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Titolo:
Photocatalytic activity of transition-metal-loaded titanium(IV) oxide powders suspended in aqueous solutions: Correlation with electron-hole recombination kinetics
Autore:
Ikeda, S; Sugiyama, N; Pal, B; Marci, G; Palmisano, L; Noguchi, H; Uosaki, K; Ohtani, B;
Indirizzi:
Hokkaido Univ, Catalysis Res Ctr, Sapporo, Hokkaido 0600811, Japan Hokkaido Univ Sapporo Hokkaido Japan 0600811 oro, Hokkaido 0600811, Japan Hokkaido Univ, Grad Sch Environm Earth Sci, Sapporo, Hokkaido 0600810, Japan Hokkaido Univ Sapporo Hokkaido Japan 0600810 oro, Hokkaido 0600810, Japan Univ Palermo, Dipartimento Ingn Chim Proc & Mat, I-90128 Palermo, Italy Univ Palermo Palermo Italy I-90128 im Proc & Mat, I-90128 Palermo, Italy Hokkaido Univ, Grad Sch Sci, Sapporo, Hokkaido 0600810, Japan Hokkaido Univ Sapporo Hokkaido Japan 0600810 oro, Hokkaido 0600810, Japan
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 2, volume: 3, anno: 2001,
pagine: 267 - 273
SICI:
1463-9076(2001)3:2<267:PAOTTO>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIFFUSE-REFLECTANCE SPECTROSCOPY; CHARGE-CARRIER DYNAMICS; LIQUID-SOLID INTERFACE; AMINO-ACID SOLUTIONS; HETEROGENEOUS PHOTOCATALYSIS; CDS COLLOIDS; SEMICONDUCTOR PHOTOCATALYSIS; WATER CLEAVAGE; ACETIC-ACID; FEMTOSECOND;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Ikeda, S Hokkaido Univ, Catalysis Res Ctr, Sapporo, Hokkaido 0600811, Japan Hokkaido Univ Sapporo Hokkaido Japan 0600811 aido 0600811, Japan
Citazione:
S. Ikeda et al., "Photocatalytic activity of transition-metal-loaded titanium(IV) oxide powders suspended in aqueous solutions: Correlation with electron-hole recombination kinetics", PHYS CHEM P, 3(2), 2001, pp. 267-273

Abstract

Photocatalytic reactions by transition-metal (V, Cr, Fe, Co, Cu, Mo, or W)loaded TiO2 (M-TiO2) powders suspended in aqueous solutions of methanol, (S)-lysine (Lys), or acetic acid were investigated. The photoactivities of various samples were compared with the rate constant (k(r)) of recombinationof photoexcited electrons and positive holes determined by femtosecond pump-probe diffuse reflection spectroscopy (PP-DRS). As a general trend, increased loading decreased the rate of formation of the main products (H-2, pipecolinic acid (PCA), and CO2) under UV (> 300 nm) irradiation, and the effect became more intense on increasing the loading. In PP-DRS, these M-TiO2 gave similar decays of absorption at 620 nm arising from excitation by a 310nm pulse (< 100 fs). The second-order rate constant (k(r)) markedly increased with loading, even at a low level (0.3%) and further increased with an increase in loading up to 5%. The photocatalytic activity of platinized M-TiO2 for H-2 and PCA production under deaerated conditions depended stronglyon k(r), but the relation between k(r) and the rate of CO2 production by unplatinized M-TiO2 under aerated conditions was ambiguous; other factor(s) might control the rate of the latter. These different k(r) dependences of photoactivity on the reaction kinetics governed by e(-)-h(+) recombination were attributed to the presence of O-2 and Pt deposits. A simple kinetic model to explain the overall rate of these photocatalytic reactions is proposed, and the effect of recombination kinetics on photoactivity is discussed.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/04/20 alle ore 09:11:52