EP3077332A1 - Metal chalcogenide thin layer electrode, method for production thereof and use thereof - Google Patents
Metal chalcogenide thin layer electrode, method for production thereof and use thereofInfo
- Publication number
- EP3077332A1 EP3077332A1 EP14820763.2A EP14820763A EP3077332A1 EP 3077332 A1 EP3077332 A1 EP 3077332A1 EP 14820763 A EP14820763 A EP 14820763A EP 3077332 A1 EP3077332 A1 EP 3077332A1
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- Prior art keywords
- metal
- substrate
- electrode
- metal chalcogenide
- elemental
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Definitions
- the invention relates to a method for producing a metal chalcogenide thin-film electrode, to a metal chalcogenide thin-film electrode producible by the method and to its use for electrochemical water splitting.
- Transition-metal oxides represent a particularly active class of materials for (photo) electrochemical oxygen evolution in water-splitting electrode systems (Cook et al., Chem. Rev. 1 10 (2010), pp. 6474-6502; Walter et al., Chem. Rev 1 10, (2010), pp. 6446-6473).
- the preparation of suitable electrodes is usually based on the oxidation (under anodic conditions) of metal precursors, ie on the deposition of metals by way of the electrode position on an electrode (the substrate) and their oxidation in the presence of water.
- the electrochemical deposition of RuO 2 films on an FTO substrate from an aqueous RuCl 3 solution is known (Tsuji et al., Electrochim. Acta 56, (201 1), pp. 2009-2016).
- Another approach is the electrophoretic transport of previously chemically or electrochemically formed metal oxide clusters onto an electrode surface.
- a method for the electrodeposition of Ti0 2 films on a platinum cathode in Kamada et al. (Kamada et al., Electrochimica Acta 47 (2002), 3309-3313).
- a titanium sacrificial anode is used as counterelectrode to the platinum cathode acting as a substrate for Ti0 2 deposition, and the reaction is carried out in acetone containing traces of H 2 O in the presence of iodine (I 2 ).
- titanium is oxidized by oxidation with iodine with the participation of water to Ti0 2+ , dissolved from the sacrificial anode and transported due to the electric field in the direction of the cathode.
- deposition takes place at the Pt cathode as TiO (OH) 2 and release of H 2 and subsequent conversion into TiO 2 .
- this approach requires an electrically conductive cathode.
- the invention is based on the object of proposing a method for producing a metal chalcogenide thin-film electrode for electrocatalytic oxygen evolution in the context of electrochemical water splitting, which is simple to perform and ideally based on inexpensive starting materials.
- the electrodes that can be generated by the process should have good activity in terms of electrocatalytic oxygen evolution, ideally being photoactive.
- the generated metal chalcogenide layer should have a high stability.
- a metal chalcogenide thin-film electrode a corresponding electrode which can be produced by the process and its use with the features of the independent claims.
- the method according to the invention for producing a metal chalcogenide thin-film electrode comprises the steps:
- step (a) contacting a metal or metal oxide with an elemental halogen in a nonaqueous solvent to form a metal halide compound in the solution, (b) applying a negative voltage to an electrically conductive or semiconducting substrate in contact with the solution of step (a), and
- step (c) during and / or after step (b) contacting the substrate with a
- a metal halide compound in solution is thus intermediately generated from the metal or metal oxide from which the later metal chalcogenide layer is to be formed (step a), the metal or metal oxide being partially dissolved.
- the electrochemical complexing and deposition (step b) by the substrate in which the thin film is to be deposited is occupied in the metal halide-containing solution with a negative voltage, that is connected to an anode cathodic.
- the negative charge of the substrate in contrast to the known electrophoretic deposition does not lead to the formation of an electric field, which directs a particle migration, but to the fact that the substrate acts as an electron transfer agent in the electrochemical reduction reaction.
- the metal is thus deposited by reduction on the substrate in step (b) and the substrate is an electron carrier due to the negative voltage during the reduction.
- Contacting the deposited film with the elemental chalcogen in step (c) (during or after step b) eventually results in formation of the metal chalcogenide compound.
- the elemental chalcogen is reduced by taking up electrons from the negative cathode (substrate) and reacts with the metal cations of the metal halide to form the corresponding metal chalcogenide, which is deposited on the metal chalcogenide
- the process results in the formation of a highly compact and very stable metal chalcogenide layer on the substrate.
