1,720,984 research outputs found
Raman Monitoring of Strain Induced Effects in Mechanically Deposited Single Layer Graphene
No full textPulsed laser ablation of a continuously-fed wire in liquid flow for high-yield production of silver nanoparticle
No full textUsing wires of defined diameters instead of a planar target for pulsed laser ablation in liquid results in significant increase of ablation efficiency and nanoparticle productivity up to a factor of 15. We identified several competitive phenomena based on thermal conductivity, reflectivity and cavitation bubble shape that affect the ablation efficiency when the geometry of the target is changed. On the basis of the obtained results, this work represents an intriguing starting point for further developments related to the up-scaling of pulsed laser ablation in liquid environments at the industrial level
Silver nanoplates paved PMMA cuvettes as a cheap and re-usable plasmonic sensing device
No full textSurface plasmon resonance (SPR) sensors find wide applications due to their prompt responses and because they do not need sophisticated instrumentation. One of the most explored effects is the high sensitivity of the plasmon band position due to refractive index changes in the medium. In the following, we present a cost-effective, reusable, and high-responsive SPR device based on silver nanoplate paved PMMA cuvettes. The nanostructures were obtained by the seed-growing approach. The localized surface plasmon resonance (LSPR) features, observed in the colloidal state, were successfully transferred to the paved cuvettes and their plasmon sensitivities with liquids of different refractive index were recorded. We observed refractive index sensitivities up to 280 nm/refractive index units, using nanoplates with plasmon resonances in the near-infrared region. The experimental results find correspondence and agreement with extinction cross-section calculated with a Boundary Element Method (BEM) approach. This work addresses how to build a simple, cost-effective optical device, which is suitable for integration and miniaturization
Room-Temperature Laser Synthesis in Liquid of Oxide, Metal-Oxide Core-Shells, and Doped Oxide Nanoparticles
No full textAlthough oxide nanoparticles are ubiquitous in science and technology, a multitude of compositions, phases, structures, and doping levels exist, each one requiring a variety of conditions for their synthesis and modification. Besides, experimental procedures are frequently dominated by high temperatures or pressures and by chemical contaminants or waste. In recent years, laser synthesis of colloids emerged as a versatile approach to access a library of clean oxide nanoparticles relying on only four main strategies running at room temperature and ambient pressure: laser ablation in liquid, laser fragmentation in liquid, laser melting in liquid and laser defect-engineering in liquid. Here, established laser-based methodologies are reviewed through the presentation of a panorama of oxide nanoparticles which include pure oxidic phases, as well as unconventional structures like defective or doped oxides, non-equilibrium compounds, metal-oxide core–shells and other anisotropic morphologies. So far, these materials showed several useful properties that are discussed with special emphasis on catalytic, biomedical and optical application. Yet, given the endless number of mixed compounds accessible by the laser-assisted methodologies, there is still a lot of room to expand the library of nano-crystals and to refine the control over products as well as to improve the understanding of the whole process of nanoparticle formation. To that end, this review aims to identify the perspectives and unique opportunities of laser-based synthesis and processing of colloids for future studies of oxide nanomaterial-oriented sciences
Protein Arrays for Sensing Applications: Relationship beetween Printing Conditions and Pattern Properties
No full textEfficient H2 production by photocatalytic water splitting under UV or solar light over variously modified TiO2-based catalysts
Full text linkThis paper focused for the first time on the comparison between three different approach to modify the chemico-physical properties of TiO2-based photocatalysts and their effect in the H2 production by photocatalytic water splitting both under UV and solar light irradiation, under the same experimental conditions. The application of pulsed laser irradiation to aqueous TiO2 suspensions (first approach) induced structural transformations both on the bulk and on the surface of TiO2, boosting the H2 production, under UV light irradiation, of almost three times (20.9 mmol/gcat·h) compared to bare TiO2 (7.7 mmol/gcat·h). The second strategy was based on a templating method to obtain TiO2 with a macroporous structure to favour an efficient light absorption process inside the material pores, thus allowing a high H2 production (0.64 mmol/gcat·h) under solar light irradiation. This performance was further enhanced when the macroporous TiO2 was coupled with CeO2 or W (third approach). In the latter case the H2 production increased to 0.72 mmol/gcat·h for macroporous TiO2[sbnd]CeO2 and to 0.82 mmol/gcat·h for macroporous TiO2[sbnd]W. This work highlights how it is possible to tune the TiO2 photocatalytic properties with easy and green procedures to obtain environmental friendly catalyst for hydrogen production
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Efficient H2 production by photocatalytic water splitting under visible light over modified TiO2-based catalysts
No full textEfficient H2 production by photocatalytic water splitting under visible light over modified TiO2-based catalyst
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