N2O Hydrogenation on Silver Doped Gold Catalysts, a DFT Study

Abstract

In this study, the full reaction mechanism for N2O hydrogenation on silver doped Au(210) surfaces was investigated in order to clarify the experimental observations. Density functional theory (DFT) calculations were used to state the most favorable reaction paths for individual steps involved in the N2O hydrogenation. From the DFT results, the activation energy barriers, rate constants and reaction energies for the individual steps were determined, which made it possible to elucidate the most favorable reaction mechanism for the global catalytic process. It was found that the N2O dissociation occurs in surface regions where silver atoms are present, while hydrogen dissociation occurs in pure gold regions of the catalyst or in regions with a low silver content. Likewise, N2O dissociation is the rate determining step of the global process, while water formation from O adatoms double hydrogenation and N2 and H2O desorptions are reaction steps limited by low activation energy barriers, and therefore, the latter are easily carried out. Moreover, water formation occurs in the edges between the regions where hydrogen and N2O are dissociated. Interestingly, a good dispersion of the silver atoms in the surface is necessary to avoid catalyst poison by O adatoms accumulation, which are strongly adsorbed on the surface.

High-Efficiency Electrocatalytic Reduction of N2O with Single-Atom Cu Supported on Nitrogen-Doped Carbon

“…Previous studies have also identified a comparable N 2 O decomposition mechanism on Cu atoms in Cu-ZSM-5 and Cu-porphyrins . The breaking of the N–O bond after N 2 O’s O-terminal adsorption was considered to be the rate-determining step, followed by N 2 desorption. ,, The residual *O subsequently accepted *H, leading to the formation of *OH and H 2 O …”

“…57,59,60 The residual *O subsequently accepted *H, leading to the formation of *OH and H 2 O. 61 The charge density difference diagram of Cu 1 −NCB illustrated the electron interactions between the adsorbed *OH and Cu−N 4 sites, highlighting electron accumulation (yellow regions) and depletion (blue regions) near the Cu atom (Figure 6b). The charge distribution predominantly occurred around the Cu site, forming an electron-rich region that facilitated the reaction.…”

Deoxygenation reactions of nitrous oxide assisted by oriented external electric field

“…N 2 O is a chemically stable and kinetically inert molecule [16], its deoxygenation reaction remains difficult, as even thermal decomposition is limited by a high kinetic barrier despite being thermodynamically favorable [14, 17, 18]. According to the previous reports, most of the degradation of N 2 O relied on metal catalysts, such as Mn, Fe, Co, Ni, Cu, Bi, Ru, Re [19–32]. However, those metals exist obvious weaknesses more or less, such as the complicated ligand preparation process, the harsh reaction conditions, rare and expensive, or the low selectivity from the abundant metals [33, 34].…”