- the metal chalcogenide layer thus produced has a high electrochemical anodic oxygen evolution activity in electrochemical water splitting.
- a metal is used which is capable of forming a metal halide compound in which the metal is in the +2 or higher oxidation state, that is, can bind two or more halide anions.
- the metal is a transition metal.
- it is selected from the group consisting of iron (Fe), cobalt (Co) and nickel (Ni) and mixtures and alloys comprising or consisting of these.
- the alloy or mixture may also contain metals for which halide formation at room temperature is not documented, such as chromium (Cr) or manganese (Mn). These metals are also co-deposited by means of the method according to the invention as a metal chalcogenide. As a result, Mischmetallchalkogenid Anlagenen can be deposited, for example, mixed oxides of various metals, whereby the catalytic properties of the electrode can be modified.
- a particular advantage of the method is the fact that metallic solids can be used as the starting metal, in particular industrial metals or scrap metals.
- inexpensive raw materials, if necessary after chemical or mechanical purification of the metal, can be used as the starting material.
- the chalcogen is preferably elemental oxygen, elemental sulfur or elemental selenium, and thus metal oxide, metal sulfide or metalloid can be used in the process according to the invention Metallselenid Anlagenen be generated.
- metal oxide, metal sulfide or metalloid can be used in the process according to the invention Metallselenid harshen be generated.
- nickel oxide Ni x O y, cobalt oxide Co x O y, and iron oxides Fe x O y are, in particular.
- Various metal sulfides have appropriate photoactive substrates particularly good electrocatalytic properties, so that they photovoltaic in the Iron sulphides, such as iron disulphide FeS 2 (pyrite), or various CuZnSnS compounds, such as kesterite Cu 2 (Zn, Fe) SnS 4 , can be used here, in contrast to the state of the art, the hydrogen sulphide for the production use appropriate sulfides offer t the inventive method a less toxic preparation route.
- Iron sulphides such as iron disulphide FeS 2 (pyrite)
- CuZnSnS compounds such as kesterite Cu 2 (Zn, Fe) SnS 4
- the substrate itself does not chemically participate in the various reactions of the process, in particular it does not serve as a sacrificial anode as in the prior art as a supplier of the metal or other reaction components.
- the substrate is electrically conductive or semiconducting and can function as an electron dispenser.
- the substrate used is fluorine doped tin oxide (FTO for fluorine doped tin oxide).
- FTO fluorine doped tin oxide
- an n-type semiconductor material is used as a substrate, which generates holes under the action of light, ie is photoactive. n-type semiconductor materials are particularly suitable as photoanode for the evolution of oxygen in the electrolysis of water.
- the holes generated on exposure to light are transported from the substrate into the metal chalcogenide layer to reach from there the solid / electrolyte interface and to catalyze the oxidation of O 2 to "0 second particular, silicon is used as n-type semiconductor material for the substrate n-doped in Question.
- oxide-free, conductive substrates are particularly preferred in order to avoid a reductive dissolution of the substrate and a concomitant formation of water.
- Silicon (etched) therefore represents a preferred choice both for the cathode on which the film is to be deposited and for the anode which acts as an electron acceptor to complete the closed circuit.
- an elemental halogen is used for the metal halide production in step (a) of the process.
- Suitable elemental halogens include in particular iodine l 2 , which can be used as a solid, or bromine Br 2 , which can be bubbled as a gas into the solvent.
- iodine l 2 which can be used as a solid
- bromine Br 2 which can be bubbled as a gas into the solvent.
- crystalline iodine is used.
- an organic solvent is preferably used as the nonaqueous solvent.
- the organic solvent particularly preferably has a carbonyl group (CO) or cyanide group (CN). It is believed that such solvents, the metal cation of the halide compound with the lone pairs of carbonyl or electron
- the process is carried out with the greatest possible exclusion of water, since this inhibits the formation of metal chalcogenides.
- the amount of water in the non-aqueous solvent used is at most 0.2% by weight, more preferably at most 0.1% by weight.
- contained residues of water are expelled from the solvent prior to deposition and / or prior to the formation of the haloiodide.
- This is preferably done by a pre-electrolysis, wherein, for example, two electrodes are introduced into the already halogen-containing solvent. Applying a voltage to the two electrodes (in particular in the range of 5 to 20 V, preferably 7 to 12 V, particularly preferably 10 V), the residual water is decomposed, thereby takes place at one of the electrodes (the anode) oxidation, while At the other electrode (the cathode) molecular hydrogen is produced, which leaves the electrolyte as gas.
