scholarly journals Development of a new biocathode for a single enzyme biofuel cell fuelled by glucose

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Asta Kausaite-Minkstimiene ◽  
Algimantas Kaminskas ◽  
Anton Popov ◽  
Arunas Ramanavicius ◽  
Almira Ramanaviciene
Keyword(s):  
Open Circuit Potential ◽  
Glucose Solution ◽  
Initial Response ◽  
Open Circuit ◽  
Biofuel Cell ◽  
Amide Bond ◽  
Optimal Conditions ◽  
Additional Layer ◽  
Graphite Rod ◽  
Single Enzyme

AbstractIn this study, we reported the development of Prussian blue (PB), poly(pyrrole-2-carboxylic acid) (PPCA), and glucose oxidase (GOx) biocomposite modified graphite rod (GR) electrode as a potential biocathode for single enzyme biofuel cell fuelled by glucose. In order to design the biocathode, the GR electrode was coated with a composite of PB particles embedded in the PPCA shell and an additional layer of PPCA by cyclic voltammetry. Meanwhile, GOx molecules were covalently attached to the carboxyl groups of PPCA by an amide bond. The optimal conditions for the biocathode preparation were elaborated experimentally. After optimization, the developed biocathode showed excellent electrocatalytic activity toward the reduction of H2O2 formed during GOx catalyzed glucose oxidation at a low potential of 0.1 V vs Ag/AgCl, as well as good electrochemical performance. An electrocatalytic current density of 31.68 ± 2.70 μA/cm2 and open-circuit potential (OCP) of 293.34 ± 15.70 mV in O2-saturated 10 mM glucose solution at pH 6.0 were recorded. A maximal OCP of 430.15 ± 15.10 mV was recorded at 98.86 mM of glucose. In addition, the biocathode showed good operational stability, maintaining 95.53 ± 0.15% of the initial response after 14 days. These results suggest that this simply designed biocathode can be applied to the construction of a glucose-powered single enzyme biofuel cell.

scholarly journals Miniaturization effect of electroosmotic self-propulsive microswimmer powered by biofuel cell

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Toshiro Yamanaka ◽  
Fumihito Arai
Keyword(s):  
Theoretical Model ◽  
Femtosecond Laser ◽  
Polymer Composites ◽  
Open Circuit Potential ◽  
Vascular System ◽  
Conductive Polymer ◽  
Open Circuit ◽  
Biofuel Cell ◽  
Remarkable Feature ◽  
Conductive Polymer Composites

AbstractFor future medical microrobotics, we have proposed the concept of the electroosmotic self-propulsive microswimmer powered by biofuel cell. According to the derived theoretical model, its self-propulsion velocity is inversely proportional to the length of the microswimmer, while it is proportional to the open circuit potential generated by the biofuel cell which does not depend on its size. Therefore, under conditions where those mechanisms work, it can be expected that the smaller its microswimmer size, the faster its self-propulsion velocity. Because of its remarkable feature, this concept is considered to be suitable as propulsion mechanisms for future medical microrobots to move inside the human body through the vascular system, including capillaries. We have already proved the mechanisms by observing the several 10 μm/s velocity of 100 μm prototypes fabricated by the optical photolithography using several photomasks and alignment steps. However, the standard photolithography was not suitable for further miniaturization of prototypes due to its insufficient resolution. In this research, we adopted femtosecond-laser 3D microlithography for multi-materials composing of the conductive polymer composites and nonconductive polymer composite and succeeded in fabricating 10 μm prototypes. Then we demonstrated more than 100 μm/s velocity of the prototype experimentally and proved its validity of the smaller and faster feature.

