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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Contrasting transient photocurrent characteristics for thin films of vacuum-doped ``grey{''} TiO2 and ``grey{''} Nb2O5

Texto completo
Autor(es):
de Araujo, Moises A. [1, 2] ; Gromboni, Murilo F. [2] ; Marken, Frank [1] ; Parker, Stephen C. [1] ; Peter, Laurence M. [1] ; Turner, Josh [3] ; Aspinall, Helen C. [3] ; Black, Kate [3] ; Mascaro, Lucia H. [2]
Número total de Autores: 9
Afiliação do(s) autor(es):
[1] Univ Bath, Dept Chem, Claverton Down, Bath BA2 7AY, Avon - England
[2] Univ Fed Sao Carlos, Dept Chem, Rod Washigton Luiz, Km235, BR-13565905 Sao Carlos, SP - Brazil
[3] Univ Liverpool, Sch Engn, Liverpool L69 3GH, Merseyside - England
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: APPLIED CATALYSIS B-ENVIRONMENTAL; v. 237, p. 339-352, DEC 5 2018.
Citações Web of Science: 1
Resumo

Photo-catalytic performance for oxide films, here for inkjet-printed TiO2 (ca. 1 mu m thickness on PTO) and for spray-pyrolysis-coated Nb2O5 (ca. 1 mu m thickness on PTO), is affected by oxygen vacancies that form during vacuum-heat treatment at 550 degrees C. The effects of the oxygen vacancies are associated with formation of Ti(III) and Nb(IV) sites, respectively, and therefore optically visible as ``grey{''} coloration. Photo-electrochemical light-on-off transient experiments are performed in the limit of thin film photoanodes, where front and back illumination result in the same photo-current responses (Le. with negligible effects from internal light absorption gradients). It is shown that generally the magnitude of photo-currents correlates linearly with light intensity, which is indicative of dominant ``photo-capacitive{''} behaviour. At an applied voltage of 0.4 V vs. SCE (in the plateau region of the photo-current responses) the potential and also the pH (going from 1.0 M KOH to 0.1 M HClO4 in the presence of methanol quencher) have no significant effect on photo-currents; that is, surface chemical/kinetic effects appear to be unimportant and interfacial hole transfer may be rate limiting. Under these conditions (and based on a simplistic mechanistic model) changes in photo-currents introduced by oxygen vacancy doping (detrimental for TiO2 and beneficial for Nb2O5) are assigned primarily to changes in electron mobility. (AU)

Processo FAPESP: 16/12681-0 - Obtenção e caracterização de filmes finos do semicondutor ternário sulfeto de antimônio e estanho, TAS (T=estanho,A=antimônio e S=enxofre), para aplicação em células fotovoltaicas
Beneficiário:Moisés Albuquerque de Araújo
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
Beneficiário:Elson Longo da Silva
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 14/50249-8 - Green chemistry: sustainable synthetic methods employing benign solvents, safer reagents, and bio-renewable feedstock
Beneficiário:Arlene Gonçalves Corrêa
Linha de fomento: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia