| 1. |
- Asfaw, Habtom Desta, 1986-, et al.
(författare)
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Over-Stoichiometric NbO2 Nanoparticles for a High Energy and Power Density Lithium Microbattery
- 2017
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Ingår i: ChemNanoMat. - : Wiley. - 2199-692X. ; 3:9, s. 646-655
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Tidskriftsartikel (refereegranskat)abstract
- Effective utilization of active materials in microbatteries can be enhanced by rational design of the electrodes. There is an increasing trend of using 3D electrodes that are coated in nanosized active materials to boost both energy and power densities. This article focuses on the fabrication of 3D electrodes based on monolithic carbon foams coated in over-stoichiometric NbO2 nanoparticles. The electrodes exhibit remarkable energy and power densities at various current densities when tested in lithium microbatteries. An areal capacity of around 0.7mAhcm(-2) and energy density up to 45mWhcm(-3) have been achieved. More than half of the areal capacity can be accessed at a current density of about 11mAcm(-2), with the corresponding energy and power densities being 21mWhcm(-3) and 1349mWcm(-3). These values are comparable to those of microsupercapacitors containing carbon and MnO2 nanomaterials. Furthermore, the electrochemical reversibility improves progressively upon cycling along with substantial increase in the charge transfer kinetics of the electrode. Based on impedance analyses almost a fourfold decrease in the charge transfer resistance has been observed over 25 cycles. Such enhancement of the electronic properties of NbO2 can account for the high electrochemical rate performance of the 3D electrodes.
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| 2. |
- Divagar, M, et al.
(författare)
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Self-assembled polyamidoamine dendrimer on poly (methyl methacrylate) for plasmonic fiber optic sensors
- 2019
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Ingår i: ChemNanoMat. - : John Wiley & Sons. - 2199-692X.
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel one-step polyamidoamine (PAMAM) dendrimer based polymethyl methacrylate (PMMA) surface functionalization strategy for the development of polymeric optical fiber (POF) based plasmonic sensors utilizing gold nanoparticles (AuNP). Simple contact angle measurements over PMMA sheets reveal the ability of the dendrimers to strongly bind to PMMA surface without additional acid/alkali pretreatment, unlike the conventional hexamethylene diamine (HMDA) based surface modification. Subsequently, U-bent POF probes with high evanescent wave absorbance sensitivity were exploited for relative quantification of the surface amine groups using fluorescein isothiocyanate (FITC) binding and efficient chemisorption of gold nanoparticles (AuNP) in order to identify the optimum conditions viz. dendrimer concentration, incubation time and dendrimer generation. While FITC binding showed a proportional increase in amine functional density with PAMAM concentration and time, interestingly the AuNP (40 nm) binding studies revealed the formation of loose PAMAM multilayers and their desorption. PAMAM (G4) concentration as low as 5 mM and incubation time of 24 h provide faster binding rate with densely packed AuNP and the RI sensitivity of ~15 (A546 nm/RIU). This simpler and inexpensive strategy could also be exploited for the development of functional PMMA substrates for various applications including nanotechnology, bio-imaging, drug delivery and analytical separations.
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| 3. |
- Epifani, Mauro, et al.
(författare)
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Solvothermal Synthesis, Gas-Sensing Properties, and Solar Cell-Aided Investigation of TiO2-MoOx Nanocrystals
- 2017
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Ingår i: ChemNanoMat. - : John Wiley & Sons. - 2199-692X. ; 3:11, s. 798-807
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Tidskriftsartikel (refereegranskat)abstract
- Titania anatase nanocrystals were prepared by sol-gel/solvothermal synthesis in oleic acid at 250 °C, and modified by co-reaction with Mo chloroalkoxide, aimed at investigating the effects on gas-sensing properties induced by tailored nanocrystals surface modification with ultra-thin layers of MoOx species. For the lowest Mo concentration, only anatase nanocrystals were obtained, surface modified by a disordered ultra-thin layer of mainly octahedral MoVI oxide species. For larger Mo concentrations, early MoO2 phase segregation occurred. Upon heat treatment up to 500 °C, the sample with the lowest Mo concentration did not feature any Mo oxide phase segregation, and the surface Mo layer was converted to dense octahedral MoVI oxide. At larger Mo concentrations all segregated MoO2 was converted to MoO3. The two different materials typologies, depending on the Mo concentration, were used for processing gas-sensing devices and tested toward acetone and carbon monoxide, which gave a greatly enhanced response, for all Mo concentrations, to acetone (two orders of magnitude) and carbon monoxide with respect to pure TiO2. For the lowest Mo concentration, dye-sensitized solar cells were also prepared to investigate the influence of anatase surface modification on the electrical transport properties, which showed that the charge transport mainly occurred in the ultra-thin MoOx surface layer.
