The Active State of Supported Ruthenium Oxide Nanoparticles during Carbon Dioxide Methanation

Abstract

Ruthenium catalysts supported on TiO 2 have been shown to have competitive activity and selectivity for the methanation of CO 2 . In particular, a catalyst using pre-formed RuO 2 nanoparticles deposited on the TiO 2 support, showed competitive performances in a previous study. Here, ambient-pressure X-ray photoelectron spectroscopy was employed to determine the chemical state of this catalyst under reaction conditions. The active state of ruthenium is shown to be the metallic one. Surface adsorbates were monitored in the steady state, and CH x species were found to be favored over adsorbed carbon monoxide upon temperature increase.

Describing inorganic nanoparticles in the context of surface reactivity and catalysis

“…In the first case, the nanoparticles came from a ligand-free sol-gel reaction and were deposited on a TiO 2 support: they can be regarded as "bare nanoparticles" ( Figure 8A). 62 After the reduction step, XPS of Ru 3d 5/2 showed a main peak at a binding energy of 280.0 eV, similar to these of bulk ruthenium metal ( Figure 8A, indicated by a red dotted line). This metallic state persisted under CO 2 methanation conditions at 200 °C.…”

Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support

“…The most reported ruthenium-based Sabatier reaction catalysts consist of metallic ruthenium supported on metal oxides such as TiO 2 . [69] While RuO 2 can be reduced in a hydrogen environment, we do not expect our RuO 2 to be greatly reduced due to the large size of the nanocrystals used and the low temperature reaction conditions Adv. [61] Whereas metallic ruthenium can readily form surface metal hydrides, which facilitates methanation, very little is known about the methanation details of RuO 2 .…”

Ambient Pressure Photoelectron Spectroscopy: Opportunities in Catalysis from Solids to Liquids and Introducing Time Resolution

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