rhodium in an aqueous solution prior to an electrothermal atomic absorption spectrometric determination. The detection limit (3S/N) of rhodium was 16 pg mL⁻¹ under the optimum conditions. Even though matrix elements existed in 10³ fold excess in aqueous solution, the rhodium adsorption could be not affected by the matrix. The present method could be applied to the determination of Rh in an aqueous solution. The advantages are easy preparation of the adsorbent and fast magnetic separation.

Attenuated total reflectance–far ultraviolet (ATR-FUV) spectra of Li⁺ and polyether ligands, such as glymes and poly (ethylene glycol) (PEG), in solution give information about changes in the electronic states of the ligands. From the ATR-FUV spectra, the coordination numbers between Li⁺ and monoglyme, diglyme, triglyme, and PEG400 were determined to be 4, 5, 6, and 5, respectively. Our results indicate that Li⁺ is coordinated only by the ligands rather than its counter-ions.

Soft X-ray absorption spectroscopy (XAS) involving excitation processes of a core electron to unoccupied states is an effective method to study local structures around excited C, N, and O atoms in liquid samples. Since soft X-rays are strongly absorbed by air and liquid itself, we have developed transmission-type liquid flow cells, where the absorbance of liquid samples can be easily reduced and optimized by controlling the liquid thickness. By using the transmission-mode XAS techniques, we have investigated local structures of several liquid samples such as concentration dependence of aqueous pyridine solutions and unexpected temperature-dependent structural changes in liquid benzene from the precise energy shift measurements in XAS spectra with the help of molecular dynamics simulation and inner-shell calculations. These XAS techniques are also applied to in situ/operando observation of chemical processes in solutions such as catalytic and electrochemical reactions.

The Python programing language is becoming a promising tool for data analysis in various fields. However, little attention has been paid to using Python in the field of analytical chemistry, though recent advances in instrumental analysis require robust and reliable data analysis. In order to overcome the difficulty in accurate analysis, multivariate analysis, or chemometrics, has been widely applied to various kinds of data obtained by instrumental analysis. In the present work, the potential usefulness of Python for chemometrics and related fields in chemistry is reviewed. Many practical tools for chemometrics, e.g., principal component analysis (PCA), partial least squares (PLS), support vector machine (SVM), etc., are included in the scikit-learn machine learning (ML) library for Python. Other useful libraries such as pyMCR for multivariate curve resolution (MCR), 2Dpy for two-dimensional correlation spectroscopy (2D-COS), etc. can be obtained from GitHub. For these reasons, a computational environment for chemometrics is easily constructed in Python.

A systematic study on the EDXRF determination of multi-elements using fusion bead specimens and a universal calibration procedure was carried out. Beads of multi-elements were prepared by mixing MERCK multi-elemental standard solutions with the fusion flux. The elemental X-ray lines of K, Ca, Ba, Cr, Mn, Fe, Co, Ni, Cu and Zn were excited using a Ge secondary target and that of Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Pb, Bi and Sr using a Rh primary target. The relative sensitivities of the elemental X-ray lines obtained using different excitation modes were calculated using a single bead. Using this relative sensitivity, the concentration of elements in other bead samples was determined. The average precision obtained was 3% (1 s) and the average deviation from expected values, calculated on the basis of sample preparation, was 6%. In order to further countercheck the validity of this methodology, a standard soil sample received from IAEA was analyzed.

Purine metabolism in the human body leads to the production of uric acid (UA) at the end. But an abnormal level of UA in the human body creates health problems. The sensing and quantification of UA is essentially required to prevent and diagnose hypertension, arthritis, gout, hyperuricemia or Lesch–Nyhan syndrome, etc. Herein, the development of a sensing platform for the measurement of UA using Au nanoparticle-based hybrid self-assembly is described. The self-assembling of a thiol-terminated silicate network functionalized graphene oxide hybrid on a polycrystalline Au surface yields a three-dimensional assembly. The oxygen functionalities of the self-assembly were partially reduced by an NaBH₄ treatment. The free –SH groups of the self-assembly were successfully used for the immobilization of Au nanoparticles by chemisorption. The nanoparticle-based hybrid self-assembly is highly sensitive toward UA, and shows a wide linear response with a detection limit of 40 nM UA (S/N = 7) without interference from co-exiting ascorbic acid. Its practical application was demonstrated using human serum samples.

A highly sensitive and selective electrochemical sensor has been fabricated by the electrodepositing of nickel hexacyanoferrate (NiHCF) on a Ni–Al layered double hydroxides (Ni–Al–LDH) modified Au electrode for the quantification of doxorubicin hydrochloride (DOX). The characterization of synthesized nanomaterials has been conducted by scanning electron microscopy, energy dispersive X-ray spectroscopy and electrochemical methods. The synergistic effect of NiHCF and Ni–Al–LDH not only excellently improves the performance of DOX electro-reduction, but also promotes electron transfer between DOX and the NiHCF/Ni–Al–LDH/Au sensor. The differential pulse voltammetric response of the NiHCF/Ni–Al–LDH/Au sensor shows a linear relationship with the concentration of DOX in the range of 1.0 × 10⁻⁸ – 6.2 × 10⁻⁶ mol L⁻¹, a limit of detection of 1.9 × 10⁻⁹ mol L⁻¹ (S/N = 3) and a sensibility of 14.71 A mol L⁻¹ cm⁻². The developed sensor exhibits good sensitivity, reproducibility, anti-interference and a long-term stability property. Furthermore, the NiHCF/Ni–Al–LDH/Au sensor has been successfully applied to determine DOX in biological samples and human blood serum samples.