scholarly journals The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy

2021 ◽  
Vol 22 (23) ◽  
pp. 12653
Author(s):  
Christian Rodenbücher ◽  
Yingzhen Chen ◽  
Klaus Wippermann ◽  
Piotr M. Kowalski ◽  
Margret Giesen ◽  
...  

Protic ionic liquids are promising electrolytes for fuel cell applications. They would allow for an increase in operation temperatures to more than 100 °C, facilitating water and heat management and, thus, increasing overall efficiency. As ionic liquids consist of bulky charged molecules, the structure of the electric double layer significantly differs from that of aqueous electrolytes. In order to elucidate the nanoscale structure of the electrolyte–electrode interface, we employ atomic force spectroscopy, in conjunction with theoretical modeling using molecular dynamics. Investigations of the low-acidic protic ionic liquid diethylmethylammonium triflate, in contact with a platinum (100) single crystal, reveal a layered structure consisting of alternating anion and cation layers at the interface, as already described for aprotic ionic liquids. The structured double layer depends on the applied electrode potential and extends several nanometers into the liquid, whereby the stiffness decreases with increasing distance from the interface. The presence of water distorts the layering, which, in turn, significantly changes the system’s electrochemical performance. Our results indicate that for low-acidic ionic liquids, a careful adjustment of the water content is needed in order to enhance the proton transport to and from the catalytic electrode.

2019 ◽  
Vol 9 (11) ◽  
pp. 2207 ◽  
Author(s):  
Christian Rodenbücher ◽  
Klaus Wippermann ◽  
Carsten Korte

Ionic liquids have become of significant relevance in chemistry, as they can serve as environmentally-friendly solvents, electrolytes, and lubricants with bespoke properties. In particular for electrochemical applications, an understanding of the interface structure between the ionic liquid and an electrified interface is needed to model and optimize the reactions taking place on the solid surface. As with ionic liquids, the interplay between electrostatic forces and steric effects leads to an intrinsic heterogeneity, as the structure of the ionic liquid above an electrified interface cannot be described by the classical electrical double layer model. Instead, a layered solvation layer is present with a structure that depends on the material combination of the ionic liquid and substrate. In order to experimentally monitor this structure, atomic force spectroscopy (AFS) has become the method of choice. By measuring the force acting on a sharp microfabricated tip while approaching the surface in an ionic liquid, it has become possible to map the solvation layers with sub-nanometer resolution. In this review, we provide an overview of the AFS studies on ionic liquids published in recent years that illustrate how the interface is formed and how it can be modified by applying electrical potential or by adding impurities and solvents.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 713 ◽  
Author(s):  
Hong Guo ◽  
Angela Rina Adukure ◽  
Patricia Iglesias

Friction and wear of sliding surfaces are responsible for important energy losses and negative environmental effects. The use of environmentally friendly and cost-effective protic ionic liquids as neat lubricants and lubricant additives has the potential to increase the efficiency and durability of mechanical components without increasing the environmental damage. In this work, three halogen-free protic ionic liquids with increasing extent of ionicity, 2-hydroxyethylammonium 2-ethylhexanoate, 2-hydroxymethylammonium 2-ethylhexancate, and 2-hydroxydimethylammonium 2-ethylhexanoate, were synthesized and studied as neat lubricants and additives to a biodegradable oil in a steel–steel contact. The results show that the use of any protic ionic liquid as a neat lubricant or lubricant additive reduced friction and wear with respect to the biodegradable oil. The ionic liquid with the lowest ionicity reached the highest wear reduction. The one possessing the highest ionicity presented the poorest friction and wear behaviors as a neat lubricant, probably due to the more ionic nature of this liquid, which promoted tribocorrosion reactions on the steel surface. This ionic liquid performed better as an additive, showing that a small addition of this liquid in a biodegradable oil is enough to form protective layers on steel surfaces. However, it is not enough to accelerate the wear process with detrimental tribocorrosion reactions.


