Dynamic Brønsted Acid Site Compensation Enables Water-Tolerant Low-Temperature NH3-SCR over Co-WO3/FeCu-SSZ-13

Water-induced deactivation of catalysts under low-temperature and high-humidity conditions remains a major challenge for the practical application of NH 3 -selective catalytic reduction (NH 3 -SCR) technology. Herein, a dynamic Brønsted acid site compensation strategy based on the heterolytic dissociation of H 2 O is proposed to improve the water tolerance of Cu-based chabazite catalysts. Following this strategy, a Co-WO 3 /FeCu-SSZ-13 catalyst was rationally designed. Co doping effectively modulates the d-band center of WO 3 , enabling heterolytic H 2 O dissociation and the in situ generation of hydroxyl groups that act as Brønsted acid sites, thereby significantly enhancing NH 3 adsorption and activation. Simultaneously, preferential utilization of H 2 O for Brønsted acid site compensation mitigates its competitive occupation of the intrinsic metal active sites in FeCu-SSZ-13, preserving the NO oxidation pathway under high-humidity conditions. Therefore, this synergistic regulation of dynamic compensation of Brønsted acid sites and the release of active metal sites enables Co-WO 3 /FeCu-SSZ-13 to achieve a NO x conversion exceeding 90% at 165 ° C in the presence of 20 vol % H 2 O. This work highlights the dual role of H 2 O in simultaneously regulating the acid and redox cycles, offering a general strategy for designing water-tolerant NH 3 -SCR catalyst.