SrO‐Induced Local Alkaline Microenvironment for Enhanced CO ₂ Electroreduction to C ₂ Products

ABSTRACT Electrocatalytic CO ₂ reduction has emerged as a promising pathway toward carbon neutrality, with C ₂ products attracting considerable interest due to their high economic value. However, the efficiency and selectivity of this process are limited by the high kinetic barrier of C─C coupling and strong competition from the hydrogen evolution reaction (HER). In this work, we propose a strategy to promote C─C coupling by constructing a local alkaline microenvironment and accordingly design and fabricate a heterojunction catalyst composed of SrO‐modified CuO (SrO/CuO). In‐depth investigations reveal that the incorporation of SrO enhances ^* CO intermediate coverage, facilitates the hydrogenation of ^* CO to ^* CHO, and promotes the subsequent asymmetric ^* CHO─ ^* CO coupling. More critically, SrO functions as an efficient water‐dissociation center, generating an OH ⁻ ‐enriched local microenvironment. This alkaline setting not only suppresses the competing HER but also stabilizes the C─C coupling transition state ( ^* CHO─ ^* CO) and provides ample ^* H to accelerate ^* CO hydrogenation, thereby greatly enhancing selective C ₂ production. Electrochemical tests demonstrate that SrO/CuO achieves a high C ₂ Faradaic efficiency of 71.4% at −1.5 V vs. RHE in a flow cell, while maintaining excellent stability over a wide potential window.