We report the photooxidation of toluene over nitrogen doped TiO(2) (TiO(2-x)N(x)) under visible light irradiation. The photocatalytic oxidation of toluene in air over TiO(2-x)N(x) powders was studied using diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), gas chromatography (GC), ion chromatography (IC), and gas chromatography mass spectrometry (GC-MS), focusing on the photocatalytic decomposition processes of toluene. Results obtained indicate that toluene, weakly adsorbed on the catalyst surface, is initially photooxidized to benzaldehyde which adsorbs onto the TiO(2-x)N(x) surface more strongly, leading to the formation of ring-opening products such as carboxylic acids and aldehydes. No gaseous intermediates were detected during the photooxidation. Major intermediates adsorbed at the catalyst surface were oxalic acid, (COOH)(2), acetic acid, CH(3)COOH, formic acid, HCOOH, and pyruvic acid, CH(3)COCOOH, whereas more complicated carboxylic species, including propionic acid, CH(3)CH(2)COOH, isovaleric acid, (CH(3))(2)CHCH(2)COOH, and succinic acid, (CH(2)COOH)(2), were also found in the early stage of the photooxidation. These intermediate products were gradually photodegraded to CO(2) and H(2)O under visible light irradiation.
received her bachelor and master degrees from Nara Women's University. She joined Toyota CRDL in 1992 and received he Ph.D. Degree from Tokyo Institute of Technology in 2009. Currently, she is a senior researcher of the Morikawa Senior Fellow Laboratory in Toyota CRDL. She has been working on development of inorganic catalyst materials for artificial photosynthesis. Takeshi MorikawaTakeshi Morikawa received his bachelor and master degrees from Nagoya University. He joined Toyota CRDL in 1989 and received his Ph.D. Degree in 2005. He has been working on development of sensors for automotive controls, magnetic materials, semiconductor photocatalyst, and CO 2 recycling systems by artificial photosynthesis. He is currently a manager of the Morikawa Senior Fellow Laboratory in Toyota CRDL. AbstractA highly crystalline, 10 nm-sized red rust water oxidation catalyst composed of pure β-phase FeOOH(Cl) nanorods (ca. 3 © 13 nm) doped with Ni ions (β-FeOOH(Cl):Ni) and surfacemodified with amorphous Ni(OH) 2 (a-Ni(OH) 2 , at a Ni to Fe ratio of 22 at.%) was synthesized by a facile one-pot process at room temperature. The overpotential during the electrochemical oxygen evolution reaction (OER) over the β-FeOOH:Ni/ a-Ni(OH) 2 stacked nanorod anodes was 170 mV, and an OER current of 10 mA/cm 2 was obtained at an overpotential of 430 mV in a 0.1 M KOH solution. X-ray absorption fine structure analysis, Mössbauer spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, X-ray diffraction and impedance spectroscopy suggested that surface modification with the a-Ni(OH) 2 lowered the OER overpotential of β-FeOOH(Cl):Ni, resulting in the very high current density at low potential compared with Fe-rich oxide and oxyhydroxide electrodes reported previously. Mössbauer spectroscopy suggested interaction between Fe and Ni species, which may be crucial evidence for the enhanced activity in the Fe-rich OER system.
Crystalline aromatic dicarboxylate, also known as intercalated metal–organic frameworks, electrodes can be used in sustainable lithium-ion batteries owing to their low resource risks and eco-friendly syntheses via CO2 sequestration. However, little consideration has been given to understanding the phase transition mechanism during electrochemical charge–discharge processes. Here, we report a comparative study on the phase transition mechanism and associated Li+ diffusivity (D Li) in crystalline aromatic dicarboxylate lithium salts with naphthalene and biphenyl frameworks by electrochemical techniques and energy-state analyses using synchrotron radiation. The naphthalene framework, with a strong Li+ interaction and two stable Li+-intercalated structures, forms an energetically stable Li+-storage state through a metastable state, predominantly providing a two-phase reaction, and, at the end of charge and discharge, a solid-solution reaction with low D Li of 10–14–10–12 cm2 s–1. In contrast, the biphenyl framework, weakly interacting with Li+, forms an energetically unstable Li+-storage state, providing a solid-solution reaction with high D Li of 10–12–10–8 cm2 s–1 over the entire region. These findings contribute toward superior stability and high-rate capability in organic electrodes.
We have developed a synthetic route that uses sodium for the production of intermetallic Pt5Ce nanoparticles (ca. 6 nm average diameter) supported on carbon powder. Sodium melt was demonstrated to reduce a powder mixture of PtCl2 and CeCl3 to form submicrometer Pt5Ce particles with the simultaneous formation of NaCl. The NaCl–CeCl3 melt mixture and Na melt were formed during heating, which led to a uniform reaction between Pt and Ce, and the melt induced grain growth. The synthetic procedures were then modified to supply sodium vapor to the vicinity of the metal sources supported on carbon powder with an aim to suppress grain growth. Pt5Ce nanoparticles were successfully formed on the carbon support with high loading and dispersity.
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