A flat-lying dimer as a key intermediate in NO reduction on Cu(100)

Abstract

The reaction of nitric oxide (NO) on Cu(100) is studied by scanning tunneling microscope, electron energy loss spectroscopy and density functional theory calculations. The NO molecules adsorb mainly as monomers...

Partial reduction of NO to N2O on Cu{311}: role of intermediate N2O2

“…The first of these two steps we calculated to involve an activation barrier amounting to 0.78 eV, while the second involves a barrier of just 0.18 eV. It must be remarked, however, that the first of these barriers is relatively high, given our expectation that the reaction should proceed at temperatures in the vicinity of 100 K. By way of contrast, in the recent work of Kuroishi et al [29] on the Cu{100} surface, a barrier of just 0.21 eV was calculated for a similar stage in their proposed pathway. Crucially, the route proposed here is nevertheless more kinetically favourable than the direct dissociation of NO.…”

“…Accordingly, it is probably rather more accurate to designate the surface intermediate as N 2 O 2 , rather than as (NO) 2 . Furthermore, recent RAIRS and Scanning Tunnelling Microscopy (STM) experiments, performed by Shiotari et al [24,[27][28][29], suggest a key role for closely coadsorbed NO molecules that may map onto the weakly bound (NO) 2 concept a little more closely than the N 2 O 2 species predicted by theory.…”

DFT Study of the NO Reduction Mechanism on Ag/γ-Al2O3 Catalysts

“…Formation of NO dimers has been demonstrated experimentally on the surface of bulk silver and has been shown to be profitable on the surface of Ag 2 /γ-Al 2 O 3 and Ag 2 + /γ-Al 2 O 3 systems in our previous theoretical study . NO dimers readily transfer oxygen atoms to various reductants and are experimentally proven to be a key intermediate in NO reduction on the Cu surface . Reductants (oxygen atoms acceptors) are quite abundant in the HC-SCR system.…”

“…11 NO dimers readily transfer oxygen atoms to various reductants and are experimentally proven to be a key intermediate in NO reduction on the Cu surface. 21 Reductants (oxygen atoms acceptors) are quite abundant in the HC-SCR system. In particular, in our study, acetaldehyde is considered as the potential reductant since it has been experimentally detected in the system in large quantities.…”

First-Principles Microkinetic Study of NO Reduction on Cu Catalysts

“…Based on those data, we can conclude that the presence of a flat-ONNO intermediate significantly lowers the dissociation barriers on all investigated surfaces. Therefore, dimer-mediated dissociation will be the dominant reaction at lower temperatures, as suggested by experimental works under vacuum conditions and theoretical calculations. ,,, However, the detailed mechanism of the NO reduction reaction at higher temperatures remains unclear, and thus a temperature-dependent study needs to be conducted. To this end, we employ microkinetic analysis to explore the NO reduction reaction on Cu surfaces at a wide temperature range.…”