Search

Your search keyword '"Iguchi, Shoji"' showing total 95 results
Start Over Author "Iguchi, Shoji" Language english
95 results on '"Iguchi, Shoji"'

4. Surface Modifications of Heterogeneous Photocatalysts for Photocatalytic Conversion of CO2 by H2O as the Electron Donor.

Author

Nakamoto, Takechi, Iguchi, Shoji, Naniwa, Shimpei, Tanaka, Tsunehiro, and Teramura, Kentaro

Subjects
*DIRECT energy conversion, *HETEROGENEOUS catalysis, *ELECTRON donors, *PHOTOCATALYSTS, *CARBON dioxide
Abstract

The photocatalytic conversion of CO2 using H2O over heterogeneous photocatalysts has attracted worldwide attention because it enables direct solar‐to‐chemical energy conversion. However, further development of this technology requires solutions to overcome the low formation rates of CO2 reduction products and their insufficient selectivity, mainly caused by the rapid charge recombination of photogenerated electron/hole pairs, competition for thermodynamically preferential H2 evolution from H2O, and the relatively low concentration of CO2 on the surface of the photocatalysts. Surface modification of heterogeneous photocatalysts is crucial for improving their formation rates and selectivity. This review article introduces four strategies for designing photocatalyst surfaces for the photocatalytic conversion of CO2 by H2O: (I) loading of an Ag cocatalyst, (II) utilisation of cocatalysts for H2O oxidation, (III) suppression of undesired H2 evolution, and (IV) loading of basic materials for CO2 adsorption. The strategies introduced in this review successfully enhanced the formation rates of the products and/or their selectivity in the heterogeneous photocatalytic conversion of CO2 by H2O. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

5. Promoting Effect of Pd Nanoparticles on SrTi0.8Mn0.2O3 in the Reverse Water‐Gas Shift Reaction via the Mars–Van Krevelen Mechanism.

Author

Kobayashi, Minori, Naniwa, Shimpei, Goto, Keita, Matsuo, Hiroki, Iguchi, Shoji, Tanaka, Tsunehiro, and Teramura, Kentaro

Subjects
FOURIER transform infrared spectroscopy, METAL catalysts, HIGH temperatures, WATER-gas, CARBON dioxide
Abstract

The reverse water‐gas shift (RWGS) reaction serves as a critical pathway for converting CO2 into diverse chemicals. The Mars–van Krevelen (MvK) mechanism, which leverages lattice oxygen as the oxidant and oxygen vacancies as reductants, offers an alternative catalytic strategy for the selective RWGS reaction. While Mn‐substituted SrTiO3 (i. e., SrTi0.8Mn0.2O3) has been shown to promote the RWGS reaction selectively via the MvK mechanism, achieving a sufficient conversion of CO2 necessitates elevated temperatures. This study investigated the effect of Pd‐loaded SrTi0.8Mn0.2O3 on the activation of adsorbed H2 molecules, which generated oxygen vacancies and enhanced CO2 conversion. Notably, 1.0 wt % Pd‐loaded SrTi0.8Mn0.2O3 yielded 13.4 % of CO at 673 K, whereas pristine SrTi0.8Mn0.2O3 and Pd‐loaded SrTiO3 yielded negligible or minimal amount of CO. Hydrogen temperature‐programmed reduction and X‐ray absorption spectroscopy measurements revealed that Pd promoted the formation of oxygen vacancies via both thermodynamic and kinetic mechanisms. Fourier transform infrared spectroscopy and kinetic studies revealed that the RWGS reaction over Pd‐loaded SrTi0.8Mn0.2O3 proceeded primarily via the MvK mechanism with a partial contribution from the Langmuir–Hinshelwood mechanism. This study underscores the effectiveness of combining metal and MvK‐type catalysts to enhance the efficiency of the RWGS reaction. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

40. Operando EXAFS Analysis of In/SiO2 Catalyst during NMC

Author

Kashaboina, Upendar, Sirisit, Natee, Ariga-Miwa, Hiroko, Takakusagi, Satoru, Nishikawa, Yuta, Kuriyama, Ayumu, Dipu, Arnoldus Lambertus, Dipu, Arnolduslambertus, Ogihara, Hitoshi, Iguchi, Shoji, YAMANAKA, ICHIRO, Wada, Takahiro, and Asakura, Kiyotaka

Published
2019

50. Which is an Intermediate Species for Photocatalytic Conversion of CO2 by H2O as the Electron Donor: CO2 Molecule, Carbonic Acid, Bicarbonate, or Carbonate Ions?

Author

Teramura, Kentaro, Hori, Kazutaka, Terao, Yosuke, Huang, Zeai, Iguchi, Shoji, Wang, Zheng, Asakura, Hiroyuki, Hosokawa, Saburo, and Tanaka, Tsunehiro

Subjects
Carbonic acid, Denticity, Bicarbonate, Inorganic chemistry, Electron donor, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Catalysis, chemistry.chemical_compound, General Energy, chemistry, Photocatalysis, Carbonate, Molecule, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract

In the photocatalytic conversion of CO2 using H2O as the electron donor, there are four candidates of the intermediate species in the solution: hydrated CO2 molecule (CO2(aq)), carbonic acid (H2CO3), bicarbonate (HCO3–), and carbonate (CO32–) ions. The concentrations of all four species in the system at equilibrium can be controlled by controlling the temperature, pH value, and concentration of the countercation. According to our experiments conducted under different conditions, we narrowed the possible intermediates down to two: CO2(aq) and HCO3–. The isotopic experiment using 13CO2 and in situ infrared spectroscopy revealed that CO2(aq) reacts with the hydroxyl group anchored on the Ga atom on the surface of ZnGa2O4/Ga2O3 to form bidentate HCO3–Ga, followed by the formation of bidentate HCOO–Ga via monodentate HCO3–Ga. We conclude that bidentate HCOO–Ga is the real intermediate species for the photocatalytic conversion of CO2 by H2O as the electron donor over Ag/ZnGa2O4/Ga2O3 catalyst, and it decomposes...

Published
2017

Catalog

Books, media, physical & digital resources
See catalog results