Soft Matter ◽  
2020 ◽  
Vol 16 (41) ◽  
pp. 9456-9470
Author(s):  
Dilek Yalcin ◽  
Calum J. Drummond ◽  
Tamar L. Greaves

Protic ionic liquids (PILs) are the largest and most tailorable known class of non-aqueous solvents which possess the ability to support amphiphile self-assembly.


Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 37 ◽  
Author(s):  
Urszula Dorosz ◽  
Natalia Barteczko ◽  
Piotr Latos ◽  
Karol Erfurt ◽  
Ewa Pankalla ◽  
...  

Alkyl lactates are produced from lactic acid via esterification, and are used in the production of plastics, paints, solvents and detergents. In the pursuit of an inexpensive, industry-suitable catalyst for this reaction, the application of protic ionic liquids based on nitrogen base and sulphuric acid is proposed. The ionic liquid was synthesised via a simple reaction of triethylamine and a threefold molar excess of sulphuric acid. Water was added to remove the heat of the reaction. Next, the reaction conditions for the model esterification of 2-ethylhexanol with lactic acid without additional solvent were optimised. Exceptionally mild conditions, i.e., a twofold molar excess of alcohol to lactic acid with the addition of an ionic liquid in a catalytic amount (15 mol%) at 60 °C, resulted in high yields of ethyl and 2-ethylhexyl lactates (96–97%). The driving force of this reaction is the production of a biphasic system with immiscible ester during the reaction. This phenomenon makes it possible to overcome the reaction equilibrium. Using an inexpensive ionic liquid, which could be recycled up to five times without diminution in conversion or selectivity, leads to both a greener and a more economically-viable process.


2012 ◽  
Vol 65 (11) ◽  
pp. 1502 ◽  
Author(s):  
Natalie Debeljuh ◽  
Swapna Varghese ◽  
Colin J. Barrow ◽  
Nolene Byrne

We report on the impact of changes in the protic ionic liquid (pIL) cation on the fibrilisation kinetics and the conversion of the Aβ 16–22 from monomers to amyloid fibrils. When we compare the use of primary, secondary, and tertiary amines we find that the primary amine results in the greatest conversion into amyloid fibrils. We show that the pIL is directly interacting with the peptide and this likely drives the difference in conversion and kinetics observed.


2014 ◽  
Vol 2 (22) ◽  
pp. 8258-8265 ◽  
Author(s):  
Thomas Vogl ◽  
Sebastian Menne ◽  
Ruben-Simon Kühnel ◽  
Andrea Balducci

Protic ionic liquid-based electrolytes are promising electrolytes for lithium-ion batteries.


CrystEngComm ◽  
2020 ◽  
Vol 22 (37) ◽  
pp. 6096-6100
Author(s):  
Ting Li ◽  
Yumei Mao ◽  
Yue Qi ◽  
Hongmei Zeng ◽  
Guohong Zou ◽  
...  

A mixed-valence iron phosphite was prepared under ionothermal conditions using a protic ionic liquid as a solvent, a structure-directing agent, a phosphorus source, and a reducing agent.


RSC Advances ◽  
2019 ◽  
Vol 9 (14) ◽  
pp. 7652-7663 ◽  
Author(s):  
Ahmed Al Otaibi ◽  
Fiona M. Deane ◽  
Cecilia C. Russell ◽  
Lacey Hizartzidis ◽  
Siobhann N. McCluskey ◽  
...  

The Ugi reaction (aldehyde, amine, isocyanide and an ethanoic acid) in the protic ionic liquids ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) gave excellent yields of α-phenylacetamido amides.


2010 ◽  
Vol 132 (19) ◽  
pp. 6672-6678 ◽  
Author(s):  
Hongtao Yuan ◽  
Hidekazu Shimotani ◽  
Atsushi Tsukazaki ◽  
Akira Ohtomo ◽  
Masashi Kawasaki ◽  
...  

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