Preparation of modified Ce-SAPO-34 catalysts and their catalytic performances of methanol to olefins

The modified Ce-SAPO-34 catalysts were prepared with three methods, i.e., the liquid ion exchange with air calcination, impregnation with air calcination and impregnation with steam calcination methods. The catalytic performances of the catalysts for methanol to olefins were investigated. The properties of the catalysts were characterized using XRD, BET, XRF, FT-IR and NH3-TPD. The results indicated that compared to the SAPO-34 catalyst the catalyst prepared with the impregnation and air calcination prolonged the lifetime by 40 min and improved the selectivity to ethylene by 5% （mol） and the catalyst prepared with the impregnation and steam calcination showed the best modification effect, prolonging the lifetime by 70 min and improving the ethylene selectivity by 10% （mol）. The catalyst prepared with the liquid ion exchange showed similar behaviour as the SAPO-34 catalyst. It was verified that the porous structure and surface acidity of these catalysts determined their catalytic behaviors.