Density Functional Theory Study of the Adsorption of Hydrazine on the Perfect and Defective Copper (100), (110), and (111) Surfaces

Abstract

We have calculated the adsorption of the reducing agent hydrazine (N2H4) on copper surfaces using density functional theory calculations with a correction for the long-range interactions (DFT-D2). We have modeled the perfect and a number of defective Cu(100), (110), and (111) surfaces, which are found in the experimentally produced structures of copper nanoparticles. We have studied adsorption of hydrazine at three types of defects in the surfaces, i.e., monatomic steps, Cu adatoms, and Cu vacancies. Several low-energy adsorption structures for hydrazine on each perfect and defective surface have been identified and compared. Our calculations reveal that hydrazine bridges surface copper atoms, with the molecule twisted from the gauche toward an eclipsed conformation, except on the adatom (100) and vacancy-containing (100) and (110) surfaces, where it adsorbs through one nitrogen atom in gauche and trans conformations, respectively. The strongest adsorption energy is found on the stepped (110) surface, where hydrazine bridges between the copper atoms on the step edge and the terrace, as it stabilizes the low-coordinated copper atoms. Our results show that, although the (110) surface contains a number of low-coordinated atoms that enhance the surface-molecule interactions, the addition of defects on the more stable (111) and (100) surfaces provides sites that enable hydrazine binding to almost the same extent. This study also confirms general observations of surface adsorption trends in terms of d-band center and binding energy as a function of coordination number, i.e., the stronger the molecular adsorption, the higher the d-band shifts at low-coordinated sites.

Role of Halide Ions for Controlling Morphology of Copper Nanocrystals in Aqueous Solution

“…A DFT study conducted by Tafreshi et al. also supported previous experimental results in that the shape and size of copper (Cu) nanoparticles were modified by N 2 H 4 during synthesis …”

Advancement of Supercritical Carbon Dioxide Technology through Round Robin Testing and Fundamental Modeling

“…This is in good agreement with previous calculations for the Ni(111) d-band center of -1.16 eV [21,87], -1.32 eV [88], and -1.87 eV [89]. The d-band center for the (111) facet is lower than for the (100) facet, which has been shown to be the trend for many metals including Ni [74], Pd [90], Pt [91], Cu [92][93][94], and Ag [95], and correlates well with weaker binding of O, C, and CO on the (111) facet relative to the (100) facet.…”

Probing the Reactivity of Functionalized Surfaces by Porphyrin Metalation

“…We did not observe, however, a loss of the total N1s peak intensity, which suggests that the reaction product is still adsorbed on the surface. It is most probably caused by the fact that NH 2 in its less stable monomeric (amidogen) and more stable dimeric (hydrazine) forms are known to adsorb strongly to the Cu surfaces …”

“…It is most probably caused by the fact that NH 2 in its less stable monomeric (amidogen) and more stable dimeric (hydrazine) forms are known to adsorb strongly to the Cu surfaces. [27,28] The presence of the Cl-superstructure has a remarkably different influence on the chemical properties of Cu(001). The BEs of both N1s peaks and the C1s peak originating from 2HTPP after its cold-deposition (T = 100 K) on Cl/Cu (Figure 2c,d) are significantly lower than the respective BEs on N/Cu (Figure 2a,b) or on other substrates including Au(111), Ag(111), Cu (001) and O/Cu(001) [23,26,29] and amount to 398.9 eV, 396.8 eV and 283.7 eV for pyrrolic N1s, iminic N1s and C1s, respectively.…”