In situ generation of ultrasmall sized and highly dispersed CuO nanoparticles embedded in silica matrix and their catalytic application

CuO nanoparticles (CuO NPs) with ultrasmall size (∼3.6 nm) and a highly-dispersed pattern embedded in a silica matrix were obtained in situ through a calcination process of organic copper salt. By means of rational selection of reactants, organic copper salt was introduced into Si–O–Si networks via covalent bonding during the sol–gel process under neutral conditions without any additional catalyst. The introduction of organic copper salt via covalent bonding as well as the compact Si–O–Si networks allowed for the formation of highly dispersed and ultrasmall sized CuO NPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the obtained silica complex had spherical morphology and well-dispersed small sized CuO NPs. The as-obtained CuO@SiO2 nanocomposites exhibited good catalytic property on the reduction of organic dye with NaBH4 as the reducing agent.