EP1235658B1 - Elektrode mit katalytischem pulver hergestellt - Google Patents

Elektrode mit katalytischem pulver hergestellt Download PDF

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EP1235658B1
EP1235658B1 EP00973563A EP00973563A EP1235658B1 EP 1235658 B1 EP1235658 B1 EP 1235658B1 EP 00973563 A EP00973563 A EP 00973563A EP 00973563 A EP00973563 A EP 00973563A EP 1235658 B1 EP1235658 B1 EP 1235658B1
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oxide
metal
electrode
mixture
platinum group
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French (fr)
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EP1235658A1 (de
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Yu-Min Tsou
Edmond L. Manor
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Dow Global Technologies LLC
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Dow Global Technologies LLC
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/14—Treatment of metallic powder
    • B22F1/148—Agglomerating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/17—Metallic particles coated with metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/11—Making porous workpieces or articles
    • B22F3/1103—Making porous workpieces or articles with particular physical characteristics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/002—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature
    • B22F7/004—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature comprising at least one non-porous part
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
    • C25B11/095—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one of the compounds being organic

Definitions

  • the present invention is directed to electrocatalytic electrodes. More particularly, the present invention is directed to cathodes useful in electrolysis cells such as a chlor-alkali cell.
  • Chlorine and caustic soda are typically produced by electrolysis of aqueous solutions of sodium chloride, a process commonly referred to as a chlor-alkali process.
  • the most widely used chlor-alkali processes employ either diaphragm or membrane type cells.
  • a diaphragm cell an alkali metal halide brine solution is fed into an anolyte compartment where halide ions are oxidized to produce halogen gas.
  • Alkali metal ions migrate into a catholyte compartment through a hydraulically-permeable microporous diaphragm disposed between the anolyte compartment and the catholyte compartment.
  • Hydrogen gas and aqueous alkali metal hydroxide solutions are produced at the cathode. Due to the hydraulically-permeable diaphragm, brine may flow into the catholyte compartment and mix with the alkali metal hydroxide solution.
  • a membrane cell functions similarly to a diaphragm cell, except that the diaphragm is replaced by an hydraulically-impermeable, cation-selective membrane which selectively permits passage of hydrated alkali metal ions to the catholyte compartment.
  • a membrane cell produces aqueous alkali metal hydroxide solution essentially uncontaminated with brine.
  • Electrodes are usually prepared by providing an electrocatalytic coating on a conducting substrate.
  • Useful catalytic coatings include, for example, the platinum group metals, such as ruthenium, rhodium, osmium, iridium, palladium and platinum.
  • Useful conducting substrates include, for example, nickel, iron, and steel.
  • the extra energy that is, overvoltage, is provided to overcome, among various other parameters, the electrolyte resistance and the overpotential related to the chlorine gas evolution at the anode and the overpotential related to hydrogen gas evolution and hydroxide ion formation at the cathode.
  • overvoltage is used herein to refer to the excess voltage required for an electrolytic cell
  • overpotential is used herein to refer to the excess voltage required for an individual electrode within the electrolytic cell.
  • the overpotential for an electrode is a function of its chemical characteristics and current density.
  • Current density is defined as the current applied per unit of actual surface area on an electrode. Techniques which increase the actual surface area of an electrode, such as acid etching or sandblasting the surface of the electrode, result in a corresponding decrease of the current density for a given amount of applied current and also decrease overpotential requirements.
  • Efforts to reduce overpotential requirements include, for example, those described in U.S. Patent No. 4,66,8370 and U.S. Patent No. 4,798,662, which disclose electrodes useful as cathodes in an electrolytic cell. These are prepared by coating an electrically conducting substrate such as nickel with a catalytic coating comprising one or more platinum group metals from a solution comprising a platinum group metal salt. Both of these Patents disclose electrodes designed to reduce the operating voltage of an electrolytic cell by reducing the overpotential requirements of the electrodes.
  • U.S. Patent. No. 5,035,789, U.S. Patent. No. 5,227,030, and U.S. Patent. No. 5,066,380 disclose cathode coatings which exhibit low hydrogen overpotentials.
  • EP-A-174 413 discloses an electrode wherein a conductive substrate is coated with a matrix embedding a catalytic powder.
