Recent advances in bimetallic small-pore zeolite catalysts for ammonia-assisted selective catalytic reduction of NOx

Bimetallic small-pore zeolites containing Cu ions and secondary metal ions present a potential application value for ammonia-assisted selective catalytic reduction of nitrogen oxides (NOx ), showing superior catalytic activity and excellent hydrothermal stability compared to monometallic Cu-zeolites. The idea of introducing secondary metal ions aims to modulate the properties of Cu active sites. This review first summarizes the strategies of incorporating secondary metal ions into zeolites. Then, we delve into the impacts of varying loadings of secondary metal ions on the catalytic performance of zeolites. Finally, we emphasize the synergistic interactions between secondary metal ions and active Cu sites, focusing on their effects on the distribution, stability, and activity of the Cu active sites, which are adjusted by the presence of secondary metal ions. In conclusion, we wrap up this review and provide perspectives on the design and in-depth study on metal ions-doped Cu-zeolite catalysts.