Trace Ce-modified x%Ce3%Cu-SAPO-34 zeolites prepared by a one-pot method and applied for enhanced NH3-SCR denitration activity

Abstract

A series of x%Ce3%Cu-SAPO-34 catalysts with different trace Ce contents were synthesized by a one-pot method, and their catalytic performance was investigated for NH₃-SCR denitration. Ce-doped catalysts demonstrated superior activity compared with the one without Ce doping, with 0.06%Ce3%Cu-SAPO-34 achieving optimal NO conversion at 150–440 °C. After hydrothermal aging (70 °C/650 °C), this catalyst still retained a broad activity window (200–420 °C). Characterization results revealed that the modification of Cu-SAPO-34 with Ce would increase active Z₂-Cu²⁺ and Z-[Cu(OH)]⁺ species while suppressing the aggregation of inactive CuO_x species. Ce modification is able to alter the Si and Al environments, leading to localized framework distortions that affect Cu²⁺ distribution, enhance acidity and accelerate the NH₃ adsorption and reaction rates. Compared to 3%Cu-SAPO-34, the 0.06%Ce3%Cu-SAPO-34 catalyst exhibited enhanced low/high-temperature NH₃-SCR activity, which can be attributed to the synergistic effects of stabilized Cu species, enhanced acidity, and suppressed CuO_x formation. These improvements underscore the dual role of trace Ce in modulating both the Cu²⁺ and the acidity of the catalyst. These results highlight that the trace Ce-modified catalysts can achieve the effect of “low loading and high efficiency”, balancing green advantages and economic benefits. This study may inspire the preparation of Cu-SAPO-34 with trace amounts of rare earth metals.