| 1. |
- Tehrani, Ali, 1976, et al.
(författare)
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Solubilization of hydrophobic dyes in surfactant solutions
- 2013
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 6:2, s. 580-608
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Forskningsöversikt (refereegranskat)abstract
- In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes) has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs-the critical micelle concentration (CMC)-there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.
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| 2. |
- Busch, Michael, 1983
(författare)
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Water oxidation: From mechanisms to limitations
- 2018
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Ingår i: Current Opinion in Electrochemistry. - : Elsevier BV. - 2451-9111 .- 2451-9103. ; 9, s. 278-284
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Forskningsöversikt (refereegranskat)abstract
- Water oxidation is a central reaction for energy conversion and storage. On the basis of the detailed analysis of different reaction mechanisms the limitations associated with the O2evolution reaction is analysed. We find that overpotentials lower than the 0.4 eV, which have been observed for a mono-nuclear mechanism, are possible if the problematic *-OOH intermediate is avoided. This is the case for the bi-nuclear and bi-functional reaction paths. 3-dimensional volcano plots are constructed and used to explore the performance of these reaction mechanisms. Our results suggest, that in contrast to previous analysis of the mono-nuclear mechanism, the true top of the water oxidation volcano is placed at slightly lower *=O binding energies of only 2.46 eV if combined with a suitable co-catalyst. On the basis of this new analysis, design criteria for improved catalysts are developed.
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| 3. |
- Grommet, Angela Beth, 1991, et al.
(författare)
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Molecular Photoswitching in Confined Spaces
- 2020
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Ingår i: Accounts of Chemical Research. - : American Chemical Society (ACS). - 0001-4842 .- 1520-4898. ; 53:11, s. 2600-2610
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Forskningsöversikt (refereegranskat)
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| 4. |
- Janssens, Ton, et al.
(författare)
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The [(NH 3 ) 4 Cu 2 O 2 ] 2+ -Peroxo Complex as the Key Intermediate for NH 3 -SCR Activity and Deactivation of Cu-CHA Catalysts.
- 2024
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Ingår i: ChemCatChem. - 1867-3899 .- 1867-3880. ; In Press
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Forskningsöversikt (refereegranskat)abstract
- In NH3-SCR over Cu-CHA catalysts in the low-temperature range 150–300 °C, the activation of oxygen occurs via oxidation of a pair of mobile (NH3)2CuI-complexes located in the cages of the zeolite. In this step, a reactive [(NH3)4Cu2O2]2+-peroxo complex (μ-η2,η2-peroxo diamino dicopper(II)-complex) is formed. The chemistry of this complex determines several catalytic properties of the Cu-CHA catalyst. The reaction of NO with the [(NH3)4Cu2O2]2+-peroxo complex governs the NH3-SCR activity. A reaction of the [(NH3)4Cu2O2]2+-peroxo complex with ammonia hinders the reaction of NO with the complex, thus leading to an inhibition of the NH3-SCR reaction. Finally, the deactivation in presence of SO2 is due to a reaction of SO2 with the [(NH3)4Cu2O2]2+-peroxo complex, leading to the formation of Cu−S compounds in the catalyst. In this review, the characterization and the reactions of the [(NH3)4Cu2O2]2+-peroxo complex with NO, NH3, and SO2, and mean-field kinetic models based on first principles calculations for NH3-SCR activity and SO2 poisoning are discussed.
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| 5. |
- Lundberg, Dan, 1975, et al.
(författare)
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Ester-based surfactants: Are they stable enough?
- 2023
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Ingår i: Journal of Surfactants and Detergents. - : Wiley. - 1558-9293 .- 1097-3958. ; 26:3, s. 229-236
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Forskningsöversikt (refereegranskat)abstract
- Surfactants with an ester bond connecting the polar headgroup and the hydrophobic tail are common. They are easy to synthesize, they can often be made from natural raw materials and their biodegradation profile is generally good, partly due to lipase or esterase catalyzed breakdown of the ester bond in sewage plants. A labile ester bond in the molecule may cause problems, however. Surfactants are often formulated at relatively high pH and it is important that they remain intact for a given period of time. In this article we discuss alkaline hydrolysis of different types of ester-based surfactants—cationic, anionic and nonionic—and also of surfactant mixtures. We show that the ester bond in a surfactant has a different hydrolysis pattern than ester bonds in non-surface active uncharged molecules. Cationic ester-based surfactants are hydrolyzed rapidly while anionic and also nonionic ester-containing surfactants are relatively resistant to hydrolysis.
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| 6. |
- Björnehohn, E., et al.
(författare)
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Water at Interfaces
- 2016
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 116:13, s. 7698-7726
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Forskningsöversikt (refereegranskat)abstract
- The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding.
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| 7. |
- Das, Biswanath, et al.
