(CoxMg1−x)O nanocondensates by pulsed laser ablation of bulk alloy in air

Abstract

Pulsed laser ablation of bulk CoO–MgO (solid solutions in 1 : 9, 1 : 1 or 9 : 1 molar ratios) in air was used to fabricate alloyed nanocondensates which were investigated by X-ray diffraction, transmission electron microscopy and UV-visible absorption characterization. The nanocondensates were formed as rocksalt-type (Co_xMg_1−x)O protoxide with well-developed {100} faces for coalescence as single crystals or (100) twist boundary with misorientation by 26.6°. Additional Mg-doped (8 at.%) Co_3−δO₄ spinel in the form of cubic nanocondensates and nearly spherical particulates with {011} and {121} facets were produced from the Co-rich target. The predominant (Co_xMg_1−x)O protoxide nanocondensates were able to turn the carbonaceous support into turbostratic graphene shell upon radiant heating and showed tailored paracrystalline distribution of defect clusters (ca. 1.5–2 nm interspacing), internal compressive stress (up to ca. 2 GPa), and UV absorption (3.2–3.5 eV) for potential opto-electronic catalytic applications.