GB2087433A

GB2087433A - Permionic Membrane Electrolytic Cell

Info

Publication number: GB2087433A
Application number: GB8134239A
Authority: GB
Original assignee: PPG Industries Inc
Current assignee: PPG Industries Inc
Priority date: 1980-11-17
Filing date: 1981-11-13
Publication date: 1982-05-26
Also published as: AU7637681A; SE443582B; JPS57114674A; NL8104559A; SE8105932L; FR2494305A1; AU529875B2; ES8206666A1; BE891133A; IT1144932B; NO813552L; KR830007880A; ES506561A0; CA1187442A; DE3145324C2; ES8300145A1; ES506560A0; KR890000626B1; GB2087433B; FR2494305B1

Abstract

In an electrolytic cell having an anolyte compartment, a catholyte compartment, a permionic membrane therebetween and the cathode contacting the permionic membrane, the cathodic surface of the permionic membrane has a conductive, substantially non-electrocatalytic current distributing material, (e.g. Cu, Ag, Au or Ag2O), dispersed across the face thereof. The cathode may comprise a Group VIII transition metal electrocatalyst having a lower hydrogen evolution overvoltage than the non- electrocatalytic material. In alternative embodiments: (a) the non-electrocatalytic material is bonded to the membrane, the electrocatalyst being present either as a second layer on top of the non- electrocatalytic material or on a separate electrode structure; (b) the electrocatalyst is present on the surface of the membrane in admixture with the non- electrocatalytic material; (c) the electrocatalyst and the non- electrocatalytic material are both present on and adherent to an electroconductive substrate, and removable from the membrane. f

Description

SPECIFICATION Permionic Membrane Electrolytic Cell Current Distribution Means Permionic membrane electrolytic cells, including zero gap permionic membrane electrolytic cells, have a cation selective permionic membrane. The cation selective permionic membrane separates the anolyte compartment, with an anode therein, from the catholyte compartment, with a cathode therein.

In a zero gap permionic membrane electrolytic cell the anodic electrocatalyst and the cathodic electrocatalyst are in contact with the respective faces of the permionic membrane. In a solid polymer electrolyte electrolytic cell the anodic electrocatalyst and cathodic electrocatalyst are bonded to and embedded in the permionic membrane.

The zero gap permionic membrane electrolytic cell can provide the advantage of ready removability of the electrocatalyst. That is, the anodic and cathodic electrocatalyst can be removed from contact with the permionic membrane without destruction or degradation of the permionic membrane. Another advantage offered by zero gap permionic membrane electrolytic cells over solid polymer electrolyte electrolytic cells is the higher current efficiency of the zero gap permionic membrane electrolytic cell. However, the higher current efficiency comes at a penalty of a higher cell voltage.

It has now been found that the voltage of a zero gap permionic membrane electrolytic cell may be reduced if there is present in and on the cathodic surface of the permionic membrane, suitable current distribution means, whereby to enhance electronic conduction across the cathodic surface of the permionic membrane. As herein contemplated, the cathode contacts the permionic membrane with the cathode surface of the permionic membrane having current distribution material, i.e., conductive, substantially non-catalytic materials, dispersed across the cathodic surface of the permionic membrane. The non-catalytic material may be bonded to and embedded in the cathodic surface of the permionic membrane.

Herein contemplated is an electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, and a permionic membrane therebetween, with at least the cathode contacting the permionic membrane. The permionic membrane is characterized by its cathodic surface having electrically conductive, substantially non-electrocatalytic material in contact therewith, and either adherent thereto or adherent to the cathodic electrocatalyst. By substantially noncatalytic material it is meant that the material serves the purpose of an electronic current distributor, having a metallic electrical conductivity, but having a high hydrogen evolution overvoltage, i.e., at least about 0.1 volt higher than the hydrogen evolution overvoltage of the cathodic electrocatalyst used in combination therewith.

Preferably, the electrically conductive, substantially non-catalytic material is chosen from the group consisting of Group IB metals and corrosion resistant, electrically conductive, but substantially non-electrocatalytic compounds thereof. These materials include copper, silver, and gold, as well as those oxides thereof that are stable in the aqueous, alkali metal hydroxide environment. Especially preferred, for reasons of cost, availability, and low electrocatalytic activity, are silver oxide, silver, and copper.

