SCR of NO_x with C₃H₈ over Co/H-beta modified by Zn at high GHSV

In order to improve the catalytic activity of Co-based catalysts for the selective catalytic reduction (SCR) of NO_x by C₃H₈ at high gas hourly space velocity (GHSV), the Co/H-beta catalyst was modified by Zn, and the bimetal Co-Zn/H-beta catalyst was prepared by impregnation method; its property of SCR for NO_x reduction by C₃H₈ in the presence of excess oxygen and at high GHSV range of 10000-100000 h^-1 was investigated. The results show that the catalytic activity of the prepared bimetal Co-Zn/H-beta catalyst is higher than that of single metal Co/H-beta and Zn/H-beta catalysts, and the maximum NO_x conversion ratio of about 95% over the Co-Zn/H-beta catalyst can be reach at 723 K and 20000 h^-1. It was considered that there exists cooperative effect between the Zn and Co in Co-Zn/H-beta catalyst; the oxidation of C₃H₈ is inhibited effectively by Zn addition, and the NO oxidation to NO₂ is enhanced by Co. The prepared Co-Zn/H-beta catalyst shows high activity at high GHSV, and its catalytic NO_x conversion ratio almost does not change when the GHSV is in the range of 10000-100000 h^-1.