(författare)
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The Impact of Ligand Carboxylates on Electrocatalyzed Water Oxidation
- 2021
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Ingår i: Accounts of Chemical Research. - : American Chemical Society (ACS). - 0001-4842 .- 1520-4898. ; 54:17, s. 3326-3337
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Forskningsöversikt (refereegranskat)abstract
- Fossil fuel shortage and severe climate changes due to global warming have prompted extensive research on carbon-neutral and renewable energy resources. Hydrogen gas (H-2), a clean and high energy density fuel, has emerged as a potential solution for both fulfilling energy demands and diminishing the emission of greenhouse gases. Currently, water oxidation (WO) constitutes the bottleneck in the overall process of producing H-2 from water. As a result, the design of efficient catalysts for WO has become an intensively pursued area of research in recent years. Among all the molecular catalysts reported to date, ruthenium-based catalysts have attracted particular attention due to their robust nature and higher activity compared to catalysts based on other transition metals. Over the past two decades, we and others have studied a wide range of ruthenium complexes displaying impressive catalytic performance for WO in terms of turnover number (TON) and turnover frequency (TOF). However, to produce practically applicable electrochemical, photochemical, or photo-electrochemical WO reactors, further improvement of the catalysts' structure to decrease the overpotential and increase the WO rate is of utmost importance. WO reaction, that is, the production of molecular oxygen and protons from water, requires the formation of an O-O bond through the orchestration of multiple proton and electron transfers. Promotion of these processes using redox noninnocent ligand frameworks that can accept and transfer electrons has therefore attracted substantial attention. The strategic modifications of the ligand structure in ruthenium complexes to enable proton-coupled electron transfer (PCET) and atom proton transfer (APT; in the context of WO, it is the oxygen atom (metal oxo) transfer to the oxygen atom of a water molecule in concert with proton transfer to another water molecule) to facilitate the O-O bond formation have played a central role in these efforts. In particular, promising results have been obtained with ligand frameworks containing carboxylic acid groups that either are directly bonded to the metal center or reside in the close vicinity. The improvement of redox and chemical properties of the catalysts by introduction of carboxylate groups in the ligands has proven to be quite general as demonstrated for a range of mono- and dinudear ruthenium complexes featuring ligand scaffolds based on pyridine, imidazole, and pyridazine cores. In the first coordination sphere, the carboxylate groups are firmly coordinated to the metal center as negatively charged ligands, improving the stability of the complexes and preventing metal leaching during catalysis. Another important phenomenon is the reduction of the potentials required for the formation of higher valent intermediates, especially metal-oxo species, which take active part in the key O-O bond formation step. Furthermore, the free carboxylic acid/carboxylate units in the proximity to the active center have shown exciting proton donor/acceptor properties (through PCET or APT, chemically noninnocent) that can dramatically improve the rate as well as the overpotential of the WO reaction.
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| 8. |
- Gonçalves, Rui A., et al.
(författare)
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Cationic surfactants: A review
- 2023
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Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322. ; 375
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Forskningsöversikt (refereegranskat)abstract
- Cationic surfactants have gained significant interest since their introduction. Their properties and adsorption behavior onto different surfaces have driven the development of a plethora of surfactants with distinctive functionalities. This paper reviews self-assembly, intermolecular interactions, and the properties of cationic surfactants also when interacting with co-solutes, which may be small molecules or macromolecules, and surfaces. The versatile properties of single- and double-chain cationic surfactants and other special cationics such as gemini, catanionic, bolaform, amino acid- and sugar-based surfactants, are presented and discussed together with skin toxicity and environmental considerations. The effects of cationic surfactant mixing with other surfactants, polymers, proteins, and DNA are also shown and examined. We also outline established applications of cationic surfactants as disinfectants, in fabric softening, hard surface cleaning, personal care applications, road surfacing, and oil field applications, as well as emerging applications such as soft antimicrobial agents and nucleic acid delivery, which has contributed, for instance, to the enormously successful surfactant-based mRNA COVID-19 vaccines.
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| 9. |
- Gözen, Irep, 1980
(författare)
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A Hypothesis for Protocell Division on the Early Earth
- 2019
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 13:10, s. 10869-10871
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Forskningsöversikt (refereegranskat)abstract
- I hypothesize that the division of the first protocell might have occurred before genetic polymers were synthesized and redistributed. In the light of recent findings, it is conceivable that the first division event of a primitive protocell might have occurred at the same time as its surface-assisted formation.
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| 10. |
- Martín-Yerga, Daniel
(författare)
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Electrochemical Detection and Characterization of Nanoparticles with Printed Devices
- 2019
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Ingår i: Biosensors. - : MDPI AG. - 2079-6374. ; 9:2
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Forskningsöversikt (refereegranskat)abstract
- Innovative methods to achieve the user-friendly, quick, and highly sensitive detection of nanomaterials are urgently needed. Nanomaterials have increased importance in commercial products, and there are concerns about the potential risk that they entail for the environment. In addition, detection of nanomaterials can be a highly valuable tool in many applications, such as biosensing. Electrochemical methods using disposable, low-cost, printed electrodes provide excellent analytical performance for the detection of a wide set of nanomaterials. In this review, the foundations and latest advances of several electrochemical strategies for the detection of nanoparticles using cost-effective printed devices are introduced. These strategies will equip the experimentalist with an extensive toolbox for the detection of nanoparticles of different chemical nature and possible applications ranging from quality control to environmental analysis and biosensing.
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