Poly(o-aminophenol) film electrodes: synthesis and characterization and formation mechanisms — A review article

2013 ◽  
Vol 91 (2) ◽  
pp. 91-112 ◽  
Author(s):  
R. Tucceri ◽  
P.M. Arnal ◽  
A.N. Scian
Keyword(s):  
Chemical Structure ◽  
Electrode Materials ◽  
Film Formation ◽  
Protective Layer ◽  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Formation Mechanisms ◽  
Neutral Media ◽  
Electro Oxidation ◽  
Basic Solutions

This review, which is divided into three parts, concerns electrochemical synthesis, spectroscopic characterization, and formation mechanisms of poly(o-aminophenol) (POAP) film electrodes. The first part of this review is devoted to describing the electropolymerization process of o-aminophenol (o-AP) on different electrode materials and in different electrolyte media by employing both potentiodynamic and potentiostatic methods. The evolution of the voltammogram during the electrosynthesis of POAP and the assignation of the voltammetric peaks to different species, according to the formation mechanism formulated by each author, are described. The effects of some chemical substances and electrochemical pretreatments of the electrode surface, on the electropolymerization process of o-AP, are also considered in this part of the review. The synthesis of POAP in neutral media, which yields a nonconducting polymer, and its use as component of biosensors and protective layer in corrosion processes, are analyzed at the end of the first part. The second part of this review refers to spectroscopic studies carried out by different authors to both identify the products of the o-AP electro-oxidation and elucidate the chemical structure of POAP film electrodes. This second part of the review also describes the different spectroscopic methods employed to study the redox process of POAP, which allows the demonstration of the existence of transient species during the transition of the completely oxidized form of POAP to the completely reduced one. The third part of this review shows the different mechanisms formulated to interpret the POAP film formation from both acid and basic solutions of o-AP. Also, some electrochemical and spectroscopic data which allowed to propos the corresponding formation mechanisms, especially in basic media, are described.

scholarly journals Electrosynthesis and Spectroscopic Characterization of Poly(o-Aminophenol) Film Electrodes

2012 ◽  
Vol 2012 ◽  
pp. 1-26 ◽  
Author(s):  
Ricardo Tucceri ◽  
Pablo Arnal ◽  
Alberto Scian
Keyword(s):  
Electrochemical Synthesis ◽  
Spectroscopic Data ◽  
Chemical Structure ◽  
Electrode Materials ◽  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Formation Mechanisms ◽  
The Third ◽  
Basic Solutions

This review, which is divided into three parts, concerns electrochemical synthesis, spectroscopic characterization, and formation mechanisms of poly(o-aminophenol) (POAP) film electrodes. The first part of this review is devoted to describe the electropolymerization process of o-aminophenol on different electrode materials and in different electrolyte media by employing both potentiodynamic and potentiostatic methods. The second part refers to spectroscopic studies carried out by different authors to both, identify the products of the o-aminophenol electrooxidation and elucidate the chemical structure of poly(o-aminophenol) film electrodes. The third part shows the different mechanisms formulated to interpret the POAP films formation from both acid and basic solutions of o-AP. Also, some electrochemical and spectroscopic data which allowed to propos the corresponding formation mechanisms, especially in basic media, are described.

scholarly journals Spectroscopic Characterization of Poly(ortho-Aminophenol) Film Electrodes: A Review Article

2013 ◽  
Vol 2013 ◽  
pp. 1-26 ◽  
Author(s):  
Ricardo Tucceri ◽  
Pablo Maximiliano Arnal ◽  
Alberto Néstor Scian
Keyword(s):  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Review Article ◽  
Electro Oxidation ◽  
Redox Conversion

This paper refers to spectroscopic studies carried out to identify the products ofo-aminophenol electro-oxidation and elucidate the structure of electrochemically synthesized poly(o-aminophenol) (POAP) films. Spectroscopic studies of the redox conversion of POAP are also reviewed.

