Density functional study of molecular nitrogen adsorption on gold-copper and gold-silver binary clusters

Abstract

Density functional theory calculations were performed to investigate the adsorption behaviors of nitrogen molecule on small bimetallic AunCum and AunAgm clusters, with n + m ≤ 5. In all cases the N2 forms a linear or quasi-linear M-N-N structure (M = Au, Cu or Ag). The adsorption energies of N2 on pure metal clusters follow the order CunN2 > AunN2 > AgnN2, which is due to the weaker orbital interaction between silver and N2. N2 prefers to bind to a copper atom in AunCumN2 complexes and prefers to bind to a silver atom in AunAgmN2 complexes. The combination of Cu atoms into Aun clusters makes the cluster more reactive toward N2 while the combination of Ag atoms into Aun clusters makes the cluster less reactive toward N2. The electrostatic interaction is strengthened while the back-donation from metal to N2 is reduced in bimetallic cluster nitrides, as compared to the mono cluster nitrides. The N-N stretching frequencies are all red-shifted upon adsorption and the M-N stretching frequencies are highly correlated to the atoms to which the N is attached.

A low cost bimetallic AuCu3 tetramer on Ti2CO2 MXene as an efficient catalyst for CO oxidation: a theoretical prediction

“…The Au-Cu bond lengths here are 2.48 Å along the short diagonal, and 2.54 Å along the edges, and the Au-Au bond length is 2.67 Å along the periphery. Again, the agreement with the literature 21 is excellent (2.47 Å, 2.54 Å, and 2.71 Å, respectively).…”

“…, 2.39 Å (2.27 Å) bond length for the peripheral (short diagonal) bond. 21 Similarly, the lowest energy configuration for a pure Au 4 cluster is also a rhombus with long peripheral and short diagonal Au–Au bond lengths of 2.70 Å and 2.65 Å, respectively (Fig. 1(b)).…”

“…These values are close to the corresponding bond lengths reported in ref. 21, i.e. , 2.37 Å for peripheral Cu–Cu, 2.29 Å for short diagonal Cu–Cu and 2.53 Å for Cu–Au bonds.…”

Spectroscopic characterization and in vitro studies of biological activity of bradykinin derivatives

“…Also, in BK7 (Fig. 6C), most of the Thi bands decrease in intensity compared to BK11, while the SERS signals at 1501 and 1458 cm -1 practically disappear, and the 255 cm -1 spectral feature, which is due to (Au-N), is the strongest band in the spectrum 43 . Moreover, in the low-energy region of the spectra (below 400 cm −1 ), where the (Au-S) vibrations are expected, three bands of intermediate intensity appear only for BK11 at 323, 305, and 285 cm -1 .…”

Formation of Single Cu Atomic Chain in Nitrogen Atmosphere

“…The interaction between a propane molecule and Au, which is estimated to be 0.13 eV, reduces the energy of the surface in low coordination states, and the adsorbates stabilize the Au atomic junction. 22 Since previous cluster calculation revealed the interaction between N 2 and Cu can be also estimated to be about 0.1 eV, 27 we can expect N 2 molecules which are attached on the Cu atomic junction also reduces the energy of the Cu surface in the low coordination states. Therefore, it is considered that adsorbed N 2 molecules stabilize the Cu low coordination states, which leads to the formation of Cu LACs.…”