Adsorption and Oxidation of Thiosulfate on the Platinum Electrode in a Slightly Alkaline Medium

2000 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Alkaline Medium ◽  
Oxidation Reaction ◽  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Adsorbed Layer ◽  
Open Circuit ◽  
Adsorbed Hydrogen ◽  
Oxidation Number ◽  
Hydrogen Electrode ◽  
Layer Region

The aim of this research was to study the oxidation and reduction of the adsorbed thiosulfate on the platinum electrode in a slightly alkaline medium. The adsorption was performed at the open circuit conditions. The reduction of the adsorbed layer in the hydrogen region is slower in a slightly alkaline medium than in acid. The mechanism of reduction and oxidation of adsorbed molecules is probably the same. The nonstationary currents measured in presence of thiosulfates showed that the change in the oxidation number does not take place during the adsorption in the double layer region. In the hydrogen region, thiosulfate replaces the adsorbed hydrogen while beeing reduced. Nonstationary currents at higher concentrations of thiosulfate indicate the presence of more layers on the electrode. Upon reaching higher concentrations of thiosulfate the oxidation reaction takes place between thiosulfate in solution and adsorbed product of its reduction. The open circuit potential of the platinum electrode measured in a thiosulfate solution was 0.780 and 0.783 V against the hydrogen electrode in the same solution.

scholarly journals Effects of Alloying Elements on the Corrosion Behavior of Sputter–deposited Zr–(12–21)Cr–W Alloys in 0.5 M NaCl Solution

1970 ◽  
Vol 25 ◽  
pp. 75-82
Author(s):  
Basu Ram Aryal ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Test ◽  
Open Circuit Potential ◽  
Chemical Society ◽  
Open Circuit ◽  
Sputter Deposition ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Sputter Deposited ◽  
Stable Passivity ◽  
Zirconium Metal

The synergistic effect of the simultaneous additions of tungsten and zirconium in thesputter-deposited amorphous or nanocrystalline Zr-(12-21)Cr-W alloys is studied in 0.5 MNaCl solution open to air at 25°C using corrosion tests and open circuit potentialmeasurements. Corrosion rates of the sputter-deposited Zr-(12-21)Cr-W alloys containing10-80 at % tungsten (that is, 0.95-1.85 x 10-2 mm.y-1) are more than one order of magnitudelower than that of the sputter-deposited tungsten and even lower than those of zirconium aswell as chromium in 0.5 M NaCl solution. The addition of 8-73 at % zirconium content inthe sputter-deposited binary W-(12-21)Cr alloys seems to be more effective to improve thecorrosion-resistant properties of the sputter-deposited ternary Zr-Cr-W alloys containing12-21 at % chromium in 0.5 M NaCl solution. The sputter-deposited Zr-(17-21)Cr-W alloyscontaining an adequate amounts of zirconium metal showed the more stable passivity andshowed higher corrosion resistance than those of alloy-constituting elements in 0.5 M NaClsolution open to air at 25°C.Keywords: Zr-(12-21)Cr-W alloys, sputter deposition, corrosion test, open circuit potential,0.5 M NaCl.DOI:  10.3126/jncs.v25i0.3305Journal of Nepal Chemical Society Volume 25, 2010 pp 75-82

scholarly journals Activated Carbon Open Circuit Potential Shifts in Aqueous Solutions

2019 ◽  
Vol 11 (20) ◽  
pp. 19-28 ◽  
Author(s):  
Mikhail M. Goldin ◽  
Gary J. Blanchard ◽  
Alexander G. Volkov ◽  
Mogely S. Khubutiya ◽  
Vladimir A. Kolesnikov ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Potential Shifts

Electrochemical Evaluation for Rust Preventive Properties of Rust Preventive Oils Coated on Fe-Cu-C Sintered Steel

2014 ◽  
Vol 783-786 ◽  
pp. 2537-2540 ◽  
Author(s):  
Satoshi Sunada ◽  
Norio Nunomura ◽  
Sayaka Hirata ◽  
Naoki Nagase
Keyword(s):  
Open Circuit Potential ◽  
High Viscosity ◽  
Open Circuit ◽  
Second Step ◽  
Sintered Steel ◽  
Corrosive Solution ◽  
The Third ◽  
Low Viscosity ◽  
Sintered Steels ◽  
Electrochemical Evaluation

