Synthesis of Cu/CuO nanoparticles in mesoporous material by solid state reaction

Abstract

The Mobil Composition of Matter No. 41 (MCM-41) containing 1.0 and 5.0wt.% of Cu was synthesized under solid state reaction. The calcinations of samples were done at two different temperatures, 500 and 300°C. X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) were used for samples characterization. Powder X-ray diffraction showed that when Cu(CH3COO)2 content is about 1.0wt.% in Cu/MCM-41, the guest CuO-NPs and copper ions is formed on the silica channel wall, and more exists in the crystalline state. When Cu(CH3COO)2 content exceeds this value (5.0wt.%), CuO nanoparticles and Cu2+ ions can be observed in low crystalline state. From the diffuse reflectance spectra it was confirmed that 5wt.% Cu/MCM-41 sample calcined at 500°C show plasmon resonance band due to Cu nanoparticles in the range between 500 and 600nm and small copper clusters Cun in 450nm. It also shows that some of the Cu2+ ions are present octahedrally in extraframework position in all samples. Both fourier transform infrared and diffuse reflectance spectra indicate that some of Cu2+ ions are tetrahedrally within the framework position in 1wt.% Cu/MCM-41 samples. TEM images indicated that nanoparticles size of CuO is in range of 30–40nm.