Tuning of Texture and Structure of Copper-Containing Nanocomposite Oxide Materials

For studies of textural tuning, structural tuning, or materials sintering, copper/aluminum and copper/zinc nanocomposite materials were prepared. Resistance to sintering of different phases was investigated. Thermal analysis methods were used to design feasible thermal treatment methods that can avoid destructive damages to gels. X-ray diffraction and nitrogen sorption measurements were used for structural and textural analysis. Compared with the wide distributions of pore sizes and low surface areas of the products prepared via conventional coprecipitation methods, a novel urea-gelation/thermal-modification method was developed to produce CuO/Al₂O₃ nanocomposites with narrow distributions of pore sizes and high surface areas. In comparison with the products of conventional coprecipitation methods, this novel urea-gelation/thermal-modification method produces copper/aluminum nanocomposites with significantly higher specific copper loading, which should be valuable in apparatus that have space limitations, such as vehicle fuel cell systems. Stepwise reduction and reoxidation were studied for the structural tuning and purification of Cu−Al−O spinel phases with isotropic and gradual unit-cell contractions. The textural and structural features of some copper/aluminum nanocomposite materials were observed by electron microscopy methods, that is, field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and convergent beam electron diffraction (CBED).