A5031874578- Astro and Planetary Science
- Planetary Science and Exploration
- Advanced Photocatalysis Techniques
- Catalytic Processes in Materials Science
- Electrochemical Analysis and Applications
- Spectroscopy and Quantum Chemical Studies
- TiO2 Photocatalysis and Solar Cells
- X-ray Spectroscopy and Fluorescence Analysis
- Electrocatalysts for Energy Conversion
- Isotope Analysis in Ecology
- Ion-surface interactions and analysis
- Electron and X-Ray Spectroscopy Techniques
- Advancements in Battery Materials
- Advanced battery technologies research
- Nuclear Physics and Applications
- Nanomaterials for catalytic reactions
- Advanced Glycation End Products research
- Advanced X-ray Imaging Techniques
- Geological and Geochemical Analysis
- Chemical and Physical Properties in Aqueous Solutions
- Innovative Microfluidic and Catalytic Techniques Innovation
- Dermatology and Skin Diseases
- Advanced Chemical Physics Studies
- Thermodynamic properties of mixtures
- Copper-based nanomaterials and applications
Institute for Molecular Science
2016-2025
National Institutes of Natural Sciences
2020
Kyoto University
2014
Okazaki Institute for Integrative Bioscience
2014
Nagoya University
2008-2013
Abstract Volatile and organic-rich C-type asteroids may have been one of the main sources Earth’s water. Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but meteorite record biased: only strongest types survive atmospheric entry are then modified interaction with terrestrial environment. Here we present results a detailed bulk microanalytical study pristine Ryugu particles, brought to Earth Hayabusa2 spacecraft. particles display close...
The reaction mechanism of ammonia decomposition to nitrogen and hydrogen over platinum loaded titanium oxide photocatalyst was investigated through various tests, as well ESR FT-IR spectroscopies. photoformed hole on the oxidizes NH3 form amide radical (•NH2) proton. radicals produce hydrazine (N2H4), it can be further decomposed hydrogen. On other hand, electron migrates nanoparticles conduction band reduces proton yield metals with larger work function, such platinum, provide more...
Nanodiamonds exhibit exceptional colloidal properties in aqueous media that lead to a wide range of applications nanomedicine and other fields. Nevertheless, the role surface chemistry on hydration nanodiamonds remains poorly understood. Here, we probed water hydrogen bond network dispersions by infrared, Raman, X-ray absorption spectroscopies applied situ environment. Aqueous with hydrogenated, carboxylated, hydroxylated, polyfunctional terminations were compared. A different was found...
In situ O K-edge X-ray absorption fine structure (XAFS) spectroscopy was applied to investigate the electronic and structural change in nickel–borate (Ni–Bi) electrocatalyst during oxygen evolution reaction (OER). An peak observed around 528.7 eV at 1.0 V versus Ag/AgCl a potassium borate aqueous solution, which relates with formation of nanoscale order domains edge-sharing NiO6 octahedra Ni–Bi electrocatalyst. XAFS spectra were measured variation electrode potential from 0.3 up V. The peaks...
Abstract The delivery of water to the inner Solar System, including Earth, is still a debated topic. A preferential role for hydrated asteroids in this process supported by isotopic measurements. Carbonaceous chondrite (CC) meteorites represent our main source information about these volatile-rich asteroids. However, destruction weaker materials during atmospheric entry creates bias CC data. return surface from C-type asteroid 162173 Ryugu Hayabusa2 spacecraft provides unique opportunity...
Direct aromatic ring hydroxylation of benzene derivatives by using water as an oxidant over platinum-loaded titanium oxide photocatalyst proceeded with high selectivity under the light selected wavelength. Two kinds electrophilic active species, which depended on reaction condition, were proposed: a surface oxygen radical in neutral or acidic conditions and hydroxyl basic both produced photoformed hole oxide. In cases, these species can attack to form intermediate, followed formation...
The structure of interfacial water layers around nanoparticles dispersed in an aqueous environment may have a significant impact on their reactivity and interaction with biological species. Using transmission soft X-ray absorption spectroscopy liquid, we demonstrate that the unoccupied electronic states oxygen atoms from molecules colloidal dispersions nanodiamonds different signature than bulk water. can thus probe dispersions. impacts nanodiamond surface chemistry concentration are discussed.
