Vapor phase processing of α-Fe2O3 photoelectrodes for water splitting : An insight into the structure/property interplay
Warwick, Michael E A; Kaunisto, Kimmo; Barreca, Davide; Carraro, Giorgio; Gasparotto, Alberto; Maccato, Chiara; Bontempi, Elza; Sada, Cinzia; Ruoko, Tero-Petri; Turner, Stuart; Van Tendeloo, Gustaaf (2015)
Warwick, Michael E A
Van Tendeloo, Gustaaf
Julkaisun pysyvä osoite on
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 (alpha-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 between system characteristics and the generated photocurrent. The present alpha-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.
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