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

Electrodeposited Thin Conformal TiO2 Coating Enabling Stable Operation of BiVO4 Photoanodes in Basic Media

2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1917-1917
Author(s):  
Dongho Lee ◽  
Kyoung-Shin Choi
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Synthesis Method ◽  
Protective Layer ◽  
Photoelectrochemical Cell ◽  
Semiconductor Surface ◽  
Stable Operation ◽  
Solar Water Splitting ◽  
Wide Range ◽  
Basic Solutions

Producing hydrogen via solar water splitting using a photoelectrochemical cell (PEC) persists as one of the most exciting research topics in the field of solar fuels. The construction of efficient PECs requires the integration of multiple components including a photoanode, a photocathode, an oxygen evolution catalyst, and a hydrogen evolution catalyst. Therefore, the compatibility and stability of all of these elements in a given operating condition are crucial. When the stability of a semiconductor electrode used as the photoanode or photocathode is limited in an acidic or basic condition which is optimum for the operation of the other components, a thin protective layer has been deposited on the semiconductor surface to prevent its chemical dissolution. Surface coating of a thin and conformal TiO2 layer has been proven to be successful for protecting photoelectrodes since TiO2 is chemically and electrochemically stable in a wide range of pH conditions under both anodic and cathodic conditions. In order to prevent the semiconductor surface from coming into direct contact with the corrosive electrolyte, complete coverage of the photoelectrode with TiO2 is required. At the same time, the TiO2 layer should be thin enough not to interfere with the charge transport properties of the photoelectrode. As a result, atomic layer deposition (ALD) has been the only successful tool used to date to produce an effective protective layer. However, the slow processing time and economic viability of ALD methods motivated us to develop an inexpensive and facile solution-based synthesis method for the deposition of high quality TiO2 coating layers. In this presentation, we report a new electrochemical method to deposit a thin and conformal TiO2 layer on nanoporous BiVO4 that has an intricate, high surface area morphology. BiVO4 is a promising n-type photoanode material with a relatively low bandgap (2.4~2.5 eV). However, its usage has been limited to neutral and mildly basic conditions (pH 5~9) because it is chemically unstable in strongly acidic and basic conditions. Our method allows for the deposition of a 5~6 nm thick TiO2 layer on BiVO4 within 1 min and the resulting BiVO4/TiO2 electrodes exhibit chemical stability in basic solutions (pH 12~13). Sulfite oxidation measurements of BiVO4 and BiVO4/TiO2 electrodes show that the thin TiO2 protective layer does not significantly reduce the hole transfer to the electrolyte. Finally, we demonstrate the photoelectrochemical stability of the BiVO4/TiO2 electrode for photoelectrochemical water oxidation in basic solutions by coupling the BiVO4/TiO2 electrode with appropriate oxygen evolution catalysts.

scholarly journals Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first-row transition-metal complexes

2017 ◽  
Vol 73 (8) ◽  
pp. 620-624 ◽  
Author(s):  
Katherine M. Van Heuvelen ◽  
Isabell Lee ◽  
Katherine Arriola ◽  
Rilke Griffin ◽  
Christopher Ye ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Spin State ◽  
Density Functional ◽  
Cobalt Complex ◽  
Chloride Ion ◽  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Chloride Dihydrate ◽  
Pyramidal Geometry ◽  
A Minor

The tetraazamacrocyclic ligand 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMC) has been used to bind a variety of first-row transition metals but to date the crystal structure of the cobalt(II) complex has been missing from this series. The missing cobalt complex chlorido(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane-κ4 N)cobalt(II) chloride dihydrate, [CoCl(C14H32N4)]Cl·2H2O or [CoIICl(TMC)]Cl·2H2O, crystallizes as a purple crystal. This species adopts a distorted square-pyramidal geometry in which the TMC ligand assumes the trans-I configuration and the chloride ion binds in the syn-methyl pocket of the ligand. The CoII ion adopts an S = 3 \over 2 spin state, as measured by the Evans NMR method, and UV–visible spectroscopic studies indicate that the title hydrated salt is stable in solution. Density functional theory (DFT) studies reveal that the geometric parameters of [CoIICl(TMC)]Cl·2H2O are sensitive to the cobalt spin state and correctly predict a change in spin state upon a minor perturbation to the ligand environment.

scholarly journals The Formation of Sulfide Scales on Carbon Steel in Saturated H2S

2020 ◽  
Author(s):  
Noora Alqahtani ◽  
Jiahui Qi ◽  
Aboubakr M. Abdullah ◽  
Nicholas J. Laycock ◽  
Mary P. Ryan
Keyword(s):  
Carbon Steel ◽  
Corrosion Product ◽  
Film Formation ◽  
Open Circuit ◽  
Iron Surface ◽  
Ion Concentration ◽  
Bulk Solution ◽  
Formation Mechanisms ◽  
Structure Thickness ◽  
Circuit Technique

