When CO2 Meets H2 and CH4: Real-Time Discovery of Active Sites on Co/CeO2 Catalysts

Jordi Llorca^a, Núria J. Divins^a, Lluís Soler^a, Isabel Serrano^a, Ignasi Burgués^a, Miquel Torras^a, Marina Armengol^a, Laia Pascua-Solé^a, Andrea Braga^a, Ilaria Lucentini^a, Xènia Garcia^a, Enrique Marín^a, Elías García^a

^aDepartment of Chemical Engineering and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya, EEBE, Eduard Maristany, 10-14, 08019 Barcelona, Spain

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

G4 In situ/operando characterization of energy-related materials with synchrotron X-ray techniques

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Carlos Escudero and Juan Jesús Velasco Vélez

Invited Speaker, Jordi Llorca, presentation 108
Publication date: 15th December 2025

The hydrogenation of carbon dioxide (CO₂ + 4H₂ ⇌ CH₄ + 2H₂O) offers a promising route for CO₂ valorisation through the production of synthetic methane, while the reaction of carbon dioxide with methane (CO₂ + CH₄ ⇌ 2CO + 2H₂) generates syngas, a key intermediate for the production of synthetic fuels and high-value chemicals. Cerium dioxide is a particularly attractive support due to its redox properties, strong metal-support interactions, and intrinsic basicity, which collectively enhance CO₂ activation. Cobalt supported on ceria benefits from Co–CeO₂ interfacial interactions that lower the formation energy of oxygen vacancies, thereby favouring CO₂ dissociation and boosting catalytic performance. In this contribution, we present a comprehensive operando and in situ characterization study combining XRD, XANES, XPS, DRIFT, and HRTEM to elucidate the structural and electronic dynamics of Co/CeO₂ catalysts under CO₂ hydrogenation [1] and dry reforming of methane [2]. Particular attention is given to the influence of ceria surface facets and catalyst preparation method. We show that strong interfacial bonding between Co species and CeO₂ {100} facets plays a decisive role in dictating the orientation, dispersion, and chemical reactivity of cobalt nanoparticles, an effect far less pronounced on CeO₂ {111} or {110} surfaces. Mechanochemical synthesis further yields smaller, more dynamic Co species with enhanced reducibility, catalytic activity, and long-term stability. Our findings highlight the critical role of nanoparticle size, metal-support interaction strength, and facet engineering in driving the performance of Co/CeO₂ catalysts for CO₂ hydrogenation and methane dry reforming reactions.

References:

[1] Deng, K., Wang, Y., Pérez, P., Xu, W., Llorca, J., Martínez-Arias, A., Zakharov, D.N., Rodriguez, J.A. Visualizing size-dependent dynamics of CeO2-δ {100}-supported CoOx nanoparticles under CO2 hydrogenation conditions. Journal of the American Chemical Society, 2025, 147, 19239-19252.

[2] Armengol, M., Braga, A., Pascua, L., Lucentini, I., Garcia, X., Soler, L., Vendrell, X., Serrano, I., Villar, I.J., Pérez-Dieste, V., Escudero, C., Divins, N.J., Llorca, J. Enhancing the performance of a novel CoRu/CeO2 bimetallic catalyst for the dry reforming of methane via a mechanochemical process. Applied Catalysis B: Environmental, 2024, 345, 123624.

Acknowledgements:

We acknowledge funding from projects MICIU/FEDER PID2024-156765OB-C21 and CEX2023-001300-M, supported by MCIN/AEI (10.13039/501100011033).

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