Tunable CO2 electroreduction to ethanol and ethylene with controllable interfacial wettability

Abstract The mechanism of how interfacial wettability impacts the CO 2 electroreduction pathways to ethylene and ethanol remains unclear. This paper describes the design and realization of controllable equilibrium of kinetic-controlled *CO and *H via modifying alkanethiols with different alkyl chain lengths to reveal its contribution to ethylene and ethanol pathways. Characterization and simulation reveal that the mass transport of CO 2 and H 2 O is related with interfacial wettability, which may result in the variation of kinetic-controlled *CO and *H ratio, which affects ethylene and ethanol pathways. Through modulating the hydrophilic interface to superhydrophobic interface, the reaction limitation shifts from insufficient supply of kinetic-controlled *CO to that of *H. The ethanol to ethylene ratio can be continuously tailored in a wide range from 0.9 to 1.92, with remarkable Faradaic efficiencies toward ethanol and multi-carbon (C 2+ ) products up to 53.7% and 86.1%, respectively. A C 2+ Faradaic efficiency of 80.3% can be achieved with a high C 2+ partial current density of 321 mA cm −2 , which is among the highest selectivity at such current densities.