Interfacial Lithium Cations Catalyze Biomimetic Aerobic Oxygenation via Short‐Range Electrostatic Interaction

Abstract

AbstractEnzymes often involve short‐range electrostatic interactions in the deliberate microenvironment for accelerating the catalysis. Comparatively, electrostatic interactions from ions in solutions are mostly shielded by solvent or counter‐ion shells, creating negligible catalytic effects. Herein, we discovered that the interfacial Li+ cations accumulated on electrodes catalyze the selective water‐involved O2 electro‐reduction into peroxide anion (OOH−), forming an active side‐on Li+–OOH− complex via short‐range electrostatic interaction. This complex reduces the O2 reduction energy barrier and increases the nucleophilicity, expediting the aerobic oxygenation of ketones. Aside from trapping active intermediates, Li+ cations also attract the excessive water dipoles to prevent them from quenching the active Li+–OOH− complex. By using probe‐assisted quantitative methods, we demonstrated the unique under‐coordinative characteristics of interfacial Li+ for interacting with reaction intermediates, and the effective concentration of under‐coordinative Li+ on the interface is an order of magnitude higher than in the bulk solution. These analyses provide essential evidences about the intrinsic difference between bulk ions and interfacial ions toward catalysis.