Role of base in the formation of silver nanoparticles synthesized using sodium acrylate as a dual reducing and encapsulating agent

Review on the latest design of graphene-based inorganic materials

The breathtakingly fast evolution of research on graphene and its modification methods in the recent 8 years has made possible the various preparations and applications of its derivatives. These hybrid structures exhibit excellent material characteristics including high carrier mobility and radiate recombination rate as well as long-term stability since graphene sheets possess super electrical conductivity, mechanical flexibility and good optical transparency. Besides, the versatile and fascinating properties of the nanostructures grown on graphene layers make it possible to fabricate high-performance electronic, optoelectronic and catalytic devices. This review presents an overview of the latest design of structure, synthetic methods and applications of graphene-based inorganic nanocomposites. The challenges and perspectives of these emerging hybrid heterostructures are also discussed.

Nucleation and aggregative growth process of platinum nanoparticles studied by in situ quick XAFS spectroscopy

The early stage in the nucleation and subsequent aggregative particle growth of the colloidal platinum (Pt) dispersions produced by photoreduction in an aqueous ethanol solution of poly(N-vinyl-2-pyrrolidone) (PVP) was quantitatively investigated by means of in situ quick XAFS (QXAFS) measurements. The stages of the reduction-nucleation and the association process (aggregative particle growth and Ostwald ripening) of Pt atoms to produce Pt nanoparticles was successfully discriminated in course of the photoreduction time. The present QXAFS analysis indicated that Pt nuclei (i.e., (Pt(0))(m) nucleates approximately m = 4) were continuously produced in the reduction-nucleation process at the early time, followed by the aggregative particle growth with the autocatalytic reduction of Pt ionic species on the surface of Pt nuclei to produce Pt nanoparticles. Subsequently the particle growth proceeded via Ostwald ripening, resulting in the production of larger Pt nanoparticles at a later time. It was also found that the aggregative particle growth follows a sigmoidal profile well described either by the solid-state kinetic model or by the chemical-mechanism-based kinetic model, specifically the Avrami-Erofe'ev or Finke-Watzky models. The difference in terms of the formation mechanism was observed between the reduction of Pt(IV)Cl(6)(2-) and Pt(II)Cl(4)(2-) as a source material. Also presented is that the addition of the photoactivator such as benzoin, benzophenone, and acetophenone in the system is very effective to enhance the rate for the formation of Pt nanoparticles.