Method for production of an electrode and the electrode for a fuel cell
A method for the production of an electrode for a fuel cell is provided that comprises providing a multitude of catalyst particles carried on at least one electrically conductive particle carrier, and depositing one or more atomic or molecular layers of an ionomer from the gas phase on the catalyst particles and/or the at least one particle carrier, thereby forming a proton-conducting ionomer coating. Furthermore, an electrode for a fuel cell is also provided.
1. A method for the production of an electrode for a fuel cell, comprising:
providing of a plurality of catalyst particles carried on at least one electrically conductive particle carrier; and
depositing one or more atomic or molecular layers of an ionomer from the gas phase on the catalyst particles and/or the at least one particle carrier, thereby forming a proton-conducting ionomer coating.
2. The method according to claim 1 , further comprising:
depositing atoms or molecules of at least one passivation reactant on the on a surface of the catalyst particles, thereby forming at least one passivated region on the surface of the catalyst particles prior to forming the proton-conducting ionomer coating;
depositing the proton-conducting ionomer coating away from the at least one passivated region of the surface of the catalyst particle; and
removing the at least one passivation reactant from the catalyst particles, thereby forming the proton-conducting ionomer coating having a porosity.
3. The method according to claim 2 , wherein the at least one passivation reactant is chosen from a group comprising carbon monoxide, cyanide ions, thiocyanate, isothiocyanate, sulfide, hydrogen sulfide, amine and ammonia.
4. The method according to claim 2 , wherein, the at least one passivated region of the surface of the catalyst particle is located at a particle edge or at a particle corner of the catalyst particle.
5. The method according to claim 2 , wherein the at least one passivated region of the surface of the catalyst particle is located at a particle facet of the catalyst particle.
6. The method according to claim 2 , wherein the at least one passivation reactant is removed by furnishing thermal energy to the at least one particle carrier and/or to the catalyst particles.
7. The method according to claim 2 , wherein the at least one passivation reactant is removed by applying a vacuum to the at least one particle carrier and/or to the catalyst particles.
8. The method according to claim 2 , wherein the at least one passivation reactant is removed by creating a plasma at the at least one particle carrier and/or at the catalyst particles.
9. The method according to claim 2 , wherein the at least one passivation reactant is removed by supplying at least one chemical depassivation reactant to the at least one particle carrier and/or to the catalyst particles.
10. The method according to claim 2 , wherein, after the removal of the at least one passivation reactant a radical-decomposing impregnation is applied to the at least one particle carrier and/or to the catalyst particles.
11. The method according to claim 10 , wherein the impregnation comprises a cerium salt or a cerium oxide.
12. The method according to claim 1 , wherein the particle carrier laden with the catalyst particles is present in powder form and is applied to a substrate before the proton-conducting ionomer coating is deposited thereon.
13. An electrode for a fuel cell, comprising:
a multitude of electrically conductive particle carriers, each of the electrically conductive particle carriers carrying one or more catalyst particles and having a proton-conducting ionomer coating bound at least partly to one or more of the catalyst particles,
wherein the proton-conducting ionomer coating is given a preselected porosity by a passivation reactant, the pores or channels of which are present in a predetermined or predeterminable distribution.