The electrically conductive, substantially non-electrocatalytic material may be a particulate material, for example, particles having a particle size of from about 0.1 micron to about minus 200 mesh and preferably from about 0.5 micron to about minus 325 mesh. The substantially nonelectrocatalytic, electrically conductive material is preferably adherent to the permionic membrane.

That is, it is preferably bonded to and embedded in the permionic membrane, and substantially nonremovable therefrom without degradation, partial destruction, or destruction of either the material or the permionic membrane, or both. Alternatively, especially when the non-catalytic material is of a finer mesh size than the electrocatalyst, it may be adherent to either the electrocatalyst or to the substrate carrying the electrocatalyst, as where the electrocatalyst is a particulate electrocatalyst bonded to a metallic substrate, with particulate conductor material on the substrate, and between and on the electrocatalyst particles.

Typically, the cathode electrocatalyst of the electrolytic cell is a Group VIII transition metal, having a lower hydrogen evolution overvoltage than the electrically conductive, substantially nonelectrocatalytic material. Typical cathodic electrocatalysts include iron, cobalt, nickel and the platinum group metals, especially electronically catalytic forms such as Raney nickel, platinized platinum, and platinum black.

According to the method of this invention; there is provided a method of electrolyzing an alkali metal chloride brine in an electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, and a permionic membrane therebetween. The cathode contacts the permionic membrane, preferably and removably, that is readily removable without destruction or degradation of either the cathodic electrocatalyst or the permionic membrane. As herein contemplated, the process comprises passing an electrical current from the anode to the cathode, whereby to evolve chlorine at the anode and hydroxyl ion at the cathode. The method is characterized in that the permionic membrane has on its cathodic surface electrically conductive, substantially nonelectrocatalytic material either adherent thereto or in contact therewith, as described above.

According to one exemplification herein contemplated, the current distributor may be bonded to the cathodic surface of the permionic membrane alone, that is, without electrocatalyst being present thereon. In this way, the electrocatalyst is readily removable from the surface, and is present on a separate electrode structure, i.e., a metallic screen, mesh, sheet, plate, or the like, having a coating, surface, or film of electrocatalyst as herein described.

According to an alternative exemplification, the electrocatalyst is present as a bilayer, i.e., as a second layer, atop the layer, surface, or film of particulate, electrically conductive, substantially nonelectrocatalytic material which is bonded to and embedded in the permionic membrane. According to this exemplification, the substantially non-electrocatalytic, electrically conductive material is applied first to the permionic membrane, and thereafter the electrocatalyst is applied thereto, both above and between particles of the conductive, non-catalytic material.

According to a still further exemplification of the method of this invention, electrocatalyst may be present on the surface of the permionic membrane, in admixture with the electrically conductive, substantially non-catalytic material which is also adherent to the permionic membrane surface.

According to a still further exemplification, the electrocatalyst and the non-catalytic material may both be present on and adherent to an electroconductive substrate, and removable from the permionic membrane.

The loading of the electronically conductive, current distributor may be from about 1 milligram per square centimeter to about 100 milligrams per square, and preferably from about 2 to about 20 milligrams per square centimeter. Amounts lower than about 1 milligram per square centimeter do not provide significant amounts of current distribution, while amounts greater than about 1 00 milligrams per square centimeter may substantially interfere with the electrochemical process, providing an impermeable barrier, sheet, or film on the cathodic surface of the permionic membrane.

The permionic membrane interposed between the anolyte and the porous matrix is fabricated of a polymeric fluorocarbon copolymer having immobile, cation selective ion exchange groups on a halocarbon backbone. The membrane may be from about 2 to about 25 mils thick, although thicker or thinner permionic membranes may be utilized. The permionic membrane may be a laminate of two or more membrane sheets. It may, additionally, have internal reinforcing fibers.

