Synthesis of nanosized Ce0.85M0.1Ru0.05O2−δ (M = Si, Fe) solid solution exhibiting high CO oxidation and water gas shift activity

Nanosized Ce0.85M0.1Ru0.05O2−δ (M = Si, Fe) has been synthesized using a low temperature sonication method and characterized using XRD, TEM, XPS and H2-TPR. The potential application of both the solid solutions has been explored as exhaust catalysts by performing CO oxidation. The addition of Si- and Fe- in Ce0.95Ru0.05O2−δ greatly enhanced the reducibility of Ce0.85M0.1Ru0.05O2−δ (M = Si, Fe), as indicated by the H2-TPR study. The oxygen storage capacity has been used to correlate surface oxygen reactivity to the CO oxidation activity. Both the compounds reversibly release lattice oxygen and exhibit excellent CO oxidation activity with 99% conversion below 200 °C. A bifunctional reaction mechanism involving CO oxidation by the extraction of lattice oxygen and rejuvenation of oxide vacancy with gas feed O2 has been used to correlate experimental data. The performance of both the solid solutions has also been investigated for energy application by performing the water gas shift reaction. The present catalysts are highly active and selective towards the hydrogen production and a lack of methanation activity is an important finding of present study.

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► Ru and Fe/Si modified CeO2 were synthesized and characterized.
► Excellent catalytic activity for CO oxidation and water gas shift was observed.
► Cyclic redox behavior and high OSC were observed with the catalyst.
► Relation between activity and reducibility of the catalyst was discussed.