Benzyltriethylammonium chloropentacarbonylmolybdate (1) and chloropentacarbonyltungstate (2) comp... more Benzyltriethylammonium chloropentacarbonylmolybdate (1) and chloropentacarbonyltungstate (2) complexes react with CF 3 SO 3 Ag in DME via a combination of chloride exchange and a redox process, as revealed by cyclic voltammetry and ESR spectrometry. The resulting intermediate M(I) species disproportionate to M(0) and M(II) so that 3 equiv of TfOAg are required for the quantitative conversion into the M(II) complex. Analogous PPN complexes 3 and 4 only undergo the redox process (in DME); in this instance, the chloride exchange is precluded, presumably due to strong pairing of the complex anion with the counterion.
This communication outlines the use of HFC 134a and HFC 32 in both the liquid and supercritical s... more This communication outlines the use of HFC 134a and HFC 32 in both the liquid and supercritical states. The comparatively mild critical conditions are used to show that both of these solvents are important for studying electrochemical processes in the supercritical state. The higher polarity of these media in the supercritical state circumvent many of the problems associated with solubility, conductivity and ion adsorption on the electrode surface observed with other supercritical media also. The unprecedented wide potential window of HFC 134a is demonstrated and utilised for the oxidation of Xe and Cs + .
This work demonstrates that a sustained galvanic coating of silver can be deposited onto copper s... more This work demonstrates that a sustained galvanic coating of silver can be deposited onto copper substrates from a solution of Ag + ions in an ionic liquid (IL) based on a choline chloride (ChCl) eutectic. The sustained growth of the silver deposit was facilitated by the porous nature of the film and is proven using acoustic impedance spectroscopy on a quartz crystal microbalance (QCM). The silver and copper surfaces were characterised using atomic force microscopy (AFM) and scanning electron microscopy (SEM/EDX). In the commercial process of dip coating silver from ions in aqueous media, deposition does not continue once surface coverage has been achieved, without the use of catalysts. The process reported here using ionic liquids produces silver deposits of several microns by dip coating without the use of catalysts or strong inorganic acids.
Physical chemistry chemical physics : PCCP, Jan 28, 2006
We have studied the anodic dissolution (electropolishing) of various stainless steel alloys in an... more We have studied the anodic dissolution (electropolishing) of various stainless steel alloys in an ionic liquid comprising a 2 : 1 stoichiometric mix of ethylene glycol (EG) and choline chloride. We have used a combination of electrochemical and spectroscopic methods together with in situ liquid probe microscopy. We discuss the role and influence of the surface oxide passivation layer, characterized here by X-ray photoelectron spectroscopy (XPS) and linear sweep voltammetry, on the polishing process. We address the question of dealloying during the polish in order to contribute to our understanding of the viability of the ionic liquid as a replacement industrial electropolishing medium; the current commercial process uses a corrosive mixture of phosphoric and sulfuric acids. Also, we present data from ex situ and in situ liquid AFM studies giving both a qualitative and quantitative insight into the nature and scale of morphological changes at the steel surface during the polishing pr...
Physical chemistry chemical physics : PCCP, Jan 28, 2007
In this paper, we describe the first example of a sustained galvanic coating deposited on a surfa... more In this paper, we describe the first example of a sustained galvanic coating deposited on a surface from a non-aqueous liquid. We present the surface characterization of electroless silver deposits on copper substrates from a solution of Ag(+) ions in an ionic liquid based on a choline chloride (ChCl) eutectic. Through a study of these deposits and the mechanism of formation using acoustic impedance spectroscopy (QCM), probe microscopy (AFM) and electron microscopy (SEM/EDX), we demonstrate that sustained growth of the silver deposit is facilitated by the porous nature of the silver. This is in contrast to the dip-coating reaction of silver ions in aqueous media, where the reaction stops when surface coverage is reached. Electroless silver deposits of up to several microns have been obtained by dip coating in ionic liquids without the use of catalysts of strong inorganic acids.
Physical chemistry chemical physics : PCCP, Jan 28, 2010
The deposition of aluminium from a chloroaluminate based ionic liquid was studied to elucidate th... more The deposition of aluminium from a chloroaluminate based ionic liquid was studied to elucidate the effect of a diluent (toluene) and electrolyte (LiCl) on the deposit morphology. A wide variety of analytical techniques was applied to this system to determine the speciation and mechanism of material growth. These included: (27)Al NMR, FAB-MS, cyclic voltammetry, chronocoulometry, chronopotentiometry, scanning electron microscopy and atomic force microscopy. It was found that under-potential deposition (upd) causes a change in the way in which metal grows on the electrode surface. Metal grows in two regimes which are believed to be nano-material and bulk material. The addition of toluene causes a change in speciation and a decrease in upd which in turn changes the morphology of the deposit obtained and can lead to mirror finish aluminium. The addition of LiCl has the opposite effect encouraging upd and leading to larger crystallites and a dark grey deposit. It is also shown for the fi...
