Laser Ablation In Liquid Technique Research Articles

Recent advances in single-atom alloys: preparation methods and applications in heterogeneous catalysis.

Single-atom alloys (SAAs) are a different type of alloy where a guest metal, usually a noble metal (e.g., Pt, Pd, and Ru), is atomically dispersed on a relatively more inert (e.g., Ag and Cu) host metal. As a type of atomic-scale catalyst, single-atom alloy catalysts have broad application prospects in the field of heterogeneous catalysis for hydrogenation, dehydrogenation, oxidation, and other reactions. Numerous experimental and characterization results and theoretical calculations have confirmed that the resultant electronic structure caused by charge transfer between the host metal and guest metal and the special geometric structure of the guest metal are responsible for the high selectivity and catalytic activity of SAA catalysts. In this review, the common methods for the preparation of single-atom alloys in recent years are introduced, including initial wet impregnation, physical vapor deposition, and laser ablation in liquid technique. Afterwards, the applications of single-atom alloy catalysts in selective hydrogenation, dehydrogenation, oxidation reactions, and hydrogenolysis reactions are emphatically reviewed. Finally, several challenges for the future development of SAA catalysts are proposed.

Facile synthesis of surface oxygen vacancy and Ti3+ defects in SrTiO3 perovskite coupled g-C3N4 decorated with Au ternary nanocomposites for enhancing electrocatalytic activity from acidic and natural seawater conditions

The development of efficient electrocatalysts became vital to resolving the ongoing clean energy crises and environmental issues, wherein high-performance catalysts for the improved electrocatalytic hydrogen evolution reaction (EHER) are demanded. To meet this goal, an advanced and green ultrasonic-assisted pulsed laser ablation in liquid technique was used to prepare surface oxygen vacancy and Ti3+ defects in perovskite-based ternary nanocomposites (PTNCs) decorated with Au@SrTiO3/g-C3N4. An effective cathode was designed using Au@SrTiO3/g–C3N4–decorated PTNCs for EHER that operated in an acidic media of 0.5 M H2SO4. The optimized Au@SrTiO3/g-C3N4 PTNCs revealed an improved EHER at a very low over-potential of 0.082 V at a cathodic current density (J) of −10 mA/cm2, high double-layer capacitance (679.8 μF/cm2), large electrochemical surface area (19.4 cm2), high mass activity (198.35 A/g), high specific activity (2.91 mA/cm2), high surface charge density (0.0404 C/cm2), high catalytic active sites (4.19 × 10−7 mol/cm2), and exceptional long-term stability at 50 h, respectively. The Tafel slope of 45.36 mV/dec confirmed the presence of the Volmer-Heyrovsky mechanism to explain the enhanced EHER cycle of the prepared PTNCs. The improved electrocatalytic EHER performance was attributed to the induced synergistic strong metal-support interaction (SMSI) effect of the surface oxygen vacancy and Ti3+ defects in PTNCs that increased electrochemical surface area, high exposure of abundant active sites, improved intrinsic kinetics, and fast charge transport, respectively. Moreover, Au@SrTiO3/g–C3N4–decorated PTNCs exhibit excellent natural seawater electrolysis in terms of EHER at a low over-potential of 0.300 V at a J = −10 mA/cm2 and long-term stability at 10 h, respectively. It is demonstrated that the proposed novel surface oxygen vacancy and Ti3+ defects in Au@SrTiO3/g-C3N4 PTNCs are effective electrocatalysts can be beneficial for producing hydrogen from green technologies in future energy applications via interface engineering.

Preparation of Ag@SiO2 core–shell nanoparticles for plasmonic dye-sensitized solar cell application using laser ablation in liquid technique

Preparation of Ag@SiO2 core–shell nanoparticles for plasmonic dye-sensitized solar cell application using laser ablation in liquid technique

Direct Analysis of Bio-Molecules in Solid Materials Using Electrospray Ionisation Mass Spectrometry Coupled with Laser Ablation and a Liquid Sampling Technique.

