研究目的
Investigating the synthesis of TiO2 nanoparticles using nanosecond pulse laser ablation of titanium in liquid, gaseous and supercritical CO2, and the effect of CO2 pressure and temperature on the nanoparticle size, size distribution, and phase.
研究成果
Pulsed laser ablation in pressurized CO2 is a single-step method for synthesizing anatase-TiO2/carbon nanoparticles. The nanoparticle size decreases and size distribution narrows with increasing CO2 pressure and temperature. The rutile content increases with CO2 pressure. The study demonstrates the potential of PLA in scCO2 for synthesis of core-shell particles.
研究不足
The study does not provide in-situ observations of nanoparticle formation and carbon shell growth during the ablation process. The effect of CO2 temperature on rutile content could not be conclusively determined.
1：Experimental Design and Method Selection:
Pulsed laser ablation in CO2 was carried out using a 250 ns pulse fiber laser with wavelength of 1062 nm, and repetition rate of 101 kHz. The laser beam was focused using an 80 mm telecentric f-Theta lens to a spot diameter of 35 μm on the titanium target.
2：Sample Selection and Data Sources:
Titanium target (
3：99% pure) was ablated in CO2 (> 8 % pure) at pressures 5, 10, 15, 20, and 40 MPa and temperatures 30, 40, and 50 °C. List of Experimental Equipment and Materials:
Fiber laser, titanium target, autoclave, high-pressure piston pump, chiller, pressure and temperature sensors.
4：Experimental Procedures and Operational Workflow:
The target was ablated with the laser for 30 minutes using a scanning speed of 2 m/s to cover a 7×7 mm pattern. Nanoparticle powder was collected after depressurizing the autoclave.
5：Data Analysis Methods:
Nanoparticles were characterized using (S)TEM, XPS, Raman, XRD, and UV–Vis spectroscopy techniques.
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