Physical chemistry chemical physics : PCCP, Jan 7, 2009
Here we describe for the first time the electrolytic deposition of copper and copper composites f... more Here we describe for the first time the electrolytic deposition of copper and copper composites from a solution of the metal chloride salt in either urea-choline chloride, or ethylene glycol-choline chloride based eutectics. We show that the deposition kinetics and thermodynamics are quite unlike those in aqueous solution under comparable conditions and that the copper ion complexation is also different. The mechanism of copper nucleation is studied using chronoamperometry and it is shown that progressive nucleation leads to a bright nano-structured deposit. In contrast, instantaneous nucleation, at lower concentrations of copper ions, leads to a dull deposit. This work also pioneers the use of the electrochemical quartz crystal microbalance (EQCM) to monitor both current efficiency and the inclusion of inert particulates into the copper coatings. This technique allows the first in situ quantification or particulate inclusion. It was found that the composition of composite material ...
Physical chemistry chemical physics : PCCP, Jan 28, 2013
The electrodeposition of metals from ionic solutions is intrinsically linked to the reactivity of... more The electrodeposition of metals from ionic solutions is intrinsically linked to the reactivity of the solute ions. When metal salts dissolve, the exchange of the anion with the molecular and ionic components from solution affects the speciation and therefore the characteristics of metal reduction. This study investigates the nucleation mechanism, deposition kinetics, metal speciation and diffusion coefficients of silver salts dissolved in Deep Eutectic Solvents. The electrochemical reduction of AgCl, AgNO3 and Ag2O is studied in 1 : 2 choline chloride : ethylene glycol and 1 : 2 choline chloride : urea. Cyclic voltammetry is used to evaluate electrochemical kinetics. Detailed analysis of chronoamperometric data shows that silver deposits form via multiple 3D nucleation with mass transport controlled hemispherical growth. The nucleation mechanism was found to be potential dependent, varying from progressive to instantaneous as the reduction potential becomes more cathodic. Diffusion ...
... P. Blake Powertrain, Jaguar Cars Ltd., Whitley Engineering Centre, Coventry CV3 4LF, UK KS Ry... more ... P. Blake Powertrain, Jaguar Cars Ltd., Whitley Engineering Centre, Coventry CV3 4LF, UK KS Ryder 4 AP Abbott Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK 123 Tribol Lett (2010) 37:103110 DOI 10.1007/s11249-009-9495-6 ...
In this paper, we describe the first example of a sustained galvanic coating deposited on a surfa... more In this paper, we describe the first example of a sustained galvanic coating deposited on a surface from a non-aqueous liquid. We present the surface characterization of electroless silver deposits on copper substrates from a solution of Ag(+) ions in an ionic liquid based on a choline chloride (ChCl) eutectic. Through a study of these deposits and the mechanism of formation using acoustic impedance spectroscopy (QCM), probe microscopy (AFM) and electron microscopy (SEM/EDX), we demonstrate that sustained growth of the silver deposit is facilitated by the porous nature of the silver. This is in contrast to the dip-coating reaction of silver ions in aqueous media, where the reaction stops when surface coverage is reached. Electroless silver deposits of up to several microns have been obtained by dip coating in ionic liquids without the use of catalysts of strong inorganic acids.
The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals s... more The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals studied to date in these liquids, zinc electrodeposition is not mass transport limited and the morphology of the deposit differs in the two liquids. This study shows that changing the concentration of solute affects the physical properties of the liquid to different extents although this is found to not effect the morphology of the metal deposited. EXAFS was used to show that the speciation of zinc was the same in both liquids. Double layer capacitance studies showed differences between the two liquids and these are proposed to be due to the adsorption of a species on the electrode which is thought to be chloride. The differences in zinc morphology is attributed to blocking of certain crystal faces leading to deposition of small platelet shaped crystals in the glycol based liquid.
