Performance and mechanism study for low-temperature SCR of NO with propylene in excess oxygen over Pt/TiO_2 catalyst

摘要

A 0.5 wt.% Pt/TiO_2 catalyst was prepared and used for the low-temperature selective catalytic reduction (SCR) of NO with C_3H_6 in the presence of excess oxygen. The effects of Pt loading and O_2 concentration on Pt/TiO_2 catalytic performance for low-temperature SCR were investigated. It was found that optimal Pt loading was 0.5 wt.% and excess O_2 favored low-temperature SCR of NOx. The mechanism of low-temperature SCR of NO with C_3H_6 was investigated with respect to the behavior of adsorbed species over Pt/TiO_2 at 150℃ using in situ DRIFTS. The results indicated that surface nitrosyl species (Pt~(δ+)-NO and Ti~(3+)-NO) and Pt~(2+)-CO are main reaction intermediates during the interactions of NO, C_3H_6 and O_2. A simplified NO decomposition mechanism for the low-temperature SCR of NO with C_3H_6 was proposed.