Since Fe-Cu-C sintered steels are easily rusted, they are coated with rust preventive oils. High viscosity of those rust preventive oils decrease workability, and low viscosity deteriorates rust preventive performance. Therefore, it is necessary to develop new rust preventive oils with contradictory properties of low viscosity and superior rust prevention. However, precise methodology to evaluate rust prevention ability has not been established. In this study, we developed new technique to quantitatively evaluate rust prevention ability by measuring the open circuit potential through thin corrosive solution on Fe-Cu-C sintered steels coated with a rust preventive oils. As a result, the ability for rust prevention can be measured quantitatively, and it decreases slowly over time, with repeating destruction and restoration. Furthermore, it was found that the deteriorating processes of rust prevention ability for rust prevention oils are composed of three characteristics steps respectively. That is, in the first step the great open circuit potential changes from 0V to-0.3V with repetition were observed where the excellent rust prevention ability was kept, in the second step it decreases slowly from-0.1V to-0.4V with oscillation of the small potential changes where the gradual decrease of rust prevention ability was recognized and in the third step it decreases monotonously in the lower potential than-0.4V where the rust was observed because of the remarkable deteriorating of the rust prevention ability.

Experimental Study of Propagation Stage of Pitting Corrosion of 20Cr13 Steel

2008 ◽  
Vol 38 ◽  
pp. 238-247
Author(s):  
A.D. Davydov ◽  
V.S. Shaldaev
Keyword(s):  
Pitting Corrosion ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Ph Value ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Pitting Potential ◽  
Free Corrosion Potential ◽  
External Power Source ◽  
Corrosion Of Steel

The initiation and development of pitting corrosion of steel 20Cr13 in the NaCl solutions with various concentrations, temperatures, and pH values are studied under the potentiostatic conditions and at the free-corrosion potential. The pitting and repassivation potentials are determined using the method of cycling voltammetry. In spite of the fact that thus determined pitting potential is more positive than the corrosion potential (the open-circuit potential Eo.c.), the long-term experiments, which were performed at the free-corrosion potential, showed that pitting corrosion takes place without imposing a potential using an external power source. It is concluded that the probability of pitting corrosion of steel should be determined by comparing the corrosion potential (the open-circuit potential) with the repassivation potential Erp. Steel 20Cr13 is prone to the pitting corrosion, because Erp is more negative than Eo.c.. In the potentiostatic experiments, the variation of the depth and diameter of pits and their number with the time and the effect of temperature and electrode rotation on the pit propagation are studied. The results, which were obtained at the free-corrosion potential, are much less reproducible. In this case, in contrast to the potentiostatic conditions, the pit depth increased only slightly and the pit width increased to a larger extent. The effect of concentration, pH value, and temperature of NaCl solutions on the pit propagation is considered. It is concluded that the data on the development of pitting corrosion under the potentiostatic conditions can be hardly extended to the conditions of free corrosion potential.

scholarly journals Actions of external hypertonic urea, ADH, and theophylline on transcellular and extracellular solute permeabilities in frog skin.

1975 ◽  
Vol 65 (5) ◽  
pp. 599-615 ◽  
Author(s):  
L J Mandel
Keyword(s):  
Linear Relationship ◽  
Active Transport ◽  
Transport System ◽  
Frog Skin ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Solute Permeability ◽  
Parallel Lines ◽  
Paracellular Pathways ◽  
Active Transport System