Silver is an important metal for electronic connectors, however, it is extremely soft and wear ca... more Silver is an important metal for electronic connectors, however, it is extremely soft and wear can be a significant issue. This paper describes how improved wear resistant silver coatings can be obtained from the electrolytic deposition of silver from a solution of AgCl in an ethylene glycol/choline chloride based Deep Eutectic Solvent. An up to 10-fold decrease in the wear volume is observed by the incorporation of SiC or Al(2)O(3) particles. The work also addresses the fundamental aspect of speciation of silver chloride in solution using EXAFS to probe solution structure. The size but not the nature of the composite particles is seen to change the morphology and grain size of the silver deposit. Grain sizes are shown to be consistent with previous nucleation studies. The addition of LiF is found to significantly affect the deposit morphology and improve wear resistance.
We demonstrate the first practical alternative to the use of phosphoric and sulphuric acid mixtur... more We demonstrate the first practical alternative to the use of phosphoric and sulphuric acid mixtures for the electropolishing of stainless steel. In this paper, efficient electropolishing of type 316 stainless steel is demonstrated in an ionic liquid composed of ethylene glycol (HOCH 2 CH 2 OH) ...
... Deep Eutectic Solvents Andrew P. Abbott,A,C John Collins,B Ian Dalrymple,B Robert C. Harris,A... more ... Deep Eutectic Solvents Andrew P. Abbott,A,C John Collins,B Ian Dalrymple,B Robert C. Harris,A Reena Mistry,A Fulian Qiu,A James Scheirer,A and William R. WiseA ... Filtration on a small sale was carried out using a 0.45-µm mesh filter and syringe. ...
This study has shown for the first time that digital holographic microscopy (DHM) can be used as ... more This study has shown for the first time that digital holographic microscopy (DHM) can be used as a new analytical tool in analysis of kinetic mechanism and growth during electrolytic deposition processes. Unlike many alternative established electrochemical microscopy methods such as probe microscopy, DHM is both the noninvasive and noncontact, the unique holographic imaging allows the observations and measurement to be made remotely. DHM also provides interferometric resolution (nanometer vertical scale) with a very short acquisition time. It is a surface metrology technique that enables the retrieval of information about a 3D structure from the phase contrast of a single hologram acquired using a conventional digital camera. Here DHM has been applied to investigate directly the electro-crystallization of a metal on a substrate in real time (in situ) from two deep eutectic solvent (DES) systems based on mixture of choline chloride and either urea or ethylene glycol. We show, using electrochemical DHM that the nucleation and growth of silver deposits in these systems are quite distinct and influenced strongly by the hydrogen bond donor of the DES.
Benzyltriethylammonium chloropentacarbonylmolybdate (1) and chloropentacarbonyltungstate (2) comp... more Benzyltriethylammonium chloropentacarbonylmolybdate (1) and chloropentacarbonyltungstate (2) complexes react with CF 3 SO 3 Ag in DME via a combination of chloride exchange and a redox process, as revealed by cyclic voltammetry and ESR spectrometry. The resulting intermediate M(I) species disproportionate to M(0) and M(II) so that 3 equiv of TfOAg are required for the quantitative conversion into the M(II) complex. Analogous PPN complexes 3 and 4 only undergo the redox process (in DME); in this instance, the chloride exchange is precluded, presumably due to strong pairing of the complex anion with the counterion.
This communication outlines the use of HFC 134a and HFC 32 in both the liquid and supercritical s... more This communication outlines the use of HFC 134a and HFC 32 in both the liquid and supercritical states. The comparatively mild critical conditions are used to show that both of these solvents are important for studying electrochemical processes in the supercritical state. The higher polarity of these media in the supercritical state circumvent many of the problems associated with solubility, conductivity and ion adsorption on the electrode surface observed with other supercritical media also. The unprecedented wide potential window of HFC 134a is demonstrated and utilised for the oxidation of Xe and Cs + .
This work demonstrates that a sustained galvanic coating of silver can be deposited onto copper s... more This work demonstrates that a sustained galvanic coating of silver can be deposited onto copper substrates from a solution of Ag + ions in an ionic liquid (IL) based on a choline chloride (ChCl) eutectic. The sustained growth of the silver deposit was facilitated by the porous nature of the film and is proven using acoustic impedance spectroscopy on a quartz crystal microbalance (QCM). The silver and copper surfaces were characterised using atomic force microscopy (AFM) and scanning electron microscopy (SEM/EDX). In the commercial process of dip coating silver from ions in aqueous media, deposition does not continue once surface coverage has been achieved, without the use of catalysts. The process reported here using ionic liquids produces silver deposits of several microns by dip coating without the use of catalysts or strong inorganic acids.
