Synergistic effect between rare-earth and copper species enhances hydrothermal stability of Cu-SSZ-13 for NO abatement

Cu-SSZ-13 catalysts have been demonstrated with excellent performance for selective catalytic reduction of NO _x with NH ₃ (NH ₃ -SCR), but remain a great challenge to be stable after hydrothermal aging, specifically in the scenario of a hydrogen combustion engine exhaust containing high water partial pressure. Here, we employ first-principles computational calculations to screen a series of rare earth (RE) modified Cu-SSZ-13, to investigate the impact on the low-temperature activity after hydrothermal aging. An yttrium (Y)-doping Cu-SSZ-13 has been screened out and exhibits a catalytic temperature window (175 ~ 555 ℃) of ~ 100 ℃ wider than that of conventional Cu-SSZ-13 (182 ~ 464 ℃) after hydrothermal aging. The characterizations unveil that the incorporation of Y modulates the catalytic microenvironments, generating more active and stable copper species. Further crystal orbital Hamilton population and ab initio molecular dynamics calculations interpret that RE elements, especially Y, doped in 6MRs, induce charge redistribution of Cu cations in 8MRs, increase the barrier of aggregation, and ultimately enhance the hydrothermal stability. This study reveals a clear structure-stability relationship for RE-modified Cu-SSZ-13, paving the way for the next generation of NH ₃ -SCR catalysts used in hydrogen fuel engines.