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SYEM: Symposium Emerging Materials for Renewable Energy Conversion

SYEM 1: Emerging Materials for Renewable Energy Conversion

SYEM 1.2: Hauptvortrag

Mittwoch, 20. März 2024, 10:00–10:30, H 0105

Strategies for the morphological design of photoactive oxynitride particles and electrodes for solar water-splitting. — •Simone Pokrant — Chemistry and Physics of Materials, Paris-Lodron University Salzburg, Austria

More than 50 years after the first demonstration of photocatalytic water-splitting by Fujishima and Honda in 1972, the exploitation of photocatalytic and photoelectrochemical water-splitting for solar fuel production is still hindered by an unfavorable device-efficiency-versus-cost ratio. For these applications high active surface areas and favorable charge transport properties are key features to enhance device performance. Acceptable charge transport properties are usually obtained in defect free structures such as single crystals, where the surface area is small in comparison to agglomerates of porous nanoparticles. Nanoparticles and nanoparticle agglomerates, however, suffer from reduced charge extraction and, when deposited onto electrodes for photoelectrochemical applications, from charge transport limitations to the back contact because of multiple grain and particle boundaries. Lately, the careful design of single-crystalline particles with well-defined facets and decorated with cocatalysts has served as a successful concept to achieve high efficiencies in the case of the UV light sensitive model system SrTiO3. In this contribution, perovskite-related oxynitrides will be introduced as a promising visible light absorbing photocatalytically active material class. It will be shown how the conversion of oxides to oxynitrides via thermal ammonolysis enables particle design for improved photocatalytic and photoelectrochemical performance.

Keywords: solar fuels; photelectrochemical water-splitting; photocatalyst; oxynitride; morphology