Chang Chia-Jui, Chu You-Chiuan, Yan Hao-Yu, Liao Yen-Fa, Chen Hao Ming
Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan and Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 689-5198, Japan.
Dalton Trans. 2019 Jun 7;48(21):7122-7129. doi: 10.1039/c9dt00138g. Epub 2019 Mar 6.
RuO has been generally considered as the most active catalyst for the oxygen evolution reaction (OER) to date and shows remarkably higher activity in an acidic electrolyte than under alkaline conditions. Nevertheless, the dynamic valence state and local structure of reactive centers (i.e., Ru) in both acidic and alkaline electrolytes have not been systematically investigated yet, especially through in situ approaches. Herein, we employed in situ X-ray absorption spectroscopy to study the dynamic valence state and local structure of RuO during the OER in both acidic and alkaline electrolytes. In the acidic electrolyte, the Ru center was reduced near the onset potential prior to launching the OER and was oxidized during the OER process, while the coordination numbers and the bond lengths of the Ru-O path also decreased as revealed by in situ EXAFS analysis. Besides, in the alkaline electrolyte, RuO showed a similar behavior as revealed under acidic conditions. These results provide an evident insight into the dynamic change of the RuO electrocatalyst during the OER.
迄今为止，RuO通常被认为是用于析氧反应（OER）的最具活性的催化剂，并且在酸性电解质中显示出比在碱性条件下显著更高的活性。然而，酸性和碱性电解质中反应中心（即Ru）的动态价态和局部结构尚未得到系统研究，特别是通过原位方法。在此，我们采用原位X射线吸收光谱来研究酸性和碱性电解质中OER过程中RuO的动态价态和局部结构。在酸性电解质中，Ru中心在开始OER之前在起始电位附近被还原，并在OER过程中被氧化，而原位EXAFS分析表明，Ru-O路径的配位数和键长也减小。此外，在碱性电解质中，RuO表现出与酸性条件下类似的行为。这些结果为OER过程中RuO电催化剂的动态变化提供了明显的见解。
