Zhang, Jiajun;
Yang, Bin;
Luo, Kai Hong;
(2022)
Unveiling the mechanism of controllable CO2 hydrogenation by group VIB metal single atom anchored on N-doped graphite: A density functional theory study.
International Journal of Hydrogen Energy
10.1016/j.ijhydene.2022.09.170.
(In press).
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Abstract
CO2 hydrogenation has raised considerable interest due to concerns about climate change. Realizing low-temperature reverse water gas shift (rWGS) reaction remains a significant challenge in the context of coupling it with the C–C growth reactions to convert CO2 to C2+ fuels. We carried out systematic DFT simulations to unveil the underlying low-temperature mechanism for the selective hydrogenation of CO2 to produce CO, over a variety of metal-based single atom catalysts (SACs) supported on the nitrogen-doped graphite. Group VIB metal-based SACs outperformed other 15 metal candidates in terms of versatile capacities in both selective activation of CO2 molecule and facilitating escaping of CO and H2O. Mo1/N3-Gt was especially outstanding by giving rise to spontaneous production of CO and O∗ through an effective electron injection into the CO2 molecule. Water formation has been identified as the potential rate-controlling step in such a catalytic reaction over Mo1/N3-Gt with an energy barrier of 1.10 eV. Herein, the H migration played a pivotal role and had tight affinity to the charge of H∗ on the active site of catalyst. The dynamic coordination environment of Moδ+ was revealed to be the dominant factor affecting the surface H∗ charge, leading to a variety of hydrogenation behaviors. The electron-deficient ligands of CO2 and O∗ on Mo1/N3-Gt, as well as additional adsorbed H2, were effective in adjusting the 4d and 5s electronic structure of central Mo and consequently resulted in nearly electric neutral surface H∗s, thus most benefiting the hydrogenation process. The optimal charge of the coordinated Mo for an outstanding selective hydrogenation performance in this scenario was found to be no less than +1.7e.
| Type: | Article |
|---|---|
| Title: | Unveiling the mechanism of controllable CO2 hydrogenation by group VIB metal single atom anchored on N-doped graphite: A density functional theory study |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.ijhydene.2022.09.170 |
| Publisher version: | https://doi.org/10.1016/j.ijhydene.2022.09.170 |
| Language: | English |
| Additional information: | © 2022 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Decarbonization, Micro-environment of catalyst, Thermochemical conversion |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10157645 |
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