Pt-functionalized Fe 2 O 3 photoanodes for solar water splitting: the role of hematite nano-organization and the platinum redox state

• Published in: Physical chemistry chemical physics : PCCP 2015, Vol.17 (19), p.12899-12907
• Main Authors: Warwick, M. E. A., Barreca, D., Bontempi, E., Carraro, G., Gasparotto, A., Maccato, C., Kaunisto, K., Ruoko, T.-P., Lemmetyinen, H., Sada, C., Gönüllü, Y., Mathur, S.
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/C5CP01636C

Pt/α-Fe 2 O 3 nanocomposites were synthesized on fluorine-doped tin oxide (FTO) substrates by a sequential plasma enhanced-chemical vapor deposition (PE-CVD)/radio frequency (RF) sputtering approach, tailoring the overall Pt content as a function of sputtering time. The chemico-physical properties of the as-prepared systems were extensively investigated by means of complementary techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDXS), secondary ion mass spectrometry (SIMS), and optical absorption spectroscopy, and compared to those of the homologous Pt/α-Fe 2 O 3 systems annealed in air prior and/or after sputtering. The obtained results evidenced that the material compositional, structural and morphological features, with particular regard to the Pt oxidation state and hematite nano-organization, could be finely tailored as a function of the adopted processing conditions. Pt/α-Fe 2 O 3 systems were finally tested as photoanodes in photoelectrochemical (PEC) water splitting experiments, evidencing a remarkable interplay between functional performances and the above-mentioned material properties, as also testified by transient absorption spectroscopy (TAS) results.