1. Atomically resolved dealloying of structurally ordered Pt nanoalloy as an oxygen reduction reaction electrocatalystAndraž Pavlišič, Primož Jovanovič, Vid Simon Šelih, Martin Šala, Marjan Bele, Goran Dražić, Iztok Arčon, Samo B. Hočevar, Anton Kokalj, Nejc Hodnik, Miran Gaberšček, original scientific article Abstract: The positive effect of intermetallic ordering of platinum alloy nanoparticles on oxygen reduction reaction (ORR) activity has been well established. What is still missing is an understanding of selective leaching of the less noble metal from the ordered structure and its correlation to longterm ORR performance. Using a combination of kinetic Monte Carlo simulations and advanced characterization techniques, we provide unprecedented insight into dealloying of intermetallic PtCu3 nanoparticles a well-known binary alloy. Comparison of ordered and disordered samples with identical initial compositions and particle size distributions reveals an unexpected correlation: whereas the copper dealloying rates in the ordered and disordered counterparts are almost the same, in the ordered structure Pt atoms are surrounded by 15−30% more Cu atoms throughout all the stages of acid leaching. This more convenient Pt−Cu coordination explains the statistically significant increase of 23−37% in ORR activity of the ordered structure at all stages of alloy degradation.
Found in: ključnih besedah
Summary of found: ...ORR activity, fuel cells, platinum alloy, nanoparticle stability, intermetallic ordering, kinetic Monte Carlo, dealloying,
in...
Keywords: ORR activity, fuel cells, platinum alloy, nanoparticle stability, intermetallic ordering, kinetic Monte Carlo, dealloying, in situ ICP-MS
Published: 27.09.2016; Views: 4700; Downloads: 0
 Fulltext (3,27 MB) |
2. Polymer Vesicles with a Colloidal Armor of NanoparticlesRong Chen, Daniel J. G. Pearce, Sara Fortuna, David L. Cheung, Stefan A. F. Bon, 2011, original scientific article Abstract: The fabrication of polymer vesicles with a colloidal armor made from a variety of nanoparticles is demonstrated. In addition, it is shown that the armored supracolloidal structure can be postmodified through film-formation of soft polymer latex particles on the surface of the polymersome, hereby effectively wrapping the polymersome in a plastic bag, as well as through formation of a hydrogel by disintegrating an assembled polymer latex made from poly(ethyl acrylate-co-methacrylic acid) upon increasing the pH. Furthermore, ordering and packing patterns are briefly addressed with the aid of Monte Carlo simulations, including patterns observed when polymersomes are exposed to a binary mixture of colloids of different size.
Found in: ključnih besedah
Summary of found: ...Pickering emultion, self-assemblt, Monte Carlo, simulation, nanoparticle, packing, pattern garnd canonical, colloids...
Keywords: Pickering emultion, self-assemblt, Monte Carlo, simulation, nanoparticle, packing, pattern garnd canonical, colloids
Published: 11.10.2016; Views: 3948; Downloads: 0
Fulltext (1,43 MB) |
3. Polymer Nanoparticle Sizes from Dynamic Light Scattering and Size Exclusion Chromatography: The Case Study of Polysilanes.Matjaž Valant, Tim Bencik, Irena Kralj Cigić, Andraž Mavrič, Artem Badasyan, 2018, original scientific article Abstract: Dynamic Light Scattering (DLS) and Size Exclusion Chromatography (SEC) are among the most popular methods for determining polymer sizes in solution. Taking dendritic and network polysilanes as a group of least soluble polymer substances, we critically compare and discuss the difference between nanoparticle sizes, obtained by DLS and SEC. Polymer nanoparticles are typically in poor solution conditions below the theta point and are in globular conformation therefore. Determination of particle sizes in presence of attractive interactions is not a trivial task. The only possibility to measure aggregation-free, a true molecular size of polymer nanoparticles in such regime of solution, is to operate with the dilute solution of globules (below theta point and above the miscibility line). Basing on results of our polysilane measurements, we come to a conclusion that DLS provides more reliable results than SEC for the dilute solution of globules. General implications for the size measurements of polymer nanoparticles in solutions are discussed.
Found in: ključnih besedah
Keywords: Polymer Nanoparticle, Dynamic Light Scattering, Size Exclusion Chromatography, Polysilanes
Published: 16.05.2018; Views: 3381; Downloads: 6
Fulltext (3,17 MB) |
4. Evolution of the microstructure during the early stages of sintering barium hexaferrite nanoplateletsBlaž Belec, Darja lisjak, Darko Makovec, Sašo Gyergek, Tanja Goršak, 2019, original scientific article Found in: ključnih besedah
Summary of found: ... Nanoparticle, sintering-Hexaferrite nanoplatelets, Magnetic properties, Fusion grain growth...
