Liquid-Phase Ethanol Oxidation and Gas-Phase CO Oxidation Reactions over M Doped (M = Ag, Au, Pd, and Ni) and MM′ Codoped CeO₂ Nanoparticles

Figure 3

UV-visible diffuse reflectance spectra (expressed in terms of Kubelka–Munk absorbance arbitrary unit) of undoped CeO₂ and Au and Ag doped and codoped (5/0, 0/5, 4/1, 2.5/2.5, and 1/4 mol.%) CeO₂ catalysts. Optical microscopy images (inset) show the colors of the corresponding samples.