Structure Transition Of Cuox Nanoparticles In Copper-Silica Nanocomposites

Two series Of CuOX/SiO2 nanocomposites with various Cu/Si molar ratios have been synthesized by sol-gel technique from two different copper metal precursors, cupric nitrate hydrate (Cu(NO3)(2)center dot 3H(2)O) and cupric acetylacetonate (Cu(acac)2), respectively. The influence of various chemical precursors and Cu content on the morphological evolution of CuOX nanoparticles in CuOX/SiO2 nanocomposites has been characterized by XRD, TEM, TG, FTIR, and XPS. For the first time, we demonstrated that, with the increase of Cu content, CuOX nanoparticles in CuOX/SiO2 nanocomposites performed two different morphology transitions, that is, from nanospherical aggregates to uniform nanorods using Cu(NO3)(2)center dot 3H(2)O as chemical precursor and to squarelike frames starting from Cu(acac)(2). The effects of reducing agents on these different morphology transformations of CuOX nanoparticles between the SCuN and SCuC series were also discussed.