Cu-SAPO-17: A novel catalyst for selective catalytic reduction of NOx

Abstract

The high-temperature (HT) and low-temperature (LT) hydrothermal stabilities of molecular-sieve-based catalysts are important for the selective catalytic reduction of NOx with ammonia (NH3-SCR). In this paper, we report a catalyst, Cu2+ loading SAPO-17, synthesized using cyclohexylamine (CHA), which is commercially available and inexpensive and is utilized in NH3-SCR reduction for the first time. After systematic investigations on the optimization of Si and Cu2+ contents, it was concluded that Cu-SAPO-17-8.0%-0.22 displays favorable catalytic performance, even after being heated at 353 K for 24 h and at 973 K for 16 h. Moreover, the locations of CHAs, host–guest interaction and the Brönsted acid sites were explored by Rietveld refinement against powder X-ray diffraction data of as-made SAPO-17-8.0%. The refinement results showed that two CHAs exist within one eri cage and that the protonated CHA forms a hydrogen bond with O4, which indicates that the proton bonding with O4 will form the Brönsted acid site after the calcination.