Electrochemical Treatment of Graphene

2019 ◽  
Vol 799 ◽  
pp. 197-202
Author(s):  
Alexander Usikov ◽  
Mike Puzyk ◽  
Sergey Novikov ◽  
Iosif Barash ◽  
Oleg Medvedev ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Partial Oxidation ◽  
Electrochemical Method ◽  
Counter Electrode ◽  
Reference Electrode ◽  
Electrochemical Treatment ◽  
Complete Dissolution ◽  
Graphene Films ◽  
Working Electrode ◽  
Electrode Cell

Treatment of graphene/SiC dies in inorganic electrolytes (KOH, KCl and Na2SO4) is discussed. An electrochemical method based on the cyclic voltammetry in a conventional three-electrode cell with Ag/AgCl reference electrode, a platinum counter electrode, and the graphene/SiC dies as working electrode (anode) is used for the treatment. It was observed either partial oxidation of graphene or its complete dissolution with the formation of CO2. The treatment performed resulted in the deterioration of the graphene films and change of the graphene-die resistivity depending on the range of the scanning potential applied to the graphene/SiC dies.

scholarly journals Characterisation of Electrochemical Sensor-Array for Utilisation in Construction of BOD Bioelectronic Tongue

2020 ◽  
Vol 24 (3) ◽  
pp. 39-54
Author(s):  
Kätlin Pitman ◽  
Jaak Nerut ◽  
Merlin Raud ◽  
Timo Kikas
Keyword(s):  
Cyclic Voltammetry ◽  
Industrial Wastewater ◽  
Counter Electrode ◽  
Sensor Array ◽  
Reference Electrode ◽  
Oxygen Demand ◽  
Organic Pollution ◽  
Bioethanol Production ◽  
Biosensor Array ◽  
Band Electrode

AbstractThere is need to rapidly measure biochemical oxygen demand (BOD) to estimate organic pollution in wastewater. Biosensors are able to estimate BOD values within 5–30 minutes, but they have some limitations that can be overcome with biosensor-array. This work used sensor-array, which consists of 8 × 3 electrodes. The working electrode was inner Pt circle electrode, counter electrode was a Pt band electrode and the reference electrode was a silver wire. The potentiostat was used to record cyclic voltammetry and chronoamperometry. The pumping speed was set at 1.5 cm3 min−1 or higher, to avoid the interference. Next, sensor-array was tested to measure different oxygen amounts and calibrated accordingly. Lastly, Pseudomonas putida membranes were calibrated and used to estimate BOD value. The calibration gave linear range up to 85 mg L−1 of BOD and sensitivity from 0.0018 to 0.0068. Real industrial wastewater, from lignocellulosic bioethanol production, was used to test the biosensor-array. It underestimated BOD values from 8 to 37 %. This biosensor-array allows to measure BOD value in less than 15 minutes.

scholarly journals Preparation and Application of Platinum Composite Microelectrode (PCM) for the Routine Analysis of Acetaminophen in Pharmaceutical Products

2014 ◽  
Vol 14 (2) ◽  
pp. 109-115
Author(s):  
Riyanto Riyanto ◽  
Ahmad Safarudin
Keyword(s):  
Stainless Steel ◽  
Cyclic Voltammetry ◽  
Counter Electrode ◽  
Low Cost ◽  
Reference Electrode ◽  
Pharmaceutical Products ◽  
Pharmaceutical Product ◽  
Additional Benefit ◽  
Routine Analysis ◽  
Steel Mould

