Bifunctional catalysts V-Cu/TiO2 for selective catalytic reduction of NOx and CO oxidation under oxygen-rich conditions

The simultaneous removal of CO and NOx in the sintering flue gas over a single catalyst is desirable but challenging. Herein, 2 %V2O5-5 %CuO/TiO2 bifunctional catalysts that efficiently catalyzed CO and NOx at low temperatures were reported, with CO and NOx conversions of 100 % at 200-300 degrees C. The synergistic effect between copper and vanadium oxides enhanced the redox and CO adsorption capacities of 2 %V2O5-5 %CuO/TiO2, rendering it abundant acid sites and surface chemisorbed oxygen. The in situ DRIFTS experiments demonstrated that CO oxidation over the dual-active-sites 2 %V2O5-5 %CuO/TiO2 catalyst follows the Mars-van Krevelen mechanism, while the E-R mechanism was the primary NH3-SCR pathway. Due to the presence of dual-activesites (i.e., separated of the V active sites for the NH3-SCR reaction and the Cu active sites for CO oxidation), the competition adsorption of CO and NH3 on the Cu sites was weakened, resulting in higher CO oxidation performance than the single-active-site catalysts. This work provided insights into the control of flue gas containing CO and NOx over a single catalyst.