bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of Activity of Noble Metal Nanoparticles in Oxidative Electrocatalysis through Modification with Mixed-Metal Oxo-Species
Authors: Rutkowska Iwona Agnieszka , Wadas Anna , Ozimek Weronika , Zagubien Ewelina , Sek Jakub P. , Kulesza Pawel J. 
Published: February 2020

Platinum has been recognized as the most active catalytic metal towards oxidation of ethanol at low and moderate temperatures. But Pt anodes are readily poisoned by the strongly adsorbed intermediates, namely by CO-type species, requiring fairly high overpotentials for their removal. To enhance activity of Pt catalysts towards methanol and ethanol oxidation, additional metals including ruthenium, tin, molybdenum, tungsten or rhodium are usually introduced as the alloying component. More recently it has been demonstrated that catalytic activity of platinum-based nanoparticles towards electrooxidation of ethanol has been significantly enhanced through interfacial modification with ultra-thin monolayer-type films of metal oxo species of tungsten, titanium or zirconium. Also gold in combination with platinum has been demonstrated to produce novel high performance bimetallic catalysts.
We pursue a concept of utilization of hybrid mixed metal (tungsten(VI)/zirconium(IV), tungsten(VI)/titanium(IV), tungsten(VI)/cerium(IV)) oxides as matrices for supporting and activating noble metal nanoparticles (e.g. Pt, Pt-Ru, Pd, Ru or Rh) during electrooxidation of methanol, ethanol, dimethyl ether and formic acid. Remarkable increases of electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. The most likely explanation takes into account possibility of specific interactions of noble metals with transition metal oxide species as well as existence of active hydroxyl groups in the vicinity of catalytic noble metal sites.
The concept of utilization of mixed metal oxide supports to active noble metal catalytic sites will be extended to oxidation of such inert reactants as arsenate(III) and nitrate(III) that of importance to analytical chemistry, namely to electroanalytical determinations of toxic oxoanions. Mechanistic considerations will be provided, and comparison will be made to the behavior of small organic molecules mentioned above.
Self-Assembling of Thiol Monolayers on Copper, Copper-Nickel Alloy and Nickel Using Ionic Liquid as Reducing Medium
Authors: Mekhalif Zineb , Rajalingam Sundar , Devillers Sébastien , Delhalle Joseph 
Published: February 2020

Self-assembling of molecules on metal surfaces is one way to chemically modify surfaces for various applications. Thiol self-assemblies on metal surfaces like gold, silver and copper are formed easily while thiol monolayers on economically important metal surfaces like copper, copper-nickel and nickel surfaces are yet to be explored due to the less affinity for sulphur and rapid oxidation of metal under ambient atmosphere. Seminal works from our laboratory have shown the use of electrochemical reduction using acids as a feasible way to remove metal oxides layers and form SAMs on metal.
Ionic liquids are promising as efficient solvents for surface modifications. They have several advantages such as non volatile, recyclable and in particular large electrochemical window.
In the present study, we are exploring the use of 2- hydroxyethanolamine formate (HEAF) ionic liquid ionic as a solvent to electrochemically reduce the oxide layers and and the impact on the self-assembly process of thiol monolayers on copper, copper-nickel alloy and nickel substrates. It is shown that HEAF is suitable medium to reduce the metal passive oxide layers and good quality thiol monolayers can be formed on copper, copper-nickel alloy and nickel substrates by immersion in 0.05 M ethanolic solution for 18 h. The monolayers formed were characterized using different electrochemical (CV, LSV) and spectroscopic techniques (XPS, PM-IRRAS).
Electrochemical Investigations of Benzil in Nonaqueous Media
Authors: Cheek Graham T. 
Published: February 2020

Introduction
The electrochemical behavior of the aromatic diketone benzil has been studied in a number of solvents (1-4). The benzil system is particularly interesting because of its ability to undergo various reactions accompanying the reduction process. Most of the solvent systems studied to date have involved proton-donating properties to some degree, so the use of the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ( BMPY TfO ) provides a useful contrast to the other solvents.
Experimental
All electrochemical experiments were carried out in a Vacuum Atmospheres glovebox. Cyclic voltammograms were obtained on a PAR 283 potentiostat using PowerSuite software. Potentials are reported with respect to an Ag/AgCl reference electrode. 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate (BMPY TfO) was prepared by a literature method (5). Benzil was obtained from Aldrich Chemical Company.
Results and Discussion
As can be observed from Figure 1(a), benzil undergoes electrochemical reduction in BMPY TfO in two successive, reversible electron-transfer steps. Figure 1(b) shows the voltammetric behavior for only the first process. In contrast, reduction in other nonaqueous solvents such as acetonitrile and dimethylformamide (2,3) involves considerable irreversibility for the second process. The low proton-donating ability of BMPY TfO seems largely to account for this effect. The ionic liquid BMPY TfO, then, serves as a suitable solvent for observing relatively uncomplicated voltammetric behavior of benzil, presenting the possibility of studying the effect of added proton donors in this solvent.
References

