| 1. |
- Hakim, M. Waqas, et al.
(författare)
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Enhanced Electrochemical Performance of MWCNT-Assisted Molybdenum-Titanium Carbide MXene as a Potential Electrode Material for Energy Storage Application
- 2024
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 9:8, s. 8763-8772
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) materials such as MXenes have attracted considerable attention owing to their enormous potential for structural flexibility. Here, we prepared a Mo2TiC2Tx-layered structure from parent Mo2TiAlC2Tx MAX by chemically selective etching of the aluminum layer. The prepared MXene was employed in composite formation with CTAB-grafted multiwalled carbon nanotubes (MWCNTs) to have a structure with improved electrochemical performance. The samples were characterized to analyze the structure, morphology, elemental detection, vibrational modes, and surface chemistry, followed by an electrochemical performance of the Mo2TiC2Tx MXene and MWCNTs@Mo2TiC2Tx composite using the GAMRAY Potentiostat under a 1 M KOH electrolyte. The specific capacitance of pristine Mo2TiC2Tx was 425 F g–1, which was enhanced to 1740 F g–1 (almost 4 times) at 5 mV s–1 due to the increase in active surface area and conductive paths between the MXene sheets. The charge storage mechanism was studied by further resolving the cyclic voltammograms. MWCNTs@Mo2TiC2Tx showed much improved electrochemical performance and reaction kinetics, making it an ideal material candidate for supercapacitor applications.
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| 2. |
- Li, Hu, 1986-, et al.
(författare)
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Enhanced gas sensing performance of graphene/ZnS-CdS hetero-nanowires gas sensor synthesized by Langmuir-Blodgett self-assembly method
- 2017
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Ingår i: Journal of Physics Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 922
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Tidskriftsartikel (refereegranskat)abstract
- Graphene is a promising material in the field of solid-state gas sensors due to the unique two-dimensional structure. Here, we have shown by fabricating graphene/ZnS-CdS hetero-nanowire structure, the gas sensor sensitivity has a two-fold increase to 20% under 15 ppm gaseous concentration compared to a 10% response in pristine graphene. Spectroscopy and microscopy analysis indicate that the semi-conducting ZnS-CdS hetero-nanowires are 2 nm wide and densely packed on top of graphene. By combining UV illumination, the device approaches a fast response/recovery and high gas sensitivity, thus has a potential to be used in a detection of wide range of gases.
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| 3. |
- Tahir, Rabia, et al.
(författare)
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Multiferroic and ferroelectric phases revealed in 2D Ti3C2Tx MXene film for high performance resistive data storage devices
- 2023
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Ingår i: NPJ 2D MATERIALS AND APPLICATIONS. - : Springer Nature. - 2397-7132. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Multiferroic materials, showing simultaneous ferroelectric and ferromagnetic orders, are considered to be promising candidates for future data storage technology however, the multiferroic phenomenon in two-dimensional (2D) materials is rarely observed. We report a simple approach to observe frequency-dependent ferroelectricity and multiferroicity in 2D Ti3C2Tx MXene film at room-temperature. To study the frequency and poling effect on ferroelectricity, we performed electric polarization vs. electric field (P-E) measurement at different frequencies, measured under zero and non-zero static magnetic fields. The results not only indicate a clear frequency dependence of electric domains owing to varying time relaxation during reversal dynamic but also showed magnetic field control of electric polarization thus, confirmed the presence of strong magneto-electric (ME) coupling at room-temperature. The existence of ME coupling was attributed to the coupling between disordered electric dipoles with local spin moments as well reduced dielectric loss after heat-treatment. Moreover, the ferroelectric Ti3C2Tx MXene film was employed as an active layer within the resistive data storage device that showed a stable switching behavior along with improved on/off ratio in comparison to non-ferroelectric Ti3C2Tx active layer. The unique multiferroic behavior along with ferroelectric-tuned data storage devices reported here, will help understand the intrinsic nature of 2D materials and will advance the 2D ferroelectric data storage industry.
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| 4. |
- Wani, Ishtiaq Hassan, 1985-, et al.