Increases in transepithelial solute permeability were elicited in the frog skin with external hypertonic urea, theophylline, and vasopressin (ADH). In external hypertonic urea, which is known to increase the permeability of the extracellular (paracellular) pathway, the unidirectional transepithelial fluxes of Na (passive), K, Cl, and urea increased substantially while preserving a linear relationship to each other. The same linear relationship was also observed for the passive Na and urea fluxes in regular Ringer and under stimulation with ADH or 10 mM theophylline, indicating that their permeation pathway was extracellular. A linear relationship between Cl and urea fluxes could be demonstrated if the skins were separated according to their open circuit potentials; parallel lines were obtained with increasing intercepts on the Cl axis as the open circuit potential decreased. The slopes of the Cl vs. urea lines were not different from that obtained in external hypertonic urea, indicating that this relationship described the extracellular movement of Cl. The intercept on the ordinate was interpreted as the contribution from the transcellular Cl movement. In the presence of 0.5 mM theophylline or 10 mU/ml of ADH, mainly the transcellular movement of Cl increased, whereas 10 mM theophylline caused increases in both transcellular and extracellular Cl fluxes. These and other data were interpreted in terms of a possible intracellular control of the theophylline-induced increase in extracellular fluxes. The changes in passive solute permeability were shown to be independent of active transport. The responses of the active transport system, the transcellular and paracellular pathways to theophylline and ADH could be explained in terms of the different resulting concentrations of cyclic 3'-5'-AMP produced by each of these substances in the tissue.

Experimental study of the mechanical and corrosion properties of ethyl silicate resin applied on low carbon steel

2021 ◽  
Vol 2 (108) ◽  
pp. 68-74
Author(s):  
M. Ali ◽  
J.H. Mohmmed ◽  
A.A. Zainulabdeen
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Open Circuit Potential ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Treatment Temperature ◽  
Ethyl Silicate ◽  
Low Carbon ◽  
Corrosion Properties ◽  
Mixture Ratio

Purpose: This work aimed at evaluating the properties of the ethyl silicate-based coating that can be applied on low carbon steel. Design/methodology/approach: Two mixture ratio types (2:1, and 3:2) of resin and hardener respectively were used to prepared two specimen models (A and B). Findings: It found that some mechanical properties (tensile, hardness, and impact strength) of ethyl silicate resin were evaluated according to standard criteria. Research limitations/implications: The effect of heat treatments at various temperatures (100, 150, and 200°C) and holding at different times (10, 20 & 30) min on hardness was investigated. Practical implications: Moreover, an open circuit potential corrosion test with a solution of 3.5% Sodium Chloride at room temperature and 60°C was used to determine the corrosion resistance of low carbon steel specimens coated with the two mixture types. Originality/value: The effects of mixture ratios (for resin and hardener) and heat treatment conditions on properties of ethyl silicate-based coating were studied. From obtained results, acceptable values of tensile, hardness, and toughness were recorded. Increasing heat treatment temperature and holding time leads to enhance hardness for both model types. An open circuit potential (OCP) tests show that there is an enhancement of protective properties of ethyl silicate coatings with mixture type B in comparison with type A was achieved. Generally, the results indicate that specimen model B has higher properties as compared with specimen model A.

scholarly journals From Waste to Valuable Resource: Lignin as a Sustainable Anti-Corrosion Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 454 ◽  
Author(s):  
Arman Dastpak ◽  
Kirsi Yliniemi ◽  
Mariana de Oliveira Monteiro ◽  
Sarah Höhn ◽  
Sannakaisa Virtanen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Linear Sweep Voltammetry ◽  
Corrosion Current ◽  
Polymer Coatings ◽  
Open Circuit ◽  
Linear Sweep ◽  
Cyclic Potentiodynamic Polarization

In this study, a waste of biorefinery—lignin—is investigated as an anticorrosion coating on stainless steel. Corrosion behavior of two lignin types (hardwood beech and softwood spruce) was studied by electrochemical measurements (linear sweep voltammetry, open circuit potential, potentiostatic polarization, cyclic potentiodynamic polarization, and electrochemical impedance measurements) during exposure to simulated body fluid (SBF) or phosphate buffer (PBS). Results from linear sweep voltammetry of lignin-coated samples, in particular, demonstrated a reduction in corrosion current density between 1 and 3 orders of magnitude cf. blank stainless steel. Furthermore, results from cross cut adhesion tests on lignin-coated samples demonstrated that the best possible adhesion (grade 0) of ISO 2409 standard was achieved for the investigated novel coatings. Such findings suggest that lignin materials could transform the field of organic coatings towards more sustainable alternatives by replacing non-renewable polymer coatings.

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