Bifunctional heterogeneous catalysts for selective epoxidation and visible light driven photolysis: Nickel oxide-containing porous nanocomposite

A study was conducted to synthesize multifunctional heterogeneous catalysts of nickel-oxide-containing porous nanocomposites through the coupling of the nickel oxide nanoparticles with the titanium oxide nanosheets. The XRD peaks of the nanocomposite appear broader than those of the protonated titanium oxide, which is a typical feature of an intercalation complex. This is due to an elastic deformation of the host layer upon lattice expansion. The maintenance of the lepidocrocite-type structure of titanium oxide upon intercalation was clearly evidenced by Ti K-edge X-ray absorption near edge structure (XANES) analysis. An electrostatic interaction between negatively charged titanium oxide nanosheets and positively charged nickel hydroxide clusters is a driving force for the formation of well-ordered heterostructure. The study also showed that the present intercalation hybridization route is expected to produce many porous metal oxide-based nanocomposites with multifunctional catalytic activities.