Oxygen vacancies in Ru/TiO2 - drivers of low-temperature CO2 methanation assessed by multimodal operando spectroscopy
Sebastian Cisneros,
Ali Abdel-Mageed,
Jawaher Mosrati,
Stephan Bartling,
Nils Rockstroh,
Hanan Atia,
Hayder Abed,
Jabor Rabeah,
Angelika Brückner
Affiliations
Sebastian Cisneros
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany
Ali Abdel-Mageed
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany; Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt
Jawaher Mosrati
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany; Laboratoire de chimie des matériaux et catalyse, Département de chimie, Faculté des sciences de Tunis, Université de Tunis el Manar, Tunis 1092, Tunisie
Stephan Bartling
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany
Nils Rockstroh
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany
Hanan Atia
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany
Hayder Abed
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany
Jabor Rabeah
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany; Corresponding author
Angelika Brückner
Leibniz-Institut für Katalyse, Albert-Einstein-Str. 29A, 18059 Rostock, Germany; Department Life, Light and Matter, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
Summary: Hydrogenation of CO2 is very attractive for transforming this greenhouse gas into valuable high energy density compounds. In this work, we developed a highly active and stable Ru/TiO2 catalyst for CO2 methanation prepared by a solgel method that revealed much higher activity in methanation of CO2 (ca. 4–14 times higher turnover frequencies at 140–210°C) than state-of-the-art Ru/TiO2 catalysts and a control sample prepared by wetness impregnation. This is attributed to a high concentration of O-vacancies, inherent to the solgel methodology, which play a dual role for 1) activation of CO2 and 2) transfer of electrons to interfacial Ru sites as evident from operando DRIFTS and in situ EPR investigations. These results suggest that charge transfer from O-vacancies to interfacial Ru sites and subsequent electron donation from filled metal d-orbitals to antibonding orbitals of adsorbed CO are decisive factors in boosting the CO2 methanation activity.