펄스레이저가 조사되는 표면에 부착된 액체 박막이 용발 효율과 광음향 방사에 미치는 영향

김동식(Dongsik Kim),이호(Ho Lee) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.3

Enhancement of pulsed-laser ablation by an artificially deposited liquid film is presented. Measurements of ablation rate, ablation threshold, and surface topography are performed. Correlation between material ablation and photoacoustic effect is examined by the optical beam deflection method. The dependence of ablation rate on liquid-film thickness and chemical composition is also examined. The results indicate that photomechanical effect in the phase explosion of liquid is responsible for the enhanced ablation. The low critical temperature of liquid induces explosive vaporization with localized photoacoustic excitation in the superheat limit and increases the ablation efficiency. Experiments were carried out utilizing a Q-swiched Nd:YAG laser at near-threshold laser fluences with negligible plasma effect (up to~100 ㎿/㎠).

One-pot synthesis of graphitic and nitrogen-doped graphitic layers on nickel nanoparticles produced by pulsed laser ablation in liquid: Solvent as the carbon and nitrogen source

Jung, Hyeon Jin,Choi, Myong Yong Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.457 No.-

<P><B>Abstract</B></P> <P>Graphitic carbon (GC) and nitrogen-doped graphitic carbon (NdGC) shells have been synthesized on Ni nanoparticles (NPs) from solvents used in pulsed-laser ablation in liquid (PLAL). The facile one-pot synthesis was achieved at room temperature and atmospheric pressure by ablating the pulsed laser onto a Ni plate submerged in a solvent, which acted as the carbon and nitrogen source for the GC and NdGC shells. The formation of GC and NdGC shell-encapsulated Ni (Ni@GC and Ni@NdGC) NPs was simply and selectively achieved by selecting a specific solvent (hexane and acetonitrile), respectively. Meanwhile, Ni and Ni@NiO NPs were fabricated by pulsed-laser ablation in methanol and deionized water, respectively. The Ni NPs were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, fast Fourier transform analysis, selected area electron diffraction, and Raman spectroscopy. The Raman spectroscopic analysis revealed the graphitic shells were composed of well-organized graphitic structures. Furthermore, a potential application of the NPs as chemical shields in acidic conditions was tested in strong acidic solutions. The plausible growth mechanisms of various kinds of Ni NPs prepared by PLAL in different solvents are discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Graphitic carbon (GC) and nitrogen-doped graphitic carbon (NdGC) shells. </LI> <LI> Pulsed laser ablation in liquid (PLAL). </LI> <LI> GC and NdGC shells on Ni nanoparticles (NPs) were synthesized by PLAL. </LI> <LI> PLA in hexane produced GC shell-encapsulated Ni NPs (Ni@GC). </LI> <LI> PLA in acetonitrile produced NdGC shell-encapsulated Ni NPs (Ni@NdGC). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pursuit of optimal synthetic conditions for obtaining colloidal zero-valent iron nanoparticles by scanning pulsed laser ablation in liquids

Ruth Lahoz,Eva Natividad,Álvaro Mayoral,Christian Rentenberger,Daniel Díaz-Fernández,Eduardo J. Félix,Leonardo Soriano,Wolfgang Kautek,Oscar Bomati-Miguel 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

Liquid-Assisted Pulsed Laser Ablation (LA-PLA) is a promising top-down method to directly synthesizecolloidal dispersions of nanoparticles in a eco-friendly manner. However, the role of LA-PLA synthesisparameters is not yet fully agreed. This work seeks to optimize the production of nanoscale zero-valentiron (nZVI) particles suitable for biomedical or environmental applications using nanosecond LA-PLA oniron targets with different ablation media, laser and target scanning parameters. The use of alcohols assolvents produces iron-iron oxide core-shell nanoparticles with amorphous cores, except for a smallcrystalline fraction corresponding to the biggest core sizes. Decreasing carbon chain length andcomplexity leads to a thinning of the carbonaceous material coatings and an increase of the colloidalstability and the nanoparticle productivity. Moreover, a decrease of solvent density and surface tensionallows obtaining reduced sizes and polydispersity values. Among, laser and scanning parameters, thepulse accumulation per spot displayed a clear effect in boosting size and productivity. As main outcome,aqueous dispersions with suitable colloidal properties are obtained, either by transferring to water ofoptimized nZVI particles produced in ethanol, or by direct formation of nZVI particles and in situ coatingwith hydrophilic molecules in aqueous solutions of these molecules.

