Improving catalytic performance of Cu-SSZ-13 for NOx abatement via in-situ introduction of La and Ce from spent catalyst

Designing a cost-effective and fast fabrication Cu-SSZ-13 with improved selective catalytic reduction of NO by ammonia (NH 3 -SCR) performance remains an open question. Here we report that LaCe-SSZ-13 zeolites were synthesized from spent fluid catalytic cracking catalyst within 12 h. After ion-exchanging with CuSO 4 solution, the obtained LaCeCu-SSZ-13 catalysts exhibit significantly higher catalytic activity and hydrothermal stability than conventional Cu-SSZ-13. Various characterizations reveal that La and Ce modification not only facilitates the disperse of isolated Cu 2+ species, but also effectively mitigates dealumination and inhibits copper species aggregation after hydrothermal aging. In-situ diffuse reflection infrared Fourier transform spectrum analyses demonstrate that La and Ce modification can accelerate the adsorption capacity for NH 3 and NO x and promote the decomposition of NH 4 NO 3 intermediate species on the catalyst, benefiting the improvement of low-temperature activity. The combination of experiments and theoretical calculations further demonstrate that the most stable positions of La and Ce are on different eight-membered rings in SSZ-13, and then Cu 2+ ions tend to enter eight-membered rings to enhance the NH 3 adsorption capacity and decrease the H 2 O adsorption capacity, which results in higher low-temperature activity and hydrothermal stability than Cu-SSZ-13. Our work provides a feasible strategy for preparing the efficient rare-earth-modified Cu-zeolite based NH 3 -SCR catalyst for nitrogen oxide abatement.