Preparation of High-performance Cu-SAPO-34 Catalysts without Removal of Templating Agents

Abstract

The pollution of nitrogen oxides has become a serious environmental problem. Selective catalytic reduction (SCR) with zeolites is one of the most effective ways to remove nitrogen oxides. To reduce the cost of the catalysts' preparation, a facile fabrication method of high-performance Cu-SAPO-34 catalysts without removal of templating agents was proposed. Zeolite slurry containing templating agents was directly applied as a raw material to prepare the Cu-SAPO-34 catalyst followed by pretreatment, ion exchange and one-time calcination. As prepared catalysts were systematically investigated by XRD, BET, TG, ICP, XPS, SEM, TPR, TPD, and NH3-SCR. In the ion exchange process, different pH conditions were studied and optimized. The optimized catalyst with Cu content of 2.43% performed a cubic crystal, high acidity and catalytic activity. The NO conversion rate was more than 80% in the range of 200~450℃, and the highest value was 97.8% obtained at 300℃. Compared with the catalyst prepared from commercial SAPO-34, the as-prepared Cu-SAPO-34 catalysts without removal of templating agents exhibited similar microstructure and catalytic performance. These results indicate that the presence of a small amount of templating agent in the SAPO-34 zeolites makes no difference to fabricate high-performance Cu-SAPO-34 catalysts. It is a feasible method to prepare high-performance Cu-SAPO-34 catalysts without removal of templating agents.