Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
ChemSusChem. 2012 Oct;5(10):1897-904. doi: 10.1002/cssc.201200193. Epub 2012 Aug 14.
The reaction path of the Cl(2) evolution reaction (CER) was investigated by combining electrochemical and spectroscopic methods. It is shown that oxidation and reconstruction of the catalyst surface during CER is a consequence of the interaction between RuO(2) and water. The state of the RuO(2) surface during the electrochemical reaction was analyzed in situ by using Raman spectroscopy to monitor vibrations of the crystal lattice of RuO(2) and changes in the surface concentration of the adsorbed species as a function of the electrode potential. The role of the solvent was recognized as being crucial in the formation of an oxygen-containing hydrophilic layer, which is a key prerequisite for electrocatalytic Cl(2) formation. Water (more precisely the OH adlayer) is understood not just as a medium that allows adsorption of intermediates, but also as an integral part of the intermediate formed during the electrochemical reaction. New insights into the general understanding of electrocatalysis were obtained by utilizing the vibration frequencies of the crystal lattice as a dynamic catalytic descriptor instead of thermodynamic descriptors, such as the adsorption energy of intermediates. Interpretation of the derived "volcano" curve suggests that electrocatalysis is governed by a resonance phenomenon.
采用电化学和光谱学方法研究了 Cl(2) 演化反应（CER）的反应路径。结果表明，CER 过程中催化剂表面的氧化和重构是 RuO(2) 与水相互作用的结果。通过使用拉曼光谱原位分析电化学过程中 RuO(2) 表面的状态，监测 RuO(2)晶格的振动以及吸附物种的表面浓度随电极电势的变化，来研究 RuO(2)表面的状态。溶剂的作用被认为是形成含氧亲水性层的关键，这是电催化 Cl(2)形成的关键前提。水（更确切地说是 OH 吸附层）不仅被理解为允许中间物吸附的介质，而且还被理解为电化学过程中形成的中间物的组成部分。通过利用晶格的振动频率作为动态催化描述符而不是热力学描述符（例如中间物的吸附能），获得了对电催化的普遍理解的新见解。对得出的“火山”曲线的解释表明，电催化受共振现象控制。
