The enhanced catalytic activity of Cu/SAPO-34 by ion exchange method for selective catalytic reduction of nitric oxide

Abstract

The Cu/SAPO-34 catalysts were prepared via the ion exchange process for achieving improved catalytic activity. Effects of various parameters including copper ions sources, copper ions loadings and ion exchange temperature on catalyst performance of the Cu/SAPO-34 catalysts were investigated. The results showed that the Cu/SAPO-34 catalysts roughly maintained similar cubic-like morphology and crystalline structure with the SAPO-34 catalyst, and achieved enhanced catalytic activity. Among various copper ion sources, the Cu/SAPO-34 catalyst using Cu(CH₃COO)₂ as copper ion source demonstrated high nitric oxide conversion rate. Increasing the copper ion loadings, the nitric oxide conversion rate of the Cu/SAPO-34 catalysts achieved significant improvement. However, when the copper ion loadings exceeded 0.01 mol, the nitric oxide conversion rate began to decline. The catalytic activity of the Cu/SAPO-34 also closely depended on ion exchange temperature. The nitric oxide conversion rate of the Cu/SAPO-34 catalyst showed a trend of first increasing and then decreasing with the improvement of ion exchange temperature, and the recommended ion exchange temperature was 60 °C. Hydrothermal aging treatment further confirmed the good stability of the Cu/SAPO-34 catalyst. Moreover, kinetic investigation was carried out, which was in agreement with the SCR results.