Nanostructured hematite films prepared by a sol-gel procedure were evaluated for the photo-induced oxygen evolution reaction (OER). Surface treatments such as plasma and post-annealing at 500 °C in oxygen gas flow were used in order to condition the electrode surface. Electrochemical measurements of the plasma treated samples revealed that the surface was reorganized in terms of enhanced catalytic properties and reduced recombination centers at the surface. Photocurrents in the milli-Ampere range were yielded at 0.92 V(NHE) in 1 M KOH. In contrast to the plasma samples, the post-annealing samples displayed higher bulk crystallinity resulting in a more enhanced photovoltage. XRD and TEM analysis confirmed the texturing of a beneficial highly oriented hematite film (110) parallel to the back contact. Nevertheless, lower photocurrents for this post-annealed sample compared to the plasma one indicated that the catalytic centers were not fully recovered at the surface.
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机译：通过溶胶-凝胶法制备的纳米结构赤铁矿薄膜的光诱导氧释放反应（OER）进行了评估。为了调节电极表面，使用了诸如等离子体处理和在氧气流中在500°C下进行后退火等表面处理。等离子体处理过的样品的电化学测量表明，根据增强的催化性能和减少的表面重组中心，表面进行了重组。在1 M KOH中以0.92 V（NHE）产生毫安级的光电流。与等离子体样品相比，退火后样品显示出较高的整体结晶度，从而导致光电压更高。 XRD和TEM分析证实了平行于背接触的有益的高取向赤铁矿膜（110）的织构化。然而，与等离子等离子体相比，该后退火样品的光电流较低表明催化中心在表面没有完全恢复。
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