- the contacting of the electrochemically modified substrate with the elemental chalcogen for metal chalcogenide formation can take place in various ways.
- the chalcogen may already be present in the solvent or be added to it actively.
- the solvent may contain traces of dissolved oxygen or oxygen may be introduced into the solution by stirring.
- elemental sulfur or elemental selenium may be added to the solution.
- the chalcogen may be in the atmosphere, such as oxygen, which is present in the atmosphere anyway, or actively added to the atmosphere.
- the substrate comes into contact with the atmosphere after the step (b) and thus with the chalcogen, so that the metal chalcogen is formed on the surface of the substrate.
- This procedure is particularly suitable if a metal oxide layer is to be produced and thus the atmospheric oxygen can be used.
- a chemical or electrochemical aftertreatment of the deposited layer takes place for stabilization, for example to increase the oxidation state of the metal cation. This can be done, for example, by electrochemical processing in aqueous hydroxide-containing electrolytes.
- a thermal aftertreatment takes place after formation of the metal chalcogenide layer on the substrate or after the above-mentioned (electro) chemical aftertreatment.
- the thermal aftertreatment also referred to as "armealing" leads to an increase in the crystallinity and / or the photoactivity of the deposited layer
- the specific conditions are based primarily on the chalcogen and the desired crystallinity thereof.
- the electrode comprises an electrically conductive or semiconductive substrate and a thin layer of a metal chalcogenide compound deposited thereon.
- the electrode produced by the method according to the invention is characterized in particular by the fact that carbon and / or compounds of the carbon can be detected in the metal chalcogenide thin film produced.
- the proportion of carbon and / or the carbonaceous compound (s) in the metal chalcogenide layer produced is up to 30 atomic percent.
- the carbon leads to increased strength and density of the thin film. In this way, both the charge transport from the substrate to the metal chalcogenide can be optimized and the stability of the substrate can be increased.
- the metal chalcogenide thin-film electrode according to the invention is therefore characterized by improved stability.
- the thin-film electrode according to the invention has layer thicknesses of the metal chalcogenide layer in the range of 50 to 1000 nm, in particular in the range of 100 to 500 nm.
- the deposited layer has a nanostructured surface morphology with average sizes of the electron microscopic recognizable
- Structural elements in the range ⁇ 500 nm.
- a further aspect of the present invention relates to the use of the metal chalcogenide thin-film electrode according to the invention as electrode for the evolution of oxygen for electrochemical water splitting under an applied external potential or under illumination.
- the electrode is preferably used as an anode in the water used electrolysis.
- the substrate is a photoactive semiconductor, such as n-doped silicon
- the electrode for the photoelectrochemical water splitting so as a photoanode can be used.
- the heterostructure of the photoactive semiconductor substrate and metal chalcogenide layer deposited thereon allows holes to be transported from the semiconductor into the metal chalcogenide layer under light supply in order to reach the solid / electrolyte interface therefrom.
- FIG. 2 results of the chemical analysis of a Ni x O y deposited on Si (1 1 1)
- COxOy layer a) XPS before and after anodic use, b) EDX;
- Fe x O y layer a) XPS before and after anodic use, b) EDX;
- Cu (0) layer a) XPS before and after anodic use, b) EDX;
- FIG. 6 shows investigations of a Ni x O y / Si (100) thin-film electrode; a) electricity
- FIG. 7 shows SEM photographs of a Ni x O y / Si (100) thin-film electrode; prepared a) in anhydrous solution according to the invention and b) in a solvent mixture with 25 vol .-% H 2 0;
- FIG. 8 Analysis of a Fe / Si / Ni / Cr / Co / Mn oxide layer deposited on FTO; a)
- FIG. 9 Electrochemical investigation of a tempered Fe / Si / Ni / Cr / Co / Mn
- Oxide / FTO electrode for electrochemical oxygen evolution left) dark reaction at an external voltage of 0-1, 4 V; right) intermittent illumination at a constant applied potential of 0.65 V);
- a metal is cleaned of any surface contamination and / or oxide or hydroxide layers on the surface.
- the cleaning step may be done mechanically, for example by using abrasive materials such as abrasive paper or the like.
- the cleaning can be carried out by a chemical treatment in which, for example, oxide-dissolving reactions are carried out.
- the metal used is preferably a metallic solid, which may be derived in particular from industrial or scrap metals. For use come solids of any geometry, for example in the form of sheets, powders or other.
