Noble metals supported on reducible oxides such as Fe2O3 and Co3O4 have been recently found to enhance the catalytic activity in CO oxidation in comparison to non-reducible oxides [1]. Catalytic oxidation of CO is one of the several important reactions in the very diverse aspects of the catalysis field, ranging from the treatment and control of automotive exhaust gases, to fuels cells, CO2 lasers, etc. Therefore, deeper understanding of the structure-performance relationships of these catalysts is of great practical importance.     Catalytic properties are known to be greatly enhanced by the use of nano-sized materials, due to the specific surface area and the high degree of dispersions of the noble metals active phases. However, the structural characterization of such catalysts materials can be quite challenging for the conventional diffraction techniques due to the involved small particle sizes down to nanometer level, low loading of the active phases, which may sometimes be  amorphous. These challenges make Pair Distribution Function analysis (PDF) and Small-Angle X-ray Scattering (SAXS) among the preferred techniques for the structural characterization of these materials, because these methods do not require long range periodicity of the atomic arrangements.     As opposed to the PDF studies previously reported in the literature which made use of synchrotron X-ray data, we used a multipurpose laboratory X-ray diffractometer to collect high energy X-ray diffraction data which allowed the PDF analysis with rather small loading of noble metal (oxides) on the support. Using an advanced approach named d-PDF, the differential Pair Distribution Function could be calculated, which enabled the study of the nano-sized active PdO sites distributed around the reducible nano-supports (for instance Fe2O3, see Figure 1). The SAXS method was applied by means of the same multipurpose X-ray diffractometer on the mentioned supported catalyst materials: size distributions and specific surface areas were extracted and found to be in agreement with the results obtained by HRTEM and N2 adsorption, respectively.