Formation of Au–carbon nanoparticles by laser ablation under pressurized CO₂

Pulsed laser ablation is known to be a promising method for synthesizing metal nanoparticles. Here, Au–carbon nanoparticles were synthesized by pulsed laser ablation under pressurized carbon dioxide. Au plate was ablated using a Nd:YAG laser with a wavelength of 532 nm and energy of 0.83 mJ in a high-pressure chamber. The experiments were performed at temperatures and pressures of 21–25 °C and 7–15 MPa, corresponding to carbon dioxide densities of 0.75–0.89 g/cm³, respectively. The synthesized products were collected on a silicon wafer and analyzed using field emission scanning electron microscopy, transmission electron microscopy, and a scanning transmission electron microscopy system equipped with energy-dispersive X-ray spectroscopy. The results showed that the generated metal nanoparticles exhibited spherical and nanocluster structures. Au, C, and O were clearly found on the nanoparticle products.