Zeolite-Regulated Electron-Rich Cu–O–Ce Sites for Efficient Denitrification against Alkali/Heavy Metal Poisoning

Abstract Enhancing the wide-temperature-window deNOx activity of catalysts under alkali/heavy metal poisoning conditions remains a pivotal challenge in the field of environmental catalysis. To tackle this issue, we designed a novel CuCeOx/ZSM-5 catalyst using an acid-rich zeolite-modulated electron-enriched metal site strategy. This strategy enables the contact between strong acid sites and Cu–O–Ce active sites, simultaneously regulating the efficient NH3–SCR temperature window and enhancing K/Pb poisoning resistance. Compared to CuCeOx, the engineered acid-rich interface significantly facilitates electron transfer from ZSM-5 to CuCeOx, generating electron-rich Cu–O–Ce active sites. These sites not only serve as adjacent adsorption and activation centers for reactants but also inhibit NH3 oxidation, and CuCeOx/ZSM-5 catalyst achieves >90% deNOx efficiency over a wide temperature range of 180–410 °C (T90 = 180–410 °C). K deactivates the catalyst mainly by reducing surface acidity and promoting the accumulation of less-reactive nitrate species, while Pb primarily suppresses Ce4+ → Ce3+ reduction via inducing Cu2+ → Cu+ conversion and occupying CeO2 oxygen vacancies. Notably, the poisoned CuCeOx/ZSM-5 catalyst still retains satisfactory deNOx performance, with the T90 = 230–380 °C. This work not only provides novel mechanistic insights into the deactivation pathways of NH3–SCR catalysts by alkali and heavy metal ions but also offers a viable strategy for the rational design of high-performance, poisoning-tolerant NH3–SCR catalysts tailored for complex flue gas environments.