In situ and rapid analysis of organic compounds using a combination of a newly-developed laser ablation in liquid (LAL) sampling technique combined with electrospray ionisation mass spectrometry (ESI-MS) is reported. The LAL is a technique that allows laser ablation to be conducted in a liquid medium containing organic compounds that were effectively extracted from solid materials into the liquid medium. Three organic compounds (valine, caffeine, and benzyl butyl phthalate (BBP)) were subjected to analysis. The LAL sampling was conducted in the fast-laser scanning mode using Galvanometric optics, and the total ablation time required for the sampling from a 1 mm2 area was about 3 s, thus providing rapid sampling. The resulting sample solution was directly introduced into the ESI-MS system, without the need for any chromatographic separation. To evaluate the analytical capability of the LAL technique coupled with ESI-MS, both the overall transmission efficiencies of analytes from solid materials to the ion detector, and the repeatabilities of the measurements were rigorously tested. This involved the use of synthetic, in-house prepared standard materials containing the analytes. The overall ion yields were about 1.1×10-3% for valine, 8.7×10-3% for caffeine, and 6.7×10-4% for BBP. By comparing the ion yields obtained by the injection of an analyte solution and a standard solution through the mass spectrometer, the recoveries through the LAL sampling were approximately 31% for valine, 45% for caffeine, and 37% for BBP. In addition, the analytical repeatabilities for all analytes were better than 6%. The analytical repeatabilities were mainly affected by either the heterogeneity of the in-house standard materials or changes in the plasma temperature by coexisting, laser-induced sample particles. It should be noted that not only water-soluble compounds (caffeine and valine), but also non-soluble compound (BBP) could be measured by the LAL-ESI-MS, which is one of the great advantages over the conventional liquid extraction surface analysis technique. The data obtained here clearly demonstrate that the LAL-ESI-MS has the potential for being a fast and user-friendly analytical technique for the in-situ detection for both the water-soluble and water-insoluble molecules.

Nanoparticle enhanced femtosecond laser induced breakdown spectroscopy of aluminum sheet coated with gold nanoparticle embedded nanofibers

Laser induced breakdown spectroscopy (LIBS) technique in conjunction with nanoparticles improves the sensitivity in the detection of solids like metals, precious gemstones and liquid samples. Femtosecond (fs) LIBS signals can also be enhanced in the presence of nanoparticles. We demonstrated up to two–time enhancement in the fs LIBS spectra of aluminum sheet coated with the gold nanoparticles embedded polyvinyl alcohol (PVA) nanofibers. Gold nanoparticles were fabricated using the fs laser ablation in liquid technique, the mean size of the nanoparticles was 10-15 nm. PVA nanofibers and are loaded Gold nanoparticles were prepared by electrospinning technique. The enhancements were observed in both the atomic and molecular (AlO) emissions. The technique can further be optimized for obtaining signal enhancement in the molecular bands of explosive traces.

Fabrication of Zn/ZnO Core/Shell Nanoparticles by Laser Ablation in Liquid Technique

In this research, Zn/ZnO Nanoparticles (NPs) were prepared via the Pulse Laser Ablation (PLA) method using three liquids (Ethanol, Acetone, and Distilled Water). Zn/ZnO NPs were synthesized via an Nd-YAG laser with a wavelength of 1064 nm, applied energy of 800 mJ, a frequency of 6 Hz, and 100 laser pulses at room temperature. The Zn metal plate was dipped in Ethanol, Acetone, and Distilled Water, respectively. The UV-Vis results shows sharp and single peaks at 320, 341, and 333 nm for Zn/ZnO NPs in Ethanol, Acetone, and Distilled Water respectively. FTIR testing shows peaks at about 500 cm−1 for Zn/ZnO NPs in Ethanol, Acetone, and Distilled Water, which indicates Zn-O stretching vibrations. XRD investigation shows low-angle peaks at 23.31˚, 23.81˚, and 19.20˚ for Zn/ZnO NPs in Ethanol, Acetone, and Distilled Water, respectively. In addition, a sharp peak of high intensity was observed at 13.54˚ for Zn/ZnO Core/Shell NPs in Acetone. These peaks indicate that the structure is stable and undistorted. These patterns emphasize compact pore arrangements. The lower intensity of the gradient peaks indicates that ZnO formed at a preferred site. Nor did high-angle XRD patterns appear, indicating that the formed ZnO NPs are so small to be distinct from background noise or undetectable by widish angle XRD. The broad XRD peak at 2θ angles from 20° to 30° can also confirm that ZnO is low-crystalline. The TEM images show the presence of Zn/ZnO NPs in Ethanol, Acetone, and Distilled Water with a size of less than 50 nm, and TEM analysis confirms that the primary structure of Zn/ZnO NPs is a Core/Shell.

