Electrical monitoring of single-event protonation dynamics at the solid-liquid interface and its regulation by external mechanical forces
Cong Zhao, Jiazheng Diao, Zhao Liu, Jie Hao, Suhang He, Shaojia Li, Xingxing Li, Guangwu Li, Qiang Fu, Chuancheng Jia, Xuefeng Guo
Abstract
Detecting chemical reaction dynamics at solid-liquid interfaces is important for understanding heterogeneous reactions. However, there is a lack of exploration of interface reaction dynamics from the single-molecule perspective, which can reveal the intrinsic reaction mechanism underlying ensemble experiments. Here, single-event protonation reaction dynamics at a solid-liquid interface are studied in-situ using single-molecule junctions. Molecules with amino terminal groups are used to construct single-molecule junctions. An interfacial cationic state present after protonation is discovered. Real-time electrical measurements are used to monitor the reversible reaction between protonated and deprotonated states, thereby revealing the interfacial reaction mechanism through dynamic analysis. The protonation reaction rate constant has a linear positive correlation with proton concentration, whereas the deprotonation reaction rate constant has a linear negative correlation. In addition, external mechanical forces can effectively regulate the protonation reaction process. This work provides a single-molecule perspective for exploring interface science, which will contribute to the development of heterogeneous catalysis and electrochemistry. Direct detection of chemical reactions at solid-liquid interfaces is important for a more complete understanding of interfacial effects. Here, the authors study single-event interfacial protonation reaction dynamics by single-molecule junctions and thereby identify an interfacial cationic state.