The permionic membrane may be a copolymer of (I) a fluorovinyl polyether having pendant ion exchange groups and having the formula (I) CF2=CFO"[(CX'X" )c(CFX' )d(CF2O(X'X" )0(CX"X'0CF2)f]-A where a isOor1,bisOto6,cisOto6,disOto6,eisOto6,fisOto6;X,X',andX"areH,Cl, -F, and -(CF2)gCF3; g is 1 to 5, [ ] is a discretionary arrangement of the moieties therein; and A is the pendant functional group as will be described hereinbelow.Preferably a is 1, and X, X' and X" are -F and (CF2)gCF30 The fluorovinyl polyether may be copolymerized with a (II) fluorovinyl compound (il) CF2=CF a(CFX"d)A and a (III) perfluorinated olefin (III) CF2CXX', or (I) may be copolymerized with only a (III) perfluorinated olefin, or (I) may be copolymerized with only a (II) perfluorovinyl compound.

The functional group is a cation selective group. It may be a sulfonic group, a phosphoric group, a phosphonic group, a carboxylic group, a precursor thereof, or a reaction product thereof, e.g., an ester thereof. Carboxylic groups, precursors thereof, and reactions products thereof are preferred. Thus, as herein contemplated, A is preferably chosen from the group consisting of --COOH, --COOR,, --COOM, --COF.

--COCI, -CN, CONR2R3, --SO,H, --SO,M, --SO,F, and --SO,CI where R1 is a C1 to C,O alkyl group, R2 and R3 are hydrogen or C, to C,O alkyl groups, and M is an alkali metal or a quaternary ammonium group. According to a particularly preferred exemplification, A is --COCI, --COOH, --COOR1, -SO2F, or --SO,CI where R, is a C, to C5 alkyl.

As herein contemplated, the permionic membrane is preferably a copolymer which may have: (i) fluorovinyl ether acid moieties derived from CF2=CFO[CF2b(CX'X" )C(CFX') (CF2-0-CX'X")e(CX'X"-O-CF2)f]-A, exemplified by CF2=CFOCF2CF(CF3OCF3CF2CF2COOOCH3,

CF2=CFOCF2CF(CF3)OCF(COOCH3)CF3, inter alia: (II) fluorovinyl moieties derived from CF2=CF(0)e(CFX' )dA, exemplified by CF2-CF(CF2)2-4COOCH3, CF2-CF(CF2)2-4COOCH3, CF2=CFO(CF2)2~4COOCH3t CF2=CFO(CF2)2-4COOC2H5, and CF2=CFO(CF2)2-4COOCH3, inter alia; (III) fluorinated olefin moieties derived from C F2=CXX' as exemplified by tetrafluoroethylene, trichlorofluoroethylene, hexafluoropropylene, trifluoroethylene, vinylidene, fluoride, and the like; and (IV) vinyl ethers derived from CF2=CFOR4 The permionic membrane herein contemplated may have an ion exchange capacity of from about 0.5 to about 2.0 milliequivalents per gram of dry polymer, preferably from about 0.9 to about 1.8 milliequivalents per gram of dry polymer, and in a particularly preferred exemplification, from about 1.0 to about 1.6 milliequivalents per gram of dry polymer. The permionic membrane herein contemplated may have a volumetric flow rate of 100 cubic millimeters per second at a temperature of 150 to 300 degrees Centigrade, and preferably at a temperature between 1 60 to 250 degrees Centigrade. The glass transition temperature of the permionic membrane polymer should be below 700C, and preferably below about 500C.

The permionic membrane herein contemplated may be prepared by the methods described in U.S. Patent 4.126,588, the disclosure of which is incorporated herein by reference.

Most commonly the ion exchange resins will be in a thermoplastic form, i.e., a carboxylic acid ester, e.g., a carboxylic acid ester of methyl, ethyl, propyl, isopropyl, or butyl alcohol, or a sulfonyl halide, e.g., sulfonyl chloride or sulfonyFfluoride, during the fabrication herein contemplated, and will thereafter be hydrolyzed.

According to one exemplification of this invention, an electrolytic cell may be assembled having an anode bearing upon the anodic surface of the permionic membrane, and platinum black and silver oxide, Ag20 bonded to the cathodic side of the permionic membrane. According to this exemplification, a perfluorocarbon polymer having pendant carboxylic acid ester groups, i.e., being in the thermoplastic form, may be coated with a plasticizer, i.e., bis(2-ethyl hexyl) isophthalate, one part platinum black and 4 parts silver oxide, whereby to provide a loading of about 1 2 milligrams per square centimeter of silver oxide and about 3 milligrams per square centimeter of platinum black.The coated permionic membrane may then be hot pressed, for example from about 1 800C to about 2250C and at a pressure of about 100 to 1500 pounds per square inch for about 2 to 10 minutes whereby to provide a cathodic solid polymer electrolyte surface. Thereafter an electrolytic cell may be assembled having coated titanium anode bearing upon the anodic surface of the permionic membrane, and a nickel current collector bearing upon the cathodic, solid polymer electrolyte surface of the permionic membrane.

