First-principles study of C adsorption, O adsorption, and CO dissociation on flat and stepped Ni surfaces

Abstract

The adsorption of atomic oxygen and carbon was studied with plane wave density functional theory on four Ni surfaces, Ni(110), Ni(111), Ni(210), and Ni(531). Various adsorption sites on these surfaces are examined in order to identify the most favorable adsorption site for each atomic species. The dependence of surface bonding on adsorbate coverage is also investigated. Adsorption energies and structural information are obtained and compared with existing experimental results for Ni(110) and Ni(111). In addition, activation barriers to CO dissociation have been determined on Ni(111) and Ni(531) by locating the transition states for these processes. Our results indicate that the binding energies of C are comparatively stronger on stepped surfaces than on flat surfaces, and the energy barriers associated with CO dissociation strongly favor reactions occurring near surface steps.

First-principles studies of the oxygen adsorption on unreconstructed and reconstructed Ni(110) surfaces

“…With the increase of coverage, the adsorption energy does not change remarkably with the value from 5.12 eV to 5.37 eV. The present calculation is consistent with earlier calculation [24], in which the most stable adsorption sites are found to be LB and SB sites for coverage of 1 ML and 0.5 ML. It seems that their calculation of 0.5 ML should be modeled using ð2 Â 1Þ surface cell.…”

“…The O-Ni bond lengths, and interlayer distance for oxygen adsorption on various substrate are given in Table 4. The calculated O-Ni bond length varies from 1.75 Å to 1.90 Å, which is similar with previous results [24]. This bond length of oxygen absorbed in ð1 Â nÞ substrate is larger.…”

“…Weimert et al [22] have investigated electronic structure of O adsorption on pð2 Â 1Þ Ni(1 1 0) substrate using the full potential augmented plane wave (FLAPW) method. Recently, the structural, electronic and magnetic properties of clean Ni(1 1 0) surface [23] and oxygen absorption on Ni(1 1 0) with coverage = 1 and 1/2 ML [24] are also reported. However, as shown above, the surface reconstructions induced by oxygen absorption such as pð3 Â lÞ i and pð3 Â 1Þ f are not clear from a theoretical point of view and the surface electronic and magnetic properties are still not well understood.…”

Bromine atom diffusion on stepped and kinked copper surfaces

“…High Miller index surfaces of this type are of great interest because they are intrinsically chiral [6,11,12,24]. They also provide models of surface defects that are well-suited for plane wave DFT calculations [7,13,[25][26][27][28]. On Cu(6 4 3) the terrace is three atoms wide.…”

Ab Initio Studies of Coke Formation on Ni Catalysts During Methane Reforming

“…The stepped surfaces, Ni(531) and Ni(210) exhibit higher binding energies for the atomic species than the flat surfaces, pointing to the importance of defects such as step edges as dominant adsorption sites for these species on real catalysts. A paper describing these results is currently in preparation [1].…”