Qiu, C;
Odarchenko, Y;
Meng, Q;
Dong, H;
Gonzalez, IL;
Panchal, M;
Olalde-Velasco, P;
... Beale, AM; + view all
(2023)
Compositional Evolution of Individual CoNPs on Co/TiO2 during CO and Syngas Treatment Resolved through Soft XAS/X-PEEM.
ACS Catalysis
, 13
(24)
pp. 15956-15966.
10.1021/acscatal.3c03214.
Preview |
PDF
qiu-et-al-2023-compositional-evolution-of-individual-conps-on-co-tio2-during-co-and-syngas-treatment-resolved-through.pdf - Published Version Download (6MB) | Preview |
Abstract
The nanoparticle (NP) redox state is an important parameter in the performance of cobalt-based Fischer-Tropsch synthesis (FTS) catalysts. Here, the compositional evolution of individual CoNPs (6-24 nm) in terms of the oxide vs metallic state was investigated in situ during CO/syngas treatment using spatially resolved X-ray absorption spectroscopy (XAS)/X-ray photoemission electron microscopy (X-PEEM). It was observed that in the presence of CO, smaller CoNPs (i.e., ≤12 nm in size) remained in the metallic state, whereas NPs ≥ 15 nm became partially oxidized, suggesting that the latter were more readily able to dissociate CO. In contrast, in the presence of syngas, the oxide content of NPs ≥ 15 nm reduced, while it increased in quantity in the smaller NPs; this reoxidation that occurs primarily at the surface proved to be temporary, reforming the reduced state during subsequent UHV annealing. O K-edge measurements revealed that a key parameter mitigating the redox behavior of the CoNPs were proximate oxygen vacancies (Ovac). These results demonstrate the differences in the reducibility and the reactivity of Co NP size on a Co/TiO2 catalyst and the effect Ovac have on these properties, therefore yielding a better understanding of the physicochemical properties of this popular choice of FTS catalysts.
| Type: | Article |
|---|---|
| Title: | Compositional Evolution of Individual CoNPs on Co/TiO2 during CO and Syngas Treatment Resolved through Soft XAS/X-PEEM |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/acscatal.3c03214 |
| Publisher version: | http://dx.doi.org/10.1021/acscatal.3c03214 |
| Language: | English |
| Additional information: | Copyright © 2023 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0. |
| Keywords: | redox state, FTS catalysts, CoNPs, soft XAS-X-PEEM, syngas |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10184624 |
Archive Staff Only
 |
View Item |