According to a still further exemplification of this invention, a permionic membrane electrolytic cell may be prepared having an anode bearing upon the surface of the permionic membrane and a multiple layer of silver oxide and platinum black deposited on the cathodic surface of the permionic membrane. As herein contemplated, a sheet of perfluorocarbon copolymer having pendant carboxylic acid ester groups may be coated with a suitable plasticizer as dioctylphthalate plasticizer to which 1 micron diameter silver oxide particles are applied.Thereafter, minus 325 mesh platinum black particles may be applied, and the resulting bilayer pressed at a temperature of about 180 to about 2250C, and a pressure from about 800 to about 1 500 pounds per square inch for about 2 to 10 minutes whereby to obtain a solid polymer electrolyte cathodic surface having silver oxide particles in intimate contact with the permionic membrane and external particles of platinum black.

According to a still further exemplification of this invention, an 8 mil thick permionic membrane fabricated of a perfluorocarbon copolymer having pendant carboxylic acid ester groups may be coated with didecylphthalate and minus 325 mesh copper particles. Thereafter the permionic membrane may be hot pressed at a temperature of about 1 800C to 2200C and a pressure of about 700 to 1 500 pounds per square inch for about 2 to about 10 minutes. The cathode may be a screen having about 20 mesh per inch by 30 mesh per inch and a thickness of about 0.005 of an inch with an electrodeposited coating of platinum thereon. In this way there is provided a zero gap permionic membrane cell having copper particles as electrical distributors on the surface thereof.

The use of plasticizers, for example, phthalates, phosphates, and fatty acid esters is particularly advantageous in the method of this invention whereby to enhance the adherence of the electronic current distributor to the permionic membrane, especially at reduced temperatures, pressures, and times of hot pressing.

The following examples are illustrative: Example I A permionic membrane electrolytic cell was assembled having a ruthenium dioxide coated anode bearing upon the anodic side of the permionic membrane, and platinum black and silver oxide, Ag20, bonded to the cathodic side of the permionic membrane.

An eleven mii thick by 5 inch by 5 inch Asahi Glass Co., Ltd. "Flemion"(!) HB permionic membrane fabricated of a perfluorocarbon copolymer having pendant carboxylic acid ester groups was coated with bis(2 ethyl hexyi) isophthlate plasticizervto which was added 0.2 grams of minus 325 mesh platinum black and 0.8 grams of minus 325 mesh silver oxide, Ag20, providing 3.4 milligrams per square centimeter of platinum and 12.8 grams per square centimeter of silver oxide. The coated permionic membrane was hot pressed at 200 degrees Centigrade and 20 tons force for 5 minutes.

Thereafter the electrolytic cell was assembled, with a ruthenium dioxide coated 40 mesh to the inch by 40 mesh to the inch, 3 inch by 3 inch, titanium anode pressed against the anodic surface of the permionic membrane by a 2.5 mesh to the inch by 5 mesh to the inch, 3 inch by 3 inch, ruthenium dioxide coated titanium screen. The cathode current collector was a 2.5 mesh to the inch by 5 mesh to the inch, 3 inch by 3 inch, nickel screen.

After 14 days of electrolysis the cell voltage was 3.36 volts at 400 Amperes per square foot with 86 percent cathode current efficiency.

Example II A permionic membrane electrolytic cell was assembled having a ruthenium dioxide coated titanium screen bearing upon the anodic surface of the permionic membrane and a bilayer of silver oxide, Ag20, and platinum black deposited on the cathode surface of the permionic membrane.

An eleven mil thick by 5 inch by 5 inch Asahi Glass Co., Ltd. "Flemion"O HB permionic membrane formed of perfluorocarbon copolymer having pendant carboxylic acid ester groups was coated with bis(2 ethyl hexyl) isophthlate plasticizer. Silver oxide particles, 1 micron in diameter, were applied atop the plasticizer to provide a silver oxide loading of 1 2 milligrams per square centimeter. Atop the silver oxide, minus 325 mesh platinum black was applied to provide a platinum loading of 3.4 milligrams per square centimeter. The coated permionic membrane was hot pressed at 200 degrees Centigrade and 20 tons force for 5 minutes.

