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Titolo:
The photocatalytic oxidation of water to O-2 over pure CeO2, WO3, and TiO2using Fe3+ and Ce4+ as electron acceptors
Autore:
Bamwenda, GR; Uesigi, T; Abe, Y; Sayama, K; Arakawa, H;
Indirizzi:
Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan Natl Inst Mat & Chem Res Tsukuba Ibaraki Japan 3058565 aki 3058565, Japan Sci Univ Tokyo, Fac Sci & Technol, Noda, Chiba, Japan Sci Univ Tokyo NodaChiba Japan o, Fac Sci & Technol, Noda, Chiba, Japan
Titolo Testata:
APPLIED CATALYSIS A-GENERAL
fascicolo: 1-2, volume: 205, anno: 2001,
pagine: 117 - 128
SICI:
0926-860X(20010108)205:1-2<117:TPOOWT>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
IRON(III) IONS; SUSPENSION;
Keywords:
photocatalysis; oxygen production; cerium dioxide; titanium dioxide; tungsten oxide; ferric and ceric ions;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
22
Recensione:
Indirizzi per estratti:
Indirizzo: Arakawa, H Natl Inst Mat & Chem Res, 1-1 Higashi, Tsukuba, Ibaraki 3058565, Japan Natl Inst Mat & Chem Res 1-1 Higashi Tsukuba Ibaraki Japan 3058565
Citazione:
G.R. Bamwenda et al., "The photocatalytic oxidation of water to O-2 over pure CeO2, WO3, and TiO2using Fe3+ and Ce4+ as electron acceptors", APP CATAL A, 205(1-2), 2001, pp. 117-128

Abstract

We report here the results from a study on the photocatalytic decomposition of water to oxygen over pure WO3, CeO2, and TiO2. It has been demonstrated that Fe-aq(3+) and Ce-aq(4+) species are efficient electron accepters during the photoproduction of O-2 over a variety of oxides, even at very low concentrations. The O-2 yield was found to depend on the type and surface activity of the cation used as an electron acceptor, and the salt counter anion, While Ce-aq(4+) gives slightly higher initial O-2 rates, Fe-aq(3+) tends to give higher long-term O-2 yields. The O-2 yield was found to be mainlysensitive to the intrinsic properties of a given material, such as the type of the oxide used and its physicochemical characteristics, e.g. crystal structure and level of crystallinity. For the powders tested, O-2 productionwas independent of the BET surface area and the activity does not correlate directly with the onset of light absorption of the powders. With a light having lambda greater than or equal to 330 nm, O-2 production activity decreased in the order TiO2-rutile>TiO2-anatase>WO3>CeO(2)much greater than amorphous TiO2, whereas with a light having lambda greater than or equal to 420 nm, it decreased in the order WO3>TiO2>CeO2. Small amounts of Sn on TiO2-rutile markedly improved its activity. In addition, the O-2 yield strongly depended on the concentration of the electron acceptor and the pH of the suspension. During the reaction, small amounts of hydrogen were also produced. The reaction pathways for electron scavenging by Ce-aq(4+) and Fe-aq(3+),and the process leading to O-2 evolution will be discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 10/04/20 alle ore 15:37:56