ИСТИНА

Granulated metallic nanostructures are of considerable interest because of the large potential of their widespread use. One of the most striking examples of such application is the catalysis by nanometer size metal particles, use of which can significantly improve the performance of the process as compared with conventional catalysts based on dispersed metals. Studies of the effect of sizes of nanoparticles on their catalytic properties showed that increased activity of the structures with increasing their dispersion caused by the increase of relative surface area of the metal, changing the structure of the surface of the particles and the restructuring of their energy properties. However, only knowledge about the properties of individual particles is insufficient because the interaction of these particles with each other and with the support can be important. In particular, in the structures consisting of nanoparticles with a size of 2-3 nm, a tunneling electron transport processes between system components, resulting in charged nanoparticles or their ensembles, can play an important, and sometimes a decisive role. At the same time, the issue of correlation of catalytic and electrical properties of nanostructures, hitherto practically been discussed. One of the main reasons for this situation is the lack of reliable methods for measuring charge state of the structures. This paper proposes a method for measuring charge state of nanostructures composed of nanoparticles with a size of less than 2.5 nm, immobilized on the surfaces of conductive materials. The novelty of the method is the selection of the mode of measurement of potential distribution over the surface of the structure and the development of an analytical model to reveal the charge state of the nanostructure based on the the measurements conducted. The comparison of catalytic and electrical properties of nanostructures based on the use of the results of measurements carried out in a wide range of densities of nanoparticles revealed that the catalytic activity correlated only with the density of charged nanoparticles without closely spaced neighbors. A distinguishing feature of such particles is that in their neighborhood an electric field which magnitude is greater than 107 V/cm is generated.