Interfacial coupling promotes chlorobenzene oxidation over CoMn2O4/CeTiOx catalyst.

The development of low-temperature, chlorine-tolerant catalysts for the elimination of chlorinated volatile organic compounds (Cl-VOCs) remains a persistent challenge in environmental catalysis. Herein, we report an efficient CoMn2O4/CeTiOx (CMO/CeTi) catalyst with strong oxide-oxide interfacial coupling. By integrating the spinel CoMn2O4 active phase with a structurally heterogeneous CeTiOx mixed-oxide, a strain-distorted and chemically coupled interfacial region is constructed. Aberration-corrected STEM-EELS and geometric phase analysis (GPA) reveal a nanometer-scale Co/Mn-O-Ce/Ti interphase with localized cation reduction, enriched oxygen vacancies, and pronounced lattice distortion, which are associated with enhanced interfacial redox activity and oxygen exchange. As a result, CMO/CeTi exhibits superior chlorobenzene oxidation activity (T90=300℃) and maintains approximately 90% CB conversion during a 40 h test under humid conditions. In situ DRIFTS studies suggest an H2O-involved surface pathway: under humid conditions, the vacancy-enriched interfacial region facilitates surface hydroxyl formation and the transformation of carboxylate-like intermediates, thereby promoting surface renewal. The effect of water is therefore mainly reflected in surface renewal and intermediate evolution under humid conditions. This work provides atomic-scale insight into oxide-oxide interfacial modulation and highlights interfacial redox coupling as an effective strategy for designing robust catalysts for Cl-VOC abatement.