Interaction of sulfur dioxide with titanium–carbide nanoparticles and surfaces: A density functional study

Abstract

Articles you may be interested inElectronic, magnetic structure and water splitting reactivity of the iron-sulfur dimers and their hexacarbonyl complexes: A density functional study A density functional theory study of the dissociation of H 2 on gold clusters: Importance of fluxionality and ensemble effects Adsorption, diffusion, and dissociation of molecular oxygen at defected TiO 2 (110): A density functional theory study J. Chem. Phys. 120, 988 (2004); 10.1063/1.1631922Combining density-functional calculations with kinetic models: NO/Rh (111) In the control of environmental pollution, metal carbides are potentially useful for trapping and destroying sulfur dioxide (SO 2 ). In the present study, the density functional theory was employed to study the surface structures and electronic properties of the adsorbed SO 2 on titanium carbides: metcar Ti 8 C 12 , nanocrystal Ti 14 C 13 , and a bulk TiC͑001͒ surface. The geometries and orientations of SO 2 were fully optimized on all these substrates. Our calculations show that, in spite of the high C/Ti ratio and C 2 groups, metcar Ti 8 C 12 exhibits extremely high activity towards SO 2 . The S-O bonds of SO 2 spontaneously break on Ti 8 C 12 . The products of the decomposition reaction ͑S, O͒ interact simultaneously with Ti and C sites. The C atoms are not simple spectators, and their participation in the dissociation of SO 2 is a key element for the energetics of this process. Nanocrystal Ti 14 C 13 also displays a strong interaction with SO 2 . Although the dissociation of SO 2 on Ti 14 C 13 cannot proceed as easily as that on Ti 8 C 12 , it could occur by thermal activation even at very low temperature. SO 2 is weakly bonded with the bulk TiC͑001͒ surface. By thermal activation the dissociation of SO 2 on a TiC͑001͒ surface may also take place but it should be much more difficult than that on Ti 14 C 13 . Therefore, we suggest that the carbide nanoparticles (Ti 8 C 12 and Ti 14 C 13 ) should have special chemical activity towards SO 2 removal associated with their ''magic'' structures.

Dissociation of SO2on Au/TiC(001): Effects of Au–C Interactions and Charge Polarization

“…This is, in part, a consequence of charge polarization around gold induced by Au-C interactions. Figure 1 shows S 2p photoemission spectra recorded after dosing five Langmuir (L) of SO 2 to pure TiC(001) at 150 and 300 K. In agreement with previous studies, [18,19] molecular chemisorption is seen at 150 K and some dissociative chemisorption-SO 2 (gas)!S(ads) + 2 O(ads)-at 300 K. In general terms, TiC(001) can be classified as a poor DeSOx system. [18] Au(111) and polycrystalline gold also interact weakly with SO 2 and are not efficient for the dissociation of SÀO bonds.…”

“…The DFT calculations were performed with the VASP or DMol 3 codes, as detailed in references [19,21]. VASP was used to investigate the nature of the Au-TiC(001) interactions.…”

Onset of carbon–carbon bonding in the Nb5Cy(y = 0–6) clusters: a threshold photo-ionisation and density functional theory study

“…2. The clusters Nb 5 C 2 , Nb 5 C 3 and Nb 5 C 6 show a dramatic rise from the baseline indicating good Frank-Condon overlap between the ground electronic states of the neutral and cation. Conversely, the clusters Nb 5 C, Nb 5 C 4 and Nb 5 C 5 show gradual onsets of ionisation, suggesting some geometry change between the neutral and cation.…”

Comparative studies of methanol decomposition on carbide-modified V(110) and Ti(0001)

“…Another factor is that, comparing to the single crystal surfaces, the C/Ti(0 0 0 1) and C/V(1 1 0) surfaces do not have the 1:1 metal/carbon stoichiometry, making them more active than the corresponding single crystal surfaces. More detailed studies, such as the recent DFT modeling of the ''metcar'' Ti 8 C 12 , nanocrystal Ti 14 C 13 , and bulk TiC(0 0 1) by Rodriguez and coworkers [39,40], will help to determine the relationship between the metal/carbon stoichiometry and the reactivity of carbide-modified surfaces.…”