Built-In Electric Field Triggered Interfacial Water Activation for Industrial-Level Electrosynthesis of Ethylene from CO2

Abstract

The electrochemical reduction of CO2 to ethylene (C2H4), as opposed to traditional industrial methods, stands out as an environmentally friendly benign and promising technical solution for producing value-added chemicals using renewable electricity. Here, we introduce a built-in electric field in La(OH)3-Cu (BEF@La(OH)3-Cu) electrocatalyst that can exclusively convert from CO2 to C2H4 with a maximum Faradaic efficiency of 84.2% and high intrinsic activity exceeding 842.0 mA cm−2, while maintaining robust stability of 110 h. Furthermore, the corresponding C2H4 formation rate and energy efficiency can reach 2618.0 µmol cm−2 h−1 and 31.2%, respectively. The BEF@La(OH)3-Cu electrocatalyst was constructed by stacking La(OH)3 and Cu layers, forming a built-in electric field induced by electron transfer between La→O←Cu. The electric field effectively triggered H2O dissociation on La(OH)3-Cu interface for supplying active hydrogen (*H) species, which promoted multiple protonation steps in the process of CO2-to-C2H4 conversion. The *H species then easily migrate to Cu sites, reducing the energy barrier for the conversion from *CO to *COH, thus enhancing the efficient asymmetric *CO−*COH coupling and ultimately boosting the C2H4 production under ampere-level operation.