Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
  • H01M4/8605—Porous electrodes
  • H01M4/8621—Porous electrodes containing only metallic or ceramic material, e.g. made by sintering or sputtering
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C33/00—Making ferrous alloys
  • C22C33/003—Making ferrous alloys making amorphous alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C45/00—Amorphous alloys
  • C22C45/04—Amorphous alloys with nickel or cobalt as the major constituent
• • 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
• • 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
  • C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
  • C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
  • C25B11/061—Metal or alloy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the invention provides in one aspect a metallic glass of use in electrochemical processes, said metallic glass consisting essentially of a material of the general nominal composition
• the electrodes have excellent thermal stability, improved stability in an aqueous electrolyte and can provide improved current efficiency - anodic or cathodic ove ⁇ otential performance. They are of use in the electrolysis of aqueous electrolyte solutions such as mixtures of caustic (KOH, NaOH) and water in the production of oxygen and hydrogen.
• the electrodes are comprised of low cost transition metals in combination with metalloid elements in specific ratios to permit the alloy composition to be solidified into an amorphous state. They offer improved current efficiencies via anodic or cathodic ove ⁇ otential performance and offer improved stability in both static and cyclic exposures. They can be used in concentrated alkaline solutions and at elevated temperatures for improved electrode performance.
• the electrodes are of use in the electrolysis of alkaline solutions resulting in the production of hydrogen and oxygen via the decomposition of water, and also additional uses in electrodes for fuel cells, electro-organic synthesis or environmental waste treatment.
• Fig. 4 is a schematic diagram of a three component cell used in the evaluation of the electrochemical activity and stability of the materials according to the invention.
• Fig. 5 is a diagrammatic representation of the apparatus of use in obtaining electrochemical measurements, and wherein the same numeral denotes like parts.
• This Example illustrates the preparation electrodes having a nominal composition:
• Induction heater unit 12 was comprised of an induction heater coil 28 (Fig. 2) in vacuum chamber 14, a 3-stage step-up transformer and a closed-loop water recirculator (not shown) which supplied cooling water through the induction coil during heating.
• Fig. 2 shows the arrangement of a copper wheel 30 (20 cm in diameter, 3.8 cm in width), ceramic crucible 22 induction coil 28 in high vacuum chamber 14 and ribbon guide 32.
• Planar amo ⁇ hous ribbons were formed on the surface of the wheel rotating counterclockwise and driven along the ribbon guides to the collector tube. This particular form of melt spinning is referred to as the planar flow casting technique. From the wheel rotation speed, a quenching rate was estimated to be ca 10° °C/sec. One side of the ribbon was free from contact with the wheel and had a shiny appearance (shiny side) compared with the dull appearance for the other side in contact with the wheel (wheel side). To minimize surface imperfections on the dull side due to contact with the wheel, the peripheral surface of the wheel was thoroughly polished with diamond paste and degreased with acetone before each run. Standard experimental parameters of the melt-spinning operation are summarized in Table 3.
• the first evaluation relates to the actual composition of the alloys produced as poor recoveries during melting can produce substantial deviations between the nominal and actual composition of a given alloy.
• the second evaluation relates to the structure of the alloys produced as the processing method produces a metastable structure that is amorphous or nanocrystalline in nature.
• the third evaluation relates to the electrode performance in relation to the overvoltage necessary for hydrogen production for as-melt spun ribbons under conditions related to the electrolysis of an alkaline solution.
• the fourth evaluation refers to the examination of the surface of the electrode materials used under both constant potential and conditions of potential cycling as described above.
• the second test was performed using the technique of X-ray diffraction in order to confirm the degree of crystallinity of the manufactured ribbons.
• measurements were also carried out on crystallized fragments of the amorphous alloys as well as pure elemental nickel, cobalt, chromium, boron and the intermetallic nickel boride.
• the amorphous samples were prepared by cutting ribbons into 4 mm x 10 mm rectangular pieces. The samples were then degreased with acetone, methanol and deionized water in sequence.
• the crystallized fragments had the same bulk composition as the corresponding amorphous alloy and were primarily in the form of brittle plate-like powder.
• the crystallized amo ⁇ hous alloy was ground to form a fine powder in an agate mortar and dispersed on a slide glass before measurement.
• Diffraction patterns were measured on a Siemens D5000 X-ray diffractometer using 50 kV Cu-K ⁇ radiation with a Ni filter in the range of 20 to 70 degree-2 ⁇ at a scan rate of 2 degree-2 ⁇ per minute. The data was processed by Diffrac AT software.
• the electrolytic cell shown in Fig. 4 generally as 40 had a three- compartment structure consisting of a 300 ml capacity main body formed of Teflon containing a working electrode 42 of the ribbon of alloy of the invention, a 1/2" Teflon ® tube 44 housing a counter electrode 46, and a 1/4" Teflon ® PTFE tube filled with mercury-mercuric oxide paste (Hg/HgO) 48.
• the compartments were separated by electrolyte-permeable membranes 50 in the form of a diaphragm or frit.
• the counter electrode 46 was a 25 mm x 12.5 mm platinum gauze with a surface area of ca. 4.4 cm .
• HA-501G with a 200 MHz Pentium II personal computer 60, through a GPIB interface 62 and arbitrary function generator (Hokuto Denko HA-105B) 66.
• the fourth test was performed on amorphous alloy and crystalline surfaces to compare the degree of surface roughening and hence electrode degradation by using optical and scanning electron microscopy prior to and post use as an electrocatalyst in the cell.
• Optical investigation was achieved using a light stereoscope and light metallograph. Electron imaging was accomplished using a
• the structure of the ribbon was assessed using x- ray diffraction, as it is an integral part of the electrode performance independent of the exact composition of the electrode material. It is known that a typical X-ray diffraction (XRD) pattern of an amo ⁇ hous material is a broad spectrum with no prominent sha ⁇ peaks relating to crystalline structure. Thus, qualitative confirmation of the amorphous nature of an alloy is demonstrated by a broad band peak in its XRD profile.
• XRD X-ray diffraction
• an index viz. effective crystallite dimension was calculated to evaluate the largest potential size of crystal embryos in the melt-spun ribbons.
• the effective crystallite dimension is expressed by the equation:
• D Q.91 ⁇ ⁇ cos ⁇ where D is the effective crystallite dimension in nm and ⁇ is wavelength of the Cu-
• ⁇ denotes the full width of a given diffraction peak in radians at half the maximum intensity, ⁇ is the Bragg angle of the peak maximum.
• the effective crystallite dimension was measured for all the melt-spun ribbons.
• This ranking order does not simply follow the order of magnitude of the Cr V content in the amorphous alloys, but is particular to the elemental form.
• the highest electrocatalytic activity of Ni 50 Co 25 V 5 B 20 amongst the amo ⁇ hous alloys could possibly be attributed to the synergetic effect of Ni-Co-V that may influence the nature of the oxide film formed on this amo ⁇ hous alloy.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electrochemistry (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Ceramic Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (2)

