10 research outputs found
Thermodynamic Control of Metal Loading and Composition of Carbon Aerogel Supported PtâCu Alloy Nanoparticles by Supercritical Deposition
Carbon
aerogel (CA) supported PtâCu bimetallic nanoparticles
were synthesized via simultaneous adsorption of bisÂ(1,1,1,3,5,5,6,6,6-nonafluorohexane-2,4-diiminate)Âcopper
(CuDI6) and dimethylÂ(1,5-cyclooctadiene)ÂplatinumÂ(II) (PtÂ(cod)Âme<sub>2</sub>) onto CAs in the presence of supercritical carbon dioxide
(scCO<sub>2</sub>) and subsequent thermal conversion at ambient pressure.
Binary adsorption isotherms of metal precursors on CAs in scCO<sub>2</sub> were measured at 35 °C and 10.6 MPa by analyzing the
fluid phase concentrations in a batch system and could be predicted
from pure component adsorption isotherms using ideal adsorbed solution
theory (IAST). Homogeneously dispersed PtâCu nanoparticles
were formed on the surface of the CAs via the thermal conversion of
the precursors at 400 °C. As the Pt/Cu ratio decreased from 97:3
to 21:79, both the mean and the standard deviation of the particle
size increased from 2.9 to 7.2 nm and from 1.3 to 3.7 nm, respectively.
The alloying of Pt and Cu within the nanoparticles was confirmed via
XRD peak shifts, and XPS data indicated that the surfaces of these
PtâCu alloy nanoparticles were enriched in Pt