Chemical Free Laser-Assisted Synthesis and Photocatalytic Applications of Gold–Cobalt Nanoparticles

In this study, gold–cobalt (Au/Co) bulk alloy is synthesized using the arc-melting process, and its composition is verified by laser-induced breakdown spectroscopy. Au/Co nanoparticles were synthesized using the fundamental harmonic of Nd:YAG laser, which is a facile, eco-friendly, one-step, and contamination-free approach. Standard techniques were used in order to explore the characterizations and properties of the synthesized nanoparticles. Through transmission electron microscopy, we were able to determine that the synthesized nanomaterials were composed of spherical particles that averaged 19 nm in size and 26.5 nm in crystal size as measured by x-ray diffraction. In the process of photocatalytically degrading malachite green dye (MG), the Au/Co nanoparticles showed themselves to be an effective photocatalyst. The Au/Co played an important role in the photocatalytic degradation of malachite green. Excellent degrading efficiency was obtained, reaching 90% for 5 mg concentration of Au/Co nanoparticles synthesized using the laser ablation technique, and 96% for 10 mg concentration of the same nanoparticles, respectively. The addition of the cobalt into gold will reduce the bandgap and increase the amount of surface active cites for O 2 molecules and hydroxyl ions, which potentially break the chemical bond of MG and form colorless dye molecules. This study has the potential to give some helpful insights that may be used in the generation of novel photocatalysts for the degradation of dyes.