Low-temperature catalytic oxidation of NO over Mn–Co–Ce–Ox catalyst

Abstract

A series of manganese–cobalt–cerium oxide (Mn–Co–Ce–Ox) catalysts were prepared by co-precipitation method and tested for low temperature (<200°C) catalytic oxidation of NO in the presence of O2. The experimental results showed that the best catalyst yielded about 80% NO conversion at 150°C with a space velocity of 35,000h−1. As the cerium content was increased from 0% to 20% (mass%), NO conversion increased significantly, while decreased at higher cerium contents (30–40%). As comparison, single oxides were also investigated, and their activities were slower than those of Mn–Co–Ce–Ox catalyst. The effect of O2 (0–11%) was evaluated, and it is almost constant when the concentration of O2 was above 3%. The activity was suppressed with the coexisting of H2O and SO2 due to the generation of nitrates and sulfates, and the activity was restored to 45% after turning them off. The excellent low-temperature catalytic activity is mainly due to the amorphous phase, pore structure and high specific areas.