The synthesis and nanostructure investigation of noble metal-based nanocomposite materials

The presented work follows the theme of applied chemistry toward nanomaterials and multiphase functional systems of practical importance. Structural studies of nanocomposite materials are important due to the correlation between physicochemical/structural properties and their application potential. In this work, we report the fabrication and structural characterization of nanocomposite materials constituting noble metal (plasmonic) nanoparticles (AgNP and AuNP) dispersed on selected types of nanostructured solid hosts (nonporous silica, microporous activated carbon, chitosan biopolymer, and ordered mesoporous silica). The ability to maintain a dispersed state of colloidal precursors throughout their deposition on solid hosts was assessed. The influence of the carrier role in the formation and stabilization of nanometallic phases was evaluated taking into account the physicochemical and textural properties of the support surfaces. The size and shape of nanoobjects, clustering effects, interfacial properties, and stability of the immobilized nanophase were implemented by analyzing relevant parameters of SAXS analysis. The dimensional characteristic of the scatterers was evaluated by volume-weighted particle size distribution Dv(R). The detailed overall shape and maximal particle dimension were described by the analysis of pair distance distribution functions (PDDFs). The radius of gyration (Rg) from PDDF and Guinier approximation was calculated for illustrating the dimension of scattered heterogeneities in the investigated solids. The asymptotic behavior of a scattering curve and Porod theory were applied for determining the diffusion and quality of the interfacial surfaces. The size and morphology of nanoparticles in colloidal precursor solutions have been defined as spherical and bimodal in size (~ 6 nm and 20 nm). It was observed that the spherical shape and dispersed state of nanoparticles were achieved for all systems after deposition. However, the morphology of their final form was conditioned by the solid matrices. The particle properties from SAXS were correlated with properties determined by TEM and low-temperature nitrogen sorption analysis. Obtained results suggest good compatibility and correctness of SAXS data reading of nanocomposite systems and can be successfully applied for quick, nondestructive, and effective evaluation of structural properties of complex systems.