title: Vapor Phase Processing of α-Fe₂O₃ Photoelectrodes for Water Splitting: An Insight into the Structure/Property Interplay.
abstract: Harvesting radiant energy to trigger water photoelectrolysis and produce clean hydrogen is receiving increasing attention in the search of alternative energy resources. In this regard, hematite (α-Fe2O3) nanostructures with controlled nano-organization have been fabricated and investigated for use as anodes in photoelectrochemical (PEC) cells. The target systems have been grown on conductive substrates by plasma enhanced-chemical vapor deposition (PE-CVD) and subjected to eventual ex situ annealing in air to further tailor their structure and properties. A detailed multitechnique approach has enabled to elucidate the interrelations between system characteristics and the generated photocurrent. The present α-Fe2O3 systems are characterized by a high purity and hierarchical morphologies consisting of nanopyramids/organized dendrites, offering a high contact area with the electrolyte. PEC data reveal a dramatic response enhancement upon thermal treatment, related to a more efficient electron transfer. The reasons underlying such a phenomenon are elucidated and discussed by transient absorption spectroscopy (TAS) studies of photogenerated charge carrier kinetics, investigated on different time scales for the first time on PE-CVD Fe2O3 nanostructures.
authors: †Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.
authors: Michael E A
authors: ME
authors: Warwick
authors: ‡Department of Chemistry and Bioengineering, Tampere University of Technology, 33101 Tampere, Finland.
authors: Kimmo
authors: K
authors: Kaunisto
authors: §CNR-IENI, Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.
authors: Davide
authors: D
authors: Barreca
authors: †Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.
authors: Giorgio
authors: G
authors: Carraro
authors: †Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.
authors: Alberto
authors: A
authors: Gasparotto
authors: †Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy.
authors: Chiara
authors: C
authors: Maccato
authors: ∥Chemistry for Technologies Laboratory, University of Brescia, 25123 Brescia, Italy.
authors: Elza
authors: E
authors: Bontempi
authors: ⊥Department of Physics and Astronomy, Padova University, 35131 Padova, Italy.
authors: Cinzia
authors: C
authors: Sada
authors: ‡Department of Chemistry and Bioengineering, Tampere University of Technology, 33101 Tampere, Finland.
authors: Tero-Petri
authors: TP
authors: Ruoko
authors: #EMAT, University of Antwerp, 2020 Antwerpen, Belgium.
authors: Stuart
authors: S
authors: Turner
authors: #EMAT, University of Antwerp, 2020 Antwerpen, Belgium.
authors: Gustaaf
authors: G
authors: Van Tendeloo
keywords: PE-CVD; PEC; hematite; hierarchical structures; transient absorption spectroscopy; water splitting