Comparison of NH3-SCO performance over CuOx/H-SSZ-13 and CuOx/H-SAPO-34 catalysts

Abstract

In this work, CuOx/Chabazite(CHA, SSZ-13, SAPO-34 etc) catalysts were prepared by wet impregnation method for ammonia selective catalytic oxidation. CuOx/H-SSZ-13 exhibited superior NH3 conversion and N2 selectivity compared with CuOx/H-SAPO-34 below 300 °C under both dry and wet conditions. The better low-temperature activity of CuOx/H-SSZ-13 was due to its greater NH3 adsorption and activation capacity. DRIFTS results showed that –NH2 and –NH radicals can be observed on the spectra of CuOx/H-SSZ-13, whereas, only –NH2 radicals were obtained on the spectra of CuOx/H-SAPO-34. CuOx (including CuO and Cu2O) were determined as active phases of the catalysts using XRD and XPS results. The catalytic performance of CuOx/CHA catalysts was reversibly suppressed in the presence of H2O and SO2 regarding the formation of NH4HSO4 and (NH4)2SO4 on the catalysts surface. Furthermore, CuSO4 was also formed and could not decompose until 700 °C. However, it showed less influence on the catalytic performance.