  • a desirable characteristic of a cathode coating is high porosity with large internal surface areas. Large internal surface areas result in lower effective current density and, accordingly, lower overpotentials. Another result of a porous electrode is higher resistance to impurity poisoning. Rough outer surfaces of a typical porous electrode render difficult the electrodeposition of metal ions as impurities and the large internal electroactive surface areas are not easily accessible to the impurity ions present in the electrolyte because of long Pathways for diffusion. Such characteristic is described in U.S. Patent No. 5,645,930
  • Metal plating is often used to form a reinforcement layer on the electrode.
  • U.S. Patent. No. 4,061,802 and U.S. Patent. No. 4,764,401 describe using palladium chloride to activate plastic or metal substrates prior to nickel plating by electroless deposition.
  • the present invention is advantageous because a porous coating mixture is first applied to a powder rather than being applied directly to a metal substrate, thereby creating a larger internal surface area relative to the prior art. Large internal surface areas result in lower effective current density and, accordingly, lower overpotentials. Therefore, because the surface area is enhanced using the present invention, the overpotential required for electrodes made according to the present invention is also reduced relative to electrodes of the prior art cited above.
  • FIG 1 illustrates a magnified view of a catalytic powder particle 10 of the present invention.
  • the catalytic powder particle 10 comprises a support metal particle 11 surrounded by a porous coating comprising a continuous phase 12 with a particulate material 13 dispersed therethrough.
  • the support metal particle 11 is nickel, cobalt, iron, steel, stainless steel or copper.
  • the support metal particles before the porous coating is applied thereto, have an average diameter of at least 0.2 microns, more preferably at least about 1 micron, even more preferably at least 2 microns, and yet even more preferably at least 3 microns.
  • the metal particles have an average diameter of up to 20.0 microns, more preferably up to 10.0 microns and even more preferably up to 6.0 microns.
  • the support metal particle 11 is coated with either an electrocatalytic metal or with a porous coating comprising an electrocatalytic metal continuous phase 12 in admixture with a particulate material 13. Because the coating on the support metal particle is porous and has a dendritic nature, the resulting catalytic powder particle 10 has a large internal surface area with pores 14 throughout.
  • the electrocatalytic metal continuous phase 12 is ruthenium, iridium, osmium, platinum, palladium, rhodium, rhenium, or an alloy of any one or more of these.
  • the continuous phase 12 has a particulate material 13 dispersed therethrough.
  • particulate material 13 comprises the metal oxides of ruthenium, iridium, osmium, platinum, palladium, rhodium, rhenium, technetium, molybdenum, chromium, niobium, tungsten, tantalum, manganese or lead, with the oxides of ruthenium, iridium osmium, platinum, palladium and rhodium being more preferred.
  • the first step in making the catalytic powder is to prepare a deposition solution comprising at least a palladium promoter and an organic or inorganic acid.
  • the palladium metal ion concentration suitably can be 0.001 percent to 5 percent; preferably from 0.005 percent to 2 percent and, most preferably, from 0.01 percent to 0.05 percent, by weight of the coating solution.
  • a weight percent of less than 0.001 percent is generally insufficient to promote deposition of the electrocatalytic metal.
  • a weight percentage greater than percent 5 results in the deposition of an excessive amount of electrocatalytic metal primary phase of the coating on the substrate.
  • the pH of the deposition solution may be adjusted by inclusion of organic acids or inorganic acids therein.
  • suitable inorganic acids are hydrobromic acid, hydrochloric acid, sulfuric acid, perchloric acid, and phosphoric acid.
  • organic acids are acetic acid, oxalic acid, and formic acid. Hydrobromic acid and hydrochloric acid are preferred.
  • the pH range for the deposition solution is, generally, 0 pH to 2.8 pH. Precipitation of hydrous platinum group metal oxide results at higher pHs. A low pH can encourage competing side reactions such as the dissolution of the substrate.
  • At least one electrocatalytic metal compound soluble in water or an aqueous acid is added to the deposition solution.
  • a suitable electrocatalytic metal is, generally, one that is more noble than the metal employed for the metal particles, that is, the electrocatalytic metal precursor compound has a Gibbs free energy greater than the Gibbs free energy of the metal compound from dissolution of the metal particles, such that non-electrolytic reductive deposition occurs on the metal particles.
  • such electrocatalytic metal is a platinum group metal. More details non-electrolytic reductive deposition can be found in U.S. Patent 5,645,930.
  • the electrocatalytic metal precursor compound can be present in the deposition solution in amounts sufficient to deposit an effective amount of the metal on the metal particles.
