Synthesis of Nanostructured BaTaO2N Thin Films as Photoanodes for Solar Water Splitting

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• 作者：Chizhong Wang ; Takashi Hisatomi ; Tsutomu Minegishi ; Qian Wang ; Miao Zhong ; Masao Katayama ; Jun Kubota ; Kazunari Domen
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 28, 2016
• 年：2016
• 卷：120
• 期：29
• 页码：15758-15764
• 全文大小：404K
• 年卷期：0
• ISSN：1932-7455

文摘

Synthesis of nanostructured BaTaO₂N thin films on metallic Ta substrates, and their application as photoanodes for solar-driven photoelectrochemical water oxidation were studied. Ba₅Ta₄O₁₅ nanosheets vertically grown on Ta substrates by a hydrothermal process were converted into perovskite BaTaO₂N with a branching nanostructure by thermal nitridation under an ammonia gas flow. The crystal quality and photoelectrochemical properties of the BaTaO₂N thin films were found to improve with increasing nitridation temperature up to 1000 °C. A Ta₄N₅ interfacial layer was formed between the BaTaO₂N thin film and the Ta substrate. Under simulated AM 1.5G light, the BaTaO₂N electrode generated a photoanodic current, although it rapidly decreased due to photo-oxidative corrosion. The degradation of the BaTaO₂N electrode could be alleviated by the deposition of a cobalt phosphate layer on its surface. The modified electrode maintained a photoanodic current of 0.75 mA cm^–2 at 1.23 V versus the reversible hydrogen electrode with a Faradaic efficiency of almost unity.