Preparation and application of platinum composite microelectrode (PCM) for the routine analysis of acetaminophen in pharmaceutical products has been carried out. This electrode was prepare by Pt powder and PVC in 4 mL tetrahydrofuran (THF) solvent and swirled flatly to homogeneous followed by drying in an oven at 100 °C for 3 h. The mixture was placed in 0.5 cm diameter stainless steel mould and pressed at 10 ton/cm2. The cyclic voltammetry were performed in a three electrodes system using PCM as a working electrode, an Ag/AgCl (saturated KCl) as reference electrode and platinum wire as the counter electrode. Electroanalysis of acetaminophen was performed in 0.1 M H2SO4 as an electrolyte. The result of the study showed that the correlation of determination using PCM electrode for electroanalysis acetaminophen was R2 = 0.999. Precision, recovery, LOD and LOQ of the PCM towards acetaminophen were found to be 1.04%, 100.54%, 19.52 mg/L and 65.08 mg/L, respectively. As a conclusion, the methods can be used for routine analysis of acetaminophen in pharmaceutical product. Simplicity of sample preparation and use of low cost reagents are the additional benefit of this method.

scholarly journals Homogeneous electron-transfer of chlorophyll and its derivative chlorophyllin at gold electrode

2019 ◽  
Vol 7 (1) ◽  
pp. 1-17
Author(s):  
Alhasan H ◽  
Alahmadi N ◽  
Wadhawan J
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Electrode Surface ◽  
Gold Electrode ◽  
Reference Electrode ◽  
Surface Preparation ◽  
Active Species ◽  
Bulk Solution ◽  
Photovoltaic Properties ◽  
Working Electrode

Introduction: Chlorophyll is a light harvesting pigment, which absorbs light in the visible spectrum of sunlight and promotes electron transfer, Chlorophyllin (CHL) is One of the most important derivative molecules of chlorophyll. Nowadays, chlorophyll pigment and its derivatives are utilised in organic photosynthetic solar cells for their desirable photovoltaic properties. Cyclic voltammetry (CV) is an essential technique. It is extensively used to study electroactive species to interpret the intermediates of reactions, supply information about the thermodynamics of oxidation-reduction reactions and elucidate the kinetics of electron transfer reactions. Materials and Methods: Prior to the electrochemical study, the working gold (Au) electrode surface was prepared by immersing it in the various concentrations of chlorophyllin for a period time. The electrolyte was degassed by using N2 for approximately 30 minutes inside a Faraday cage before any electrochemical experiment was performed. A three electrode system was used with, Ag/AgCl as a reference electrode, graphiteas a counter and the working electrode (Au). Results and Discussion: As a route to develop new chemical systems for artificial photosynthesis, this work reports the effectiveness of different parameters in transferring electrons between chlorophyllin (CHL) pigment and the working electrode surface (gold). These parameters such as the adsorption time, the electrolyte nature and concentration and chlorophyllin concentration are investigated. The use of chlorophyllin as a redox mediator is examined, with a gold electrode being employed. The importance of gold electrode surface preparation in determining the mechanism of redox is described, and the environment of adsorption process of the different concentrations of chlorophyllin on the surface of the gold electrode has been elucidated in this study. Conclusiones: The electrochemical method showed that the cyclic voltammetry responses of studied adsorption chlorophyllin pigment on the gold electrode were more efficient. In addition, the redox reaction was successful electrochemically in aqueous solution thanthe organic solution. It was suggested that electrons reduce to the chlorophyllin pigment by adding active species in the bulk solution homogeneous transfer. Finally, detections of chl on spinach leaves using various methods are reported.

scholarly journals Elektroplating Grafena-Polianilina pada Stainless Steel sebagai Elektroda pada Elektrolisis Air untuk Produksi Hidrogen

KOVALEN ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 109-120
Author(s):  
Rahmiani Gani ◽  
Syarifah Rabiatul Adawiah ◽  
Arfiani Nur
Keyword(s):  
Stainless Steel ◽  
Cyclic Voltammetry ◽  
Hydrogen Production ◽  
Reference Electrode ◽  
Water Electrolysis ◽  
Potential Difference ◽  
Peak Current ◽  
Working Electrode ◽  
Average Potential ◽  
Cyclic Voltammetry Method

