Synthesis, characterization and catalytic properties of palladium–cupric oxide–aluminum oxide nanocomposites

Cupric oxide–aluminum oxide (CuO–Al2O3) composites were prepared by co-precipitation of carbonates from aqueous solutions of metal nitrates followed by calcination. A novel palladium-oxide (Pd·Cu1+xAl2−xO4) composite has been synthesized by heating Pd (acetylacetonate)3 and CuO·Al2O3 in a mixture of oleic acid and oleyl amine. The sample was characterized by XRD, SEM, EDS, TEM and PL measurements. Both XRD and TEM indicate that the product is Pd dispersed in Cu1+xAl2−xO4 matrix. Emission spectra have been recorded at 220 to 470 nm excitations. The sharp PL peak observed in each case in the UV region (360–371 nm) when excited at 220, 250, 270 and 300 nm, respectively is due to the Near Band Edge Emission (NBE) of Pd·Cu1+xAl2−xO4. It has been found that the PL behavior of Pd·Cu1+xAl2−xO4 depends on the excitation wavelength. This kind of excitation wavelength dependent PL behavior is a violation of Kasha׳s rule of excitation wavelength dependence of emission spectrum. The major excitation peak was observed at 356 nm when monitored at 470 nm. Catalytic activity of Pd·Cu1+xAl2−xO4 was tested for Suzuki-Coupling reactions.