In Situ Synthesis of Cu-SAPO-34/Cordierite for the Catalytic Removal of NOx From Diesel Vehicles by C3H8

A Cu-SAPO-34/cordierite catalyst was prepared by in situ hydrothermal synthesis. The morphology and structure of the Cu-SAPO-34/cordierite samples were characterized by X-ray diffraction, scanning electron microscopy, and physical adsorption-desorption analyzer. The removal of NOx from simulated diesel vehicle exhaust gas was carried out using a fixed-bed reactor. The effects of C3H8, O-2 concentrations, and water vapor on the activity of the catalyst were studied. The results indicate that the Cu-SAPO-34 coatings obtained by the in situ synthesis are firm and compact, and the loading amount is found to be more than 20% after one synthesis operation. The surface areas of the Cu-SAPO-34/cordierite catalysts increase greatly compared with that of cordierite. The active Cu component prepared through in situ synthesis can significantly improve the activity of selective catalytic reduction of NOx by C3H8. NOx reduction over the Cu-SAPO-34/cordierite catalyst is more than 60% between 500 and 650 degrees C. The NOx conversion decreases after the addition of 10% water vapor to the feed gas but the deactivation caused by water vapor is not permanent.