Efficient Ce–Co composite oxide decorated Au nanoparticles for catalytic oxidation of CO in the simulated atmosphere of a CO2 laser

Gold nanoparticles have a high activity for CO oxidation, making them suitable to be used in a CO₂ laser which maintains its efficiency and stability via the recombination of CO and O₂ produced by the CO₂ decomposition. However, the high concentration of CO₂ in the working environment greatly reduces the activity of the catalyst and makes the already unstable gold nanoparticles even more so. A novel Au/Ce-Co-O_x/Al₂O₃ gold catalyst, prepared by a deposition precipitation method in this study, displays high activity and good stability for CO oxidation in a simulated atmosphere of a CO₂ laser with the feed gases containing a high concentration of CO₂ up to 60 vol% but a low concentration of O₂ for the stoichiometric reaction with CO. An excellent performance for CO oxidation under CO₂-rich conditions could be achieved by decorating the surface of the Al₂O₃ support with Ce–Co composite oxides. The strong interaction between gold and the composite support, accompanied by the increase of labile lattice oxygen species and the decrease of surface basicity, led to a high CO oxidation rate and resistance towards CO₂ poisoning.

Novel Au/Ce-Co-O_x/Al₂O₃ showed a very excellent performance for CO oxidation in the simulated atmosphere of CO₂-laser mainly due to SMSI and labile lattice oxygen.

Tuning the Catalytic Properties of Copper-Promoted Nanoceria via a Hydrothermal Method

Copper-cerium mixed oxide catalysts have gained ground over the years in the field of heterogeneous catalysis and especially in CO oxidation reaction due to their remarkable performance. In this study, a series of highly active, atomically dispersed copper-ceria nanocatalysts were synthesized via appropriate tuning of a novel hydrothermal method. Various physicochemical techniques including electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed in the characterization of the synthesized materials, while all the catalysts were evaluated in the CO oxidation reaction. Moreover, discussion of the employed mechanism during hydrothermal route was provided. The observed catalytic activity in CO oxidation reaction was strongly dependent on the nanostructured morphology, oxygen vacancy concentration, and nature of atomically dispersed Cu2+ clusters.