Effects of chemical etching and reduction activation of CeO2 nanorods supported ruthenium catalysts on CO oxidation

In this work, pristine and NaBH4 etched CeO2 nanorods supported ruthenium (Ru) catalysts were synthesized and employed to investigate the effects of chemical etching and reduction activation treatment on CO oxidation. With 1 wt% Ru loading, the CeO2 nanorods supported catalyst samples, after 6 wt% NaBH4 etching treatment, showed significantly promoted H2 consumption under 100 °C and low apparent activation energy (i.e., Ea ∼ 31.2 kJ/mol) for CO oxidation. In-situ CO-DRIFTS profiles revealed that, for the reduced sample, the observed CO adsorption at ∼ 2020 cm-1 at 40 °C may be related to a strong RuOx-CeO2 interaction induced by the NaBH4 etching treatment, which was supported by the oxygen vacancy analysis results of X-ray photoelectron spectroscopy and CO-temperature programmed desorption. The enriched surface defects on CeO2 support due to the chemical etching and reduction treatments are believed to promote the interaction between RuOx species and CeO2, which is responsible for the enhanced activity of CO oxidation.