- metals comprising or consisting of iron, cobalt and / or nickel are preferably used.
- step 2 metal halide formation takes place, here metal iodide formation.
- the optionally purified in step 1 metal is placed in a non-aqueous solvent having a water content of at most 0.2 wt .-%.
- the solvent used is acetone or Acetonitrile used.
- the solvent is a halogen, here crystalline iodine, in a mass ratio of solvent: iodine of at least 1: 1 or higher iodine added.
- the mixture is exposed to ultrasound to better
- reaction is carried out for a period of at least 5 minutes, preferably at room temperature. It is assumed that in this case the iodine, with partial release of metal from the solid to the corresponding metal iodide in the solution, for example, according to the following equation:
- an electrochemical processing takes place.
- two electrically conductive or semiconductive electrodes are brought into contact with the solution containing metal iodide from step 2, after the remaining solid metal body has been removed therefrom.
- One of these electrodes serves as a substrate for the thin-film electrode to be produced, while the other represents the counter-electrode for the electrochemical processing.
- the substrate electrode consists for example of a metal or a metal alloy, FTO, n-doped silicon or carbon.
- the counterelectrode can basically consist of the same or a different material than the substrate electrode.
- a voltage is applied to the electrodes, wherein the substrate electrode is covered with a negative voltage, that is, switched as a cathode.
- the applied voltage is ⁇ -2 volts, more preferably in the range of -5 to -10 volts, the sign referring to the substrate electrode on which the metal oxide film is to be deposited.
- the electrochemical deposition is preferably carried out at room temperature.
- the reaction time depends on the thickness of the metal oxide layer to be deposited and depends on the applied voltage.
- the metal iodide in the solution is coordinated by the organic solvent, in particular its carbonyl or cyanide groups, to form organometallic complexes.
- organometallic complexes show a high reactivity towards free oxygen, which is already present in traces in the solvent or in the ambient air.
- the oxygen is reduced at the cathodic (ie negatively) polarized substrate electrode to accept 0 2 " anions, which react with the metal halide to form the corresponding metal oxide, resulting in a direct deposition of the metal oxide on the substrate (see the following reaction equations). It is possible that a reaction with oxygen and the associated deposition of metal oxide only occurs on later contact with the atmospheric oxygen after the still wet, negatively polarized electrode has been removed from the solution. 1/2 0 2 + e "-" O 2 "
- the removal of the substrate electrode takes place with the layer deposited thereon from the solvent / iodide bath.
- This is preferably carried out under dry nitrogen, in order to allow the evaporation of any formed hydrogen iodide under exclusion of atmospheric moisture.
- a chemical or electrochemical aftertreatment of the deposited layers takes place with the aim of increasing the stability of the metal oxide layer.
- the aim of the aftertreatment is to increase the oxidation state of the metal, that is to further oxidize it.
- the electrode may for example be introduced into an aqueous hydroxide-containing electrolyte solution and processed electrochemically.
- a thermal aftertreatment of the electrode takes place to increase the crystallinity of the deposited metal chalcogenide layer.
- the electrode is tempered at temperatures in the range of 150 to 800 ° C for a period of 1 minute to 10 hours.
- the metal chalcogenide thin-film electrodes obtained by the method according to the invention are distinguished by particularly dense and stable metal chalcogenide layers, which are also carbonaceous.
- XPS X-ray photoelectron spectroscopy
- EDX Energy dispersive X-ray analysis
- the electrodes prepared in the examples were tested in a standard electrochemical cell for their suitability for oxygen production in 0.1 mol / l NaOH (pH 13).
- the samples were measured either in a three-electrode configuration with a Pt counterelectrode and an Ag / AgCl reference electrode or in a two-electrode configuration with short-circuiting of the Pt counter and Ag / AgCl reference electrode.
- the potential was each controlled with a potentiostat (VSP, BioLogic, France).
- Example 1 Preparation of a NixO y / FTO electrode
- FTO films (Solaronix, Switzerland, sheet resistance 7 cm 2 , 3 ⁇ 1.5 cm) were pre-cleaned with acetone.
- One FTO sample was used as the cathode (substrate) and a second as the counter electrode (Anode) placed at a distance of 5-10 mm from each other in the acetone solution.
- a potential of 10 V was applied between the substrate and counter electrodes for 5 minutes.
- the substrate electrode was removed from the solution and dried.
