Fabrication of wide temperature lanthanum and cerium doped Cu/TNU-9 catalyst with excellent NH3-SCR performance and outstanding SO2+H2O tolerance

Abstract

The effects of La on the catalytic performance, SO2 and H2O resistance of Cu–Ce/TNU-9 catalyst were studied in the selective catalytic reduction of NOx via ammonia (NH3-SCR). The results show that the La doped Ce–Cu/TNU-9 (CCL/T9) catalyst exhibits better SCR performance than Ce–Cu/TNU-9 (CC/T9) and Cu/TNU-9 (C/T9) in the wide temperature window (200–450 oC) due to La benefiting from enhancing Cu++Ce4+↔Cu2++Ce3+ to facilitate the electron transfer, which further accelerates the oxidation of NO into NO2 that leads to the “Fast SCR”. The La can also enhance the surface acidic, redox property and is beneficial to the formation of oxygen vacancy. Meanwhile, the larger content of Ce3+ can produce oxygen vacancy, resulting in rising SCR activity. The CCL/T9 has outstanding water and SO2 resistance, which may be due to the adsorbed S on the surface of these catalysts mainly existing in the form of a small amount of sulfate and sulfite, the decomposition of ammonium bisulphite under high temperature and the hydrophobicity of TNU-9 zeolite.