Family

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Family Applications (1)

Country Status (11)

Cited By (19)

Families Citing this family (11)

Citations (8)

Family Cites Families (3)

• 1999
  • 1999-10-26 CA CA002287648A patent/CA2287648C/en not_active Expired - Fee Related
• 2000
  • 2000-10-23 MX MXPA02002673A patent/MXPA02002673A/es not_active Application Discontinuation
  • 2000-10-23 WO PCT/CA2000/001251 patent/WO2001031085A2/en not_active Application Discontinuation
  • 2000-10-23 CN CN00814770A patent/CN1382229A/zh active Pending
  • 2000-10-23 BR BR0014994-2A patent/BR0014994A/pt not_active Application Discontinuation
  • 2000-10-23 EP EP00971182A patent/EP1230412A2/en not_active Withdrawn
  • 2000-10-23 JP JP2001533216A patent/JP2003513170A/ja active Pending
  • 2000-10-23 AU AU10135/01A patent/AU1013501A/en not_active Abandoned
  • 2000-10-23 KR KR1020027004542A patent/KR20020037772A/ko not_active Application Discontinuation
• 2002
  • 2002-02-27 NO NO20020957A patent/NO20020957L/no not_active Application Discontinuation
  • 2002-03-06 ZA ZA200201857A patent/ZA200201857B/xx unknown

Patent Citations (8)

Non-Patent Citations (3)

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