Band Edge Engineering in BiVO4/TiO2 Heterostructure: Enhanced Photoelectrochemical Performance through Improved Charge Transfer

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• 作者：Aadesh P. Singh ; Nisha Kodan ; Bodh R. Mehta ; Alexander Held ; Leonhard Mayrhofer ; Michael Moseler
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：August 5, 2016
• 年：2016
• 卷：6
• 期：8
• 页码：5311-5318
• 全文大小：456K
• 年卷期：0
• ISSN：2155-5435

文摘

The efficient separation of photogenerated electron–hole pairs and stability against corrosion are critical preconditions for a photoelectrode to achieve a high photoelectrochemical performance. In this work it is shown how both criteria can be met by employing a heterostructure of bismuth vanadate (BiVO₄) and titanium dioxide (TiO₂) as the photocatalyst. Using electronic structure calculations, an alteration of the band alignment is predicted at the heterojunction from type I to type II by hydrogen treatment of the top TiO₂ layer. Guided by this idea, we have fabricated heterostructures of BiVO₄ and TiO₂ and studied the effect of hydrogen treatment. The achieved band engineering results in a significant improvement in photocurrent density, up to 4.44 mA cmp>–2p> at 1.23 V vs RHE, and a low onset potential, −0.14 V vs RHE, under visible light illumination. The enhanced photoelectrochemical performance originates in facilitated hole transport to the electrode surface and enhanced photoabsorption in the TiO₂ layer. This work is an example of how hydrogenation can be used to tailor the properties of BiVO₄/H:TiO₂ heterostructures and provides valuable insights for the further development of similar material combinations.