  • concentration of electrocatalytic metal ions in the deposition solution in terms of weight percent, is, generally, from 0.01 percent to 5 percent, preferably, from 0.1 percent to 3 percent and, most preferably, from 0.2 percent to 1 percent by weight of solution.
  • An electrocatalytic metal ion concentration of greater than 5 percent is not desired, because an unnecessarily large amount of platinum group metal is used to prepare the coating solution.
  • An electrocatalytic metal ion concentration of less than 0.01 percent is not desired, because undesirably long contact times are required.
  • the optional particulate material is suspended in the deposition solution at a concentration of from 0.002 to 2 percent, preferably, 0.005 to 0.5 percent, and most preferably, 0.01 to 0.2 percent.
  • the deposition solution comprising the palladium promoter, the acid, and the optional particulate material is prepared, it is held at an elevated temperature and stirred at a high speed, while a powder comprising support metal particles is added thereto. After a period of time, the electrocatalytic metal precursor compound is added, and the electrocatalytic metal is formed and deposited on the support metal particles with simultaneous partial dissolution of the support metal particles.
  • the rate at which the electrocatalytic metal deposits to form the porous coating on the metal particles is a function of the solution temperature.
  • the temperature generally, ranges from 25°C to 90°C. Low temperatures are not practical, since uneconomically long times are required to deposit an effective amount of electrocatalytic metal on the metal particles. Temperatures higher than 90°C are operable, but generally result in an excessive amount of metal deposition and side reactions. A temperature ranging from between 40°C to 80°C is preferred, with 45°C to 65°C being most preferred.
  • the time allowed for contact between the deposition solution and the metal particles can vary from one minute to 60 minutes. However, it should be understood that the contact time required will vary with deposition solution temperature, electrocatalytic metal concentrations, and palladium ion concentration. Contact times of from 5 minutes to 60 minutes are preferred, with from 10 minutes to 40 minutes being most preferred. Generally, if shorter contact times are desired, the method described herein may be repeated a plurality of times until an effective amount of the platinum group electrocatalytic metals deposit on the surface of the metal particles.
  • the catalytic powder 10 is advantageously used to form electrodes for electrolysis cells.
  • Figure 2 illustrates a magnified view of a portion of an electrode 20 of the present invention.
  • the electrode 20 comprises a conductive metal substrate 21 and a first layer, the first layer comprising a matrix 22 with the above described catalytic powder 10 dispersed therethrough.
  • the porous dendritic nature of the catalytic powder creates a porous surface on the electrode, which in turn reduces the overpotential required for efficient operation of the electrode and electrolytic cells.
  • the conductive metal substrate 21 is nickel, iron, steel, stainless steel, cobalt, copper or silver.
  • the shape of the substrate is not critical and can be, for example, a flat sheet, a curved surface, a punched plate, a woven wire screen, or a mesh sheet.
  • the matrix 22 of the first layer comprises either a platinum group metal oxide or a mixture of a platinum group metal oxide and a valve metal oxide.
  • Platinum group metal oxides include oxides of ruthenium, iridium, rhodium, osmium, platinum, palladium or a mixture of any one or more of these.
  • Valve metal oxides are oxides of titanium, zirconium, tantalum, tungsten, niobium, bismuth, or a mixture of any one or more of these.
  • the above described catalytic powder is mixed with a dispensing medium to form a mixture which is applied to the conductive metal substrate to form a covered substrate.
  • the covered substrate is then baked in the presence of oxygen.
  • the dispensing medium forms the matrix of the electrode and comprises either a platinum group metal oxide precursor or a mixture of a platinum group metal oxide precursor and a valve metal oxide precursor.
  • Platinum group metal oxide precursors are those materials that form platinum group metal oxides upon baking in the presence of oxygen.
  • Preferred platinum group metal oxide precursors include platinum group metal halides, sulfates, nitrates, nitrites, and phosphates. More preferred are platinum group metal halides, nitrates and phosphates, with platinum group metal chlorides being the most preferred.
  • Valve metal oxide precursors arc those materials that form valve metal oxides upon baking in the presence of oxygen.
  • the valve metal oxide precursor is titanium alkoxide, tantalum alkoxide, zirconium acetylacetonate, or niobium alkoxide.
  • the dispensing medium further comprises a solvent.
  • Suitable solvents include methanol, ethanol, 1-propanol, 2-propanol, butanol, or a mixture of any of these.
