Water Oxidation on Hematite Photoelectrodes: Insight into the Nature of Surface States through In Situ Spectroelectrochernistry
Water Oxidation on Hematite Photoelectrodes: Insight into the Nature of Surface States through In Situ Spectroelectrochernistry
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DOI：
10.1021/jp500543z
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发表时间：
2014-05-15
影响因子：
3.7
通讯作者：
Hamann, Thomas
中科院分区：
文献类型：
--
作者：
Klahr, Benjamin;Hamann, Thomas
均匀的平面膜的赤铁矿（α-Fe 2 O3），沉积原子层沉积，在光诱导水氧化过程中使用原位光谱电化学检查。在光照和外加电位下，测量了水氧化过程中赤铁矿电极吸收光谱的变化。吸收与通过循环伏安法测量的电荷和通过阻抗谱测量的电容相关。改性的赤铁矿表面与氧化铝减少了吸收功能和相关的电容，这表明这些功能与表面。比较赤铁矿的光谱变化的分子类似物的吸收功能，使我们能够暂时分配的吸收和电容功能的低价铁水或铁羟基物种的氧化，以高价铁氧化学物种在表面上。
Uniform planar films of hematite (alpha-Fe2O3), deposited by atomic layer deposition, were examined using in situ spectroelectrochemistry during photoinduced water oxidation. A change in the absorption spectrum of hematite electrodes during water oxidation was measured under illumination and applied potentials. The absorption was correlated to a charge measured by cyclic voltammetry and with a capacitance measured by impedance spectroscopy. Modification of the hematite surface with alumina reduced the absorption feature and the associated capacitance, suggesting that these features are associated with the surface. Comparing the spectral change of hematite to absorption features of molecular analogues allowed us to tentatively assign the absorbance and capacitive features to the oxidation of a low valent iron-aqua or iron-hydroxyl species to a high valent iron-oxo chemical species at the surface.