Key words: ZnO nanoparticles, synthesis, organic compounds, syngas, H2O and CO2 supercritical fluids
When studying oxidation of solid and liquid zinc (Zn)S,L by sub- and supercritical water, supercritical CO2 and mixture of H2O/CO2, formation of (ZnO)n nanoparticles was found out. We have called this process chemical re-condensation (ChR). According to our investigations, nanoparticles of 2÷100 nm, nanoneedles and nanorods with 10÷100-nm diameter and up to 50-µm length, and mechanically strong nanostructured ceramics are formed, depending on the conditions of ChR. The cluster mechanism of ChR triggering was suggested. Kinetic parameters of ChR of (Zn)S,L in H2O were determined. The higher rate of ChR in H2O in comparison with CO2 is probably caused by orientation of dipole molecules of H2O in the field of contact voltage at (Zn)S,L/(ZnO)n boundary and prolongation of the molecule life time at the absorbed state. At ChR of zinc in CO2 carbon is formed together with CO, and in H2O/CO2 mixtures paraffin and aromatic hydrocarbons, alcohols and formaldehyde are formed together with H2 and CO.