Keywords: Nanoparticle, sintering-Hexaferrite nanoplatelets, Magnetic properties, Fusion grain growth
Published: 17.07.2019; Views: 2269; Downloads: 0
Fulltext (1,49 MB) |
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6. Ultralow duty cycle chopper instigated low power continuous wave laser assisted synthesis of silver nanoparticlesSankaranarayana Iyer Sankararaman, V. P. N. Nampoori, R. A. Krishnanunni, A. S. Ashik, Mohanachandran Nair Sindhu Swapna, 2020, original scientific article Abstract: This paper is the first report of advancement in the drastic reduction of the laser power density from 105 to 7.5 W/cm2 for the synthesis of silver nanoparticles (SNPs) using a low power (60 mW) continuous-wave (cw) laser and a specially designed ultralow duty cycle (3%) optical chopper wheel for modulating the laser beam at low frequencies (2 Hz). The target is irradiated by keeping it in a liquid medium at 40–60 °C to produce quantum dots to SNPs of size less than 40 nm. The UV-visible spectroscopic and electron microscopic analyses confirm the formation of quantum dots and SNPs of size-dependent bandgap energy varying from 1.92 to 2.37 eV. The photoluminescence studies not only support the above observations but also reveal the blue emission upon UV excitation through the chromaticity diagram. The proposed greener approach using the low power cw laser is cost-effective when compared with the high-power laser-assisted synthesis
of SNPs reported until now.
Found in: ključnih besedah
Summary of found: ...cw laser, silver nanoparticle, ultralow duty cycle, chopper...
Keywords: cw laser, silver nanoparticle, ultralow duty cycle, chopper
Published: 30.06.2022; Views: 395; Downloads: 17
Fulltext (3,49 MB)
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7. Boron‑rich boron carbide from sootSankaranarayana Iyer Sankararaman, H. V. Saritha Devi, Mohanachandran Nair Sindhu Swapna, 2020, original scientific article Abstract: Boron carbide is a promising super-hard semiconducting material for refractory applications ranging from the nuclear industry to spacecraft. The present work is the frst report of not only turning futile soot, containing carbon allotropes in varying
composition, into boron-rich boron carbide (BC), but also developing it by a low-cost, low-temperature, and green synthesis
method. The BC synthesised from gingelly oil soot is subjected to structural, morphological, and optical characterisations.
The feld emission scanning electron microscope shows beautiful fower-like morphology, and the thermogravimetric analysis reveals the high-temperature stability of the sample synthesised. The Tauc plot of the sample indicates a 2.38 eV direct
bandgap. The formation of BC and boron-rich carbide evidenced by X-ray difraction studies is confrmed through Raman
and Fourier transform infrared spectroscopic signatures of B–C and C–B–C bonds. The fuorescence, power spectrum, and
CIE analyses carried out suggest the blue light emission for excitation at 350 nm
Found in: ključnih besedah
Summary of found: ...boron carbide, soot, carbon nanoparticle, refractory, allotropes, green synthesis...
Keywords: boron carbide, soot, carbon nanoparticle, refractory, allotropes, green synthesis
Published: 30.06.2022; Views: 359; Downloads: 0
Fulltext (1,11 MB) |
8. Tuning the thermal diffusivity of the seed matter for enhanced biosynthesis: A thermal lens studySankararaman S, Swapna Mohanachandran Nair Sindhu, 2020, original scientific article Abstract: The thermodynamics of the seed matter after imbibition is highly significant as the growth and germination involve complex biochemical exergonic process. The germination of seed and compositional variation of the seed matter has always been a fascinating field of research. The present work unveils the thermodynamics associated with the changing thermal diffusivity of the seed matter through the green technology-based single-beam thermal lens technique. Investigations are carried out in Vigna radiata seeds, germinating in media with and without carbon allotropes, through various spectroscopic techniques. The morphology of the soot and carbon allotropes is understood from the field emission scanning electron microscope images. The thermal lens study throws light into the energy trapping nature of the seed matter of the seed growing in carbon allotropic media which facilitates biosynthesis. The observed increased rate of growth of the seed is substantiated through
the ultraviolet–visible–near-infrared (NIR), Fourier transform infrared, and photoluminescence (PL) spectroscopic analyses. The NIR and PL studies also reveal the formation of chlorophyll molecule during germination. Thus, the study suggests a mechanism for tuning the thermal diffusivity of the seed matter as to trap the biochemical energy to facilitate the further biosynthesis and thereby to enhance the growth rate.