Hydrogen production by water electrolysis can be optimalized by improve the working electrode. Stainless steel as working electrode was coated with graphene and polyaniline by using cyclic voltammetry method with Ag/AgCl as reference electrode and Pt as counter electrode. Coated electrodes were characterized by SEM-EDS and cyclic voltammetry method. Furthermore, the synthesized electrode was applied for water electrolysis by adding 1- 5 g/L NaHCO3. The characterization data showed that Stainless steel/Graphene-Polyaniline electrode can be synthesized by using cyclic voltammetry. The coating process was conducted at sweeping rate 10 mV/s on voltage -0.2 to 0.8 V for 10 cycles. The voltammograms showed that the highest cathodic peak current of electrolysis obtained at 0.491 mA by addition 2 g NaHCO3 on SS/G-PANi0,5 electrode, and the highest anodic peak current obtained at 0.191 mA by addition 2 g NaHCO3 on SS/G-PANi0,5 electrode. Based on the overpotential data, the smallest average potential difference of H+ adsorption obtained by SS/G-PANi1,0 electrode, and the smallest average potential difference of H+ desorption obtained by SS/G-PANi0,5 electrode. Keywords: Stainless steel, hydrogen production, electroplating, electrocatalyst, electrolysis

scholarly journals Graphene Oxide Functionalized Biosensor for Detection of Stress-Related Biomarkers

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 558
Author(s):  
Erican Santiago ◽  
Shailu Shree Poudyal ◽  
Sung Y. Shin ◽  
Hyeun Joong Yoon
Keyword(s):  
Graphene Oxide ◽  
Counter Electrode ◽  
Point Of Care ◽  
Protein A ◽  
Reference Electrode ◽  
Current Response ◽  
Electrochemical Response ◽  
Working Electrode ◽  
Electrochemical Current ◽  
Detection Of Stress

A graphene oxide (GO)-based cortisol biosensor was developed to accurately detect cortisol concentrations from sweat samples at point-of-care (POC) sites. A reference electrode, counter electrode, and working electrode make up the biosensor, and the working electrode was functionalized using multiple layers consisting of GO and antibodies, including Protein A, IgG, and anti-Cab. Sweat samples contact the anti-Cab antibodies to transport electrons to the electrode, resulting in an electrochemical current response. The sensor was tested at each additional functionalization layer and at cortisol concentrations between 0.1 and 150 ng/mL to determine how the current response differed. A potentiostat galvanostat device was used to measure and quantify the electrochemical response in the GO-based biosensor. In both tests, the electrochemical responses were reduced in magnitude with the addition of antibody layers and with increased cortisol concentrations. The proposed cortisol biosensor has increased accuracy with each additional functionalization layer, and the proposed device has the capability to accurately measure cortisol concentrations for diagnostic purposes.

scholarly journals Electro-deposition and re-oxidation of carbon in carbonate-containing molten salts

2014 ◽  
Vol 172 ◽  
pp. 105-116 ◽  
Author(s):  
Happiness V. Ijije ◽  
Richard C. Lawrence ◽  
Nancy J. Siambun ◽  
Sang Mun Jeong ◽  
Daniel A. Jewell ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Molten Salts ◽  
Carbon Deposition ◽  
Solid Carbon ◽  
Partial Reduction ◽  
Constant Voltage ◽  
Electro Deposition ◽  
Electrode Reactions ◽  
Electrode Cell ◽  
Potential Applications

The electrochemical deposition and re-oxidation of solid carbon were studied in CO32− ion-containing molten salts (e.g. CaCl2–CaCO3–LiCl–KCl and Li2CO3–K2CO3) at temperatures between 500 and 800 °C under Ar, CO2 or N2–CO2 atmospheres. The electrode reactions were investigated by thermodynamic analysis, cyclic voltammetry and chronopotentiometry in a three-electrode cell under various conditions. The findings suggest that the electro-reduction of CO32− is dominated by carbon deposition on all three tested working electrodes (Ni, Pt and mild steel), but partial reduction to CO can also occur. Electro-re-oxidation of the deposited carbon in the same molten salts was investigated for potential applications in, for example, direct carbon fuel cells. A brief energy and cost analysis is given based on results from constant voltage electrolysis in a two-electrode cell.

