Ce enhanced low-temperature performance of Mn modified Cu-Beta zeolite catalyst for NH₃-SCR

The zeolite-based catalyst is a promising option for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) due to its low toxicity. However, the challenge lies in its low-temperature activity. This study developed a multi-component catalytic system consisting of Ce/Mn/Cu-loaded Beta zeolite to reduce NOx. With fixed contents of Cu and Mn, we investigated the NH3-SCR process and the mechanism of action of the rare-earth species (i.e., Ce) in the system. Upon optimization of the content of Ce, the Ce/Mn/Cu-loaded Beta zeolite demonstrated enhanced low-temperature activity compared to samples loaded with Cu or Cu/Mn in the temperature range of 150-250 degrees C. When Ce was loaded in an appropriate proportion, it regulated the oxidation state of Cu, optimizing active adsorption species for NO and strengthening the strength of Bronsted acid sites in the catalyst. These synergetic effects led to improved NH3-SCR catalytic performance. This study can contribute to a better understanding of multiple metal-loaded zeolites in the NH3-SCR process and inform future design of Beta-type catalysts.