- Example 2 The preparation was carried out as in Example 1 except that 2 cm 2 of a highly pure co-metal foil (Goodfellow Corp. USA, purity> 99.95% by weight) was used as the metallic solid.
- a highly pure co-metal foil Goodfellow Corp. USA, purity> 99.95% by weight
- Example 2 The preparation was carried out as in Example 1 except that 2 cm 2 of a high-purity Fe metal foil (Goodfellow Corp. USA, purity> 99.95% by weight) was used as the metallic solid.
- a high-purity Fe metal foil Goodfellow Corp. USA, purity> 99.95% by weight
- Example 2 The preparation was carried out as in Example 1, except that 2 cm 2 of a high-purity copper metal foil (Goodfellow Corp. USA, purity> 99.95% by weight) was used as the metallic solid.
- a high-purity copper metal foil Goodfellow Corp. USA, purity> 99.95% by weight
- the preparation was carried out as in Examples 1-4, except that 2 cm 2 of an n-type Si (100) wafer (ABC Company, Germany, doping N D ⁇ 6 ⁇ 10 15 ) was used as the substrate electrode (cathode).
- the counterelectrode used was 1 -3 FTO as in Examples 1.
- the preparation was carried out as in Examples 1 to 4, except that in each case 2 cm 2 of an n-type Si (11 1) wafer (ABC Company, Germany, doping N D ⁇ 6 ⁇ 10 15 ) were used as the substrate electrode (cathode) has been.
- the Si (1 1 1) wafer was prepurified with ethanol and water and then first with NH 4 F (100 s) and finally with hydrofluoric acid (50%, 10 min) chemically etched and then dried with N 2 .
- the counterelectrode used was 1 -3 FTO as in Examples 1.
- Example 13 Preparation of a mixed oxide / FTO electrode
- Example 2 The preparation was carried out as in Example 1, except that 2 cm 2 of a steel alloy of the metals Fe / Si / Ni / Cr / Co / Mn was used as the metallic solid. Further, unlike Example 1, the sample was annealed after drying at 300 ° C for 10 minutes.
- Example 14 Preparation of a CoO / ZnO / CoZnO / Si Electrode
- Example 2 The preparation was carried out as in Example 1, except that chemically synthesized CoZnO nanoparticles were used as metal source and Si (100) n-doped as substrate.
- Comparative Example 1 Preparation of a NixO y / Si (100) electrode in the presence of water The preparation was carried out as described in Example 5 using a Ni metal foil and crystalline iodine, except that instead of the acetone, a solvent mixture of acetone and 25% by volume of H 2 O was used.
- Figure 1 a) to d) shows the current densities as a function of the applied potential of the thin-film electrodes obtained in Examples 1 to 4 during the evolution of oxygen in a 0.1 M NaOH solution, which in the dark between 0 and 2 volts against Ag / AgCl measured in a three-electrode configuration.
- the behavior of pure FTO is shown as a dashed curve in the respective graph.
- the nickel, cobalt and iron oxides show a clear activity with respect to the evolution of oxygen (FIGS. 1 a) to c)).
- the overpotentials determined from the curves range between 340 and 420 mV, with the cobalt and nickel oxide electrodes having the highest activity and the iron oxide electrode having the lowest activity.
- the copper electrode on the other hand, becomes active only at high external potentials (FIG. 1 d)). Oxygen evolution was confirmed by electrochemical differential mass spectroscopy (DEMS).
- DEMS electrochemical differential mass spectroscopy
- Information depth of the method of about 2 to 3 nm.
- the example of the Ni x O y / Si (100) thin-film electrode produced according to Example 5 shows the photoelectrocatalytic behavior in FIG. 6 a).
- the solid curve shows the current-voltage behavior for continuous lighting and the broken curve shows the current-voltage behavior for periodic lighting.
- the measurements were each in a three-electrode configuration. It can be seen that the inventive
- Ni x O y / Si (100) thin film electrode has good photoactivity. In the dark, however, it is inactive even at an applied voltage of 2 volts, resulting from the drop in the
- FIGS. 6 b), c) and d) show SEM and TEM images of the Ni x O y / Si (100) thin-film electrode from Example 5, respectively. It can be seen that the nickel oxide layer has a roughness in the nanometer range and a layer thickness of about 100 to 150 nm.
