Electric-field-driven CO₂ mass transfer at microdroplet interfaces boosts efficient ethanol generation

The electrocatalytic CO₂ reduction reaction (CO₂RR) efficiently converts CO₂ into high value-added products, but its reaction kinetics are still limited by CO₂ mass transfer from the gas atmosphere to the catalyst surface. In this work, a hydrophobic AlCu@b-COF served as a customized microdroplet system catalyst for the CO₂RR, achieving a maximum ethanol yield of 23.76 µmol L^-1 g^-1, representing a 40.97-fold enhancement compared to the conventional bulk phase system. The operando Raman spectroscopy and Debye length calculation analysis revealed an enhanced electric field gradient and compressed electric double layer due to the aggregation of CO₃ ^2- and related anions at the interface of the microdroplets. Further operando Raman measurements and classical molecular dynamics simulations provided complementary evidence for the interfacial environment associated with CO₂˙^- transport, supporting a contribution of the enhanced interfacial electric field to CO₂˙^- mass transfer. This study provides a theoretical basis and technical support for the design and mechanism exploration of microdroplet-induced high-performance reaction systems.