Key words: supercritical carbon dioxide, dispersed tungsten oxides, platinum nanoparticles, organometallic precursors, electron microscopy
A one-pot synthesis of dispersed platinum-tungsten composites was developed. Initially,
using tungsten hexacarbonyl as a precursor in solution in supercritical CO2 in the
presence of oxygen as an oxidizer promoting thermal decomposition of the precursor,
dispersed particles of tungsten oxide with a grain size of about 100 nm and an aggregate
size of 200–500 nm were synthesized. Then, these dispersed particles were used as a
substrate for the subsequent deposition of platinum nanoparticles, which included
two stages: 1) forming a film of an organometallic precursor by deposition from a
solution in supercritical CO2 and 2) thermal decomposition of the precursor. As the
two types of platinum precursors, the dimethyl(1,5-cyclooctadiene)platinum and platinum
hexafluoroacetylacetonate, which both are soluble in sc CO2, were used as the typical
ones in the practice of similar studies. The size of the formed platinum nanoparticles
was 2.3 ± 0,7 nm using the former precursor and 3.5 ± 0,8 nm using the latter. The
obtained composites are characterized by a relatively narrow size distribution of the
noble metal nanoparticles and their uniform distribution over the surface of the
particles of the dispersed carrier. Such materials may be of interest for (electro)catalysis
tasks.
doi:10.1134/S1990793119080050