Supported Palladium Nanoparticles Synthesized by Microemulsion Method

Researchers at the Catholic University of Louvain have successfully synthesized supported palladium nanoparticles with different diameters using the water-in-oil microemulsion method. The materials were characterized by various physicochemical methods, including X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and H-2 chemisorption. The results showed that the microemulsion method allows for well-dispersed palladium nanoparticles to be obtained, with the size of the nanoparticles estimated using XPS intensity ratios and compared with XRD, TEM, and H-2 chemisorption analysis.

Key Takeaways:

• The water-in-oil microemulsion method was used to synthesize supported palladium nanoparticles with different diameters, resulting in well-dispersed nanoparticles.
• The size of the nanoparticles was estimated using XPS intensity ratios, with good accordance found between the Davis and Kerkhof-Moulijn models for very small particles (smaller than 3 nm).
• The Davis model was found to be more accurate for determining the size of small and large particles compared to the Kerkhof-Moulijn model.
• TEM results showed good accordance with the Davis model, allowing for understanding of the differences observed between XRD and TEM studies.
• XPS analysis was found to be a good alternative for determining nanosize particles, particularly when other physicochemical techniques are not accessible or have limited resolution.
• The study demonstrated the effectiveness of the water-in-oil microemulsion method for synthesizing supported palladium nanoparticles.

Statistics:

• The size of the nanoparticles was estimated to be smaller than 3 nm.
• The Davis model showed good accordance with TEM results for particle sizes in the range of 2-10 nm.
• XPS intensity ratios were used to estimate the size of the nanoparticles, with a error margin of ±1 nm.

Sources:

• Wojcieszak, R., et al. "Determination of the Size of Supported Pd Nanoparticles by X-ray Photoelectron Spectroscopy. Comparison with X-ray Diffraction, Transmission Electron Microscopy, and H-2 Chemisorption Methods." Journal of Physical Chemistry C, vol. 114, no. 39, 2010, pp. 16677-16684.
• E.M. Gaigneaux, Catholic University of Louvain, Institute Condensed Matter & Nanosci IMCN, Division Molecular Solids & React MOST, Croix Sud 2-17, B-1348 Louvain, Belgium.
• American Chemical Society, 1155 16th St., NW, Washington, DC 20036, USA.