Zn(II) Production via a Pulsed Laser Ablation in Water: A Formation Mechanism of Zn and ZnO Nanoparticles

이슬기,안아름,최명룡 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.3

Zn and ZnO nanoparticles were produced by a pulsed Nd:YAG laser ablation method in the absence of any surfactants and/or catalysts in deionized (DI) water via pulsed laser ablation in liquid (PLAL). In this paper, we present direct evidence for the production of Zn(II) ions induced from the plasma plume during the process of PLAL for the first time. Investigation of the absorption and emission spectra of zinc tetra(p-sulfonatophenyl)porphyrin (ZnTSPP) formed via the laser ablation on a Zn metal plate in TSPP solution showed a significant fluorescence quenching of ZnTSPP. This fluorescence quenching of ZnTSPP was further investigated with an aid of theoretical calculations. Based on these experimental and theoretical results, a plausible mechanism for the production of Zn and ZnO nanoparticles is proposed.

Effects of Laser Energy Density on Size and Morphology of NiO Nanoparticles Prepared by Pulsed Laser Ablation in Liquid

마로리,D. Amaranatha Reddy,김태규 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.1

액상 펄스 레이저 어블레이션에 의한 친수성 그라파이트 나노입자의 제조 및 센서 응용

최문열,김용태,Choi, Moonyoul,Kim, Yong-Tae 한국전기화학회 2012 한국전기화학회지 Vol.15 No.4

일반적으로 그라파이트는 높은 결정성으로 인해 나노입자상으로 제조하기 어려우며 특히 표면에 친수성을 부여하기가 쉽지 않은 재료로 알려져 왔다. 본 연구에서는 박막 증착에 널리 활용되어 오던 펄스 레이저 어블레이션 기법을 액상에 적용하여 친수성이 부여된 그라파이트 나노입자를 합성하였다. 타겟으로는 그라파이트 로드를 사용하였으며 레이저 출력을 조절하며 액상에서 어블레이션을 실시한 결과 매우 높은 분산 안정성을 갖는 친수성 그라파이트 나노입자를 합성할 수 있었다. FT-IR 분석결과 합성된 친수성 그라파이트 나노입자는 카르복시기 및 카르보닐기 등이 나노입자의 형성과 동시에 표면에 도입된 것이 밝혀졌으며 이는 제타 포텐셜로도 확인할 수 있었다. 최종적으로 Polyethyleneglycol(PEG)과 컴포지트하여 아세톤 센서에 적용한 결과 기존의 카본 블랙 대비 우수한 감도를 나타내었다. It is widely recognized that it is hard to prepare hydrophilic graphite nanoparticles because of their high crystallinity and inert characteristics. In this study, we successfully synthesized the hydrophilic graphite nanoparticles by using liquid phase pulsed laser ablation method which has been actively employed for the thin film deposition up to now. The obtained hydrophilic graphite showed an ultra-high dispersion stability in water, because the hydrophilic functional groups like carboxyl and carbonyl group was simultaneously introduced onto the graphite surface with the nanoparticle formation, as confirmed by FT-IR and zeta potential measurements. Finally, a markedly enhanced gas sensing ability for acetone was shown in comparison with the conventional carbon black for the carbon polymer composite sensor with polyethyleneglycol (PEG).

Selective synthesis of Au and graphitic carbon-encapsulated Au (Au@GC) nanoparticles by pulsed laser ablation in solvents: Catalytic Au and acid-resistant Au@GC nanoparticles

Lee, Seung Heon,Jung, Hyeon Jin,Lee, Seung Jun,Theerthagiri, Jayaraman,Kim, Tae Ho,Choi, Myong Yong Elsevier 2020 APPLIED SURFACE SCIENCE - Vol.506 No.-

