Selective Catalytic Reduction of NO by Hydrocarbons on a Stepped Pt Surface: Influence of SO₂ and O₂

Abstract

The catalytic reduction of NO by hydrocarbons (C 2 H 4 and its derivatives) in the presence of both S 18 O 2 and O 2 on Pt(332) was investigated. S 18 O 2 -C 2 H 4 interactions are much stronger than NO-C 2 H 4 interactions. Co-adsorbed S 18 O 2 molecules consume most of the H atoms from C 2 H 4 dissociation before NO dissociation, a major cause for suppressing the NO-C 2 H 4 reaction. The S 18 O 2 molecules also reduce the reactivity of Pt(332) toward NO-C 2 H 4 reaction by passivating the metal surface and by blocking the step sites for NO adsorption. NO-C 2 H 4 reactions are also suppressed by co-adsorbed O(ads.) atoms due to the stronger Pt-O interaction and facile H-O reaction. However, when the coverage of O atoms is appropriate, the O atoms effectively lifts the suppressive effect of S 18 O 2 , a result of the facile O-S 18 O 2 reaction, which scavenges the S 18 O 2 related species and consequently gives the Pt(332) surface a more reactive pathway toward the NO dissociation (compared to that covered with sulfur oxides).

Mechanistic insight into the selective catalytic reduction of NOx with propene on the Ce0.875Zr0.125O2 (110) surface

“…ZSM-5 27,28 ), and supported noble metals (e.g. Cu, 11,19,21 Pt 29,30 ). Among these catalysts, metal oxide-based catalysts have higher catalytic effectiveness, hydrothermal stability, flexible compositions, and low cost.…”

Water Effect on Preparation of Ag/Al2O3 Catalyst for Reduction of NOx by Ethanol

“…Compared with lean-burn gasoline engines, the use of diesel engines has become a popular strategy to improve fuel economy. However, emission control, especially NOx abatement, is a major challenge for environmental catalysis under an oxidizing atmosphere. − Since the pioneering work of Iwamoto et al and Held et al, selective catalytic reduction of NOx by hydrocarbons (HC-SCR) has drawn more and more attention for the removal of NOx from lean-burn exhaust. − Among the available catalysts, Ag/Al 2 O 3 is deemed one of the most effective materials for HC-SCR of NOx. , In particular, when ethanol is used as a reductant, good activity , and moderate tolerance to water and SO 2 can be achieved . Currently, the low-temperature activity , (<350 °C) of Ag/Al 2 O 3 and the complexity of its preparation still remain bottlenecks for the development of HC-SCR.…”