CuO/TiO2 has been shown to be a superior sorbent for selective, revers
ible adsorption of NO from hot combustion gases. High NOx adsorption c
apacities at 200 and 300 degrees(C) were obtained with a 5% CuO/TiO2 s
orbent, and the NOx desorbed rapidly at 450 degrees C. Doping with 2%
Ce an the CuO/TiO2 sorbent further increased both uptake rates (50% in
crease in initial rate) and NOx capacity (by 30%). in a direct compari
son with the most promising known sorbent, MnO/ZrO2 (1:1 molar ratio),
reported by Eguchi et al. (J. Catal. 1996, 158, 420), the Ce-CuO/TiO2
sorbent showed both higher uptake rates (by 100% in initial rate) and
higher NOx capacity (by 15%). The effects of CO2, H2O, and SO2 on NOx
sorption on the Ce-CuO/TiO2 sorbent were studied at 200 degrees C. CO
2 slightly decreased the initial uptake rate but increased the NOx cap
acity. H2O coadsorbed with NOx on different sites, both reversibly (i.
e. desorbed at 450 degrees C). SO2 irreversibly adsorbed (likely to su
lfate the surface of TiO2) and decreased the NOx capacity by approxima
tely 20%. The BET surface area of the TiO2 support was 50 m(2)/g. Furt
her studies with TiO2 of higher surface areas are in progress.