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What are the steps to be followed while polishing a glassy carbon electrode (GCE)?
By MTX Labs Team
/ October 19, 2023
Position the GCE vertically and aim it towards the alumina slurry existing in the glass pad, drawing a continuous 8 line in the pad with mild pressure as shown in Fig 1, and not a zigzag or horizontal line as shown in Fig 2 and 3. Wash the polished GCE using distilled water (DI) followed by sonication for few minutes using acetone/ ethanol, or DI water.
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Is it recommended to polish the Glassy Carbon Electrode (GCE) with alumina and diamond slurry prior to its usage or is it possible to use it without polishing?
By MTX Labs Team
/ October 19, 2023
Yes, polishing of GCE is highly recommended prior to the experimentation using alumina and diamond slurries to obtain clean and uniform surface. Also, to remove the residues of the previous experiments. In this way, the repeatability, sensitivity, and stability of the electrode can be improved. It could be feasible to utilize a GCE without polishing but the surface of the electrode is awry, which could lead to inconsistent electrochemical performance.
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What makes a glassy carbon electrode a flexible option to use it as working electrode in electrochemical applications?
By MTX Labs Team
/ October 19, 2023
In general, Glassy Carbon Electrode (GCE) is the preferred working electrode in electrochemistry because of their chemical inertness, easy fabrication, high hardness, wide range potential, high electrical conductivity, low capacitance, and low current background. GCE is made of amorphous, non-graphitic carbon that has been thoroughly purified. Due to its low reactivity (high corrosion resistance) makes a flexible option for most of the electrochemical applications.
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Can a Vycor Frit Tip be cleaned and used again?
By MTX Labs Team
/ October 19, 2023
Vycor frit can be cleaned and reused by using a small blub or other suction device, forcibly pressurize the inner volume of water slightly to cause drainage out the frit. If the contamination increases over time, cleaning them is a challenging process, therefore we must replace the frit for better results. If the frit is broken, cracked, or soiled, as seen in Figure 1, it cannot be reused.
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Why does a reference electrode contain a frit?
By MTX Labs Team
/ October 19, 2023
The porous frit at the tip of the reference electrode (RE) acts as a semi-permeable membrane facilitating ions exchange between RE’s filling solution (3M NaCl/KOH) and electrolyte while avoiding direct physical interaction between the two as shown in Fig 1. The primary function of the frit is to lower the leak rate and to determine the stability of the reference electrode (RE) while using a potentiostat. The reference electrode without frit tip will lead to electrolyte contamination. For example, A junction potential arises at the interface of two ionic solutions due to differences in the compositions, concentrations, and mobility of...
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How do calomel electrode and silver chloride electrode vary from one another?
By MTX Labs Team
/ October 14, 2023
Listed below is a comparative study between Saturated Calomel Electrode (SCE) and Silver - Silver Chloride Electrode (Ag/AgCl): Sl.No Features/Category Saturated Calomel Electrode (SCE) Silver - Silver Chloride Electrode (Ag/AgCl) 1 Notation Hg|Hg2Cl2, KCl(aq), (sat) Ag|AgCl, KCl(aq), (sat) 2 Filling solution Saturated KCl 3M KCl 3 Potential Vs SHE +0.241V Sat KCl +0.197 V Un sat KCl +0.205 V 4 Advantages Easy to setup and reproducible. Wider potential range. Convenient and easy to transport. No need of salt bridge Simple and stable Non-toxic 5 Disadvantage Toxic Short lifetime and light-sensitive 6 ...
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What are the steps for calibrating a reference electrode?
By MTX Labs Team
/ October 14, 2023
Make sure the electrode is free from contamination and it is clean. To achieve equilibrium, immerse the electrode in a 3M (KCl/NaOH) solution. Choose the standard reference electrode with known potential. As illustrated in Fig 1, place both electrodes in a cell containing saturated 3M (KCl/NaOH) and connected to a voltmeter. It is useful for determining the potential of the reference electrode. If the voltage value is zero, the reference electrode is functioning properly. If the voltage value is non-zero or near to zero, the difference is very small and it may be acceptable. If the voltage value fluctuates more...
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How can the Ag/AgCl reference electrode’s functionality be tested?
By MTX Labs Team
/ October 14, 2023
A basic voltmeter can be used to measure the potential, which can then be compared to a standard reference electrode such as a Saturated Calomel Electrode (SCE) or Silver Silver Chloride (Ag/AgCl) and a cell containing 3M KCl. Another method is to evaluate redox potentials (peak-to-peak separation potential) by performing a experiments using a standard redox probe potassium ferric cyanide [K3Fe(CN)6] Estimating the Ag/AgCl electrode potential by conducting the hydrogen evolution reaction (HER) with a Standard Hydrogen Electrode (SHE) in 1M HCl, (purging the hydrogen gas continuously, at 1 atm pressure)
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In a 3-electrode cell setup, why is the reference electrode located near the working electrode?
By MTX Labs Team
/ October 14, 2023
The electrochemical cell based on two or three electrode system of working electrode (WE), reference electrode (RE) and counter electrode is placed in a suitable electrolyte solution. During the redox process, the solution resistance will rise if the gap between the WE and RE is wider. As a result, as indicated in Fig 1, it is essential to place the WE and RE as close as possible. If the experiments are conducted in non-aqueous or ionic liquids, the constant distance needs to be maintained throughout the experiment, and monitoring is recommended. The Luggin capillary setup can be utilized to lower the WE...
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What is the purpose of storing a calomel electrode in a KCl solution?
By MTX Labs Team
/ October 14, 2023
The KCl solution not only serves as a reservoir for Cl-, but it also aids in the transfer of electrons and ions between the calomel electrode and the solution, which is required for the electrode to work effectively. The electrode potential can be controlled by changing the concentration of the KCl solution, which also acts as a salt bridge. The potential of the Saturated Calomel Electrode (SCE) is governed by the Cl- ions which are in equilibrium with Hg and Hg2Cl2.
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When and why is a salt bridge is used in an electrochemical cell?
By MTX Labs Team
/ October 11, 2023
When the electrodes are in a single container, an electrochemical cell can function without a salt bridge, because electron flow happens naturally within the system. However, if the electrode is situated in two different containers, as shown in Fig 1 and Fig 2, the salt bridge aids in transferring charges from one electrolyte to another. Inert electrolytes such as KCl or NaOH must be used to fill the salt bridge. These electrolytes have similar migration rates and conductivities, and they do not participate in any chemical reactions in electrolytic cells.
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