Electrode Cleaning

Electrode Material
Link to Publication
Cleaning Process
Copper
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Clean copper electrodes by first wiping with acetone, then sanding, wiping with dilute HCl (to remove loose copper particles) and rinsing with acetone
Copper
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Copper-coated graphite
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The electrodes were carefully cleaned with water and acetone
Platinum
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can be flame cleaned to remove any oxide layer for very sensitive processes.
Platinum
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Pt microelectrode was cleaned by polishing in 50 nm alumina slurry and rinsed with acetone
Platinum
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Clean the Pt electrode by submerging it in concentrated nitric acid (~70%) for 5 min, followed by rinsing it with water and then acetone. Run the Pt plate through the flame of a butane torch until it glows orange. Allow it to cool for 1 min before any future use.
Platinum
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Alternate the polarity of the working electrode by setting the potential to 500 mV and switching the polarity switch between (+) and (-). Perform at least 10 cycles, pausing at each potential for a few seconds. Return the potential to the desired value and test the response with a standard solution. If the response does not improve, disassemble the cell and polish the electrode with a methanol-soaked lab tissue. Use firm pressure. Rinse the block with methanol and reassemble. Proceed polishing with abrasives only if the response is still too low compared to earlier performance.
Platinum
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Cleaned by heating to red-hot in a flame
Platinum
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The former were prepared from electrodes cleaned as described previously, which were then polarized cathodically to hydrogen evolution and then anodically for 5 min at 25 mA cm-2 in acetate solution. They were finally cleaned again by boiling in concentrated hydrochloric acid, washing with water and standing overnight in a sulphuric-nitric acid cleaning mixture.
Platinum
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“ Reduced ” electrodes were prepared by polarizing cleaned electrodes for 30 min at a constant potential of 0.1 V more positive than the reversible hydrogen electrode.
Platinum
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Aqua Regia, Pulse electrolysis then flame treatment. See paper for full details of each step
Platinum Wire
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After each reaction, the electrodes are left to soak in a saturated aqueous Ca2CO3 solution for 10 minutes. After this they were rinsed with water, washed with acetone then left to dry in a 70 ⁰C for several hours before use. Occasionally, there was an amorphous film that is resistant to cleaning, thus at this point the platinum wire is unwound and cleaned with a paper towel soaked in acetone. After re-winding the platinum wire around the PTFE tube, the electrodes are used to apply a potential difference of 10 V to a solution of CH3CN and nBu4NBF4 (0.2M) for 30 minutes. After this the electrodes are re-cleaned with acetone and left to dry in a 70 ⁰C for several hours before use.
Glassy Carbon
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polished with an alumina slurry if necessary but often rinsing is enough. In addition, several cyclic voltammograms with dilute sulfuric acid can clean contaminants within the electrode
Glassy Carbon
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Glassy carbon GC electrodes were chemical and electrochemically pretreated before electropolymerization of o-AP. The electrode surfaces were polished carefully to a mirror finish and then cleaned ultrasonically with triply distilled water for 3 min. This kind of electrode was denoted in [15] as an “untreated” electrode. In addition, electrochemical treatment of the electrodes was achieved by placing the polished electrodes in 0.1 M H2SO4 at 1.85 V (SCE) for 5 min, and then they were cycled between −0.2 V and 0.7 V for 15 min. Chemical pretreatment of the electrodes was achieved by immersing the electrodes in concentrated nitric acid (67% wt/wt) and sulfuric acid (98% wt/wt)
Glassy Carbon
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Rinse with water then MeOH, wet polishing pad with distilled water, add alumina suspension and polish, polish in fig 8, rinse with distilled water. Sonicate for 5 mins in distilled water if necessary
Glassy Carbon
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Using the electrode as the anode in a ~1 M solution of sulfuric acid and running a constant potential of 1-3 V for a few minutes can help clean the electrode by oxidizing impurities on the surface. This procedure however should only be used for glassy carbon and the boron doped diamond electrodes.
RVC
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1M NaOH, 1 M HCl, sandpaper not appropriate as electrode is fragile. Wash with water and acetone
RVC
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Wash with 1 N HCl, H2O several times, and acetone, sequentially, and allow to dry before setting up the next reaction. If the exterior of electrodes is shiny black with a metallic luster obviously, we recommend you do not reuse them again
Graphite
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first rinsing the electrode with the reaction solvent and then cleaning it in an ultrasonic bath with reaction solvent, then acid, water and again the reaction solvent
Graphite
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Graphite electrodes could be used several times by renewing the top surface of the graphite. This was achieved by scraping away the top layer with a razor blade, sonicating in MeCN for 5 minutes, followed by oven-drying for 30 mins
Graphite
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was polished with 400-grit sandpaper, rinsed and cleaned in 1 N HCl for 16 hours.
