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In Situ Studies of Ru-CeO 2 –TiO 2 Catalysts for Selective CO 2 Hydrogenation to Methane: Importance of Metal ↔ Oxide–Oxide Interactions

Barba-Nieto, Irene [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:000000017793685X)·Fernández-García, Marcos [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Catalisis y Petroleoquimica] (ORCID:0000000299870289)·Reddy, Kasala Prabhakar [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000216165374)·Wang, Yuxi [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Kubacka, Anna [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Catalisis y Petroleoquimica] (ORCID:0000000235040032)·Moncada, Jorge [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Lenz, Guilherme Felipe [Universidade Federal do Paraná (UFPR), Palotina (Brazil)]·Hwang, Sooyeon [Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)] (ORCID:0000000156066728)·Senanayake, Sanjaya D. [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000339914232)·Rodriguez, José A. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Stony Brook University, NY (United States)] (ORCID:0000000256804214)
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Abstract

Here, this work investigates Ru-CeO 2 -TiO 2 catalysts for the CO 2 methanation reaction and compares their performance with previously studied Ru-CeO 2 systems. Despite the lower Ru loading, the TiO 2 -containing catalysts exhibit significantly higher activity. To understand this behavior, in situ X-ray absorption spectroscopy (XAS) was carried out at the Ru K-edge and Ce L 3 -edge. Unlike Ru-CeO 2 , which displays reversible redox behavior of Ru, the Ru-CeO 2 -TiO 2 catalysts show irreversible Ru reduction and a substantially higher fraction of Ce 3+ species under all tested conditions (H 2 , CO 2 , H 2 /CO 2 ). The stabilization of metallic Ru during methanation, together with the enhanced formation of Ce 3+ promoted by TiO 2 through interfacial electronic transfer, accounts for their superior performance. Complementary in situ DRIFTS measurements reveal the formation and rapid consumption of bidentate carbonates and formates. These species act as a key intermediate in methane formation. Overall, these findings highlight the crucial role of the mixed CeO 2 -TiO 2 oxide in tuning the surface chemistry of the catalysts by stabilizing metallic Ru, enhancing ceria reducibility, and promoting efficient reaction pathways for CO 2 methanation. The manipulation of metal↔oxide-oxide interactions can be a very useful tool when dealing with the valorization of CO 2 .

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYCO2 hydrogenationceriamethanerutheniumtitania

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Barba-Nieto, Irene [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:000000017793685X), Fernández-García, Marcos [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Catalisis y Petroleoquimica] (ORCID:0000000299870289), Reddy, Kasala Prabhakar [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000216165374), Wang, Yuxi [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Kubacka, Anna [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Catalisis y Petroleoquimica] (ORCID:0000000235040032), Moncada, Jorge [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Lenz, Guilherme Felipe [Universidade Federal do Paraná (UFPR), Palotina (Brazil)], Hwang, Sooyeon [Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)] (ORCID:0000000156066728), Senanayake, Sanjaya D. [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000339914232), Rodriguez, José A. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Stony Brook University, NY (United States)] (ORCID:0000000256804214). 2026-01-28. In Situ Studies of Ru-CeO 2 –TiO 2 Catalysts for Selective CO 2 Hydrogenation to Methane: Importance of Metal ↔ Oxide–Oxide Interactions. https://doi.org/10.1021/acscatal.5c07042

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