ScholarWorks@경상국립대학교

초록

In this study, the dynamics of laser-induced cavitation bubbles (LICBs) during pulsed laser ablation (PLA) of a nickel (Ni) target in different solvents was investigated by measuring the time-resolved formation of LICBs utilizing an intensified charge-coupled device (ICCD) camera. Intriguingly, it was found that the lifetime of LICBs depended on the liquid environment (i.e., methanol, deionized water, hexane, and acetonitrile). It was also determined that the phases of the Ni nanoparticles (NPs) were strongly defined by the lifetime of the LICBs during PLA. Specifically, a face-centered cubic (fcc)/hexagonal closest packed (hcp) mixed Ni phase and pure fcc Ni NPs were formed in the presence of LICBs exhibiting short and long lifetimes, respectively. The prepared Ni NPs were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM). Following fabrication on a glassy carbon electrode (GCE), the obtained Ni NPs were employed as electrochemical sensors for toxic 4-nitrophenol (4-NP) detection. The electrocatalytic behavior was examined by cyclic voltammetry (CV). The CV profiles showed a linear increase in the peak current with increasing concentration of 4-NP from 20 to 150 mu M. The fcc/hcp Ni structure displayed enhanced sensitivity, electrochemical performance (0.4040 mu A mu M-1 cm(-2)), and limit of detection (LOD) (0.66 mu M) compared to the pure fcc Ni phase (0.2956 mu A mu M-1 cm(-2) and 1.72 mu M, respectively). This was predominantly attributed to the presence of more electrocatalytically active surface sites in the multiphase structure. The current study provides a concise explanation of the selective formation of Ni NPs with specific crystal phases during PLA in various solvents. Notably, the fabricated fcc/hcp Ni structure demonstrated potential for application as an electrochemical sensor.

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