Thereafter the electrolytic cell was assembled, with a ruthenium dioxide coated, 40 mesh to the inch by 40 mesh to the inch, 3 inch by 3 inch titanium anode pressed against the anodic surface of the permionic membrane by a ruthenium dioxide coated, 2.5 mesh to the inch by 5 mesh to the inch, 3 inch by 3 inch titanium screen.

After 31 days of electrolysis the cell voltage was 3.56 volts at 396 Amperes per square foot and the cathode current efficiency was 87 percent.

Example Ill A permionic membrane electrolytic cell was assembled having a ruthenium dioxide coated titanium anode screen bearing upon the anodic surface of the permionic membrane, and a platinum coated nickel cathode bearing upon the silver oxide coated, cathodic surface of the permionic membrane.

An 11 mil thick by 5 inch by 5 inch Asahi Glass Co., Ltd. "Flemion"O type HB permionic membrane fabricated of a perfluorocarbon copolymer having pendant carboxylic acid ester groups was coated with bis(2-ethyl hexyl) isophthlate plasticizer. To this membrane was added 0.8 grams of 1 micron silver oxide, Ag20. The membrane was then hot pressed at 200 degrees Centigrade and 20 tons force for 5 minutes.

The cathode was prepared by electrolytically depositing platinum black onto a 40 mesh to the inch by 40 mesh to the inch, 3 inch by 3 inch, 0.005 inch thick expanded mesh nickel screen. The electrolytic cell was assembled with a ruthenium dioxide coated, 40 mesh to the inch by the 40 mesh to the inch, 3 inch by 3 inch titanium screen anode bearing against the anodic surface of the permionic membrane, and the platinum black coated nickel screen bearing against the silver oxide coated cathodic surface of the permionic membrane.

After 22 days of electrolysis the cell voltage was 3.41 volts at 396 Amperes per square foot, and the cathode current efficiency was 83.7 percent.

Example IV A permionic membrane electrolytic cell was assembled having a ruthenium dioxide coated titanium anode screen bearing against the anodic surface of the permionic membrane and nickel screen cathode bearing against the silver oxide coated, cathodic surface of the permionic membrane.

An 11 mil thick by 5 inch by 5 inch Asahi Glass Co., Ltd. "Flemion"t 3 type HB permionic membrane fabricated of a perfluorocarbon copolymer having pendant carboxylic acid ester groups was coated with bis(2-ethylhexyl) isophthlate plasticizer. To this membrane was added 0.8 grams of 1 micron silver oxide, Ag20, powder. The membrane was then hot pressed at 200 degrees Centigrade and 20 tons force for 5 minutes.

The cathode was an uncoated, 20 mesh to the inch by 30 mesh to the inch, 3 inch by 3 inch, 0.005 inch thick nickel screen. The electrolytic cell was assembled with a ruthenium dioxide coated, 40 mesh to the inch, 3 inch by 3 inch, titanium screen anode against the anodic surface of the permionic membrane, and the nickel cathode pressed against the silver oxide coated, cathodic surface of the permionic membrane.

After 29 days of electrolysis the cell voltage was 3.31 volts at 396 Amperes per square foot, and the cathode current efficiency was 87.1 percent.

Example V A permionic membrane electrolytic cell was prepared by depositing cathodic electrocatalyst into the cathodic side of the permionic membrane by utilizing a plasticizer in conjunction with the electrocatalyst prior to hot pressing the cathodic electrocatalyst into the permionic membrane.

An 11 mil thick by 5 inch by 5 inch Asahi Glass Company, Ltd. "Flemton"O type HB permionic membrane fabricated of a perfluorocarbon copolymer having pendant carboxylic acid ester groups was coated with bis(2-ethyl hexyl) isophthalate plasticizer. To the plasticizer coated surface of the permionic membrane was added 0.8 gram of minus 325 mesh platinum black. The platinum black was added by air brushing.