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Figure 1. Cyclic voltammetry of 40 mM benzil in BMPY TfO at glassy carbon ( 1 mm diameter ).
Scan rate 100 mV/s
(a) Scan to -2.50 V [ black curve ]
(b) Scan reversal at -1.50 V [ red curve ]
Formation Features of Anodic Oxide Films in the KNO3 Melt
Authors: Skatkov Leonid , Gomozov Valeriy 
Published: February 2020

The present communication is considered as an extension of earlier investigations of niobium anodized in nitrate melts of salts at oxide recrystallization temperatures. Studied patterns of growth and crystallization of oxide layers are currently subject to be completed with investigations of AOF phase and elemental composition considering the available general data on applicability of the process of metal substrate oxygen saturation and inclusion of electrolyte components to oxide at anodic oxidation [1].
Examination of phase composition applying Auger spectroscopy at layer-by-layer etching with Argon ions has shown that generated films instead of being entire niobium pentoxide layer, as it was seemed to be, has occurred to be a «sandwich» of Nb2O5 , NbO2 and NbO phases (in the direction from oxide surface to niobium). This is similar to what is taking place at thermal oxidation [2]; at the same time within anodic oxidation oxygen is intensively dissolved in niobium substrate, penetrating into it on the depth which substantially exceeds the oxide thickness.
Studying of the possibility of electrolyte components being included into oxide has lead to a result which from the first sight may be considered as contradictory: at growth anodic oxide is saturated not only with anions (which could have been expected similar to anodic oxidation in hydrous electrolytes), but also with cations.
Considering the fact that the issue of cations presence in AOF is of great interest, potassium quantitative content in oxide has additionally been inspected by the method of fluorescent X-ray test as to intensity of K-fluorescent X-rays excluding background. As for potassium model KCl crystal has been applied. Assuming 50% potassium content in the model and linear dependence of radiation intensivity from concentration of the element it has been calculated potassium concentration value constituting the rate close to 9%, which together with the abovementioned data of X-ray diffractometry survey allows to point on formation of potassium solid compounds in niobium oxide at AOF crystallization.
An Electrochemical Study of Uranium (III) and (IV) Species in Fused Alkali Chlorides
Authors: Maltsev Dmitry S. , Volkovich Vladimir A. , Vladykin Evgeny N. , Vasin Boris D. 
Published: February 2020

Pyroelectrochemical methods are considered as prospective technique for reprocessing spent nuclear fuels (SNF). These methods have a number of obvious advantages in comparison with the existing aqueous extraction processes. The advantages include significantly lower volumes of liquid radioactive wastes, high radiation stability of alkali chlorides used as working media, absence of neutron moderators. The eutectic mixture of lithium, potassium and sodium chlorides is one of possible low melting solvents (Tf= 529 K) that can be employed for practical realization of the process. However, there is no information concerning uranium behavior and properties in this melt. In the present work we studied the behavior and determined main electrochemical and thermodynamic properties of uranium in LiCl-KCl-CsCl eutectic melt. The measurements were performed between 573–1073 K employing potentiometry, chronopotentiometry and cyclic voltammetry.
Uranium formal standard electrode potentials in LiCl-KCl-CsCl eutectic were determined using electromotive force method. E*U(III)/U(0)linearly increases with temperature and between 576-1067 K can be described by the following equation:
E*U(III)/U(0) = -2.901 + 6•10-4• T (± 0.029) V [1]
From the results of the electrochemical measurements the Gibbs free energy change of the formation of uranium trichloride in LiCl-KCl-CsCl melt at 576-1067 K was calculated:
ΔG*UCl3 = -839.8 + 161.7•10-3• T (± 2.6) (kJ/mol) [2]
The results (Е*U(III)/U(0), ΔG*UCl3) obtained in the present work for LiCl-KCl-CsCl melt are in a good agreement with the available literature data for the melts of other cationic composition, Fig. 1.
Uranium (IV)/(III) electrochemical reduction was studied using cyclic voltammetry and chronopotentiometry. Examples of the experimental results are shown in Figs 2 and 3. Analysis of the cyclic voltammograms showed that U(IV) → U(III) reduction is a reversible one-electron diffusion controlled process, and this conclusion was confirmed by chronopotentiometric data. The diffusion coefficients of U(III) and U(IV) ions were obtained using both techniques, Fig.4-5, and they are satisfactorily described by the equations [3-6]:
cyclic voltammetry:
lgDU(III) = -3268.47/T – 0.82 (±0.15) cm2/s [3]
lgDU(IV) = -2033.43/T – 2.26 (±0.13) cm2/s [4]
chronopotentiometry:
lgDU(III) = -2470.14/T – 0.79 (±0.17) cm2/s [5]
lgDU(IV) = -4331.02/T + 1.25 (±0.11) cm2/s [6]
(Max Bredig Award in Molten Salt & Ionic Liquid Chemistry) Molten Salts and Ionic Liquids: Where Have We Been and Where Are We Going? An Electrochemist’s Perspective
Authors: Hussey Charles L. 
Published: February 2020