Preparation and study of some physical properties of copper nanoparticles by pulsed laser ablation in liquids technique

In this paper, the pulsed ablation laser in liquids (PLAL)method was used to obtain copper nanoparticles from material copper, One of the first signs of nanoparticle production or generation using the pulsed laser is a change in the color of the sample's solution as the concentration of nanoparticles increases. In our study, deionized distilled water with a volume of 5 mL was used to prepare the samples with energy (300, 500)mj. With number of pulsed (50, 100, 150, 200) pulse respectively. We noticed a change in the color of the solution to a dark white color, indicating the presence of silver nanoparticles. In another side study the obsorbancy and transmission by using UV-Visible spectroscopy, the peaks of all samples were at wave length at (250-260) nm. This confirms that nanoparticles have been obtained from silver material. The determined mean energy gab for direct transition allowed of the samples is 2.74 eV.

Preparation and study of some physical properties of silver nanoparticles by pulsed laser ablation in liquids technique

In this paper, the pulsed laser method was used to obtain silver nanoparticles, and one of the first signs indicating the production or generation of nanoparticles using the pulsed laser is the change in the color of the solution. In our study, deionized distilled water with a volume of 5 mL was used to prepare the samples with energy (300, 500)mj With pulsed (50, 100, 150, 200) pulse. We observed change in color of solution to a dark yellowish color that means obtained silver nanoparticles. In another side study the obsorbancy and transmission by using U-Visible spectroscopy, the peaks of all samples were at 400 nm this confirms that nanoparticles have been obtained. The mean energy gab calculated for direct transition allowed of the samples are 2.94 eV.

Up/down-conversion luminescence of monoclinic Gd2O3:Er3+ nanoparticles prepared by laser ablation in liquid

Multifunctional luminescent materials are attracting attention nowadays. In this work, monoclinic Gd2O3:Er3+ nanoparticles, which possess up-conversion luminescence and down-conversion luminescence properties, were successfully synthesized by laser ablation in liquid (LAL) technique. Up-conversion luminescence and down-conversion luminescence of monoclinic Gd2O3:Er3+ nanoparticles were got under the excitation of 980 nm and 379 nm, respectively. In addition, tunable luminescence was got. Furthermore, the cytotoxicity of the nanoparticles is low and the fluorescence of the nanoparticles in cell is also strong enough. The results indicate that the Gd2O3:Er3+ nanoparticles synthesized by LAL technique are promising candidates for bio-imaging or other fields that require controllable fluorescence.

Colloidal MnOX NPs/Carbon sheets nanocomposite synthesis by laser ablation in liquids

MnOxNPs/Cnanosheets composite based colloidal suspensions were synthesized using the laser ablation in liquids technique. The colloids were obtained by ablating a manganese target immersed in a carbon nanosheets suspension, which was previously prepared through laser fragmentation of microsized carbon powder suspended in acetone. The microsized carbon powder was characterized by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The as-obtained nanostructures were characterized by Raman microspectroscopy and transmission electron microscopy (TEM). Raman microspectroscopy results indicate that the composite is constituted by manganese oxide (a mixture of the MnO and Mn3O4 crystalline phases) and carbon. TEM images show that the nanocomposite is composed by manganese oxide nanoparticles embedded in carbon nanosheets. The colloidal suspensions were studied by means of photoluminescence (PL). The two distinct colloidal suspensions (i. e. the carbon nanosheets colloid and the MnOx NPs/C nanosheets composite colloid) show PL. The carbon nanosheets PL is enhanced significantly (in the order of 2.5 times) when the MnOx NPs have been synthesized in the composite. Also, the MnOx NPs provide an intense UV emission to the composite. Several potential applications can be envisioned for this MnOx NPs/C nanosheets composite in the fields of opto-electronics and biomedicine.

Carbon Nanoparticles Synthesis By Different Nd:Yag Laser Pulse Energy

One of the most important techniques for preparing nanoparticle material is Pulsed Laser Ablation in Liquid technique (PLAL). Carbon nanoparticles were prepared using PLAL, and the carbon target was immersed in Ultrapure water (UPW) then irradiated with Q-switched Nd:YAG laser (1064 nm) and six ns pulse duration. In this process, an Nd:YAG laser beam was focused near the carbon surface. Nanoparticles synthesized using laser irradiation were studied by observing the effects of varying incident laser pulse intensities (250, 500, 750, 1000) mJ on the particle size (20.52, 36.97, 48.72, and 61.53) nm, respectively. In addition, nanoparticles were characterized by means of the Atomic Force Microscopy (AFM) test, pH easurement, and an Electrical Conductivity (EC) test of the nano solution. The smallest particle size was produced with (250) mJ laser pulse energy.