  • the dispensing medium further includes a compound soluble in alkaline solutions.
  • soluble compounds include aluminum chloride and zinc chloride.
  • alkaline soluble compounds are useful in generating pores in the coating after they are dissolved in an alkaline solution.
  • Any appropriate method may be used for dispersing the catalytic powder in the dispensing medium. Examples include mechanical stirring, sonicating, or combinations thereof.
  • the application of the catalytic powder/dispensing medium mixture can be accomplished using any suitable method.
  • An example is spraying through a nozzle.
  • the spraying forms a platinum group metal loading in the resulting electrode of, generally, 50 ug/cm 2 to 2000 ug/cm 2 calculated as the metal in the "atomic" form.
  • the amount of metal in the electrode is measured by x-ray fluorescence.
  • a preferred loading for both the elemental metal and combined oxide is from 400 ug/cm 2 to 1500 ug/cm 2 with a most preferred loading of from 500 ug/cm 2 to 1000 ug/cm 2 . Loading less than 50 ug/cm 2 are generally insufficient to provide a satisfactory reduction of cell overvoltage.
  • Loadings greater than 2000 ug/cm 2 do not significantly reduce the applied overvoltage when compared to lesser loadings within the preferred range. It should be understood that the effective amount of deposition specified above refers only to loading of the platinum group electrocatalytic metal and metal oxides in the electrode and does not include the amount of the palladium metal promoter which can be used to provide increased loading or any optional secondary electrocatalytic metal or the metal particles.
  • the substrate is protected before the mixture is applied thereto, by, for example, electroless nickel plating.
  • electroless nickel plating Such a process is described in U.S. Patent No. 4,061,802.
  • a baking step is used to convert the platinum group metal oxide precursor and valve metal oxide precursor to an oxide form.
  • the coated substrate is baked in the presence of oxygen at a temperature of preferably at least 350°C more preferably at least 420°C and even more preferably at least 450°C.
  • the coated substrate is baked at a temperature of not more than 550°C more preferably not more than 500°C even more preferably not more than 480°C
  • the baking step occurs for anywhere from 30 to 90 minutes. It is important that the coated substrate be baked in the presence of oxygen, be it air or some other oxygen-containing substance, so that the platinum group metal oxide precursor and the valve metal oxide precursor convert to platinum group metal oxide and valve metal oxide.
  • the result is a two-phase first layer of the electrode, one phase being the matrix, and the second phase being the catalytic powder particles dispersed through the matrix.
  • the electrode of the present invention further comprises a reinforcement layer 23.
  • a reinforcement layer 23 preferably comprises a transition metal or alloy thereof. More preferably, the reinforcement layer is nickel, cobalt, copper, or alloys thereof with boron, phosphorous or sulfur.
  • a second electroless plating step which consists of plating the coated substrate with a transition metal or a transition metal alloy.
  • a reinforcement layer helps hold the catalyst powder and matrix together and also helps ensure that the first layer adheres to the substrate. More details forming the reinforcement layer can be found in U.S. Patent No. 5,645,930.
  • a porous coating solution was prepared, with PdCl 2 as palladium promoter and 0.5 N HCl as acid. The solution was heated to a reaction temperature and continuously stirred. RuCl 3 xH 2 O was added as the electrocatalytic platinum group metal compound. The resulting solution was held at the reaction temperature and stirred using a COWLES high-speed disperser, while 3-micron nickel powder (Aldrich) was added. After stirring the mixture at the elevated temperature for a desired contact time, the resulting Ru-coated nickel powder was collected on a filter paper, dried for several hours at 90 °C and weighed. The amount of Ru in the powder was determined using X-ray fluorescence. Table I lists the variables and the results.
  • Example 1 2 3 0.5N HCl solution (grams) 500 1420 1577 PdCl 2 (milligrams) 20.9 59.3 6.32 Reaction temp. (°C) 64 61 61.7 RuCl 3 added (grams) 2.095 5.95 2.681 Nickel powder (grams) 35.2 100 100.4 Reaction time (minutes) 15 5 5 Total weight after drying (grams) 28.13 83.7 85.22 Percent Ru in powder 3.1 3.0 3.14
  • a porous coating solution was prepared, with PdCl 2 as palladium promoter and 0.5 N HCl as acid. The solution was heated to a reaction temperature and continuously stirred. RuO 2 was added as the platinum group metal oxide. The resulting solution was held at the reaction temperature and stirred using a COWLES high-speed disperser operated at 3000 rpm, while 3-micron nickel powder (Aldrich) was added. RuCl 3 xH 2 O was then added as the electrocatalytic platinum group metal compound. After stirring the mixture at the elevated temperature for a desired contact time, the resulting Ru-coated nickel powder was dried and weighed. The amount of Ru in the powder was determined using X-ray fluorescence. Table II lists the variables and the results.
