Improved Stability of Polycrystalline Bismuth Vanadate Photoanodes by Use of Dual-Layer Thin TiO2/Ni Coatings

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• 作者：Matthew T. McDowell ; Michael F. Lichterman ; Joshua M. Spurgeon ; Shu Hu ; Ian D. Sharp ; Bruce S. Brunschwig ; Nathan S. Lewis
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 28, 2014
• 年：2014
• 卷：118
• 期：34
• 页码：19618-19624
• 全文大小：383K
• ISSN：1932-7455

文摘

Ultrathin dual layers of TiO₂ and Ni have been used to stabilize polycrystalline BiVO₄ photoanodes against photocorrosion in an aqueous alkaline (pH = 13) electrolyte. Conformal, amorphous TiO₂ layers were deposited on BiVO₄ thin films by atomic-layer deposition, with Ni deposited onto the TiO₂ by sputtering. Under simulated air mass 1.5 illumination, the dual-layer coating extended the lifetime of the BiVO₄ photoanodes during photoelectrochemical water oxidation from minutes, for bare BiVO₄, to hours, for the modified electrodes. X-ray photoelectron spectroscopy showed that these layers imparted chemical stability to the semiconductor/electrolyte interface. Transmission electron microscopy revealed the structure and morphology of the polycrystalline BiVO₄ film as well as of the thin coating layers. This work demonstrates that protection schemes based on ultrathin corrosion-resistant overlayers can be applied beneficially to polycrystalline photoanode materials under conditions relevant to efficient solar-driven water-splitting systems.