From the very beginnings of molten or fused salt chemistry in the early 19th century with the preparation of alkali metals from their molten hydroxides by Sir Humphrey Davy, the formulation of the laws of electrolysis by Michael Faraday from experiments with molten lead halides, and the eventual development of the civilization-changing Hall-Héroult process for the large scale production of aluminum in 1886, there has always existed a common theme of electrochemical applications. Molten salt electrolytes can be prepared from almost any stable salt, but the most commonly employed systems are based on alkali carbonates, halides, hydroxides, and nitrates and their mixtures. These melts have found applications in batteries and fuel cells; the electrowinning, surface treatment, and heat treatment of metals; and even in the electrochemical processing of spent nuclear fuel. Many are commonly employed at temperatures well over 1000 oC!
Latecomers to the field of molten salt chemistry include the class of materials known as “ionic liquids,” which are by agreement salts that melt below 100 oC and are usually, but not absolutely, based on organic cations and inorganic anions. Although they can trace their origin to the first report of the room-temperature protic salt, ethylammonium nitrate, by Paul Walden in 1914, their novel properties and electrochemical applications were not really appreciated until the pioneering work of Frank H. Hurley and Thomas P. Wier, who electrodeposited aluminum from room-temperature mixtures of ethylpyridinium bromide and aluminum chloride (U.S. Patents 2,446,331; 2,446,349; and 2,446,350) in 1944. In a sense, it is the work by these early pioneers from which everything else pertaining to ionic liquids has flowed, including the development of the ubiquitous dialkylimidazolium chloride salts and many other quaternary ammonium salts that form the backbones of the fascinating, highly-stable hydrophobic ionic liquids we use as electrochemical solvents today.
In this presentation, the award recipient will provide a brief historical perspective about the electrochemical applications of molten salts and their ionic liquid progeny. He will also describe his work with previous Bredig Award recipients and with many other long-time collaborators and students in the field of molten salts and ionic liquids.
Durability of Active ORR Electrocatalysts
Authors: Balbuena Perla B , Ramos-Sanchez G , Godinez Fernando , Solorza-Feria O. , Gurrola Mayra Polett , Arriaga Luis Gerardo 
Published: February 2020

Obtaining extended life of active oxygen reduction reduction (ORR) electrocatalysts is still one of the hardest barriers to overcome for the successful implementation of low-temperature fuel cells. Significant research activity during the last decade has allowed the development of a variety of electrocatalyst materials with excellent activity. Among them, core-shell alloys are the most popular. However, in general their cycle life is very limited.
First-principles calculations based on density functional theory (DFT) have advanced to the point where they are able to provide reasonable predictions not only for activity but also to help elucidating the factors causing catalyst degradation and giving trends for durability of materials in harsh environments.
In this work, we first discuss the requirements of a core-shell alloy for extended durability, on the basis of DFT analysis. We then report results of experiments and DFT simulations about changes induced by the presence of oxides in core-shell structures. Physical and electrochemical characterization confirms the presence of core-shell nanoparticles with a high electrochemical activity towards the ORR. Periodic DFT calculations are used to analyze the shift in the onset of the oxidation potential for Pt, Ni@Pt and NiO@Pt with different number of layers in the shell, and associated changes in electrochemical activity. We conclude with a general discussion of the potential effect of catalyst/substrate interactions to improve the durability of ORR electrocatalysts.
Graphene-Polyaniline Nanofibers Composite as Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media
Authors: Sankararao Mutyala , Mathiyarasu Jayaraman 
Published: February 2020

