Catalytic reduction of nitric oxide with carbon monoxide on copper-cobalt oxides supported on nano-titanium dioxide

摘要

A series of copper-cobalt oxides supported on nano-titanium dioxide were prepared for the reduction of nitric oxide with carbon monoxide and characterized using techniques such as XRD, BET and TPR. Catalyst CuCoO_x/TiO_2 with Cu/Co molar ratio of 1/2, Cu-Co total loading of 30% at the calcination temperature of 350℃ formed CUCo_2O_4 spinel and had the highest activity. NO conversion reached 98.9% at 200℃. Mechanism of the reduction was also investigated, N_2O was mainly yielded below 100℃, while N_2 was produced instead at higher temperature. O_2 was supposed to accelerate the reaction between NOx and CO for its oxidation of NO to give more easily reduced NO_2, but the oxidation of CO by O_2 to CO_2 decreased the speed of the reaction greatly. Either SO_2 or H_2O had no adverse impact on the activity of NO reduction; however, in the presence of both SO_2 and H_2O, the catalyst deactivated quickly.