There are three contributing elements of corrosion of Carbon Steel in H₂ S environment: the effect of H2S on water chemistry; electrochemical reactions of the bare iron surface (both anodic and cathodic processes); and the formation and growth of corrosion product layers. The electrochemical reaction commonly contains three stages: first, the reactant transported from the solution (bulk) to the metal surface; then the transfer of the charge reaction on the surface, followed by the reaction product transported away from the iron surface to the bulk solution or the formation and development of the corrosion product which then can decrease the corrosion rate. Development of a robust corrosion model to predict the corrosion process in H2S requires a mechanistic understanding of all these elements. An experimental study was carried out to assess the corrosion of C-steel under open-circuit technique conditions and in solutions at several ranges of time and temperatures. The effect of film composition, morphology, structure, thickness, and ion- concentration of corrosion product films formed on pipeline Carbon Steel in an acid sour solution were examined. The electrochemical behavior of the filmed steel was measured, and the film properties assessed using a range of advanced techniques including Scanning Electron Microscopy (SEM), and Raman spectroscopy (RS). The data will be discussed in terms of film formation mechanisms.

scholarly journals New Membrane-Forming Aromatic Co-Poly(amide-imide)s: Influence of the Chemical Structure on the Morphological, Thermal and Transport Properties

Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 91
Author(s):  
Svetlana V. Kononova ◽  
Danila A. Kuznetsov ◽  
Galina N. Gubanova ◽  
Elena V. Kruchinina ◽  
Anatoly Ya. Volkov ◽  
...  
Keyword(s):  
Transport Properties ◽  
Chemical Structure ◽  
Film Formation ◽  
Membrane Properties ◽  
Morphological Parameters ◽  
Asymmetric Membranes ◽  
Residual Solvent ◽  
New Information ◽  
Film Preparation ◽  
Separation Problems

Polymer film membranes are used to solve specific separation problems that dictate structural requirements. Structural and morphological parameters of film membranes based on glassy polyheteroarylenes can be controlled in the process of preparation from solutions that opens up prospects for obtaining structured membranes required for targeted separation. In the case of aromatic poly(amide-imide)s, the possibility of controlling film formation and structure virtually has not been studied. In the present work, a series of homologous co-poly(amide-imide)s differing in the number of repeating units with carboxyl-substituted aromatic fragments was synthesized by polycondensation. Comparative analysis of the processes of formation of membranes with different morphologies based on these polymers under equal conditions was performed. New information was obtained about the influence of the amounts of carboxyl groups and the residual solvent on structural properties of asymmetric membranes. The influence of these factors on transport properties of dense membranes under pervaporation conditions was studied. It was demonstrated that in the case of carboxyl-containing poly(amide-imide)s, the domains formed during film preparation had a significant effect on membrane properties.

Chemical and Spectroscopic Characterization of Humic Acids Extracted from Filter Cake using Different Basic Solutions

Sugar Tech ◽  
2019 ◽  
Vol 22 (2) ◽  
pp. 311-318
Author(s):  
Hamid Reza Behravan ◽  
Paul Voroney ◽  
Reza Khorassani ◽  
Amir Fotovat ◽  
Abdol Amir Moezei ◽  
...  
Keyword(s):  
Humic Acids ◽  
Filter Cake ◽  
Spectroscopic Characterization ◽  
Basic Solutions

Extraction of novel sulfated polysaccharides from Aphanothece sacrum (Sur.) Okada, and its spectroscopic characterization

2007 ◽  
Vol 79 (11) ◽  
pp. 2039-2046 ◽  
Author(s):  
Maiko Okajima-Kaneko ◽  
Masateru Ono ◽  
Kiyotaka Kabata ◽  
Tatsuo Kaneko
Keyword(s):  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Environmentally Benign ◽  
Sulfated Polysaccharides ◽  
Nmr Studies ◽  
H Nmr ◽  
Elemental Analyses ◽  
Gelation Behavior ◽  
Long Time ◽  
Swelling Volume

We extracted polysaccharides (PS) from Aphanothece sacrum using a hot alkaline solution which degraded other biopolymers such as proteins and nucleotides. The spectroscopy and elemental analyses indicated the PS contain carboxyls and sulfate groups. The degree of sulfation was estimated as about 10 mol %. 1H NMR studies demonstrated that the PS of A. sacrum had a dimethylated fucose unit. The combination of sulfate group and fucose in the prokaryotic PS was first evidenced by the direct spectroscopic studies. The PS showed efficient gelation behavior, binding to metal ions abundant in soil, and the swelling volume of the gel was approximately 250 times the dry volume. These results imply that PS of A. sacrum, which has been mass cultivated in Japan for a long time, may have potential as an environmentally benign water absorbent.

Sign in / Sign up

Export Citation Format

Share Document