  • Example 4 5 6 0.5N HCl solution (grams) 1405 1402 1413 PdCl 2 (milligrams) 60 60 60 Reaction temp. (°C) 51 52.8 50.6 RuO 2 (grams) 0.714 0.720 0.714 Nickel powder (grams) 38.84 38.63 38.14 RuCl 3 (grams) 8.74 8.75 8.57 Reaction time (minutes) 50 50 110 Total weight after drying (grams) 16.57 16.70 15.98 Percent Ru in powder 26.0 25.86 26.5
  • a 5 inch by 6 inch plate was electroless nickel-plated according to procedures described in U.S. Patent No. 4,061,802.
  • the powder weight percent in the spraying mixture was around 10 percent.
  • the platinum group metal oxide precursor in the dispensing medium was RuCl 3
  • the valve metal oxide precursor compound in the dispensing medium was titanium isopropoxide.
  • the solvent in the dispensing medium was a combination of methanol and 2-propanol
  • the compound soluble in alkaline solutions was aluminum chloride or zinc chloride
  • Example 7 9 RuCl 3 xH 2 O (wt. percent) 2.37 2.37 2.37 Ti(isopropoxide) (wt. percent) 6.69 6.69 6.69 Methanol (wt. percent) 76.5 76.5 5.00 2-propanol (wt. percent) 9.73 9.73 81.07 Compound soluble in alkaline solution (wt.
  • a 5inch by 6 inch plate was electroless nickel-plated according to procedures described in U.S. Patent 4,061,802.
  • the powder weight percent in the spraying mixture is around 10 percent.
  • the dispensing medium comprises 2.37 weight percent RuCl 3 xH 2 O as the platinum group metal oxide precursor, 2.87 weight percent titanium isopropoxide as the valve metal oxide precursor, 8.86 weight percent methanol and 83.80 weight percent 2-propanol as the solvent, and 2.10 weight percent AlCl 3 x6H 2 O as the compound soluble in an alkaline solution.
  • Example 10 11 12 13 Percent Ru in catalytic powder 25.86 25.86 25.86 26.0 Metal loading ( ⁇ g/cm 2 ) 521 555 766 428
  • the plates were dipped in the following mixture of solutions for a period of five minutes at ambient temperature: 25cc 0.01 M (NH 4 )2PdCl 4 in methanol, 50cc 0.1 M poly(4-vinylpyridine) in methanol, and 425cc methanol.
  • the coated plates were then dried in a horizontal position at 90°C. The dipping and drying steps were repeated.
  • the coated plates were placed in a plastic horizontal container with the thread of the plate fitted in a fitting in the bottom of the container.
  • the solution was then poured out and 500ml of an electroless nickel-plating solution was then added to the container and electroless plating was conducted for 20 min.
  • Example 4 Weight gains for Example 4 (Example 7), Example 5 (Example 8) and Example 6 (Example 9) were 2.63 mg/cm 2 , 3.26 mg/cm 2 , and 2.69 mg/cm 2 , respectively.
  • the plates were connected to a nickel rod and placed in a caustic bath at an elevated temperature. A platinum plate welded to a nickel rod was used as the anode. Current densities of 0.46 amps per square inch (ASI), 1.0 ASI, and/or 1.09 ASI were applied to the cathode sample and the anode from a rectifier. The potential of the cathode was measured with the aid of a LUGGIN probe with a Hg/HgO reference electrode. The parameters and results were listed in Table V.
  • Example 14 15 16 Percent caustic in bath 11.75 11.75 32 Temperature of caustic bath (°C) 70 70 90 Voltage at 0.46 ASI -0.960 -0.962 -1.007 Voltage at 1.0 ASI -- -0.979 -- Voltage at 1.09 ASI -- -- -1.025
  • Example 10 Weight gains for Example 10 (Example 17), Example 11 (Example 18), Example 12 (Example 19) and Example 13 (Example 20) are 0.550g, 0.578g., 0.683g, and 0.489g, respectively.