Physical chemistry chemical physics : PCCP, Jan 28, 2006
We have studied the anodic dissolution (electropolishing) of various stainless steel alloys in an... more We have studied the anodic dissolution (electropolishing) of various stainless steel alloys in an ionic liquid comprising a 2 : 1 stoichiometric mix of ethylene glycol (EG) and choline chloride. We have used a combination of electrochemical and spectroscopic methods together with in situ liquid probe microscopy. We discuss the role and influence of the surface oxide passivation layer, characterized here by X-ray photoelectron spectroscopy (XPS) and linear sweep voltammetry, on the polishing process. We address the question of dealloying during the polish in order to contribute to our understanding of the viability of the ionic liquid as a replacement industrial electropolishing medium; the current commercial process uses a corrosive mixture of phosphoric and sulfuric acids. Also, we present data from ex situ and in situ liquid AFM studies giving both a qualitative and quantitative insight into the nature and scale of morphological changes at the steel surface during the polishing pr...
Physical chemistry chemical physics : PCCP, Jan 28, 2007
In this paper, we describe the first example of a sustained galvanic coating deposited on a surfa... more In this paper, we describe the first example of a sustained galvanic coating deposited on a surface from a non-aqueous liquid. We present the surface characterization of electroless silver deposits on copper substrates from a solution of Ag(+) ions in an ionic liquid based on a choline chloride (ChCl) eutectic. Through a study of these deposits and the mechanism of formation using acoustic impedance spectroscopy (QCM), probe microscopy (AFM) and electron microscopy (SEM/EDX), we demonstrate that sustained growth of the silver deposit is facilitated by the porous nature of the silver. This is in contrast to the dip-coating reaction of silver ions in aqueous media, where the reaction stops when surface coverage is reached. Electroless silver deposits of up to several microns have been obtained by dip coating in ionic liquids without the use of catalysts of strong inorganic acids.
Physical chemistry chemical physics : PCCP, Jan 28, 2010
The deposition of aluminium from a chloroaluminate based ionic liquid was studied to elucidate th... more The deposition of aluminium from a chloroaluminate based ionic liquid was studied to elucidate the effect of a diluent (toluene) and electrolyte (LiCl) on the deposit morphology. A wide variety of analytical techniques was applied to this system to determine the speciation and mechanism of material growth. These included: (27)Al NMR, FAB-MS, cyclic voltammetry, chronocoulometry, chronopotentiometry, scanning electron microscopy and atomic force microscopy. It was found that under-potential deposition (upd) causes a change in the way in which metal grows on the electrode surface. Metal grows in two regimes which are believed to be nano-material and bulk material. The addition of toluene causes a change in speciation and a decrease in upd which in turn changes the morphology of the deposit obtained and can lead to mirror finish aluminium. The addition of LiCl has the opposite effect encouraging upd and leading to larger crystallites and a dark grey deposit. It is also shown for the fi...
Physical chemistry chemical physics : PCCP, Jan 7, 2009
Here we describe for the first time the electrolytic deposition of copper and copper composites f... more Here we describe for the first time the electrolytic deposition of copper and copper composites from a solution of the metal chloride salt in either urea-choline chloride, or ethylene glycol-choline chloride based eutectics. We show that the deposition kinetics and thermodynamics are quite unlike those in aqueous solution under comparable conditions and that the copper ion complexation is also different. The mechanism of copper nucleation is studied using chronoamperometry and it is shown that progressive nucleation leads to a bright nano-structured deposit. In contrast, instantaneous nucleation, at lower concentrations of copper ions, leads to a dull deposit. This work also pioneers the use of the electrochemical quartz crystal microbalance (EQCM) to monitor both current efficiency and the inclusion of inert particulates into the copper coatings. This technique allows the first in situ quantification or particulate inclusion. It was found that the composition of composite material ...
Physical chemistry chemical physics : PCCP, Jan 28, 2013
The electrodeposition of metals from ionic solutions is intrinsically linked to the reactivity of... more The electrodeposition of metals from ionic solutions is intrinsically linked to the reactivity of the solute ions. When metal salts dissolve, the exchange of the anion with the molecular and ionic components from solution affects the speciation and therefore the characteristics of metal reduction. This study investigates the nucleation mechanism, deposition kinetics, metal speciation and diffusion coefficients of silver salts dissolved in Deep Eutectic Solvents. The electrochemical reduction of AgCl, AgNO3 and Ag2O is studied in 1 : 2 choline chloride : ethylene glycol and 1 : 2 choline chloride : urea. Cyclic voltammetry is used to evaluate electrochemical kinetics. Detailed analysis of chronoamperometric data shows that silver deposits form via multiple 3D nucleation with mass transport controlled hemispherical growth. The nucleation mechanism was found to be potential dependent, varying from progressive to instantaneous as the reduction potential becomes more cathodic. Diffusion ...