scholarly journals THE PREPARATION OF AN IODATE SELECTIVE ELECTRODE USING SILVER IODATE AS THE ACTIVE AGENT IN A CHITOSAN SUPPORT

2010 ◽  
Vol 7 (3) ◽  
pp. 284-287
Author(s):  
Ani Mulyasuryani ◽  
Qonitah Fardiyah ◽  
Rizki Sugiri
Keyword(s):  
Detection Limit ◽  
Response Time ◽  
Active Agent ◽  
Reference Electrode ◽  
Chitosan Solution ◽  
Precipitation Reaction ◽  
Selective Electrode ◽  
Cell Potential ◽  
Chitosan Membrane ◽  
Electrode Cell

The iodate-selective electrode based on the principle of precipitation reaction could be made by coating the platinum wire with silver iodate (AgIO3). In this research was carried out optimization the iodate-selective electrode using chitosan membrane as an AgIO3 support. The AgIO3 were added in the 2 mL 1% chitosan solution, is 0.5 to 2.5 % (w/v). The thickness of the membrane used is 6 to 12 µm. The electrode cell potential is measured against Ag/AgCl electrode as a reference electrode. The optimum electrode performance was at 2.0 % of AgIO3 with thickness a membrane of 10 µm. The iodate-selective electrode has a Nernstian factor is 52.96 mV/decade and a response time of 10 seconds. The concentration range was determined from 10-3 M to 10-1 M and the detection limit is 1.12 x 10-5 M.   Keywords:  Ion Selective Electrode, Iodate, Chitosan Membrane

scholarly journals Cu(I) Coordination Complex Precursor for Randomized CuOx Microarray Loaded on Carbon Nanofiber with Excellent Electrocatalytic Performance for Electrochemical Glucose Detection

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5353
Author(s):  
Sorina Motoc ◽  
Carmen Cretu ◽  
Otilia Costisor ◽  
Anamaria Baciu ◽  
Florica Manea ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Glucose Oxidation ◽  
Carbon Nanofiber ◽  
Limit Of Detection ◽  
Electrochemical Treatment ◽  
Open Circuit ◽  
Coordination Complex ◽  
Glucose Detection ◽  
Optimized Conditions ◽  
Paste Electrode

A homoleptic ionic Cu(I) coordination complex that was based on 2,2′-biquinoline ligand functionalized with long alkyl chains (Cu(I)–C18) was used as a precursor to modify a carbon nanofiber paste electrode (Cu–C18/CNF). Randomized copper oxide microelectrode arrays dispersed within carbon nanofiber paste (CuOx/CNF) were obtained by electrochemical treatment of Cu–C18/CNF while using cyclic voltammetry (CV). The CuOx/CNF exhibited high electrocatalytic activity towards glucose oxidation at +0.6 V and +1.2 V vs. Ag/AgCl. Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) characterized the electrodes composition. Cyclic voltammetry (CV), square wave-voltammetry (SWV), and multiple-pulsed amperometry (MPA) techniques provided optimized conditions for glucose oxidation and detection. A preconcentration step that involved 10 minutes accumulation at open circuit potential before SWV running led to the lowest limit of detection and the highest sensitivity for glucose detection (5419.77 µA·mM−1·cm−2 at + 1.1 V vs. Ag/AgCl) vs. Cu-based electrodes reported to date in literature.

scholarly journals Photoelectric current as a highly sensitive readout for potentiometric sensors

2020 ◽  
Vol 56 (27) ◽  
pp. 3879-3882 ◽  
Author(s):  
Xu Hun ◽  
Xiaoli Xiong ◽  
Jiawang Ding ◽  
Wei Qin
Keyword(s):  
Reference Electrode ◽  
Ion Selective Electrode ◽  
Potentiometric Sensors ◽  
Polymeric Membrane ◽  
Selective Electrode ◽  
Photoelectric Current ◽  
Working Electrode ◽  
Highly Sensitive

The photocurrent at a working electrode coated with a ZnSe/r-GO composite can be modulated by a polymeric membrane ion-selective electrode that works as a reference electrode.

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