Time-Resolved Mapping of Interface Charge Transfer for Real-Time Observation of Microscopic Chemical Reactions.

Real-time monitoring of microscopic chemical reactions offers valuable insight into reaction mechanisms, intermediate species, and the reaction kinetics involved. Mainstream electrochemical and chromatographic techniques are often complex, low-sensitivity, failing to capture transient phenomena or distinguish similar chemical species within the reaction, limiting their accessibility for real-time and continuing monitoring. Here, high-resolution interface charge transfer mapping (ICTM) generated by liquid-solid contact electrification is used in situ for continuously monitoring potential chemical changes in the reactions. As liquid reactants slide dropwise over time along an insulating reclined plane, the ICTMs along the sample trajectory over time are recorded and is used to analysis chemical changes within the reactions. By means of time-resolved ICTM measurements at statically charged dielectric surface, we have probed the dynamic evolution of redox reactions, tracked the organocatalytic reactions, and evaluated the agglomeration state of metal catalysts with a time resolution on the scale of seconds.