Porous Silica Gels Doped with Gold Nanoparticles: Preparation, Microstructure, Optical and Textural Properties

Area of Science:

• Materials Science
• Nanotechnology

Background:

• Gold nanoparticles (AuNPs) exhibit unique optical and electronic properties.
• Silica gel is a versatile porous material with applications in catalysis and pigments.
• Controlling the synthesis of nanocomposites is crucial for tailoring their properties.

Purpose of the Study:

• To synthesize porous silica gel powders doped with gold nanoparticles (AuNPs).
• To investigate the effect of heating temperature on the properties of SiO2:AuNPs nanocomposites.
• To evaluate the potential applications of these nanocomposites as ceramic pigments and catalysts.

Main Methods:

• Sol-gel synthesis of silica gel doped with 1-dodecanethiol and tetrachloroauric acid.
• Heat treatment at 450 °C, 700 °C, and 900 °C.
• Characterization using X-ray diffraction, TEM/EDS, UV/Vis reflectance spectroscopy, DTA/TG, and BET analysis.

Main Results:

• The color and microstructure of SiO2:AuNPs (0.03% Au) samples are dependent on the heating temperature.
• UV/Vis reflection spectra align with Mie's theory, explaining optical properties.
• Samples exhibit significant surface area (S_BET = 200-350 m²/g), mean pore diameter (D_AV ≈ 10 nm), and pore volume (V_t = 0.5-0.8 cm³/g).

Conclusions:

• The synthesized AuNPs-doped silica gels are promising for ceramic glaze pigments, akin to Purple of Cassius.
• The materials' textural properties suggest suitability for catalytic applications, comparable to aerogel-like materials.