Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes
Mesoscopic anatase nanocrystalline TiO2 (nc-TiO2) electrodes play effective and efficient catalytic roles in photoelectrochemical (PEC) H2O oxidation under short circuit energy gap excitation conditions. Interfacial molecular orbital structures of (H2O)3 &OH(TiO2)9H as a stationary model u...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2015-05-01
|
Series: | Molecules |
Subjects: | |
Online Access: | http://www.mdpi.com/1420-3049/20/6/9732 |
id |
doaj-7d9629f5217a4006bb397adc672c7b09 |
---|---|
record_format |
Article |
spelling |
doaj-7d9629f5217a4006bb397adc672c7b092020-11-24T22:19:02ZengMDPI AGMolecules1420-30492015-05-012069732974410.3390/molecules20069732molecules20069732Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 ElectrodesShozo Yanagida0Susumu Yanagisawa1Koichi Yamashita2Ryota Jono3Hiroshi Segawa4Frontier Research Institute, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, JapanDepartment of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1, Senbaru, Nishihara, Okinawa 903-0213, JapanDepartment of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, JapanDepartment of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, JapanResearch Center for Advance Science and Technology, The university of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, JapanMesoscopic anatase nanocrystalline TiO2 (nc-TiO2) electrodes play effective and efficient catalytic roles in photoelectrochemical (PEC) H2O oxidation under short circuit energy gap excitation conditions. Interfacial molecular orbital structures of (H2O)3 &OH(TiO2)9H as a stationary model under neutral conditions and the radical-cation model of [(H2O)3&OH(TiO2)9H]+ as a working nc-TiO2 model are simulated employing a cluster model OH(TiO2)9H (Yamashita/Jono’s model) and a H2O cluster model of (H2O)3 to examine excellent H2O oxidation on nc-TiO2 electrodes in PEC cells. The stationary model, (H2O)3&OH(TiO2)9H reveals that the model surface provides catalytic H2O binding sites through hydrogen bonding, van der Waals and Coulombic interactions. The working model, [(H2O)3&OH(TiO2)9H]+ discloses to have a very narrow energy gap (0.3 eV) between HOMO and LUMO potentials, proving that PEC nc-TiO2 electrodes become conductive at photo-irradiated working conditions. DFT-simulation of stepwise oxidation of a hydroxide ion cluster model of OH−(H2O)3, proves that successive two-electron oxidation leads to hydroxyl radical clusters, which should give hydrogen peroxide as a precursor of oxygen molecules. Under working bias conditions of PEC cells, nc-TiO2 electrodes are now verified to become conductive by energy gap photo-excitation and the electrode surface provides powerful oxidizing sites for successive H2O oxidation to oxygen via hydrogen peroxide.http://www.mdpi.com/1420-3049/20/6/9732DFTHOMOLUMOspin densityconductivityTiO2 photocatalysisDSCHonda/Fujishima effect |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Shozo Yanagida Susumu Yanagisawa Koichi Yamashita Ryota Jono Hiroshi Segawa |
spellingShingle |
Shozo Yanagida Susumu Yanagisawa Koichi Yamashita Ryota Jono Hiroshi Segawa Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes Molecules DFT HOMO LUMO spin density conductivity TiO2 photocatalysis DSC Honda/Fujishima effect |
author_facet |
Shozo Yanagida Susumu Yanagisawa Koichi Yamashita Ryota Jono Hiroshi Segawa |
author_sort |
Shozo Yanagida |
title |
Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes |
title_short |
Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes |
title_full |
Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes |
title_fullStr |
Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes |
title_full_unstemmed |
Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes |
title_sort |
theoretical verification of photoelectrochemical water oxidation using nanocrystalline tio2 electrodes |
publisher |
MDPI AG |
series |
Molecules |
issn |
1420-3049 |
publishDate |
2015-05-01 |
description |
Mesoscopic anatase nanocrystalline TiO2 (nc-TiO2) electrodes play effective and efficient catalytic roles in photoelectrochemical (PEC) H2O oxidation under short circuit energy gap excitation conditions. Interfacial molecular orbital structures of (H2O)3 &OH(TiO2)9H as a stationary model under neutral conditions and the radical-cation model of [(H2O)3&OH(TiO2)9H]+ as a working nc-TiO2 model are simulated employing a cluster model OH(TiO2)9H (Yamashita/Jono’s model) and a H2O cluster model of (H2O)3 to examine excellent H2O oxidation on nc-TiO2 electrodes in PEC cells. The stationary model, (H2O)3&OH(TiO2)9H reveals that the model surface provides catalytic H2O binding sites through hydrogen bonding, van der Waals and Coulombic interactions. The working model, [(H2O)3&OH(TiO2)9H]+ discloses to have a very narrow energy gap (0.3 eV) between HOMO and LUMO potentials, proving that PEC nc-TiO2 electrodes become conductive at photo-irradiated working conditions. DFT-simulation of stepwise oxidation of a hydroxide ion cluster model of OH−(H2O)3, proves that successive two-electron oxidation leads to hydroxyl radical clusters, which should give hydrogen peroxide as a precursor of oxygen molecules. Under working bias conditions of PEC cells, nc-TiO2 electrodes are now verified to become conductive by energy gap photo-excitation and the electrode surface provides powerful oxidizing sites for successive H2O oxidation to oxygen via hydrogen peroxide. |
topic |
DFT HOMO LUMO spin density conductivity TiO2 photocatalysis DSC Honda/Fujishima effect |
url |
http://www.mdpi.com/1420-3049/20/6/9732 |
work_keys_str_mv |
AT shozoyanagida theoreticalverificationofphotoelectrochemicalwateroxidationusingnanocrystallinetio2electrodes AT susumuyanagisawa theoreticalverificationofphotoelectrochemicalwateroxidationusingnanocrystallinetio2electrodes AT koichiyamashita theoreticalverificationofphotoelectrochemicalwateroxidationusingnanocrystallinetio2electrodes AT ryotajono theoreticalverificationofphotoelectrochemicalwateroxidationusingnanocrystallinetio2electrodes AT hiroshisegawa theoreticalverificationofphotoelectrochemicalwateroxidationusingnanocrystallinetio2electrodes |
_version_ |
1725780402076909568 |