Photoelectrochemical water splitting using WO3 photoanodes: The substrate and temperature roles

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Paula Dias (Author) FEUP; Tânia Lopes (Author) FEUP; Laura Meda (Author) Other; Luísa Andrade (Author) FEUP; Adélio Mendes (Author) FEUP

Journal

Title: Physical Chemistry Chemical Physics

Serial No. 7 Vol. 18

Pages: 5232-5243

ISSN: 1463-9076

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 46 Citations

ISI Web of Science

Scopus - 78 Citations

Scientific classification

CORDIS: Technological sciences > Engineering > Chemical engineering

FOS: Engineering and technology > Chemical engineering

Associated Projects

H2Solar - Células fotoelectroquímicas para produção de hidrogénio a partir de energia solar

NanoPEC - Nanostructured photoelectrodes for energy conversion

LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia

BI-DSC - Building Integrated Dye Sensitized Solar Cells

Other information

Authenticus ID: P-00K-6VJ

DOI: 10.1039/c5cp06851g

Abstract (EN): The influence of a substrate on the performance of WO3 photoanodes is assessed as a function of temperature. Two samples were studied: WO3 deposited on a FTO glass and anodized on a tungsten foil. Current–voltage curves and electrochemical impedance spectroscopy measurements were used to characterize 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, a negative shift of the dark current onset was also observed. The intrinsic resistivity of this substrate limits the 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 affects the 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 the stability test, which may justify the current decrease observed after the aging period. The WO3/metal remained 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 responsible for its better and more stable performance. These findings provide crucial information for allowing further developments on the preparation of WO3 photoanodes, envisaging their commercial application in PEC water splitting cells.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12