Abstract
For the purpose of looking for the catalyst for the reduction of NO by CO, CuO catalysts with the addition of rare earths were investigated.
Addition effects of rare earths were exhibited by each of Nd, Tb, Dy and Ho, respectively, improving the activity at lower temperatures about 200°C With Dy, in particular, an appreciable addition effect was found even with addition of small amounts, say 2.5%. By the addition of two kinds of rare earths a higher addition effect than single addition was obtained for (Ho+Tb) and (Ho+Nd). Catalysts consisting of (Ho+Nd)-CuO with the addition of Cr or Ba exhibited a high activity even in the presence of oxygen and water.
It is considered that the catalytic reduction of NO by CO proceeds according to a redox mechanism, the reduction process of active sites is rate controlling, and Dy added increases the rate constant of the reduction process at active sites and facilitate the activity of catalyst.
It is considered that the catalytic reduction of NO by CO proceeds according to a redox mechanism, the reduction process of active sites is rate controlling, and Dy added increases the rate constant of the reduction process at active sites and facilitate the activity of catalyst.
