Department of Chemistry and Biochemistry, Queens College-CUNY, Flushing, New York 11367, United States.
Langmuir. 2013 Feb 5;29(5):1346-50. doi: 10.1021/la304694d. Epub 2013 Jan 23.
The electrocatalytic oxygen reduction reaction (ORR) is central to alternative energy systems and sensors. An important practical issue in these systems is the loss of active surface area of the catalyst. The unexpected dissolution of Pt at moderately negative potentials during ORR in water and organic media was detected by combining nanoelectrochemistry with AFM imaging. The possibility to connect this phenomenon with the previously observed formation of hydroxyl radicals has been explored. The loss of Pt occurred only under the experimental conditions at which the formation of hydroxyl radicals was reported in the literature. This process can contribute to cathode degradation in fuel cells and other electrochemical systems. In electrochemical experiments employing a Pt electrode at negative potentials, the reduction of oxygen may be accompanied by the dissolution of the electrode surface.
电催化氧气还原反应（ORR）是替代能源系统和传感器的核心。在这些系统中，一个重要的实际问题是催化剂的有效表面积损失。通过将纳米电化学与原子力显微镜成像相结合，检测到在水和有机介质中的 ORR 过程中，Pt 在中等负电位下意外溶解。已经探索了将这种现象与之前观察到的羟基自由基形成联系起来的可能性。只有在文献中报道形成羟基自由基的实验条件下，Pt 才会发生损失。这个过程可能导致燃料电池和其他电化学系统的阴极降解。在采用负电位的 Pt 电极进行的电化学实验中，氧气的还原可能伴随着电极表面的溶解。
