Barawi Mariam, Gomez-Mendoza Miguel, Oropeza Freddy E, Gorni Giulio, Villar-Garcia Ignacio J, Giménez Sixto, de la Peña O'Shea Victor A, García-Tecedor Miguel
Photoactivated Processes Unit, IMDEA Energy, Avda. Ramón de La Sagra, 3, Móstoles 28935, Spain.
CLÆSS Beamline, ALBA Synchrotron, Carrer de La Llum 2-26, Cerdanyola del Valles 08290, Spain.
ACS Appl Mater Interfaces. 2022 Jul 27;14(29):33200-33210. doi: 10.1021/acsami.2c07451. Epub 2022 Jul 18.
The present study proposes a laser irradiation method to superficially reduce BiVO photoelectrodes and boost their water oxidation reaction performance. The origin of this enhanced performance toward oxygen evolution reaction (OER) was studied using a combination of a suite of structural, chemical, and mechanistic advanced characterization techniques including X-ray photoelectron (XPS), X-ray absorption spectroscopy (XAS), electrochemical impedance spectroscopy (EIS), and transient absorption spectroscopy (TAS), among others. We found that the reduction of the material is localized at the surface of the sample and that this effect creates effective n-type doping and a shift to more favorable energy band positions toward water oxidation. This thermodynamic effect, together with the change in sample morphology to larger and denser domains, results in an extended lifetime of the photogenerated carriers and improved charge extraction. In addition, the stability of the reduced sample in water was also confirmed. All of these effects result in a two-fold increase in the photocurrent density of the laser-treated samples.
本研究提出了一种激光辐照方法，以表面还原BiVO光电极并提高其水氧化反应性能。使用包括X射线光电子能谱（XPS）、X射线吸收光谱（XAS）、电化学阻抗谱（EIS）和瞬态吸收光谱（TAS）等一系列结构、化学和机理先进表征技术相结合的方法，研究了这种对析氧反应（OER）增强性能的起源。我们发现材料的还原局限于样品表面，并且这种效应产生了有效的n型掺杂，并使能带位置向更有利于水氧化的方向移动。这种热力学效应，连同样品形态向更大、更致密区域的变化，导致光生载流子寿命延长和电荷提取改善。此外，还证实了还原样品在水中的稳定性。所有这些效应导致激光处理样品的光电流密度增加了两倍。