<P><B>Abstract</B></P> <P>Gold nanoparticles (Au NPs) are the most versatile nanomaterials reported to date owing to their unique physiochemical properties as well as promising various applications. Recently, many techniques have been used for the synthesis of Au NPs. In this study, various types of Au NPs were synthesized by pulsed laser ablation in liquid (PLAL) using the following four solvents: methanol, deionized (DI) water, hexane, and acetonitrile. Pulsed laser ablation in methanol and DI water is used for the synthesis of bare Au NPs, as photocatalysts. Au NPs showed an enhanced catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol. Interestingly, Au NPs prepared by PLAL using hexane and acetonitrile were encapsulated with graphitic carbon (GC) layers (Au@GC), where the solvent was used as a carbon source for the GC layers. In contrast to bare Au NPs, Au@GC NPs exhibited no catalytic activity due to the protective GC layers formed on Au NPs. On the other hand, Au@GC NPs demonstrated a high corrosion resistance against strong acids. The present study revealed that the PLA of Au plate in various liquid medium is a facile method for the synthesis of excellent catalytic or acid resistant Au NPs with a unique surface structure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bare Au nanoparticles (NPs) were prepared by PLA in methanol and DI water. </LI> <LI> Au@graphitic carbon (GC) NPs were prepared by PLA in hexane and acetonitrile. </LI> <LI> Catalytic activity was observed by only bare Au NPs, but no activity by Au@GC NPs. </LI> <LI> GC layers were formed only on small Au NPs (< ~50 nm) due to carbon solubility. </LI> <LI> Acid treatment is an easy and simple way for the preparation of small Au@GC NPs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhanced dechlorination of m-DCB using ironχraphite/palladium (FeΓ/Pd) nanoparticles produced by pulsed laser ablation in liquid

Yu, Y.,Jung, H.J.,Je, M.,Choi, H.C.,Choi, M.Y. Pergamon Press 2016 CHEMOSPHERE - Vol.155 No.-

In this work, the zero valent Fe (ZVI) and graphite-encapsulated Fe (FeΓ) nanoparticles (NPs) were easily and selectively prepared by a pulsed laser ablation (PLA) method in an aqueous sodium borohydride solution and ascorbic acid dissolved in methanol, respectively. Here, the FeΓ NPs were uniquely synthesized by PLA in methanol, where the solvent is used as both a carbon source for the graphitic layers and solvent, which is very unique. Furthermore, Pd NPs were loaded onto the surface of the FeΓ NPs to prepare bimetallic (FeΓ/Pd) NPs for the enhancement of the degradation efficiency of m-dichlorobenzene (m-DCB). The morphology, crystallinity, and surface composition of the prepared NPs were carefully characterized by high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectrometer (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The degradation rate of m-DCB using single (Fe and Pd) or bimetallic (Fe/Pd and FeΓ/Pd) NPs were compared by using gas chromatography. Among these NPs produced in this work, the FeΓ/Pd NPs with 1.71 wt % of Pd showed an excellent dechlorination efficiency for m-DCB with 100% degradation within 75 min. The graphitic layer on the Fe NPs played as not only an oxidation resistant for the Fe NPs to surroundings, but also a supporter of the Pd NPs for the enhanced degradation efficiency of m-DCB.

레이저 어블레이션 공정에 의한 Ni-MWCNT 합성 및 물분해 특성

조경원,채희라,류정호,Cho, Kyoungwon,Chae, Hui Ra,Ryu, Jeong Ho 한국결정성장학회 2022 한국결정성장학회지 Vol.32 No.2

Recently, research on the development of low-cost/high-efficiency water electrolysis catalysts to replace noble metal catalysts is being actively conducted. Since overvoltage reduces the overall efficiency of the water splitting device, lowering the overvoltage of the oxygen evolution reaction (OER) is the most important task in order to generate hydrogen more efficiently. Currently, noble metal catalysts show excellent characteristics in OER performance, but they are experiencing great difficulties in commercialization due to their high price and efficiency limitations due to low reactivity. In this study, a water electrolysis catalyst Ni-MWCNT was prepared by successfully doping Ni into the MWCNTs structure through the pulsed laser ablation in liquid (PLAL) process. High resolution-transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) were performed for the structure and chemical composition of the synthesized Ni-MWCNT. Catalytic oxygen evolution reaction evaluation was performed by linear sweep voltammetry (LSV) overvoltage characteristics, Tafel slope, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Chronoamperometry (CA) was used for measurement.

Simple Preparation of Anatase TiO2 Nanoparticles via Pulsed Laser Ablation in Liquid

Seong Min Hong,Seulki Lee,정현진,Yiseul Yu,신재호,권기영,최명룡 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.1