  • Example 17 To measure the hydrogen potential for the plates prepared in Examples 17-20, the plates were connected to a nickel rod and placed in an 11.75 percent caustic bath at 70°C. A platinum plate welded to a nickel rod was used as the anode. A current density of 0.46 ASI was applied to the cathode plate and the anode from a rectifier. The potential of the cathode was measured with the aid of a LUGGIN probe versus a Hg/HgO reference electrode.
  • Example 18 Example 21
  • Example 19 Example 22
  • Example 20 Example 23
  • Example 23 The hydrogen potential measurements for Example 17 (Example 20).

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Claims (16)

  1. Eine Elektrode umfassend:
    ein leitfähiges Metallsubstrat, und
    eine erste Schicht umfassend eine Matrix mit einem darin dispergierten katalytischen Pulver, wobei die Matrix ein Platingruppenmetalloxid oder eine Mischung eines Platingruppenmetalloxids mit einem oder mehreren aus Titanoxid, Zirkoniumoxid, Tantaloxid, Wolframoxid, Nioboxid oder Wismutoxid umfasst, wobei das katalytische Pulver Partikel eines Trägermetalls umfaßt, das Nickel, Kobalt, Eisen, Stahl, rostfreier Stahl oder Kupfer ist, und wobei die Trägermetallpartikel mit einem porösen Überzug überzogen sind, wobei der poröse Überzug ein elektrokatalytisches Metall umfasst, das Ruthenium, Iridium, Rhodium, Osmium, Platin, Palladium, Rhenium oder eine Mischung davon ist.
  2. Elektrode gemäß Anspruch 1, wobei der poröse Überzug weiterhin ein teilchenförmiges Material gemischt mit dem elektrokatalytischen Metall umfasst.
  3. Elektrode gemäß Anspruch 1, wobei das leitfähige Metallsubstrat Nickel, Eisen, Stahl, rostfreier Stahl, Kobalt, Kupfer oder Silber ist.
  4. Elektrode gemäß Anspruch 2, wobei das teilchenförmige Material im porösen Überzug der ersten Schicht ein teilchenförmiges Metalloxidmaterial ausgewählt aus einem Platingruppenmetalloxid, Rheniumoxid, Technetiumoxid, Molybdänoxid, Chromoxid, Nioboxid, Wolframoxid, Tantaloxid, Manganoxid und Bleioxid ist.
  5. Elektrode gemäß einem der vorhergehenden Ansprüche, wobei das Platingruppenmetalloxid in der Matrix Rutheniumoxid, Iridiumoxid, Osmiumoxid, Platinoxid, Palladiumoxid oder eine Mischung davon ist.
  6. Elektrode gemäß einem der vorhergehenden Ansprüche, weiterhin umfassend eine zweite Verstärkungsschicht bestehend im wesentlichen aus einem Übergangsmetal oder einer Legierung davon.
  7. Elektrode gemäß Anspruch 6, wobei das Übergangsmetall oder eine Legierung davon Nickel, Kobalt, Kupfer oder eine Legierung davon mit Phosphor, Bor oder Schwefel ist.
  8. Verfahren zur Herstellung einer Elektrode umfassend die Schritte:
    Bilden eines katalytischen Pulvers durch Überziehen von Partikeln eines Trägermaterials, welches Nickel, Kobalt, Eisen, Stahl, rostfreier Stahl oder Kupfer ist, mit einem porösen Überzug umfassend ein elektrokatalytisches Metall, welches Ruthenium, Iridium, Rhodium, Osmium, Platin, Palladium, Rhenium oder eine Mischung davon ist, gemischt mit einem teilchenförmigen Material,
    Mischen des katalytischen Pulvers mit einem Verteilungsmedium umfassend eine Mischung eines Platingruppenmetalloxidvorläufers und eines Vorläufers von einem oder mehreren aus Titanoxid, Zirkoniumoxid, Tantaloxid, Wolframoxid, Nioboxid oder Wismutoxid, um eine Mischung zu bilden,
    Aufbringen der Mischung auf ein leitfähiges Metallsubstrat, um ein überzogenes Substrat zu bilden, und
    Backen des überzogenen Substrates in Anwesenheit von Sauerstoff.
  9. Verfahren gemäß Anspruch 8, wobei der poröse Überzug durch ein nichtelektrolytisches reduktives Abscheidungsverfahren, ein Elektroabscheidungsverfahren oder ein Sinterverfahren gebildet wird.