... P. Blake Powertrain, Jaguar Cars Ltd., Whitley Engineering Centre, Coventry CV3 4LF, UK KS Ry... more ... P. Blake Powertrain, Jaguar Cars Ltd., Whitley Engineering Centre, Coventry CV3 4LF, UK KS Ryder 4 AP Abbott Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK 123 Tribol Lett (2010) 37:103110 DOI 10.1007/s11249-009-9495-6 ...
In this paper, we describe the first example of a sustained galvanic coating deposited on a surfa... more In this paper, we describe the first example of a sustained galvanic coating deposited on a surface from a non-aqueous liquid. We present the surface characterization of electroless silver deposits on copper substrates from a solution of Ag(+) ions in an ionic liquid based on a choline chloride (ChCl) eutectic. Through a study of these deposits and the mechanism of formation using acoustic impedance spectroscopy (QCM), probe microscopy (AFM) and electron microscopy (SEM/EDX), we demonstrate that sustained growth of the silver deposit is facilitated by the porous nature of the silver. This is in contrast to the dip-coating reaction of silver ions in aqueous media, where the reaction stops when surface coverage is reached. Electroless silver deposits of up to several microns have been obtained by dip coating in ionic liquids without the use of catalysts of strong inorganic acids.
The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals s... more The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals studied to date in these liquids, zinc electrodeposition is not mass transport limited and the morphology of the deposit differs in the two liquids. This study shows that changing the concentration of solute affects the physical properties of the liquid to different extents although this is found to not effect the morphology of the metal deposited. EXAFS was used to show that the speciation of zinc was the same in both liquids. Double layer capacitance studies showed differences between the two liquids and these are proposed to be due to the adsorption of a species on the electrode which is thought to be chloride. The differences in zinc morphology is attributed to blocking of certain crystal faces leading to deposition of small platelet shaped crystals in the glycol based liquid.
Silver is an important metal for electronic connectors, however, it is extremely soft and wear ca... more Silver is an important metal for electronic connectors, however, it is extremely soft and wear can be a significant issue. This paper describes how improved wear resistant silver coatings can be obtained from the electrolytic deposition of silver from a solution of AgCl in an ethylene glycol/choline chloride based Deep Eutectic Solvent. An up to 10-fold decrease in the wear volume is observed by the incorporation of SiC or Al(2)O(3) particles. The work also addresses the fundamental aspect of speciation of silver chloride in solution using EXAFS to probe solution structure. The size but not the nature of the composite particles is seen to change the morphology and grain size of the silver deposit. Grain sizes are shown to be consistent with previous nucleation studies. The addition of LiF is found to significantly affect the deposit morphology and improve wear resistance.
We demonstrate the first practical alternative to the use of phosphoric and sulphuric acid mixtur... more We demonstrate the first practical alternative to the use of phosphoric and sulphuric acid mixtures for the electropolishing of stainless steel. In this paper, efficient electropolishing of type 316 stainless steel is demonstrated in an ionic liquid composed of ethylene glycol (HOCH 2 CH 2 OH) ...
... Deep Eutectic Solvents Andrew P. Abbott,A,C John Collins,B Ian Dalrymple,B Robert C. Harris,A... more ... Deep Eutectic Solvents Andrew P. Abbott,A,C John Collins,B Ian Dalrymple,B Robert C. Harris,A Reena Mistry,A Fulian Qiu,A James Scheirer,A and William R. WiseA ... Filtration on a small sale was carried out using a 0.45-µm mesh filter and syringe. ...
This study has shown for the first time that digital holographic microscopy (DHM) can be used as ... more This study has shown for the first time that digital holographic microscopy (DHM) can be used as a new analytical tool in analysis of kinetic mechanism and growth during electrolytic deposition processes. Unlike many alternative established electrochemical microscopy methods such as probe microscopy, DHM is both the noninvasive and noncontact, the unique holographic imaging allows the observations and measurement to be made remotely. DHM also provides interferometric resolution (nanometer vertical scale) with a very short acquisition time. It is a surface metrology technique that enables the retrieval of information about a 3D structure from the phase contrast of a single hologram acquired using a conventional digital camera. Here DHM has been applied to investigate directly the electro-crystallization of a metal on a substrate in real time (in situ) from two deep eutectic solvent (DES) systems based on mixture of choline chloride and either urea or ethylene glycol. We show, using electrochemical DHM that the nucleation and growth of silver deposits in these systems are quite distinct and influenced strongly by the hydrogen bond donor of the DES.
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