Method for the preparation of a gas diffusion layer and a gas diffusion layer obtained or obtainable by such method

1 . A method for preparation of a gas diffusion layer, containing the steps of:

a) preparing a carrier-binder paste comprising a solvent, a fluorinated binder and conductive carrier particles;

b) preparing an adhesive composition comprising:

a solvent

a fluorinated binder and

essentially no or equal to or less than 15 wt. % of conductive carrier particles, based on the total weight of the fluorinated binder in the adhesive composition and the conductive carrier particles in the adhesive composition; and

c) combining a layer of supporting material, a layer of the adhesive composition and a layer of the carrier-binder paste, wherein the layer of the adhesive composition is applied between the layer of the supporting material and the layer of the carrier-binder paste, wherein the layer of the carrier-binder paste has a thickness in a range from equal to or more than 1.1 mm to equal to or less than 1.5 mm; and

pressing the combination of supporting material, adhesive composition and carrier-binder paste at a pressure of at least 15 kilopascal and/or

heating the combination of supporting material, adhesive composition and carrier-binder paste at a temperature of at least 300° C.;

wherein the carrier-binder paste comprises equal to or less than 0.3 grams fluorinated binder per milliliter of solvent, and wherein the adhesive composition comprises equal to or more than 0.3 grams fluorinated binder per milliliter of solvent.

2 . The method according to claim 1 , wherein the conductive carrier particles are carbon particles.

3 . The method according to claim 1 , wherein the fluorinated binders comprise one or more fluorinated polymers chosen from the group consisting of polytetrafluoroethylene polymers, perfluoroalkoxy polymers, fluorinated ethylene propylene polymers and polyvinylidene difluoride polymers.

4 . The method according to claim 1 , wherein the carrier-binder paste contains, based on the total weight of fluorinated binder in the carrier-binder paste and conductive carrier particles in the carrier-binder paste together, in the range from equal to or more than 20 wt. % to equal to or less than 60 wt. % of fluorinated binder and in the range from equal to or more than 40 wt. % to equal to or less than 80 wt. % of conductive carrier particles.

5 . The method according to claim 1 , wherein the solvent in the carrier-binder paste and/or the adhesive composition contains or consists of water and/or an alkanol.

6 . The method according to claim 5 , wherein the solvent in the carrier-binder paste and/or the adhesive composition contains an alkanol, and wherein a suspension of the fluorinated binder in such solvent is prepared by:

combining the fluorinated binder and the solvent; and

mixing the fluorinated binder and the solvent during a period in the range from equal to or more than 10 seconds to equal to or less than 15 minutes.

7 . The method according to claim 1 , wherein the adhesive composition comprises a higher concentration of fluorinated binder, based on grams of fluorinated binder per milliliter of solvent, than the carrier-binder paste.

8 . The method according to claim 1 , wherein, in step a), the carrier-binder paste is prepared by making a suspension of the fluorinated binder in the solvent and subsequently mixing the conductive carrier particles with the suspension.

9 . The method according to claim 1 , wherein, in step c), a layer of the adhesive composition is coated onto a side of the layer of the carrier-binder paste, whereafter the supporting material is attached to the coated side of the layer of carrier-binder paste.

10 . A gas diffusion layer obtained or obtainable by the method according to claim 1 .

11 . A method for preparation of a gas diffusion electrode, containing the steps of:

a) preparing a carrier-binder paste comprising a solvent, a fluorinated binder and conductive carrier particles;

b) preparing an adhesive composition comprising

a solvent,

a fluorinated binder and

essentially no or equal to or less than 15 wt. % of conductive carrier particles, based on the total weight of the fluorinated binder in the adhesive composition and the conductive carrier particles in the adhesive composition;

c) combining a layer of supporting material, a layer of the adhesive composition and a layer of the carrier-binder paste, wherein the layer of the adhesive composition is applied between the layer of supporting material and the layer of the carrier-binder paste, wherein the layer of the carrier-binder paste has a thickness in a range from equal to or more than 1.1 mm to equal to or less than 1.5 mm; and

pressing the combination of supporting material, adhesive composition and carrier-binder paste at a pressure of at least 15 kilopascal and/or heating the combination of supporting material, adhesive composition and carrier-binder paste at a temperature of at least 300° C.; and

d) applying a catalytic layer, which catalytic layer comprises a catalyst, onto the layer of the carrier-binder paste on a side opposite of a side where the layer of the adhesive composition was applied

wherein the carrier-binder paste comprises equal to or less than 0.3 grams fluorinated binder per milliliter of solvent, and wherein the adhesive composition comprises equal to or more than 0.3 grams fluorinated binder per milliliter of solvent.

12 . The method according to claim 11 , wherein the catalytic layer comprises the catalyst, a fluorinated binder and conductive carrier particles.

13 . The method according to claim 11 , wherein the catalyst comprises indium, bismuth or a combination of indium and bismuth.

14 . A gas diffusion electrode comprising a gas diffusion layer obtained or obtainable by a method according to claim 11 .

15 . A process for electrochemically reducing carbon dioxide, comprising:

introducing an anolyte to a first cell compartment of an electrochemical cell, the first cell compartment comprising an anode;

introducing a catholyte and carbon dioxide to a second cell compartment of the electrochemical cell, the second cell compartment comprising a cathode; and

applying an electrical potential between the anode and the cathode sufficient to reduce the carbon dioxide to a reduced reaction product,

wherein the cathode comprises a gas diffusion layer, the gas diffusion layer

obtained by a method containing the steps of:

a) preparing a carrier-binder paste comprising a solvent, a fluorinated binder and conductive carrier particles;

b) preparing an adhesive composition comprising:

a solvent,

a fluorinated binder and

essentially no or equal to or less than 15 wt. % of conductive carrier particles, based on the total weight of the fluorinated binder in the adhesive composition and the conductive carrier particles in the adhesive composition; and

c) combining a layer of supporting material, a layer of the adhesive composition

and a layer of the carrier-binder paste, wherein the layer of the adhesive

composition is applied between the layer of supporting material and the layer of

the carrier-binder paste, wherein the layer of the carrier-binder paste has a thickness in a range from equal to or more than 1.1 mm to equal to or less than 1.5 mm; and

pressing the combination of supporting material, adhesive composition and carrier-binder paste at a pressure of at least 15 kilopascal and/or

heating the combination of supporting material, adhesive composition and carrier-binder paste at a temperature of at least 300° C.;

wherein the carrier-binder paste comprises equal to or less than 0.3 grams fluorinated binder per milliliter of solvent, and wherein the adhesive composition comprises equal to or more than 0.3 grams fluorinated binder per milliliter of solvent.