Graphite
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Silver
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Rinse with water then MeOH, wet polishing pad with distilled water, add alumina suspension and polish, polish in fig 8, rinse with distilled water. Sonicate for 5 mins in distilled water if necessary
Silver
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After each electrolysis, the silver-gauze working electrode was cleaned by using ultrasonication in an aqueous sodium bicarbonate paste for 30 min; it was then rinsed with distilled water and dried in an oven at 180 °C.
Nickel
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Rinse with water then MeOH, wet polishing pad with distilled water, add alumina suspension and polish, polish in fig 8, rinse with distilled water. Sonicate for 5 mins in distilled water if necessary
Nickel
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cleaned by immersion in warm dilute hydrochloric acid and boiling distilled water
Nickel
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Nickel Foam
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Nickel foam (about 3.3 cm x 1 cm) was carefully cleaned with concentrated HCl solution (37 wt.%) in an ultrasound bath for 5 min in order to remove the surface oxide layer. And then deionized water and absolute ethanol were used for 5 min each to ensure the surface of the Ni foam was well cleaned.
Nickel Foam
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1M NaOH, 1 M HCl, no sandpaper. Wash with water and acetone
Nickel Foam
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Nickel foam (about 3.3 cm x 1 cm) was carefully cleaned with the concentrated HCl solution (37 wt.%) in an ultrasound bath for 5 min in order to remove the surface oxide layer. And then deionized water and absolute ethanol were used for 5 min each to ensure the surface of the Ni foam was well cleaned.
Stainless Steel
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The stainless steel electrodes were cleaned with ethanol-acetone mixture 50-50% (v/v), then with a fluoronitric acid solution 2-20%, and finally thoroughly washed with distilled water.
Stainless Steel
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1M NaOH, sandpaper as needed. Care with HCl as this will dissolve surface. Wash with water and acetone
Gold
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In acidic aqueous electrolytes (e.g., 0.5 mol/L H2SO4), platinum forms surface oxides at about 1 V vs. SCE, which can be reductively dissolved at about 0.8 V [12]. At potentials lower than 0.4 V, a platinum electrode is covered with adsorbed hydrogen. These surface reactions cause high background currents in a wide potential range. They also change the characteristics of the electrode surface. Hence, in many cases, a platinum electrode must be re-polished after each electrochemical measurement. Both platinum and gold electrodes are activated by polishing with alumina slurry on a smooth glass plate. The sizes of alumina particles are between 1 μm and 0.05 μm. The polishing starts with the largest size and continues using successively smaller sizes. After a mirror-like finish is obtained, the electrode is cleaned by rinsing with deionized water and ultrasonication in water for 15 min. For the best results the electrode should be used immediately after polishing [1
BDD
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A new type of carbon electrode material is electrically conducting diamond doped with boron, which is grown as a thin film on a conducting substrate [33]. Boron-doped diamond electrode is very hard and can be used in the combination with ultrasonic mixing [34]. Furthermore, it is characterized by the wide working window, low and stable background current and corrosion resistance. Contaminants adsorbed on the electrode surface can be removed by the exposure to clean organic solvents for half an hour [35], or by heating the electrode to about 500◦C under high-vacuum conditions for 30 min [36]. Electrochemical activation is achieved by potential cycling between −0.5 V and 1.5 V vs. SCE in 0.5 M KNO3 at 50 mV/s [37
BDD
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Using the electrode as the anode in a ~1 M solution of sulfuric acid and running a constant potential of 1-3 V for a few minutes can help clean the electrode by oxidizing impurities on the surface. This procedure however should only be used for glassy carbon and the boron doped diamond electrodes. Do not sandpaper
Lead
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Leaded Bronze
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Tungsten
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Niobium
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Titanium
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Magnesium
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1M NaOH, sandpaper as needed. Care with HCl as this will dissolve surface. Wash with water and acetone
Zinc
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Sandpaper as needed. Care with acid & base as this will dissolve surface. Wash with water and acetone
Zinc
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Before each use, the surface of electrodes is polished with 1000 grit sandpaper and sonicated in acetone. After wiping the surface with a paper towel, the electrodes are dried and kept under high vacuum
Platinum Plated
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1M NaOH, care with acid, definitely no sandpaper
Gold Plated
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1M NaOH, 1 M HCl, no sandpaper. Wash with water and acetone
Silver Plated
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1M NaOH, 1 M HCl, no sandpaper. Wash with water and acetone
Aluminium
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Sandpaper as needed. Care with acid & base as this will dissolve surface. Wash with water and acetone
Tin
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1M NaOH, 1 M HCl, sandpaper as needed. Wash with water and acetone
Tin
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Before each use, the surface of electrodes is polished with 1000 grit sandpaper and sonicated in acetone. After wiping the surface with a paper towel, the electrodes are dried and kept under high vacuum
Metal Electrodes
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Unless they are coated, can be sanded with fine sandpaper (i.e. P1200). Electrodes with a metal coating can only be rinsed and wiped down