CO2 methanation on Ru-doped ceria

We study the methanation of CO2 catalyzed by ceria doped with Ni, Co, Pd, or Ru. Ce0.96Ru0.04O2 and Ce0.95Ru0.05O2 perform best, converting 55% of CO2 with a 99% selectivity for methane, at a temperature of 450 °C. This is comparable to the best catalysts found previously for this reaction. Ce0.95Ru0.05O2 was characterized by XRD, electron microscopy, BET, XPS, IR spectroscopy, and temperature-programmed reaction with Ar, H2, CO, and CO2 + H2. Steady-state methanation was studied at several temperatures between 100 and 500 °C. We find that the methanation reaction takes place on the reduced Ce0.95Ru0.05O2, and the role of the dopant is to make the reduction possible at lower temperature than on pure ceria. We discuss the potential for local and global effects of the dopant on catalytic chemistry.

The performance of doped ceria for CO2 reaction with CH4.Figure optionsDownload high-quality image (82 K)Download as PowerPoint slideResearch highlights
► CeO2 doped with Ru is a good catalyst for CO2 methanation.
► The catalyst is the reduced Ce0.95Ru0.05O2. The Ru dopant facilitates the reduction.
► The hydrogenation mechanism is not the usual CO2 to CO, to CH4.
► Ce0.95Ru0.05O2 is very easily contaminated by traces of CO2 to make carbonates.