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Hydrogen treatment and FeOOH overlayer: Effective approaches for enhancing the photoelectrochemical water oxidation performance of bismuth vanadate thin films
Catalysis Today ( IF 5.2 ) Pub Date : 2018-03-22 , DOI: 10.1016/j.cattod.2018.03.041
Aadesh P. Singh , Nishant Saini , Bodh R. Mehta , Anders Hellman , Beniamino Iandolo , Björn Wickman

The water oxidation capability of the promising photoanode bismuth vanadate (BiVO4) is hampered by poor bulk electron transport and by high rates of charge recombination at the semiconductor/electrolyte interface. Here, we demonstrate that a dual modification of BiVO4 by: (i) annealing in a hydrogen-containing environment and (ii) coating with FeOOH overlayer substantially enhances the water oxidation ability of BiVO4 photoanodes. Hydrogen treated, FeOOH coated BiVO4 photoanodes exhibit a water oxidation photocurrent density of 2.16 mA cm−2 at 1.23 VRHE, which is 5 times higher than for untreated BiVO4 films. Moreover, they showed an impressive low photocurrent onset potential of −0.11 VRHE. A stable photocurrent was observed for 1 h of water oxidation measurement at 1.23 VRHE under 1 Sun illumination. The enhanced photocurrent of FeOOH/H:BiVO4 photoanode is ascribed to an improved bulk charge transport, as confirmed by impedance spectroscopy measurements and Mott-Schottky analysis. The cathodic shift of the onset potential originates from a lowering of the flat band potential and from an improvement of the charge transport at the semiconductor/electrolyte interface. The dual modification strategy used here offers a simple but effective approach of improving the water oxidation performance of BiVO4.



中文翻译:

氢处理和FeOOH覆盖层:增强钒酸铋薄膜光电化学水氧化性能的有效方法

有前景的光阳极钒酸铋(BiVO 4)的水氧化能力受到不良的体电子传输和半导体/电解质界面处高电荷复合率的阻碍。在这里,我们证明了BiVO 4的双重改性:(i)在含氢环境中进行退火,以及(ii)用FeOOH覆盖层进行涂覆,实质上增强了BiVO 4光电阳极的水氧化能力。经过氢气处理的FeOOH涂层BiVO 4光电阳极在1.23 V RHE下的水氧化光电流密度为2.16 mA cm -2,是未经处理的BiVO 4的5倍电影。此外,它们显示出令人印象深刻的低光电流起始电位-0.11 V RHE。在1个阳光照射下,在1.23 V RHE下水氧化测量1小时,观察到稳定的光电流。FeOOH / H:BiVO 4光电阳极的增强光电流归因于整体电荷传输的改善,如通过阻抗谱测量和Mott-Schottky分析所证实的。起始电位的阴极位移源自平带电位的降低和半导体/电解质界面处电荷传输的改善。这里使用的双重修饰策略提供了一种简单而有效的方法来改善BiVO 4的水氧化性能。

更新日期:2018-03-22
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