Kinetics of oxygen evolution at alpha-Fe2O3 photoanodes: a study by photoelectrochemical impedance spectroscopy

Closed access. This article was published in the journal, Physical Chemistry Chemical Physics [© Royal Society of Chemistry] and the definitive version is available at: http://dx.doi.org/10.1039/C0CP02408BPhotoelectrochemical Impedance Spectroscopy (PEIS) has been used to characterize the kinetics of electron transfer and recombination taking place during oxygen evolution at illuminated polycrystalline α-Fe2O3 electrodes prepared by aerosol-assisted chemical vapour deposition from a ferrocene precursor. The PEIS results were analysed using a phenomenological approach since the mechanism of the oxygen evolution reaction is not known a priori. The results indicate that the photocurrent onset potential is strongly affected by Fermi level pinning since the rate constant for surface recombination is almost constant in this potential region. The phenomenological rate constant for electron transfer was found to increase with potential, suggesting that the potential drop in the Helmholtz layer influences the activation energy for the oxygen evolution process. The PEIS analysis also shows that the limiting factor determining the performance of the α-Fe2O3 photoanode is electron–hole recombination in the bulk of the oxide

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

Vapor Phase Processing of α-Fe2O3Photoelectrodes for Water Splitting: An Insight into the Structure/Property Interplay

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

An introduction to the Slovene language

Prispevek je rayvojni pregled slovenskega jezika od začetkov do danes. Kronološko predstavlja obdobijske normativno-razlagalne faze od izvora in poimenovanja slovenščine prek prvih zapisov in postopnega pravorečno- pravopisnega normiranja do slovničnih opisov in razlag in več- ali dvojezičnih slovarjev ter enojezičnih razlagalnih slovarjev slovenščine.The article is a survey of the development of Slovene language from its beginnings to the present. Chronologically, it presents normative-descriptive phases from its origins and the name "Slovene"its first recordings and gradual orthoepic-orthographic normalization to grammar descriptions and explanations and multi- or bi-lingual dictionaries to monolingual dictionaries of Slovene