Change in valence of Fe ions aqueous iron sulfate solutions at different potentials has been studied by L-edge soft X-ray absorption spectroscopy (XAS) transmission mode. Each XAS spectrum is measured a constant potential using liquid cell with built-in electrodes. A nonlinear oxidation Fe(II) to Fe(III) observed when the increased from 0.0 0.9 V. Two processes are found oxidation: one simple process and other involving ions. The peak latter changed scanning rates because affect electrode...
A palladium catalyst hybridised with a titanium dioxide photocatalyst can promote cyanomethylation of an aromatic ring by using acetonitrile, where the activates acetonitrile to form cyanomethyl radical before C-C bond formation catalyst.
Interaction between water molecules and alkali metal ions in aqueous salt solutions has been studied by the oxygen K-edge soft X-ray absorption spectroscopy (XAS) transmission mode. In measurement of several halide with different chlorides (Li, Na, K) sodium halides (Cl, Br, I), pre-edge component arising from hydration shows a blue shift peak energy as strongly depending on cations but not anions. temperature dependent measurement, beyond first shell same behavior that pure liquid water. On...
Abstract Micrometeorites, a possible major source of Earth’s water, are thought to form from explosive dispersal hydrated chondritic materials during impact events on their parental asteroids. However, this provenance and formation mechanism have yet be directly confirmed using asteroid returned samples. Here, we report evidence mild shock metamorphism in the surface particles Ryugu based electron microscopy. All dominated by phyllosilicates but lack dehydration textures, which indicative...
Electrophilic oxygen species photocatalytically derived from water molecules can selectively react with the aromatic ring of both benzene and its derivatives to produce corresponding phenols hydrogen over platinum-loaded titanium oxide when illuminated light appropriate wavelength in absence oxygen.
Abstract UVSOR is a Japanese low-energy synchrotron light source that has been operational since 1983. It 750 MeV electron beam energy and circumference of 53 m. The machine undergone two major upgrades now called UVSOR-III, with moderately small emittance 17 nm·rad operated in the top-up mode at 300 mA. six undulators. Three in-vacuum undulators provide high-brightness VUV-SX to beamlines BL3U, BL4U, BL6U. BL3U BL4U are actively used for chemistry life sciences using situ operando...
Water activity recorded in asteroids offers a perspective on their habitability. Aqueous alteration, namely the interaction of liquid water with minerals, occurred parent body C-type asteroid Ryugu. However, Ryugu is not wet body, and processes that led to loss along its chemical environment remain unclear. We report presence sodium carbonates, chlorides sulfates samples, which indicate alkaline, salt-rich once flowed through body. Highly concentrated brine probably formed evaporation or...
Active species generated from aqueous ammonia with a platinum-loaded titanium oxide photocatalyst can selectively aminate the aromatic ring of benzene and some substituted benzenes.
The reaction mechanism of photocatalytic aromatic ring amination benzene and the derivatives with aqueous ammonia was clarified by some experiments electron spin resonance spectroscopy as follows: a platinum-loaded titanium oxide photocatalyst oxidizes an to form amide radical (·NH2) proton, attacks produce intermediate, followed abstraction hydrogen atom from it on platinum sites aniline. Simultaneously, also promotes reduction proton sites, reacts abstracted molecular hydrogen. proceeded...
In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s cyclic voltammetry (CV), we have developed an operando observation system for by soft X-ray absorption spectroscopy (XAS) with potential modulation method. XAS spectra are measured using transmission-type liquid flow cell built-in electrodes. The electrode is swept at fixed photon energy, and coefficients different potentials time. By repeating each it...
A layered manganese oxide catalyst containing K+ cations [K/MnOx catalyst] was developed, and its ability to efficiently decompose water demonstrated. Operando hard/tender/soft X-ray absorption fine structure (XAFS) techniques were used investigate the function of K/MnOx under working conditions. The Mn valency depended on potential amount cation adsorption. K-edge (hard X-ray) XAFS measurements for suggested that in an Mn3+ species with octahedral δ-MnO2 at a lower electrode potential,...
Nitrogen K-edge X-ray absorption (XA) spectroscopy of aqueous ammonia reveals a splitting in the main-edge, which through theoretical modeling is shown to be related symmetry breaking hydrogen bonding. The XA main-edge NH3 formed by pair degenerate core-excitations into extended molecular orbitals. In solution, these form an antibonding mixture with orbitals surrounding water molecules. Although spectral response distortions complex, we show that degeneracy lifted asymmetry bond donation...