Selective Catalytic Reduction of NO by NH3 over One-Pot Prepared Cu-SSZ-13 Catalysts with Different Si/Al Molar Ratio

A series of Cu-SSZ-13 catalysts with different Si/Al molar ratio (10.6, 13.0, and 16.0) were prepared via one-pot method and investigated for the selective catalytic reduction by NH3. It was found that Cu-SSZ-13 with Si/Al ratio of 13.0 exhibited the best NH3-SCR performance with more than 94% NO conversion from 200 to 550°C. The influence of Si/Al molar ratio on the physical structure, redox behavior, surface acidity and Cu species distribution on the Cu-SSZ-13, together with the NH3 and nitrate adsorption species on the surface of Cu-SSZ-13 were characterized by N2-BET, XRD, NH3-TPD, H2-TPR, XPS, and in-situ DRIFTS, respectively. The characterization results indicated that the BET surface area, zeolite structure, surface acidity, redox properities, Cu2+ concentration, NH3 and nitrate adsorption species on the catalyst surface were closely related to the Si/Al ratio, all of these factors played important roles in the NH3-SCR performance for the Cu-SSZ-13.