Engineering of Sn‐O‐Sn Sites in CuMOF via Atomic Layer Infiltration for Efficient CO 2 RR in Neutral Aqueous Media

ABSTRACT Developing copper‐based catalysts that suppress HER, ensure high selectivity, and activate CO 2 is vital for efficient neutral aqueous CO 2 electroreduction (CO 2 RR). However, due to electronic complexity and the adsorption energy‐selectivity paradox, the precise microstructural design of copper‐based catalysts remains challenging. Herein, we use a gas‐phase atomic layer infiltration (ALI) strategy to precisely control the copper microenvironment in CuBDC, enabling the uniform distribution of Cu‐O‐Sn‐O‐Sn‐O‐Cu active sites while maintaining structural integrity. Electrochemical characterization reveals that atomic‐level engineering simultaneously enhances the number of active sites and optimizes charge transfer dynamics, while in situ Raman spectroscopy confirms the formation of Sn‐CO intermediates. This multifaceted synergy drives a significant improvement in catalytic performance: CO selectivity increases from 15% to 99%, while H 2 selectivity is effectively suppressed from 85% to 1% in an aqueous CO 2 RR system. Density functional theory calculations reveal that the presence of Sn‐O‐Sn sites enhances CO 2 adsorption stability, lowers the formation energy barrier of the key intermediate COOH * , and creates a HER‐inert region. This study establishes a new paradigm for designing highly efficient neutral aqueous CO 2 RR electrocatalysts by synergistically regulating reaction pathways and charge transfer through atomic‐level optimization of electronic, geometric, and structural properties of CuMOF.