Catalytic oxidation of CO over mesoporous copper-doped ceria catalysts via a facile CTAB-assisted synthesis

Nanosized copper-doped ceria CuCe catalysts with a large surface area and well-developed mesoporosity were synthesized by a surfactant-assisted co-precipitation method. The prepared catalysts with different Cu doping concentrations were characterized by XRD, DLS analysis, TEM, BET, Raman, H2-TPR and in situ DRIFTS techniques. The influence of Cu content on their catalytic performance for CO oxidation was also studied. The XRD results indicate that at a lower content, the Cu partially incorporates into the CeO2 lattice to form a CuCe solid solution, whereas a higher Cu doping causes the formation of bulk CuO. Copper doping favors an increase in the surface area of the CuCe catalysts and the formation of oxygen vacancies, thereby improving the redox properties. The CuCe samples exhibit higher catalytic performance compared to bare CeO2 and CuO catalysts. This is ascribed to the synergistic interaction between copper oxide and ceria. In particular, the Cu0.1Ce catalyst shows the highest catalytic performance (T 50 = 59 °C), as well as excellent stability. The in situ DRIFTS results show that CO adsorbed on surface Cu+ (Cu+-CO species) can easily react with the active oxygen, while stronger adsorption of carbonate-like species causes catalyst deactivation during the reaction.

Optimum Preferential Oxidation Performance of CeO2-CuO x-RGO Composites through Interfacial Regulation

Interfacial regulation offers a promising route to rationally and effectively design advanced materials for CO preferential oxidation. Herein, we initiated an interfacial regulation of CeO₂-CuO _x-RGO composites by adjusting the addition sequence of the components during the support formation. The presence of RGO along with the sequence tuning of the components is confirmed to survey the changes of the oxidation state of copper species, the content and distribution of the Cu⁺ site, and the synergistic interactions between Cu-Ce mixed oxides and reduced graphene oxide (RGO) over the catalysts. These catalysts were systematically characterized by inductively coupled plasma, X-ray diffraction, transmission electron microscopy/high-resolution transmission electron microscopy, hydrogen temperature-programmed reduction, X-ray photoelectron spectra, thermal gravimetric analysis, Raman spectra, and in situ diffuse reflectance infrared Fourier transform spectroscopy measurements. The results show that RGO is favorable for the generation of Cu⁺ and the dispersion of copper-cerium species in the as-prepared catalysts. Furthermore, by multi-interfacial regulation of the CeO₂-CuO _x-RGO composites, the catalyst CeO₂/CuO _x-RGO exhibits a strikingly high catalytic oxidation activity at a low temperature coupled with a broader operation temperature window (i.e., CO conversion >99.0%, 140-220 °C) in the CO-selective oxidation reaction, which has been attributed to the high content of the active species Cu⁺ enriched on the surface, the highly dispersed copper oxide clusters subjected to a strong interaction with ceria, and the synergistic interactions between Cu-Ce mixed oxides and RGO.

A novel preparation of resin-based electrical contact material impregnated with sulfonated graphene

A novel type of resin-based electrical contact material (RECM) was prepared for the first time via the second curing of a sulfonated graphene/waterborne epoxy resin after pore formation.