- FIG. 7 shows the product according to Comparative Example 1 in which the solution contained 25% by volume of water for the comparison of the Ni x O y / Si (100) thin-film electrode produced in accordance with the anhydrous method according to the invention from Example 5 (FIG. 7b) ). It can be seen that the presence of water largely prevents layer formation. Only single Ni, O and C containing islands are observable (confirmed by EDX analysis).
- FIG. 8 shows the results of the analysis of the metal oxide layer according to Example 13 (before and after the thermal aftertreatment) using as a starting material for the metal a steel alloy containing, in addition to the main constituents iron and chromium, additions of nickel, cobalt, manganese and silicon ,
- the energy range is from 0 to 5 keV at the top and from 5 to 10 keV at the bottom.
- the EDX analysis shows that all elements contained in the steel are deposited as an oxide form on the FTO substrate.
- FIG. 9 shows the electrochemical characterization of the same sample as in FIG. 8 as an anode for the evolution of oxygen.
- the current-voltage behavior is shown on the left with an applied external voltage between 0 and 1, 4 V without exposure to light.
- the electrode exhibits an oxygen evolution overvoltage of about 300 mV, confirming its electrocatalytic activity.
- the measurement at an applied constant potential of 0.65 volts with intermittent illumination is shown on the right side of FIG. This measurement confirms an existing photoactivity of the electrode.
- Example 14 The thin film formed by Example 14 using CoZnO nanoparticles as the starting material for the thin film to be deposited was also analyzed (results not shown). The analysis showed two distinct, distinct layers. Immediately on the n-Si (100) substrate, a thin film of the oxides CoO and ZnO could be identified, which also contained portions of carbon. On this amorphous CoO / ZnO / C layer, a second layer consisting of deposited CoZnO particles corresponding to the starting material was detectable. It is believed that the two thin films of this heterostructure are generated on different reaction paths. In this case, the metal oxide particles are partially dissolved in contact with the iodine-containing solution, wherein the metallic components go as metal iodides in solution. The subsequent electrochemical treatment produces (in a rapid reaction phase) the amorphous carbonaceous barrier layer on the substrate. In contrast, the unresolved remaining oxide particles are deposited (in a slower reaction phase) on this boundary layer by electrophoretic transport.
- Example 14 shows that chemically synthesized powder-produced metal oxides can be deposited on substrate by the method so that an (amorphous) protective layer is formed on the substrate. This allows the corrosion-free operation of the resulting substrate / oxide heterostructure. This is particularly advantageous in light-assisted water splitting using sensitive semiconductor substrates.
- Example 3 As a by-product of the iron oxide film formation in Example 3 under o.a. cathodic conditions left a dispersion of black particles in solution. These particles showed paramagnetic properties, i. they were attracted to the magnetic field of a permanent magnet without being permanently magnetized, as in ferromagnetism. For the particles in solution, this means that they redisperse as the external magnetic field is removed.
- the method can thus also be used to produce nanoparticles of iron or other metallic materials.
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DE102013224900.4A DE102013224900A1 (en) | 2013-12-04 | 2013-12-04 | Metal chalcogenide thin-film electrode, process for its preparation and use |
PCT/EP2014/076591 WO2015082626A1 (en) | 2013-12-04 | 2014-12-04 | Metal chalcogenide thin layer electrode, method for production thereof and use thereof |
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DE102022102484A1 (en) | 2022-02-02 | 2023-08-03 | ENINNO GmbH | Process for producing a graphite-containing metal oxide electrode, graphite-containing metal oxide electrode, use of the graphite-containing metal oxide electrode and electrolytic cell |
WO2023147820A2 (en) | 2022-02-02 | 2023-08-10 | ENINNO GmbH | Process for producing a graphite-containing metal oxide electrode, graphite-containing metal oxide electrode, use of the graphite-containing metal oxide electrode and electrolysis cell |
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DE1195285B (en) | 1963-05-07 | 1965-06-24 | Basf Ag | Process for the production of anhydrous solutions of iron (II) chloride |
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KR101840819B1 (en) * | 2012-01-17 | 2018-03-21 | 삼성전자 주식회사 | Water splitting oxygen evolving catalyst, method of prepararing the catalyst, electrode having the catalyst and water splitting oxygen evolving device having the electrode |
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US20050089681A1 (en) * | 2003-10-23 | 2005-04-28 | Transfert Plus, S.E.C. | Electrode having a CoS layer thereon, process or preparation and uses thereof |
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US20160305035A1 (en) | 2016-10-20 |
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