The catalytic oxygen reduction reaction (ORR) has engrossed rising attention due to its importance in energy converting system such as fuel cells. However, the commercialization of fuel cells is still mired by several factors, including the insufficient kinetics of ORR, high cost of noble metal catalysts, and the meager stability of the catalysts especially in alkaline medium. Thus, the important task is to develop a low-cost, stable and more active electrocatalysts for the ORR in alkaline fuel cells. Low-Pt loading or non noble metal cathode catalysts are currently receiving more and more research attention1, 2.
The present work reports the synthesis of a novel Pt free cathode catalyst i.e., graphene-polyaniline nanofiber (GP) composite for ORR. Initially, the polyaniline (PANI) nanofibers and graphene sheets are individually synthesized using simple chemical route. Here, the polymer fibers are acting as interconnecting agents between graphene sheets, which are confirmed by Transmission electron microscopy showed in Fig.1A. Further, the catalytic activity and durability of GP composite were evaluated by linear sweep voltammetry in 0.1 M KOH solution, as showed in Fig.1B. The results confirmed that GP composite exhibited a 100 mV shift in ORR onset potential with enhanced activity compared to graphene alone. The possible ORR mechanism may be given as follows:
.
At graphene
H2O +1/2 O2 → H2O2 (2 electron transfer reaction)
At GP composite
O2 + 2H2O → 4OH- (4 electron transfer reaction)
In addition, the GP composite showed good stability during a potential cycling test. Further structural and composition of graphene and GP composite were characterized using Field emission scanning electron microscopy (FESEM) and Raman spectroscopy (Figures are not shown). Fig. 1A shows the schematic of glassy carbon electrode modified with GP composite. Thus, the present composite developed may be a simple, cost effective one that showed a long durability for ORR. Therefore, it may be an excellent catalyst material of choice for practical fuel cells.

Figure caption

Fig.1 (A) Schematic representation of GP composite preparation, and glassy carbon electrode modification. (B) Liner sweep voltammogram curves for ORR in O2 saturated 0.1 M KOH on (a) Graphene, (b) GP composite and (c) Pt/C 20% . Scan rate 10 mV/s.

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Keynote: In-Situ Visualization of Non-Linear Phenomena during Metastable Pitting Corrosion on Stainless Steel
Authors: Rotermund Harm Hinrich 
Published: February 2020

Stainless steels and many other alloys are designed to be corrosion resistant. Nevertheless they can undergo localized pitting corrosion, which may rapidly lead to their failure, with the possibility of catastrophic events as a result. To study the initial steps of metastable pit formation in situ and in real time we adapted the ellipso-microscope for surface imaging (EMSI) [1] and a high resolution, contrast enhanced optical microscope to the electrolyte - stainless steel interface. Utilizing these methods we have been able to explain the sudden corrosion onset by an explosive autocatalytic growth in the number of metastable pits [2].
By applying those different but complementary imaging methods simultaneously the correlation between oxide film weakening and the nucleation of individual pits could be confirmed. The existence of front propagation as a component of the transition to pitting corrosion shows that characteristics of this process are consistent with the behavior of stochastic reaction-diffusion systems [3].
Recently we implemented digital in-line holography as a third imaging tool simultaneously to gather three-dimensional information within the electrolyte, in close proximity to the exposed surface. This enhances the sensitivity for small pitting events and opens new avenues for investigating and understanding the underlying processes. For instance we are now able to follow the trajectories of particles ejected from a pit [4].
Using this arsenal of in situ and real time imaging tools allows us to efficiently study methods to enhance the pitting corrosion resistance of stainless steels; initial results of simple treatments such as emerging the sample just in high purity deionized water at 90 °C for an hour, but nevertheless improving the pitting corrosion resistance in NaCl solutions dramatically, will be discussed [5].
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[2] C. Punckt et al., Science 305, 1133-1136 (2004)
[3] M. Dornhege et al., J. Electrochem. Soc. 154, C24-C27 (2007)
[4] P.E. Klages et al., Corrosion Science 65, 128–135 (2012)
[5] P.E. Klages et al., Electrochemistry Communications 15, 54–58 (2012)
Invited: Advantages of Plasma Synthesis of Copper Oxide Nanowires
Authors: Filipič Gregor , Cvelbar Uro 
Published: February 2020

Copper oxide is a semiconductor with a narrow band-gap (2.1 or 1.2 eV, depending on the oxidation state of the copper) and was as such a candidate for growing it in nanowire form. The nanowires can be used for electron field emission1, gas and cholesterol detection2,3, solar cells4, and photo-catalysis of water to hydrogen5. Due to extensive research and advancement it is no longer a question of “if we can grow copper oxide nanowires”, nor is it a question of “size or crystallinity”. Up to now the variety of methods have been developed which enable us a control over many attributes of the nanowires: we can grow them long or short, thick or thin, single- or poly-crystalline, we can also chose the oxidation number of copper (copper I or copper II oxide nanowires)6. The research has now progressed into finding how fast we can grow them, what is the most efficient way to grow them, and how precisely can we place them7,8.
Copper oxide nanowires can be grown using different routes: solution based1,9,10, hydrothermal11,12, thermal oxidation13,14 or plasma oxidation15,16. Each has different approach, specifications and results. While other methods are fully described elsewhere, the introduction of the low pressure plasma method for growing copper oxide nanowires on surface of copper will be made. The results of the oxidation will be presented. Furthermore, the advantages and disadvantages of the said process will be exposed especially in comparison to thermal oxidation.

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