  10. Verfahren gemäß Anspruch 8, wobei das teilchenförmige Material im porösen Überzug ein teilchenförmiges Metalloxidmaterial ausgewählt ist aus einem Platingruppenmetalloxid, Rheniumoxid, Technetiumoxid, Molybdänoxid, Chromoxid, Nioboxid, Wolframoxid, Tantaloxid, Manganoxid, Bleioxid und einer Mischung davon.
  11. Verfahren gemäß Anspruch 8, wobei der Aufbringungsschritt unter Verwendung von Lösungsmittelsprayen, elektrostatischem Sprayen, Plasmasprayen oder Schmelzsprayen durchgeführt wird.
  12. Verfahren gemäß Anspruch 8, wobei der Platingruppenmetalloxidvorläufer Rutheniumchlorid ist und der Ventilmetalloxidvorläufer Titanalkoxid, Tantalalkoxid, Zirkoniumacetylacetonat oder Niobalkoxid ist.
  13. Verfahren gemäß Anspruch 8, wobei das Verteilungsmedium weiterhin Aluminiumchlorid oder Zinkchlorid umfasst.
  14. Verfahren gemäß Anspruch 8, wobei das Verteilungsmedium weiterhin ein Lösungsmittel ausgewählt aus Methanol, Ethanol, 1-Propanol, 2-Propanol, Butanol oder Mischungen davon umfasst.
  15. Verfahren gemäß Anspruch 8, weiterhin umfassend den Schritt des Überziehen des überzogenen Materials mit einem Übergangsmetall oder einer Übergangsmetalllegierung, um eine Verstärkungsschicht zu bilden.
  16. Verfahren gemäß Anspruch 15, wobei das Übergangsmetall Nickel, Kobalt, Kupfer oder eine Legierung davon mit Phosphor, Bor oder Schwefel ist.
EP00973563A 1999-10-20 2000-10-13 Elektrode mit katalytischem pulver hergestellt Expired - Lifetime EP1235658B1 (de)

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TW200304503A (en) 2002-03-20 2003-10-01 Asahi Chemical Ind Electrode for generation of hydrogen
EP1859850A1 (de) * 2006-05-24 2007-11-28 Globe Union Industrial Corp. Metallgestützter Photokatalysator und Herstellungsverfahren dafür
CN101077478B (zh) * 2006-05-24 2010-06-30 深圳成霖洁具股份有限公司 光催化剂复合结构体及其制备方法
KR100839372B1 (ko) * 2006-11-01 2008-06-19 삼성에스디아이 주식회사 연료 전지용 촉매의 제조 방법
CN101335166B (zh) * 2007-06-27 2010-06-30 中国科学院电子学研究所 一种阴极用三元合金膜及制备覆膜浸渍扩散阴极的方法
JP4857255B2 (ja) * 2007-12-17 2012-01-18 株式会社日立製作所 電気分解用電極とその製造方法、ならびに水素製造装置
ITMI20090880A1 (it) * 2009-05-19 2010-11-20 Industrie De Nora Spa Catodo per processi elettrolitici
JP2013014813A (ja) * 2011-07-06 2013-01-24 Murata Mfg Co Ltd 多孔質金属粒子及びその製造方法
CN103145222B (zh) * 2012-12-29 2014-07-23 胜宏科技（惠州）股份有限公司 一种电催化处理废棕化液的方法
JP2016204732A (ja) * 2015-04-28 2016-12-08 旭化成株式会社 電解用電極
JP6733904B2 (ja) * 2016-06-20 2020-08-05 仲山貴金属鍍金株式会社 焼結体およびその製造方法
WO2019045805A2 (en) * 2017-08-31 2019-03-07 A123 Systems Llc PROCESS FOR METALLIZING ELECTROCHEMICALLY ACTIVE POWDERS
TW202146707A (zh) 2020-01-24 2021-12-16 英商億諾斯技術有限公司 電極總成及電解器

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EP0174413A1 (de) * 1984-09-17 1986-03-19 Eltech Systems Corporation Katalytisches Kompositmaterial besonders für Elektrolyse-Elektroden und Verfahren zu ihrer Herstellung
IN164233B (de) * 1984-12-14 1989-02-04 Oronzio De Nora Impianti
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WO2001028714A1 (en) 2001-04-26
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CN1379703A (zh) 2002-11-13
CA2387563A1 (en) 2001-04-26

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