Integrated　CO2capture　and　electrochemical　utilization　(ICCU)　is　promising　for　decarbonization　by　bypassing　energy-intensive　desorption/compression　steps　compared　to　conventional　CO2capture　and　utilization　(CCU)　systems.　However,　the　critical　barrier　in　ICCU　is　the　mass　transfer　limitations　of　carbon-containing　species　from　amine　solutions　to　electrode　surfaces,　leading　to　a　low　CO2conversion　and　a　high　hydrogen　evolution　reaction　(HER).　To　address　this　issue,　we　introduce　an　interfacial　engineering　strategy　to　create　a　microenvironment　using　quaternary　ammonium　cationic　surfactants　for　enhanced　CO2conversion.　In　the　cetyltrimethylammonium　bromide　(CTAB)-modified　monoethanolamine　(MEA)　system,　a　Ag　nanoparticle　achieved　63.4%　CO　Faradaic　efficiency　at　−0.82　V　vs　RHE,　representing　a　4.7-fold　improvement　over　unmodified　system.　Chain-length　optimization　revealed　that　short-chain　surfactants　lacked　sufficient　hydrophobicity,　while　long-chain　variants　increased　the　mass　transfer　resistance,　positioning　CTAB　(C16)　as　the　optimal　candidate.　The　strategy　demonstrates　amine　versatility　and　50　h　of　recyclability　without　catalyst/amine　degradation.　In　situ　spectra　and　density　functional　theory　calculation　elucidated　that　CTAB　has　dual　roles,　i.e.,　CTAB　cation　(CTA+)　adsorption　repels　the　aggregation　of　protonated　amine　(MEAH+)　on　the　electrode　surface　and　the　hydrophobic　alkyl　chains　enrich　the　carbon-containing　species.　This　work　provides　a　mechanistic　framework　for　designing　efficient　and　stable　ICCU　systems　through　creating　a　microenvironment.　©　2025　American　Chemical　Society