Low-temperature selective catalytic reduction of NO with propylene in excess oxygen over the Pt/ZSM-5 catalyst

Abstract

A 0.5 wt% Pt/ZSM-5 catalyst was used for the low-temperature selective catalytic reduction (SCR) of NO with C 3H 6 in the presence of excess oxygen. Under an atmosphere of 150 ppm NO, 150 ppm C 3H 6 and 18 vol% O 2 (GHSV 72,000 h −1), Pt/ZSM-5 showed remarkably high catalytic performance giving 77.1% NO reduction to N 2 + N 2O and 79.7% C 3H 6 conversion to CO 2 simultaneously at 140 °C. The samples were characterized by means of NO temperature programmed desorption (TPD), NO/C 3H 6 temperature programmed oxidation (TPO), BET surface area, XRD and TEM. The catalytic activities of C 3H 6 combustion and NO oxidation are improved by well-dispersed platinum significantly. It is found that the enhanced activity of Pt/ZSM-5 for the low-temperature SCR is associated with its outstanding activities in the TPO processes of NO to NO 2 and C 3H 6 to CO 2 in low temperature range.