One-pot synthesis of Cu-Ce co-doped SAPO-5/34 hybrid crystal structure catalysts for NH_3-SCR reaction with SO_2 resistance

SAPO-34, SAPO-5/34 based catalysts doped with Cu, Ce as active components were synthesized via a one-pot hydrothermal method by using different amounts of additive (α-cellulose), and their catalytic activities were measured for selective catalytic reduction (SCR) of NO with NH₃. The synthesized Cu–Ce co-doped products switch from cubic SAPO-34, to flower-like aggregated SAPO-5/34, hybrid crystal SAPO-5/34, and finally to spherical aggregated SAPO-34 with the increase of α-cellulose amount. The Cu–Ce co-doped SAPO-5/34 hybrid crystal structure catalysts with 0.75 mol ratios of C/P (Cu–Ce/SP-0.75) exhibit excellent NH₃-SCR activity with higher than 90% NO_x conversion in the temperature range of 180–450 °C, at WHSV of 20000 mL/(g·h). Furthermore, the catalyst displays outstanding sulfur resistance and NO_x conversion maintains above 90% at 200–450 °C after adding 100 ppm of SO₂. The characteristic results suggest that the high deNO_x performance of Cu–Ce/SP-0.75 is due to the enhanced accessibility, abundant activity species, excellent redox property and high adsorptive and activated capacity for NH₃.