Gas diffusion electrode for carbon dioxide treatment, method for production thereof, and electrolysis cell having a gas diffusion electrode

Abstract

A gas diffusion electrode for carbon dioxide treatment includes a metal substrate and an electrically conductive catalyst layer which is applied thereto and has hydrophilic pores and/or channels and hydrophobic pores and/or channels, the catalyst layer including metal particles which are coated at least in regions with a polymeric binder material. A method produces a gas diffusion electrode for CO2 treatment, and an electrolysis cell has a corresponding gas diffusion electrode.

1 - 16 . (canceled) 
     
     
         17 . A gas diffusion electrode for utilization of carbon dioxide, comprising:
 a metallic support, and   an electrically conductive catalyst layer which has been applied to this metallic support and has hydrophilic pores and/or channels and hydrophobic pores and/or channels,   wherein the catalyst layer comprises metallic particles which are coated at least in subregions with a polymeric binder,   wherein, in the production of the gas diffusion electrode, the metallic particles are coated with fibers of the binder material before application to the support.   
     
     
         18 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the catalyst layer has a bubble formation point above 40 mbar.   
     
     
         19 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the flooding pressure of the catalyst layer is above 150 mbar.   
     
     
         20 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein silver particles have been used as metallic particles.   
     
     
         21 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the average particle diameter of the metallic particles is in the range from 1 μm to 10 μm.   
     
     
         22 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the metallic particles have a specific BET surface area in the range from 0.1 m2/g to 10 m2/g.   
     
     
         23 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein from 0.1 to 30% by weight of the polymeric binder in each case based on a catalyst/binder mixture from which the catalyst layer is formed, have been used.   
     
     
         24 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the average particle diameter of the polymeric binder is in the range from 0.5 μm to 20 μm.   
     
     
         25 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the porosity of the catalyst layer is in the range from 60% to 80%.   
     
     
         26 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the ratio of hydrophilic pores and/or channels and hydrophobic pores and/or channels in the catalyst layer is in the range from 50:50 to 20:80.   
     
     
         27 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein a gauze, preferably a silver gauze having a mesh opening in the range from 0.3 mm to 1.4 mm, has been used as metallic support.   
     
     
         28 . The gas diffusion electrode as claimed in  claim 17 ,
 wherein the gauze has a wire diameter in the range from 0.1 mm to 0.25 mm.   
     
     
         29 . A process for producing a gas diffusion electrode for utilization of CO 2 , comprising:
 producing a mixture of metallic particles and at least one binder material to form a mixture,   applying the mixture to a metallic support, and   embedding the applied mixture into the metallic support,   wherein the metallic particles are coated at least in subregions with the polymeric binder material during the production of the mixture and the metallic particles are coated with fibers of the binder material before application to the support and wherein an electrically conductive catalyst layer having hydrophilic pores and/or channels and hydrophobic pores and/or channels is produced by:   embedding the mixture by means of an extraction process into the metallic support, or   embedding the mixture by dry rolling-on into the metallic support.   
     
     
         30 . An electrolysis cell, comprising:
 a gas diffusion electrode as claimed in  claim 17 .   
     
     
         31 . The gas diffusion electrode as claimed in  claim 18 ,
 wherein the catalyst layer has a bubble formation point is in the range from 80 mbar to 150 mbar.   
     
     
         32 . The gas diffusion electrode as claimed in  claim 19 ,
 wherein the flooding pressure of the catalyst layer is in the range from 200 mbar to 1000 mbar.   
     
     
         33 . The gas diffusion electrode as claimed in  claim 21 ,
 wherein the average particle diameter of the metallic particles is in the range from 2 μm to 5 μm.   
     
     
         34 . The gas diffusion electrode as claimed in  claim 23 ,
 wherein from 5 to 25% by weight of the polymeric binder, in each case based on a catalyst/binder mixture from which the catalyst layer is formed, have been used.   
     
     
         35 . The gas diffusion electrode as claimed in  claim 23 ,
 wherein from 15 to 20% by weight of the polymeric binder, in each case based on a catalyst/binder mixture from which the catalyst layer is formed, have been used.