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Author(s): Paula Dias
Tânia Lopes
Laura Meda
Luísa Andrade
Adélio Mendes
Title: Photoelectrochemical water splitting using WO3 photoanodes: The substrate and temperature roles
Issue Date: 2016
Abstract: The influence of a substrate on the performance of WO3 photoanodes is assessed as a function oftemperature. Two samples were studied: WO3 deposited on a FTO glass and anodized on a tungstenfoil. Current-voltage curves and electrochemical impedance spectroscopy measurements were used tocharacterize these samples between 25 1C and 65 1C. The photocurrent density increased with temperature for both samples and the onset potential shifted to lower potentials. However, for WO3/FTO, anegative shift of the dark current onset was also observed. The intrinsic resistivity of this substrate limitsthe photocurrent plateau potential range. On the other hand, this behavior was not observed for WO3/metal. Therefore, the earlier dark current onset observed for WO3/FTO was assigned to the FTO layer.The optimal operating temperatures observed were 45 1C and 55 1C for WO3/FTO and WO3/metal,respectively. For higher temperatures, the bulk electron-hole recombination phenomenon greatly affectsthe overall performance of WO3 photoanodes. The stability behavior was then studied at these temperatures over 72 h. For WO3/FTO, a crystalline-to-amorphous phase transformation occurred during thestability test, which may justify the current decrease observed after the aging period. The WO3/metalremained stable, maintaining its morphology and good crystallinity. Interestingly, the preferential orientation of the aged crystals was shifted to the (222) and (222) planes, suggesting that this was responsiblefor its better and more stable performance. These findings provide crucial information for allowing furtherdevelopments on the preparation of WO3 photoanodes, envisaging their commercial application in PECwater splitting cells.
Subject: Engenharia química, Engenharia química
Chemical engineering, Chemical engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia química
Engineering and technology::Chemical engineering
Related Information: info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projectos de I&DT em Todos os Domínios Científicos/PTDC/EQU-EQU/107990/2008/Células fotoelectroquímicas para produção de hidrogénio a partir de energia solar/H2Solar
info:eu-repo/grantAgreement/COMISSÃO EUROPEIA/7.º Programa-Quadro de IDT/227179 /Nanostructured photoelectrodes for energy conversion/NanoPEC
info:eu-repo/grantAgreement/COMISSÃO EUROPEIA/7.º Programa-Quadro de IDT/321315/Building Integrated Dye Sensitized Solar Cells/BI-DSC
info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/UID/EQU/00511/2013 - POCI-01-0145-FEDER-006939/Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia/LEPABE
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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