Study the effect of gamma ray on silver nanoparticles prepared by pulse laser ablation in liquid technique (PLAL)

Silver nanoparticles in this study were prepared using the method of laser ablation in liquids (PLAL) at two energies (540 and 700) mJ and the count of pulses were (100,200,300 and 400) pulse . The prepared samples were divided into three groups: the first group of the samples were kept as they are without any irradiation but the second and third group were irradiated by Co-60 source with two amount of doses (7.5 and 11) KGy respectively . A series of measurements and studies were done, and from the pictures of Transmitted Electron Microscope (TEM) , it was observed that the prepared nanoparticles at laser energy (540) mJ with pulses count (400) pulse were spherical but the prepared nanoparticles at laser (700) mJ with pulses cont (400) pulse were nano rods shape. The gamma irradiation effect was studied through its effect on the optical properties of the nanoparticles at different preparation conditions , represented by a change in the pulses and the energy of the laser used. The results showed that there was an increase the absorbance peaks when increasing the irradiated dose. The (TEM) image showed we get spherical nanoparticles in shape and nano composition. The average diameter of the prepared silver nanoparticles at (540) mJ laser energy in the range of (30-40) nm.

Laser-Generated Grain Boundaries in Ruthenium Nanoparticles for Boosting Oxygen Evolution Reaction

Highly active and stable catalysts are very crucial for boosting the oxygen evolution reaction (OER) and converting water into clean fuel. Here, we adopt the laser ablation in liquid technique to p...

Characterization and electrical enhancement of PVP/PVA matrix doped by gold nanoparticles prepared by laser ablation

In this study, Polyvinyl Pyrrolidone (PVP)/Polyvinyl Alcohol (PVA) blend embedded by gold nanoparticles (AuNPs) was synthesized via traditional casting method to study the enhanced electrical conductivity of the blend. AuNPs were synthesized by Laser Ablation in Liquids Technique (PLAL). The physical characterization of the prepared PVP/PVA/AuNPs films have been performed by various techniques. The electrical conductivity of the prepared samples was evaluated. The structural characterization shows significant sharp diffraction peak at 2 theta = 38° attributed to the plane (111) related to the presence of AuNPs. UV–Vis absorption spectra reveals the distinctive peak of AuNPs at 536 nm. SEM diffractograms approve the embedding of AuNPs in the surface of PVP/PVA. The electrical conductivity data approved enhancement the performance of the pure blend PVP/PVA after embedded with AuNPs prepared by laser ablation. Ac conductivity have been increased by increasing the ratio of AuNPs within PVP/PVA blend. Thus, these observations reflect the use of PVP/PVA/AuNPs samples in electrical applications.

Gold Nanoparticles in Liquid Based on Photonic Crystal Fiber PCF for Sensors Application

The effect of laser wavelength on gold nanoparticle (Au NPs) fabrication is reported by using the laser ablation in the liquid method in the ethanol. The Pulsed Laser ablation in liquid technique of the gold target was ablated using an Nd:YAG laser nanopulsed nanosecond after that the investigation of the gold NPs was tested by the AFM (Atomic Force Microscopy), and the (XRD) X-ray diffraction. The results showed the characteristics of prepared NPs, depending on XRD, AFM. NPs obtained by 532 nm laser possess better properties than that achieved by 1064 nm laser according to the highest intensity of shorter wavelengths.

Laser-assisted preparation of Pd nanoparticles on carbon cloth for the degradation of environmental pollutants in aqueous medium.

Laser ablation in liquid (LAL), one of the attractive methods for fabrication of nanoparticles, was used for the modification of carbon cloth (CC) by deposition of palladium nanoparticles (Pd NPs); a simple stirring method was deployed to deposit Pd NPs on the CC surface. Characterization techniques viz X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) were applied to study the surface of the ensuing samples which confirmed that LAL technique managed to fabricate and deposit the Pd NPs on the surface of CC. In addition, the catalytic prowess of the carbon cloth-Pd NPs (CC/Pd NPs) was investigated in the NaBH4- or HCOOH-assisted reduction of assorted environmental pollutants in aqueous medium namely hexavalent chromium [Cr(VI)], 4-nitrophenol (4-NP), congo red (CR) and methylene blue (MB). The CC/Pd NPs system has advantages such as high stability/sustainability, high catalytic performance and easy reusability.

