Yttrium Tantalum Oxynitride Multiphases as Photoanodes for Water Oxidation

Wenping Si, Zahra Pourmand Tehrani, Fatima Haydous, Nicola Marzari, Ivano E. Castelli, Daniele Pergolesi,, Thomas Lippert*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

The perovskite yttrium tantalum oxynitride is theoretically proposed as a promising semiconductor for solar water splitting because of the predicted band gap and energy positions of band edges. In experiments, however, we show here that depending on the processing parameters, yttrium tantalum oxynitrides exist in multiphases, including the desired perovskite YTaON2, defect fluorite YTa(O,N,□)4, and N-doped YTaO4. These multiphases have band gaps ranging between 2.13 and 2.31 eV, all responsive to visible light. The N-doped YTaO4, perovskite main phase, and fluorite main phase derived from crystalline fergusonite oxide precursors exhibit interesting photoelectrochemical performances for water oxidation, while the defect fluorite derived from low-crystallized scheelite-type oxide precursors shows negligible activity. Preliminary measurements show that loading an IrOx cocatalyst on N-doped YTaO4 significantly improves its photoelectrochemical performance, encouraging further studies to optimize this new material for solar fuel production.
Original languageEnglish
JournalThe Journal of Physical Chemistry Part C
Volume123
Issue number43
Pages (from-to)26211-26217
ISSN1932-7447
DOIs
Publication statusPublished - 2019

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