H⁺- and Al²⁺-Codoped Al₂O₃ Nanoparticles with Spinel-Type Related Structures by Pulsed Laser Ablation in Water

Abstract

Pulsed laser ablation in water under a high peak power density of 1.8 × 1011 W/cm2 using Q-switch mode and 1064 nm excitation was used to fabricate (H+,Al2+)-codoped Al2O3 nanocondensates having γ- and its derivative θ-type structure as characterized by electron microscopy and spectroscopy. The as-formed γ- and θ-Al2O3 nanocondensates are mainly 10 to 100 nm in size and have a significant internal compressive stress (>10 GPa) according to cell parameters and vibrational spectroscopy, due to a significant shock loading effect in water. The γ-Al2O3 nanocondensates are nearly spherical in shape but become cuboctahedra when grown to ca. 100 nm to exhibit more facets as a result of martensitic γ→θ transformation following the crystallographic relationship (3̅11̅)θ//(02̅2)γ; (02̅4̅)θ//(3̅11)γ. The formation of dense and (H+,Al2+)-codoped γ/θ-Al2O3 rather than aluminum hydrates sheds light on the favored phases of the Al2O3−H2O binary at high temperature and pressure conditions in natural dynamic settings. The nanocondensates thus formed have a much lower minimum band gap (5.2 eV) than bulk α-Al2O3 for potential optocatalytic applications.

Preparation of Aluminum Oxide Nanoparticles by Laser Ablation and a Study of Their Applications as Antibacterial and Wounds Healing Agent

“…This method offers some advantages such as rapid and high purity process compared with other methods [8]. Moreover, synthesizing NPs through laser ablation via liquid is simpler than the by gas atmosphere [9,10]. The present study attempted to prepare AlO 2 NPs by using liquid particles treated with laser technology (1064 nm) and energy (350 MJ), and to study their medical application as antibacterial and stimulation of wound healing.…”

Nano Aluminum Oxides as Adsorbents in Water Remediation Methods: A Review

“…Pulse lasers of short duration are also employed in the synthesis of nanoparticles of Al2O3. [30][31][32] In the relatively simple, Sol-gel methods, precursors such as aluminum triisopropylate 33 , aluminum nitrate 34,35 and aluminum secondary butoxide 36 are used. Parida et al(2009), synthesized γ-alumina using aluminum nitrate as precursor and found that the precipitation by NH4HCO3 resulted in spherical particles of4.7-5.7 nm size with 190 m 2 /g surface area and nearly 0.467 cm 3 /g pore volume.…”

Oxide or carbide nanoparticles synthesized by laser ablation of a bulk Hf target in liquids and their structural, optical, and dielectric properties

“…Hz, 850 mJ) of an Al target in DI water [22] while ablation in aqueous solution of NaOH (0.05-1 M) lead to the fabrication of epitaxial β-NaAlO 2 and γ-Al 2 O 3 nanoparticles [23]. Hollow amorphous Al 2 O 3 micro/nanoparticles which may had weak crystallization were synthesized by pulsed KrF excimer laser ablation (30 ns, 248 nm, 10 Hz, 2.3 J/cm 2 ) of a bulk Al target in distilled water [24].…”