Electronic metal-support interactions and their promotional effect on CO2 methanation on Ru/ZrO2 catalysts

Discrimination between electronic and structural effects in metal-support interactions (MSIs) is often hampered by contributions from either one. We report results of a combined experimental/theoretical study that directly demonstrate the action of electronic MSIs (EMSIs), while structural modifications like a partial overgrowth of metal nanoparticles by a partly reduced oxide due to SMSI, can be excluded. This is demonstrated for CO2 methanation on Ru/ZrO2 with small Ru NPs (similar to 2nm), where a high-temperature reductive treatment results in a significantly increased methanation rate. Based on operando / in situ spectroscopies and other characterizations, SMSI induced structural modifications can be excluded; the enhanced activity results from charge transfer from O-vacancies in the ZrOx surface region to adjacent Ru nanoparticles. DFT calculations reveal that the transferred charge is localized at the interface, leading to stronger Ru-CO bonding and enhanced COad methanation. We believe that these trends are generally relevant for reactions in a reductive atmosphere. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In metal-support interactions, discrimination between electronic and structural effects is often difficult due to contributions from both. A combined experimental/theoretical study showed the direct action of EMSIs, excluding the impact of structural modifications like partial overgrowth of metal nanoparticles. Charge transfer from O-vacancies in the ZrOx surface region to adjacent Ru nanoparticles played a key role in enhancing catalytic activity.