Found in: ključnih besedah
Summary of found: ...seed matter, thermal diffusivity, thermal lens, carbon nanoparticle, soot...
Keywords: seed matter, thermal diffusivity, thermal lens, carbon nanoparticle, soot
Published: 04.07.2022; Views: 334; Downloads: 0
Fulltext (2,68 MB) |
9. Carbon nanoparticles assisted energy transport mechanism in leaves: A thermal lens studySwapna Mohanachandran Nair Sindhu, 2019, original scientific article Abstract: In the world of increasing population and pollution due to carbon emissions, the research for effective utilization of futile diesel soot for fruitful applications has become a necessity for a sustainable development. The contribution to pollution from vehicles and industries due to the aging of engines has caused a crisis. Carbon nanoparticles (CNPs) have been the subject of interest because of their good physical, chemical, and biological properties. The present work investigates the role of CNPs produced by internal combustion engines on the energy transport mechanism among leaf pigments using the sensitive and nondestructive single beam thermal lens technique. The studies reveal the absorption changes by various chlorophyll pigments with the concentration of CNPs sprayed on the leaves. Though for low concentrations CNPs lower the photon absorbance by chlorophyll pigments, the effect gets reversed at higher concentrations. The variation of thermal diffusivity with CNP concentration and its role in the energy transport mechanism among chlorophyll pigments are also studied. It is found that CNP concentrations of 625-2500mg/l are good for better intra-pigment energy transport leading to increased rate of photosynthesis and plant yield and thereby helping in attaining food security. The variation of CNP assisted energy transport among leaf pigments on the production of nicotinamide adenine dinucleotide phosphate (NADPH) and carbohydrates is also studied with ultraviolet (UV) and near-infrared (NIR) spectroscopy.
Found in: ključnih besedah
Summary of found: ...carbon nanoparticle, soot, energy transport, thermal lens, photosynthesis...
Keywords: carbon nanoparticle, soot, energy transport, thermal lens, photosynthesis
Published: 05.07.2022; Views: 381; Downloads: 0
Fulltext (1,84 MB) |
10. Optical emission diagnosis of carbon nanoparticle incorporated chlorophyll for sensing applicationsSankararaman S, SARITHA DEVI H V, RAJ VIMAL, Swapna Mohanachandran Nair Sindhu, 2019, original scientific article Abstract: Chlorophyll fluorescence (Chl F) is widely used in sensing applications to understand terrestrial vegetation
and environmental and climatic variations. The increasing rates of industrialization and carbon emission
from internal combustion engines (ICEs) pose a threat to sustainable development. This study analyses
the impact of carbon nanoparticles (CNPs) from ICEs on the optical absorption and fluorescence emission of leaf pigments. Leaf pigments without and with CNPs were subjected to UV-visible and photo-luminescence (PL) spectroscopy analyses. The field emission scanning electron microscopy and high-resolution transmission electron microscopy images of CNPs showed their morphology. The Jablonski diagram of the CNP-incorporated chlorophyll system helped in understanding the fluorescence emission,internal conversion, and the exchange of energy between them. The variations in (i) total chlorophyll, (ii)
optical absorbance by total chlorophyll, (iii) PL emission peak (at 675 nm and 718 nm) intensities for different excitation wavelengths, and (iv) normalized absorbance at the PL emission peaks with different CNP concentrations were analysed by dividing into three regions. In Region I (0–0.625 mg ml−1 ), the
radiative component dominated the nonradiative component as a result of energy transfer from CNPs to chlorophyll. In Region II (0.625–1.2 mg ml−1 ), the increase in CNP concentration initiated diffusion into chloroplasts, resulting in the increase in the nonradiative part of total energy and decrease in PL peak
intensity. In Region III (1.2–2.5 mg ml−1
), the energy absorbed by the CNPs dissipated more nonradiatively, leading to a slow rate of increase in the radiative part. The visual response of PL emission, color purity,
and the distribution of the emitted energy over the spectrum studied with the help of CIE plots, power spectrum, and confocal fluorescence microscopy revealed the fluorescence emission in the red region. This study suggests the possibility of employing Chl F in agricultural, environmental, and biological fields
for sensing applications.
Found in: ključnih besedah
Keywords: carbon nanoparticle, optical emission, fluorescence
Published: 05.07.2022; Views: 314; Downloads: 0
Fulltext (1,92 MB) |