(författare)
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A sub 20 nm metal-conjugated molecule junction acting as a nitrogen dioxide sensor
- 2019
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 11:14, s. 6571-6575
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of a gas molecule with a sensing material causes the highest change in the electronic structure of the latter, when this material consists of only a few atoms. If the sensing material consists of a short, conductive molecule, the sensing action can be furthermore probed by connecting such molecules to nanoelectrodes. Here, we report that NO2 molecules that adhere to 4,4'-biphenyldithiol (BPDT) bound to Au surfaces lead to a change of the electrical transmission of the BPDT. The related device shows reproducible, stable measurements and is so far the smallest (<20 nm) gas sensor. It demonstrates modulation of charge transport through molecules upon exposure to nitrogen dioxide down to concentrations of 55 ppb. We have evaluated several devices and exposure conditions and obtained a close to linear dependence of the sensor response on the gas concentration.
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| 8. |
- Zheng, Xiaoxiao, et al.
(författare)
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Graphene-Oxide-Based Fluoro- and Chromo-Genic Materials and Their Applications
- 2022
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 27:6
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Tidskriftsartikel (refereegranskat)abstract
- Composite materials and their applications constitute a hot field of research nowadays due to the fact that they comprise a combination of the unique properties of each component of which they consist. Very often, they exhibit better performance and properties compared to their combined building blocks. Graphene oxide (GO), as the most widely used derivative of graphene, has attracted widespread attention because of its excellent properties. Abundant oxygen-containing functional groups on GO can provide various reactive sites for chemical modification or functionalization of GO, which in turn can be used to develop novel GO-based composites. This review outlines the most recent advances in the field of novel dyes and pigments encompassing GO as a key ingredient or as an important cofactor. The interactions of graphene with other materials/compounds are highlighted. The special structure and unique properties of GO have a great effect on the performance of fabricated hybrid dyes and pigments by enhancing the color performance of dyes, the anticorrosion properties of pigments, the viscosity and rheology of inks, etc., which further expands the applications of dyes and pigments in dyeing, optical elements, solar-thermal energy storage, sensing, coatings, and microelectronics devices. Finally, challenges in the current development as well as the future prospects of GO-based dyes and pigments are also discussed. This review provides a reference for the further exploration of novel dyes and pigments.
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| 9. |
- Ghajeri, Farnaz, et al.
(författare)
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Case Study of a Green Nanoporous Material from Synthesis to Commercialisation : Quartzene®
- 2018
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Ingår i: Current Opinion in Green and Sustainable Chemistry. - : Elsevier. - 2452-2236. ; 12, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic amorphous silicas with high porosity (94–97%) are introduced and various pathways for their synthesis are presented. The materials have structures with high surface area (300–750 m2/g) and are commercialised under the name of Quartzene®. Low cost silica sources and ambient pressure drying enable production in large scale with approximately 70% cost reduction as compared to conventional method silica aerogels. The structure is analysed, properties are reported as low density (0.04–0.15 g/ml), low thermal conductivity (24–26 mW/m·K), etc. Formaldehyde gas adsorption tests reveal that the uptake level of samples made by Quartzene® is significantly increased as compared to commercially available adsorbents. Thermal conductivity at elevated temperatures for mixtures of Quartzene® and stone wool shows a 23% reduction at 650 °C as compared to pure stone wool. Scaling up process for this green material meeting environmental sustainability demands in industrial manufacturing is discussed and challenges/current developments are presented.
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| 10. |
- Grigoriev, Anton, et al.
(författare)
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Comment on "Quantum interference effects in biphenyl dithiol for gas detection" by J. Prasongkit and A. R. Rocha, RSC Adv., 2016, 64, 59299-59304
- 2020
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:4, s. 2073-2074
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The paper [Prasongkit et al., RSC Adv., 2016, 64, 59299] by Prasongkit and Rocha calculates the binding energy of gas molecules attached to 1-8-biphenyl-dithiol (BPDT) molecules. We find from our calculations, that the binding energies calculated for the NO2 molecules are too low, most likely due to lacking optimization of the site at which the gas molecule binds to the BPDT. Though not shown explicitly here, the same statement might apply to the other gas molecules used in this paper.
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