Cerium oxide catalysts for oxidative coupling of methane reaction: effect of lithium, samarium and lanthanum dopantsCerium oxide catalysts for oxidative coupling of methane reaction: effect of lithium, samarium and lanthanum dopants Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2024-02-022022enThe work presented herein reports on the oxidative coupling of methane (OCM) performance of a series of Li-free and Li-doped CeO2 and CeO2 modified with Sm3+ and La3+ catalysts. The supporting materials (Ce, Sm-Ce and La-Sm-Ce metal oxides) were synthesized using the microwave assisted sol-gel method in order to achieve nanophase complex materials with increased particle surface energy and reactivity. Lithium ions were added, using the wet impregnation technique, in order to further improve the physicochemical characteristics and reinforce the activity and selectivity, in terms of C2H6 and C2H4 production. All materials were characterized using N2 adsorption-desorption, XRD, Raman spectroscopy, CO2-TPD, H2-TPR, SEM and XPS. We showed that the addition of lithium species changed the reaction pathway and drastically enhanced the production of ethylene and ethane, mainly for the promoted catalysts (Li/Sm-Ce and Li/La-Sm-Ce). In particular, the presence and the synergy between the electrophilic oxygen species (peroxide and superoxide), population of oxygen vacancy sites and the surface moderate basic sites determined the reaction pathway and the desirable product distribution.NDC, IVY and MAG are grateful for financial support from the European Union and Greek national funds through the operational program Competitiveness, Entrepreneurship and Innovation, under the call Research-Create-Innovate (Project code: T1EDK-00782). GIS is grateful for financial support by Greece and ESF through the Operational Programme "Human Resources Development, Education and Lifelong Learning" in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (ΙΚΥ).http://creativecommons.org/licenses/by/4.0/Journal of Environmental Chemical Engineering102 Siakavelas Georgios I. Charisiou Nikolaos D. Alkhoori Ayesha Sebastian Victor Hinder Steven John Baker Mark Gentekakis Ioannis Γεντεκακης Ιωαννης Polychronopoulou Kyriaki Goula Maria A. Elsevier Oxidative coupling of methane Cerium-doped catalysts Trivalent ions Electrophilic oxygen species C2 production