CuO(200)–CuO(1̅11) Interface Enables Efficient Low-Temperature Catalytic Decomposition of CH3SH

The catalytic degradation of sulfur-containing volatile organic compounds (S-VOCs), especially methyl mercaptan (CH3SH), is often limited by the insufficient low-temperature activity of conventional catalysts. Herein, an inverse Cu–Ce catalyst featuring a well-defined CuO(200) facet and CuO(200)–CuO(1̅11) interface, denoted as CuO/CeO2–CP(7), is constructed through facet regulation and interfacial engineering. The catalyst enables complete conversion of CH3SH at 150 °C and exhibits a substantially lower apparent activation energy, demonstrating superior intrinsic activity compared with most reported catalysts. Structural-activity correlation reveals that the interface architecture stabilizes Cu+ species, enhances active-oxygen migration-replenishment, and significantly strengthens CH3SH adsorption and activation, thereby driving a stepwise deep-conversion route of CH3SH → CH3SSCH3 → CH3SCH3/HCOOH → CH4. In-situ FTIR confirms that Cu+–O* cooperative sites govern the coupling, rearrangement, and deep-reduction processes, while deactivation analysis identifies disrupted oxygen cycling as the primary cause of activity loss. This work highlights the critical role of CuO–CuO interfacial modulation in advancing low-temperature S-VOCs degradation and provides an effective strategy for designing highly active inverse Cu–Ce catalysts.