Epitaxial Oxide Interfaces Create Poison-Resistant CuO Sites for Environmental Catalysis.

Real exhaust streams rarely contain a single pollutant: NOx coexists with volatile organic compounds (VOCs) in flue gas from petrochemical production, chemical manufacturing, and waste incineration, yet catalysts that couple NH3-SCR with VOC oxidation typically suffer competitive adsorption, sulfur poisoning, and HCN byproduct formation. Here we engineer an epitaxially stabilized CuO overlayer on Ti1-xInxO2 that breaks the activity-selectivity-stability constraint by creating electron-poor, high-symmetry Cu-O sites and activating lattice-oxygen redox at the oxide-oxide interface. Interfacial strain and charge transfer increase Cu-O covalency and Lewis acidity, accelerating NOx reduction via an Eley-Rideal pathway while diverting sulfate deposition away from Cu. Concurrently, interface-activated lattice oxygen sustains deep oxidation of CH3SH (a representative S-VOC) through a Mars-van Krevelen cycle, suppressing HCN. Epitaxial interfaces thus offer a general route to poison-resistant multipollutant catalysis.