Effect of nanostructured metal oxides (CdO, Al2O3, Cu2O) embedded in PVA via Nd:YAG pulsed laser ablation on their optical and structural properties

Abstract The physiochemical properties of Polyvinyl Alcohol (PVA) film was enhanced by embedding with nanostructured metal oxides (CdO, Al2O3, and Cu2O) via one-pot and green method, nanosecond Nd:YAG pulsed laser ablation in liquids technique (PLAL). This process was carried by ablation of metal targets (cadmium, copper, and aluminum) immersed in PVA solution by high intensity pulsed laser in the focusing condition. The enhancing of the PVA properties were appeared by studying the structure, optical and morphology of the prepared films before and after embedding by several technique as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–Visible, Photoluminescence (PL), Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). From structural investigation, the XRD patterns showed a reduction of CdO, Al2O3, and Cu2O nanoparticles within PVA chain. From optical investigation, the interaction and the structural modifications occurred between PVA chains and each metal oxide nanoparticles appeared in stretching vibration bands, the optical energy band gap (Eg) values by using Tauc equation equaled to 2.33, 3.63, and 3.54 eV for the oxide of Cd, Al, and Cu, respectively, are a good agreement with previous work, and the Photoluminescence spectra showed decreasing in emission intensity in the case of embedding with metal oxides. From morphological investigation, the FE-SEM images showed a homogeneous distribution with spherical shape of metal oxides through the polymer of PVA. The qualitative and semi-quantitative elemental analysis of the prepared samples via EDX technique confirmed the embedding of the metal oxide in the PVA structure. This work helps to open the route to produce various properties of PVA by embedded with different nanostructured metal oxides.

Optical Properties Study of II-VI Semiconductors NPs Prepared by Laser Ablation in Liquid Technique

Optical Properties Study of II-VI Semiconductors NPs Prepared by Laser Ablation in Liquid Technique

Synthesis of bilayer graphene nanosheets by pulsed laser ablation in liquid and observation of its tunable nonlinearity

Bilayer graphene nanosheets (B-GNSs) have been synthesized from dry-cell graphite electrode by using facile laser ablation in liquid technique in ambient condition. The plasma plume generated on incidence of ns pulsed Nd: YAG laser fundamental radiation of 1064 nm has facilitated the transformation of bulk graphite (BG) into B-GNSs via liquid carbon phase within 30 min of laser irradiation, and the layer number is are found to be increased with further increase in laser ablation time. The thickness dependent coherent nonlinear optical (NLO) response of the synthesized materials in aqueous dispersion has been determined by spatial self-phase modulation technique. The oxygen-containing surface defects in multilayer GNSs (M-GNSs) have led to scarcity in amount of e-h pairs in compared to that in B-GNSs. Therefore, a better NLO polarization has been observed in B-GNSs in compared to that of M-GNSs. Moreover, the thickness dependent thermal conductivity and hydrodynamic performance of GNSs-water dispersion has led to the observation of tunable NLO response with change in temperature as well as with the intensity of pump laser. The experimental findings obtained in this work may be considered as a key step towards fabrication of graphene from graphitic waste materials for development of future nonlinear photonics devices.

Solar-Blind Self-Powered Photodetector Using Solution-Processed Amorphous Core–Shell Gallium Oxide Nanoparticles

Solution-processed deep ultraviolet (DUV) photodetectors based on wide band gap oxide semiconductors (WBGS) working in the <280 nm wavelength range are drawing increasing attention of the research community because of their cost-effective production and potential use in diverse applications. Here, we report on the synthesis of novel core-shell amorphous gallium oxide nanoparticles (NPs) (a-Ga2Ox/GaOx NPs) that have not been previously obtained. The amorphous gallium oxide NPs were synthesized from gallium nitride using the femtosecond laser ablation in liquid technique. Transmission electron microscopy and electron energy-loss spectroscopy measurements revealed the amorphous NP nature with a Ga-rich core and oxide-rich shell. Optical properties of these core-shell amorphous gallium oxide NPs were investigated by time-resolved spectroscopy and photoluminescence. As a proof of concept, the amorphous gallium oxide NPs were used as an active layer in a solar-blind DUV photodetector with high responsivity (778 mA/W) at 244 nm, which is the highest responsivity recorded to date for any solution-processed DUV photodetector. This work on a high-performance solution-processed device paves the way for large-scale industrial application of the WBGS.