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| 4. |
- Faisal, Nadimul Haque, et al.
(författare)
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Application of Thermal Spray Coatings in Electrolysers for Hydrogen Production : Advances, Challenges, and Opportunities
- 2022
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Ingår i: ChemNanoMat. - : Wiley-VCH Verlagsgesellschaft. - 2199-692X. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Thermal spray coatings have the advantage of providing thick and functional coatings from a range of engineering materials. The associated coating processes provide good control of coating thickness, morphology, microstructure, pore size and porosity, and residual strain in the coatings through selection of suitable process parameters for any coating material of interest. This review consolidates scarce literature on thermally sprayed components which are critical and vital constituents (e. g., catalysts (anode/cathode), solid electrolyte, and transport layer, including corrosion-prone parts such as bipolar plates) of the water splitting electrolysis process for hydrogen production. The research shows that there is a gap in thermally sprayed feedstock material selection strategy as well as in addressing modelling needs that can be crucial to advancing applications exploiting their catalytic and corrosion-resistant properties to split water for hydrogen production. Due to readily scalable production enabled by thermal spray techniques, this manufacturing route bears potential to dominate the sustainable electrolyser technologies in the future. While the well-established thermal spray coating variants may have certain limitations in the manner they are currently practiced, deployment of both conventional and novel thermal spray approaches (suspension, solution, hybrid) is clearly promising for targeted development of electrolysers.
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| 5. |
- Ibrahem, Ismail, et al.
(författare)
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Copper Nanoparticles on Controlled Pore Glass and TEMPO for the Aerobic Oxidation of Alcohols
- 2018
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Ingår i: ChemNanoMat. - : Wiley. - 2199-692X. ; 4:1, s. 71-75
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report on the facile synthesis of a heterogeneous copper nanocatalyst and its combination with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) for the aerobic oxidation of alcohols to their corresponding carbonyl compounds. This low cost copper nanocatalyst was found to exhibit excellent recyclability, making it a highly attractive catalytic system from an economical and environmental point of view. Extensive characterization of the catalyst by a number of techniques revealed that it was comprised of well-dispersed Cu(I/II) nanoparticles with an average size of around 6nm.
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| 6. |
- Minero, Gabriel Antonio S., et al.
(författare)
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Real-time analysis of switchable nanocomposites of magnesium pyrophosphates and rolling circle amplification products
- 2020
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Ingår i: ChemNanoMat. - : Wiley. - 2199-692X. ; 6:8, s. 1276-1282
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Tidskriftsartikel (refereegranskat)abstract
- Rolling circle amplification (RCA) is a robust isothermal nucleic acid amplification method producing nanocomposites of DNA and inorganic magnesium pyrophosphate precipitates. Although the conformation and structure of such nanocomposites impact applications, most studies of them have been performed at the end-point after exposure to a treatment. Here, we use real-time optomagnetic measurements of the hydrodynamic size of magnetic nanoparticles (MNPs) to study the growth of RCA products grafted onto MNPs as well as the effect of post-RCA temperature annealing and chemical treatment. As a key result, we show that secondary structures in the RCA products trap and partially protect magnesium pyrophosphate precipitates and that these are reversibly released upon heating above a characteristic temperature defined by the sequence of the RCA product. These findings provide a deeper mechanistic understanding of the synthesis and structure of DNA nanocomposites, which impacts applications of DNA nanocomposites in sensing and drug delivery.
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| 7. |
- Song, Man, et al.
(författare)
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Efficient Gelation of Graphene Oxide Aqueous Dispersion Induced by Sonication-Promoted Leuckart Reaction
- 2018
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Ingår i: ChemNanoMat. - : John Wiley & Sons. - 2199-692X. ; 4:11, s. 1145-1152
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Graphene oxide (GO) undergoes a rapid gelation process in the presence of ammonium hydroxide and formic acid at room temperature which is promoted by ultrasonication. Infrared and X-ray photoelectron spectroscopy proved partial reduction of GO and nitrogen incorporation, resulting from sonication-promoted Leuckart reactions at GO carbonyl groups. The amine groups produced via Leuckart reactions undergo further reactions that result in salt bridges with carboxylic groups and covalent cross-links, both of which contribute to the stabilization of the resulting hydrogel. The resultant GO hydrogel exhibits enhanced thermal stability.
