Electrostatic Charges Regulate Chemiluminescence by Electron Transfer at the Liquid-Solid Interface.

The role of the electrostatic environment in chemical reactions has long been an important research field, but most studies have focused on the influence of external electric fields on chemical processes, while the effect from the intrinsic electrostatic charges on the solution itself has been ignored. How an electrostatic field generated by contact electrification affects the solvent environment in a chemical reaction and then the chemical reactivity is still ambiguous. Here, based on the inspiration of the droplet triboelectric nanogenerator, electrostatic interactions between a statically charged luminol droplet and the surrounding directional electrostatic field were analyzed, and we demonstrate a relationship between the sign of the luminol sample (negatively or positively charged) and its effect on the reaction reactivity. Our results show that the increased reaction activity and the enhanced chemiluminescence (CL) only occurred when the luminol droplet yields positive charges, while a negatively charged luminol, on the contrary, tends to inhibit the CL, which brings direct evidence of the charge carriers of triboelectricity being electrons at the liquid-solid interface. This work provides a strategy for electrostatically regulating CL by simply statically charging a reaction solution with a dielectric solid and also carries a cautionary message on what to consider when preparing a sample for a chemical reaction.