Novel promoting effect of SO2 on the selective catalytic reduction of NOx by ammonia over Co3O4 catalyst

Spinel nano-Co3O4 was prepared by solid-state reaction at room temperature and investigated for selective catalytic reduction of NOx by NH3 (NH3-SCR). Although suffering from pore filling and plugging, treatment of this catalyst by SO2 showed novel promoting effect on NH3-SCR above 250 °C. Bulk cobalt sulfate was observed over the sulfated Co3O4 with XRD, which would be an active component for NH3-SCR. The sulphated Co3O4 catalyst exhibited good resistance to SO2 (500 ppm, 100 ppm) and 10% H2O at a space velocity of about 25 000 h−1 at 300 °C, as tested for 12 h.