Please use this identifier to cite or link to this item:
http://hdl.handle.net/2445/165637
Title: | Surface activity of early transition-metal oxycarbides: CO2 adsorption case study |
Author: | Kunkel, Christian Viñes Solana, Francesc Illas i Riera, Francesc |
Keywords: | Carburs Metalls de transició Adsorció Carbides Transition metals Adsorption |
Issue Date: | 14-Feb-2019 |
Publisher: | American Chemical Society |
Abstract: | Theoretical studies and experiments have suggested that transition metal carbides (TMCs) can be useful materials for carbon capture and storage or use technologies from air sources. However, TMCs are known to become easily oxidized in the presence of molecular oxygen, and their properties jeopardized while being transformed into transition metal oxycarbides (TMOCs), which can affect the TMCs chemical activity, e.g. towards CO2. Here, by means of density functional theory (DFT) based calculations including dispersion we address the possible effect of oxycarbide formation in the CO2 capture course. A careful analysis of different models show that for group 4 TMCs (TM = Ti, Zr, Hf), their oxidation into TMOCs involves a negligible structural distortion of the outermost oxide surface layer, whereas severe rumplings are predicted for group 5 and 6 TMOCs (TM = V, Nb, Ta, Mo). The large surface distortion in the latter TMOCs results in a weak interaction with CO2 with adsorption energies below -0.27 eV. On the contrary, on group 4 TMOCs surfaces CO2 adsorption becomes stronger, with the adsorption values strengthening by 0.44-1.2 eV, a fact that, according to adsorption/desorption rates estimates, increments the air CO2 capture temperature window by 175-400 K. The present DFT results point to group 4 TMCs, TiC in particular, as promising materials for air CO2 capture and storage/conversion, even in the presence of oxygen and the possible formation of transition metal oxycarbides. |
Note: | Versió postprint del document publicat a: https://doi.org/10.1021/acs.jpcc.8b11942 |
It is part of: | Journal of Physical Chemistry C, 2019, vol. 123, num. 6, p. 3664-3671 |
URI: | http://hdl.handle.net/2445/165637 |
Related resource: | https://doi.org/10.1021/acs.jpcc.8b11942 |
ISSN: | 1932-7447 |
Appears in Collections: | Articles publicats en revistes (Ciència dels Materials i Química Física) |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
696477.pdf | 8.21 MB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.