Three-dimensionally ordered macroporous CeZrVOx catalyst with remarkable NH3-SCR performance and SO2 tolerance: Key roles of the morphology and highly dispersed V species

Developing effective low-temperature deNOx catalysts with high activity, SO2 tolerance, and stability is crucial yet challenging. Thus, in this work, CeZrVOx catalyst with a three-dimensional ordered macroporous structure was successfully prepared using the PMMA hard template method, and the catalyst has a macropore diameter of up to 110−140 nm. The modification with highly dispersed V significantly enhances the low-temperature activity and broadens the activity temperature window of the catalyst. This is mainly attributed to the increased number of surface acid sites, as well as the higher proportion of Ce3+ and active surface oxygen species induced by V modification. The V species prepared by this method are highly dispersed on the CeZrOx solid solution and combine with Ce to form CeVO4, which is also an important factor in enhancing catalytic activity. The catalyst does not react with SO2 to produce inactive sulfate species; even the formed cerium sulfate species are beneficial for high-temperature performance. More importantly, due to its unique interconnected three-dimensional ordered structure, the catalyst can significantly inhibit the blockage coverage of NH4HSO4 on the catalyst, thereby exhibiting remarkable resistance to physical poisoning caused by SO2. Even in high concentrations of sulfur-containing atmospheres, the catalyst still shows high catalytic activity. This work offers meaningful guidance into developing denitration catalysts that show superior performance and robust resistance to both physical and chemical poisoning induced by SO2.