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US 4,541,908 AGranted
Heme protein immobilized electrode and its use
AssigneeAjinomoto Co., Inc.
InventorsKatsumi Niki, Hiroo Inokuchi, Tatsuhiko Yagi, Asao Nakamura
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AssigneeAjinomoto Co., Inc.
InventorsKatsumi Niki, Hiroo Inokuchi, Tatsuhiko Yagi, Asao Nakamura
Estimating the term…
An electrical conducting solid electrode on the surface of which cytochrome c.sub.3 is immobilized in an amount ranging from 20%-100% of the monolayer coverage, said electrode thereby provided with the electrocatalytic capability of the direct four-electron reduction of dioxygen to water, and its uses.
An electrode comprising a solid electrical conducting material on the surface of which cytochrome c.sub.3 is immobilized in an amount ranging between 20% and 100% of monolayer coverage.
A method of catalytic four-electron reduction of dioxygen directly to water in an aqueous solution which comprises placing an oxygen electrode comprising a solid electrical conducting material on the surface of which cytochrome c.sub.3 is immobilized in an amount ranging between 20% and 100% of monolayer coverage into a first aqueous electrolyte solution at a pH of from about 4 to 10, placing a second electrode into a second aqueous electrolyte solution, said second electrolyte solution and second electrode being in communication with said first electrolyte solution and said first electrode in a manner to complete an electrical circuit, and
An electrode comprising a solid electrical conducting material on the surface of which cytochrome C.sub.3 is immobilized in an amount ranging from about 20%-100% of monolayer coverage which is prepared by soaking said electrode in a solution comprising cytochrome C.sub.3 in a concentration of from about 10.sup.-5 M to 10.sup.-3 M.
An electrode comprising a solid electrical conducting material on the surface of which cytochrome C.sub.3 is immobilized in an amount ranging from about 20%-100% of monolayer coverage which is further treated by:
An electrode comprising a solid electrical conducting material on the surface of which cytochrome C.sub.3 is immobilized in an amount ranging from about 20-100 percent of monolayer coverage which is prepared by:
Dependencies are inferred from the claim text.
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Fuel cells; Manufacture thereof: biochemical fuel cells, i.e. cells in which microorganisms function as catalysts
Measuring or testing processes involving enzymes, nucleic acids or microorganisms ; Compositions therefor; Processes of preparing such…
Electrodes; Manufacture thereof not otherwise provided for: characterised by the material
Characterised by the material: electrodes formed of a single material
Term ended 17 Sep 2002 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The invention relates to an electrical conducting solid electrode on the surface of which cytochrome c.sub.3 is immobilized, such an electrode being provided with the electrocatalytic activity of the direct four-electron reduction of dioxygen and enzymatic activities, and its uses.
During the last five years, there has been a great deal of interest in the fabrication of chemically modified electrodes or catalytic electrodes. The fabrication of oxygen electrodes catalzying the electrochemical reduction of dioxygen given by the following two schemes:
______________________________________ Scheme I: O.sub.2 + 2e + 2H.sup.+ .fwdarw. H.sub.2 O.sub.2 (a) H.sub.2 O.sub.2 + 2e + 2H.sup.+ .fwdarw. 2H.sub.2 O (b) Scheme II: O.sub.2 + 4e + 4H.sup.+ .fwdarw. 2H.sub.2 O ______________________________________
FIG. 1 (left side) shows the arrangement of a ring electrode and a disk electrode of the present invention. The top arrow indicates the direction of rotation of the electrode. FIG. 1 (right side) depicts a typical arrangement of the electrode, the electrolyte, the counter electrode, the salt bridge, a reference electrode, and a gas trap for collecting the gas which is evolved during operation of the cell. Also indicated in the drawing is the possibility that the cell may be connected to a potentiogalvanostat.
The invention is further illustrated with reference to the following examples and comparative experiments, but not intended to be restricted by them.
A graphite electrode was pretreated by radio frequency plasma under vacuum so that a more than 100-fold surface area was generated.
The pretreated graphite electrode (surface area 2.times.2 cm.sup.2) was soaked in a 1.times.10.sup.-7 M cytochrome c.sub.3 buffer solution having a pH of 7 (phosphate buffer) for half an hour and about 50% of the surface was covered with cytochrome c.sub.3. The cytochrome c.sub.3 had been extracted from a D. vulgaris Miyazaki strain.