Preparation of Cu Nanocluster-Modified Mesoporous BEA Zeolite and Its Performance in Selective Catalytic Reduction of Nox

Nitrogen oxides (NOx) are one of the main pollutants from the combustion of fossil fuels and industrial emissions. The selective catalytic reduction of NH3 (NH3-SCR) is the most effective technology for removing NOx. Therefore, the development of efficient, environmentally friendly and stable SCR catalysts is of vital importance. Among them, Cu-based zeolite catalysts have attracted much attention due to their excellent low-temperature activity and hydrothermal stability. In this study, mesoporous Cu nanaoclusters-modified BEA zeolite (meso Cu/BEA) has been successfully prepared by a one-step synthesis method. The structure, morphology, distribution of Cu species, redox sites and acidic sites of the catalyst have been analyzed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption, H2 programmed temperature reduction (H2-TPR) and NH3 programmed temperature desorption (NH3-TPD). Additionally, the catalytic reduction activity and selectivity of product N2 in the NH3-SCR reaction have been systematically investigated. The results show that the introduction of mesoporous structures is conducive to the dispersion of Cu nanoclusters, exposing more active sites, and enabling meso Cu/BEA to exhibit excellent NOx conversion rate (80%) from 250 to 600 °C,and N2 selectivity (>97%) within a wide temperature window (200–575 °C). This is attributed to the synergistic effect between Cu nanoclusters and zeolite acidic sites. This study provides a new idea for the design of efficient and stable catalysts for the NOx reduction.