XPS ANALYSIS OF THE SURFACE OF SILVER NANOPARTICLES OBTAINED BY CHEMICAL REDUCTION AND EVAPORATING OF METAL

The chemical composition of silver nanoparticles surface obtained by initial metal evaporation and chemical reduction from silver salts was investigated by X-ray photoelectron spectroscopy method. Differences in electronic state of atoms of silver nanoparticles depending on the method of obtaining them are shown. The authors revealed that silver atoms of nanoparticles obtained by reduction from salts are in the covalent state. Positive chemical shift of the binding energy of Ag3d core level of silver nanoparticles in comparison with a bulk metal is fixed. The deviation of electronic properties of chemically synthesized silver nanoparticles from the properties of evaporated nanoparticles in the form of decrease of conductivity, the changes of valence band, kinetic energy of Auger lines and Wagner parameter was discovered. Small changes related to the influence of oxygen on the state of superficial silver atoms were observed in silver core level spectra. The nature of different adsorption states of oxygen on silver nanoparticles surface depending on their type and temperature was investigated. It is shown that molecular oxygen forms stabilize on silver surface in normal conditions. The increase of adsorption temperature up to 450 K and the use of evaporating nanoparticles leads to the appearance of O 1s lines of oxygen atoms with more ion character of bonds with silver atoms in spectrum.

silver, metal nanoparticles, chemical reduction, surface, chemical composition, X-ray photoelectron spectroscopy, XPS

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