Electrode catalyst for electrochemical reaction, process for producing the electrode catalyst and electrode for electrochemical reaction having the electrode catalyst

Abstract

The present invention provides an electrode catalyst for electrochemical reaction, the electrode catalyst having: a conductive diamond particle having fine pores on a surface thereof; and a carbon-reactive catalyst metal in the fine pores, a process for producing the electrode catalyst, and an electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view exemplifying a fuel cell that uses a gas diffusion cathode of the invention.

FIG. 2 is a schematic view exemplifying a three-chamber brine electrolytic bath provided a gas diffusion cathode of the invention.

FIG. 3 is a schematic view exemplifying a two-chamber brine electrolytic bath provided a gas diffusion cathode of the invention.

FIG. 4 is a SEM photograph (multiplication: 6000 times) of raw material diamond fine particles used in example 1.

FIG. 5 is a SEM photograph (multiplication: 6000 times) of conductive diamond particles having fine pores generated by a process of example 1.

FIG. 6 is a SEM photograph (multiplication: 6000 times) of catalyst particles generated on a diamond surface by a heat treatment of example 1.

FIG. 7 is a SEM reflection image photograph (multiplication: 6000 times) of catalyst particles generated on a diamond surface by a heat treatment of example 1.

Claims

1. An electrode catalyst for electrochemical reaction, the electrode catalyst comprising: a conductive diamond particle having fine pores on a surface thereof; anda carbon-reactive catalyst metal in the fine pores.

2. The electrode catalyst according to claim 1, wherein a representative diameter of the fine pores is 1 nm to 10 μm.

3. The electrode catalyst according to claim 1, wherein the carbon-reactive catalyst metal is at least one of:at least one metal selected from the group consisting of platinum, gold, silver, copper, palladium, ruthenium and iridium; andan alloy of at least one metal selected from the group consisting of platinum, gold, silver, copper, palladium, ruthenium and iridium.

4. A process for producing an electrode catalyst for electrochemical reaction, the process comprising: forming a thin layer containing a carbon-reactive catalyst metal component on a conductive diamond particle as a base material; andheat-treating the conductive diamond particle having the thin layer in a reducing gas atmosphere to carry out a carbon reducing reaction due to the catalyst metal so as to form fine pores on a surface of the conductive diamond particle and to carry the catalyst metal in the fine pores.

5. The process for producing an electrode catalyst according to claim 4, wherein a temperature of the heat-treatment is 600 to 900° C.

6. An electrode for electrochemical reaction, the electrode comprising: an electrode substrate; anda mixture of the electrode catalyst according to claim 1 and a binder, the mixture being carried on a surface of the electrode substrate.