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| 8. |
- Song, Man, et al.
(författare)
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Nitrogen-doped Reduced Graphene Oxide Hydrogel Achieved via a One-Step Hydrothermal Process
- 2019
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Ingår i: ChemNanoMat. - : WILEY-V C H VERLAG GMBH. - 2199-692X. ; 5:9, s. 1144-1151
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Tidskriftsartikel (refereegranskat)abstract
- We report an efficient one-step method to achieve highly reduced graphene oxide (rGO) hydrogel doped with nitrogen where the rGO sheets are interconnected forming a porous structure by means of hydrothermal process. During the synthesis, ammonium formate is used as reducing reagent and simultaneously as nitrogen supplier, which delivers nitrogen-doped rGO (NRGO) hydrogel that exhibits C/O atomic ratio as high as at ~11.1 and contains decent ~5.4 at.% nitrogen. As comparison, the reduction efficiency is only half of the value and no nitrogen doping can be obtained when L-ascorbic acid is used as reducing reagent. The resultant NRGO shows enhanced electrocatalytic ability for oxygen reduced reaction indicating its great potential of the one-step method for the catalyst and energy applications.
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| 9. |
- Valenti, Marco, et al.
(författare)
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The Role of Size and Dimerization of Decorating Plasmonic Silver Nanoparticles on the Photoelectrochemical Solar Water Splitting Performance of BiVO4 Photoanodes
- 2016
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Ingår i: ChemNanoMat. - Weinheim : WILEY-V C H VERLAG GMBH. - 2199-692X. ; 2:7, s. 739-747
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Tidskriftsartikel (refereegranskat)abstract
- Ag nanoparticles (NPs) are deposited on BiVO4 photoanodes to study their effect on the photoelectrochemical (PEC) water splitting performance of the semiconductor. 15 nm light-absorbing NPs and 65 nm light scattering NPs were studied separately to compare their light trapping ability for enhancing the semiconductors absorption through light concentration and light scattering, respectively. The 15 nm NPs enhanced the BiVO4 external quantum efficiency throughout the semiconductors absorption range (e.g.,approximate to 2.5 fold at lambda=400 nm). However, when a hole scavenger was added to the electrolyte, no enhancement was ob-served upon NP deposition, indicating that the NPs only facilitate the injection of holes from the semiconductor surface to the electrolyte but do not enhance its absorption. On the other hand, the 65 nm scattering NPs not only facilitated hole injection to the electrolyte, but also enhanced the absorption of the semiconductor (by approximate to 6%) through light scattering. Such a dual effect, i.e., of enhancing both the surface properties and the absorption of the semiconductor, makes light scattering Ag NPs an ideal decoration for PEC water splitting photoelectrodes.
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| 10. |
- Vardanyan, Ani, et al.
(författare)
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Synthesis of Cyclen-Functionalized Ethenylene-Based Periodic Mesoporous Organosilica Nanoparticles and Metal-Ion Adsorption Studies
- 2020
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Ingår i: Chemnanomat. - : Wiley. - 2199-692X. ; 6, s. 1625-1634
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Tidskriftsartikel (refereegranskat)abstract
- The preparation of two cyclens both possessing two triethoxysilyl groups through click chemistry is described. These two cyclens were incorporated into bis(triethoxysilyl)ethenylene-based periodic mesoporous organosilica nanoparticles (PMO NPs) at different proportions of bis(triethoxysilyl)ethenylene/cyclens (90/10, 75/25). The obtained nanorods were analyzed with different techniques and showed high specific surface areas at low proportion of cyclens. The nanorods containing free amino groups of cyclen were then used for Ni(II) and Co(II) removal from model solutions. The kinetics and isotherms of adsorption of Ni(II) and Co(II) were determined, and the materials showed high uptake of metals (up to 3.9 mmol . g(-1)). They demonstrated pronounced selectivity in separation of rare earth elements from late transition metals, e. g. Ni(II) and Co(II) by adsorption and even more so by controlled desorption.
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