Thereafter the permionic membrane was hot pressed at 200 degrees Centigrade and 20 tons force for 5 minutes. The cell was then assembled by pressing a 40 mesh to the inch by 40 mesh to the inch, 3 inch by 3 inch, ruthenium dioxide coated titanium mesh screen against the anodic surface of the permionic membrane, and a 20 mesh to the inch by 30 mesh to the inch, 3 inch by 3 inch, cathode current collector against the platinum black coated, cathodic surface of the permionic membrane.

After 31 days of electrolysis the cell voltage was 3.86 volts at 396 Amperes per square foot, and the cathode current efficiency was 87.0 percent.

Example VI A permionic membrane electrolytic cell was prepared by depositing cathodic electrocatalyst into the cathodic surface of the permionic membrane utilizing a plasticizer in conjunction with particulate cathodic electrocatalyst.

A 5 mil thick by 3 inch by 3 inch Asahi Glass Company Co., Ltd. "Flemion"(E) type H permionic membrane fabricated of a perfluorocarbon copolymer having pendant carboxylic acid ester groups was coated with bis(2-ethyl hexyl) isophthlate plasticizer. To the plasticizer coated surface of the permionic membrane was air brushed 0.4 grams of platinum black. The membrane was then hot pressed as 200 degrees Centigrade and 20 tons force for 5 minutes to adhere the catalyst to the membrane.

The cell was then assembled by pressing a 40 mesh to the inch by 40 mesh to the inch, 3 inch by 3 inch ruthenium dioxide coated titanium mesh screen against the anodic surface of the permionic membrane, and 20 mesh to the inch by 30 mesh to the inch, 3 inch by 3 inch cathode current collector against the platinum black coated, cathodic surface of the permionic membrane.

After 13 days of electrolysis the cell voltage was 3.79 volts at 396 Amperes per square foot, and the cathode current efficiency was 75.2 percent.

While the invention has been described with respect to certain preferred exemplifications and embodiments, the scope of protection is not intended to be limited thereby, but only by the claims appended hereto.

Claims

1. An electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, and a permionic membrane therebetween, said cathode contacting the permionic membrane, characterised in that the cathodic surface of the permionic membrane has electrically conductive, substantially non-electrocatalytic material in contact therewith.

2. An electrolytic cell as claimed in claim 1 wherein the electrically conductive, substantially nonelectrocatalytic material is chosen from Group IB metals and corrosion resistant, electrically conductive compounds thereof.

3. An electrolytic cell as claimed in claim 1 or 2 wherein the electrically conductive, substantially non-electrocatalytic material is a particulate material.

4. An electrolytic cell as claimed in claim 3 wherein the particulate material is bonded to and embedded in the permionic membrane.

5. An electrolytic cell as claimed in any of claims 1 to 4 wherein the cathode comprises an electrocatalyst a croup Vlli transition metal having a lower hydrogen evolutiun overvoltage than the electrically conductive, substantially non-electrocatalytic material.

6. An electrolytic cell as claimed in claim 5 wherein the electrically conductive, non-catalytic material and the electrocatalyst are bonded to the same substrate.

7. In a method of electrolyzing an alkali metal chloride brine in an electrolytic cell having an anolyte compartment with an anode therein, a catholyte compartment with a cathode therein, and a permionic membrane therebetween, said cathode contacting the permionic membrane, which method comprises passing an electrical current from the anode to the cathode, evolving chlorine at the anode and hydroxyl ion at the cathode; the improvement wherein said permionic membrane has an anodic surface and a cathodic surface, the cathodic surfacing having electrically conductive, substantially nonelectrocatalytic material in contact therewith.

8. A method as claimed in claim 7 wherein the electrically conductive, substantially nonelectrocatalytic material is chosen from Group IB metals and corrosion resistant, electrically conductive compounds thereof.

9. A method as claimed in claim 1 or 2 wherein the electrically conductive, substantially nonelectrocatalytic material is a particulate material.

10. A method as claimed in claim 9 wherein the particulate material is bonded to and embedded in the permionic membrane.

11. A method as claimed in any of claims 7 to 10 wherein the cathode comprises an electrocatalyst of a Group VIII transition metal having a lower hydrogen evolution overvoltage than the electrically conductive, substantially non-electrocatalytic material.

12. A method as claimed in claim 11 wherein the electrically conductive, non-catalytic material and the electrocatalyst are bonded to the same substrate.