Preparation of Cu/La 2O 3-ZrO 2-Al 2O 3 catalyst and its catalytic properties for selective reduction of NO

Abstract

The La 2O 3-ZrO 2-Al 2O 3 composite support was prepared by co-precipitation method with the mixed aqueous solution of La(NO 3) 3, Al(NO 3) 3, and ZrOCl 2 dropping into the precipitant of (NH 4) 2CO 3 aqueous solution. The Cu/La 2O 3-ZrO 2-Al 2O 3 catalyst was prepared by the impregnation of La 2O 3-ZrO 2-Al 2O 3 with active component Cu 2+ aqueous solution. The effects of the catalyst on the selective catalytic reduction of NO with propylene in excess oxygen were investigated. The relationships among the preparation method, structure, and properties of the Cu/La 2O 3-ZrO 2-Al 2O 3 catalyst were also explored by means of Scanning electron microscope (SEM), X-ray diffraction (XRD), Surface area measurements (BET), Pyridine absorption infrared spectrum (Py-IR), thermal gravimetry (TG), and Temperature-programmed reduction (TPR). The results indicate that the support J-Al 2O 3 prepared by Al(NO 3) 3 dropping into (NH 4) 2CO 3 can remarkably enlarge the surface area; the addition of La 2O 3 contributes mainly to the enhancement of the thermal stability; and the introduction of ZrO 2 can increase the amount of Lewis and BrInsterd acid. Consequently, the catalyst Cu/La 2O 3-ZrO 2-Al 2O 3 has excellent activity for the selective reduction of NO with propylene in excess oxygen. The NO conversion is up to 88.9% at 300°C and 81.9% even at the presence of 10% volume fraction of water vapor.