N.e. Chemcat Corporation

Takuya Tsubaki

Yoko Nakamura

Tomoteru Mizusaki

Kiyotaka Nagamori

Hiroshi Igarashi

Yasuhiro Seki

Provided is a method for producing a gas diffusion electrode, with which it is possible to more effectively improve electrode performance, in cases in which a core-shell catalyst is used as an electrode catalyst. This method for producing gas diffusion electrode comprises: a first step in which a support layer having electron conductivity, water-repellency and gas diffusion properties is soaked in water; a second step in which the constituent materials of ink for forming a catalyst layer are put into a mixer and mixed by agitation to prepare an ink for forming a catalyst layer; and a third step in which the ink for forming a catalyst layer is used to form a catalyst layer on the surface of the support layer obtained in the first step. The ink for forming the catalyst layer contains a core-shell catalyst, a polyelectrolyte, water and alcohol. The alcohol is only a polyvalent alcohol.

Method for producing gas diffusion electrode and method for producing membrane electrode assembly (MEA)

Provided is an electrode catalyst that can exhibit sufficient performance, is suitable for mass production, and is suitable for reducing production costs, even when containing a relatively high concentration of chlorine. The electrode catalyst has a core-shell structure including a support; a core part that is formed on the support; and a shell part that is formed so as to cover at least one portion of the surface of the core part. A concentration of bromine (Br) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 500 ppm or less, and a concentration of chlorine (Cl) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 8,500 ppm or less.

Electrode catalyst, composition for forming gas diffusion electrode, gas diffusion electrode, membrane-electrode assembly, and fuel cell stack

Provided is an electrode catalyst production method capable of obtaining, through an easy operation, an electrode catalyst whose chlorine (Cl) species content has been reliably and sufficiently reduced, even when using as an electrode catalyst raw material an electrode catalyst precursor containing a high concentration of chlorine. The method is to produce an electrode catalyst having a core-shell structure including a support, a core part formed on the support and a shell part formed to cover at least a part of a surface of the core part. The method includes a first step (1) of retaining a liquid containing ultrapure water, a reductant such as a hydrogen-containing gas and an electrode catalyst precursor under at least one stage of a predetermined temperature for a predetermined retention time, such electrode catalyst precursor being produced using a material containing chlorine (Cl) species, and exhibiting a chlorine (Cl) species concentration not lower than a predetermined first chlorine (Cl) species concentration when measured by X-ray fluorescence (XRF) spectroscopy.

Production method of electrode catalyst, electrode catalyst, composition for forming gas diffusion electrode, gas diffusion electrode, membrane-electrode assembly (MEA), and fuel cell stack

Provided is an electrode catalyst that can exhibit sufficient performance, is suitable for mass production, and is suitable for reducing production costs, even when containing a relatively high concentration of chlorine. The electrode catalyst has a core-shell structure including a support; a core part that is formed on the support; and a shell part that is formed so as to cover at least one portion of the surface of the core part. The electrode catalyst concurrently fulfills conditions expressed by the following formulae (1) and (2): (X1/M)&#x2266;1.2 . . . (1) (X2/M)&#x2266;47.0 . . . (2) (in the formula (1) and the formula (2), M represents an amount of substance (number of atoms) of one or more constituent metal elements of the shell part, X1 represents an amount of substance (number of atoms) of bromine (Br), and X2 represents an amount of substance (number of atoms) of chlorine (Cl)).

Provided is a production method of an electrode catalyst that can reduce the content of chlorine species reliably and sufficiently through a simple operation, even when using an electrode catalyst precursor containing a high concentration of chlorine (Cl) species as a raw material of the electrode catalyst. The production method of the electrode catalyst has a core-shell structure including a core part formed on a support and a shell part formed to cover at least a part of a surface of the core part. The production method includes a first step (1) of preparing a first liquid with an electrode catalyst precursor (I) being dispersed in ultrapure water by adding the electrode catalyst precursor (I) to the ultrapure water, the electrode catalyst precursor (I) being produced using a material containing chlorine (Cl) species, and exhibiting a chlorine (Cl) species concentration not lower than a first chlorine (Cl) species concentration when measured by X-ray fluorescence (XRF) spectroscopy; and a second step (2) of preparing a second liquid by dispersing an electrode catalyst precursor (II), the electrode catalyst precursor (II) being obtained by filtrating and washing the electrode catalyst precursor (I) contained in the first liquid with ultrapure water, and then performing washing until an electric conductivity &#x3c1; of a filtrate has become a first value or lower.

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Bando, Japan

Takuya Tsubaki