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Type: Artigo de evento
Title: Photoelectrochemical And Photocatalytic Properties Of Nanocrystalline Tio2 Electrodes
Author: Oliveira H.G.
Nery D.C.
Paschoalino M.P.
Jardim W.F.
Longo C.
Abstract: The electrochemical and photocatalytic properties of a TiO2 film deposited on transparent electrodes were investigated. Its electrochemical behavior was typical of an n-type semiconductor electrode. Its photocatalytic activity, investigated for phenol degradation on an optical bench (area of 1 cm2, 5 mL of solution), revealed small currents (3 μA) and poor total organic carbon (TOC) removal (5 %) when the electrode was biased at + 1.1 V in the dark for 3 h. Under polychromatic irradiation, the electrode presented 25 μA of current and 12 % of phenol degradation. A better performance was achieved for photoelectrocatalytic configuration, when the electrode was irradiated and biased with + 0.6 V. Experiments done under irradiation with a metallic vapor lamp using 9 cm2 electrodes and 10 mL of solution revealed that heterogeneous photocatalysis configuration (HPC) resulted in 50 % of TOC removal, while 85 % was achieved by the electro-assisted process (EHPC). Both the configurations exhibited pseudo-first order kinetics for phenol degradation, but the rate constant was two times that of EHPC. The application of a potential bias to the TiO2 porous electrode must enhance the photogenerated electron/hole separation, which minimize the charge recombination and increases its photocatalytic activity towards organic pollutant degradation.
Rights: aberto
Identifier DOI: 10.1117/12.734419
Date Issue: 2007
Appears in Collections:Unicamp - Artigos e Outros Documentos

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