First-Principles Microkinetic Study of NO Reduction on Cu Catalysts

We have studied the NO reduction reaction on several Cu surfaces over a wide range of temperatures, with two dissociation pathways considered: monomer dissociation and dimer-mediated dissociation. Density functional theory was employed to estimate reaction energies, which were then used for microkinetic analysis. Under ultrahigh vacuum conditions, NO reduction occurs via a dimer-mediated dissociation pathway at lower temperatures, while NO is desorbed at higher temperatures. NO, N-2, and N2O gases are formed, as observed in surface science experiments. Under catalytic conditions, dimer-mediated dissociation is the predominant reaction during the cold start period (T < 600 K), leading to high NO conversion. However, at typical three-way catalyst temperatures (600 K < T < 1200 K), monomer dissociation occurs along with NO desorption, leading to a decrease in NO conversion. Our result suggests that Cu is a promising catalyst for NO reduction, particularly at cold start temperatures.

Automated summary

In this study, the NO reduction reaction on different Cu surfaces was investigated at various temperatures. It was found that the reaction can occur through monomer dissociation and dimer-mediated dissociation pathways. During the cold start period, dimer-mediated dissociation is the predominant reaction, while at typical catalyst temperatures, monomer dissociation also takes place, leading to a decrease in NO conversion.