Composite multilayered electrocatalysts for CO
The invention relates to a composite multilayer carbon dioxide (CO 2 ) reduction catalyst, comprising a catalyst layer comprising at least one metal compound, the catalyst layer having opposed first and second sides; a hydrophobic gas-diffusion layer provided on the first side of the catalyst layer; a current collection structure provided on the second side of the catalyst layer. The metal is preferably copper. The invention also relates to a method for electrochemical production of a hydrocarbon product, such as ethylene, using said catalyst.
1. A composite multilayer carbon dioxide (CO 2 ) reduction catalyst, comprising:
a catalyst layer comprising at least one metal compound, the catalyst layer having opposed first and second sides;
a hydrophobic gas-diffusion layer provided on the first side of the catalyst layer wherein the hydrophobic gas-diffusion layer is an electrically insulating polymeric material;
a current collection structure provided on the second side of the catalyst layer wherein the catalyst layer comprises copper.
2. The multilayer CO 2 reduction composite catalyst according to claim 1 characterized in that the hydrophobic gas-diffusion layer has:
a porosity with pores having a diameter ranging from 0.01 to 2 micrometers as determined by scanning electron microscopy; or
a thickness ranging between 20 and 500 micrometers as determined by scanning electron microscopy.
3. The multilayer CO 2 reduction composite catalyst according to claim 1 , characterized in that the catalyst layer is disposed directly on the hydrophobic gas-diffusion layer.
4. The multilayer CO 2 reduction composite catalyst according to claim 1 , characterized in that:
the catalyst layer has a thickness ranging between 1 and 2000 nm as determined by scanning electron microscopy; or
the current collection structure has a thickness ranging between 1 to 100 micrometers as determined by scanning electron microscopy.
5. The multilayer CO 2 reduction composite catalyst according to claim 1 , characterized in that the current collection structure comprises:
a stabilization layer disposed on the catalyst layer, and
a current collection layer disposed on the stabilization layer.
6. The multilayer CO 2 reduction composite catalyst according to claim 5 , characterized in that the stabilization layer comprises carbon nanoparticles; or the current collection layer comprises graphite and forms a graphite electrode layer.
7. The multilayer CO 2 reduction composite catalyst according to claim 1 , characterized in that the current collection structure is composed of at least one electrically conductive carbon compound.
8. The multilayer CO 2 reduction composite catalyst according to claim 1 , wherein the hydrophobic gas diffusion layer is a fluorocarbon polymer.
9. The multilayer CO 2 reduction composite catalyst according to claim 1 , wherein the hydrophobic gas diffusion layer is polytetrafluoroethylene.
10. The multilayer CO 2 reduction composite catalyst according to claim 1 , wherein the hydrophobic gas diffusion layer has a porosity with pores having a diameter ranging from 0.01 to 2 micrometers as determined by scanning electron microscopy.
11. A fuel cell comprising a reaction cell receiving an electrolyte;
an oxygen evolution catalyst; and
a composite multilayer CO 2 reduction catalyst according to claim 1 .
12. A system for CO 2 reduction, comprising:
an electrolytic cell configured to receive a liquid electrolyte and CO 2 gas;
an anode;
a cathode comprising a composite multilayer CO 2 reduction catalyst as defined in claim 1 .
13. Use of the composite multilayer CO 2 reduction catalyst according to claim 1 in a fuel cell or for production of a hydrocarbon product.
14. A method for electrochemical production of a hydrocarbon product, comprising:
a) contacting CO 2 gas and an electrolyte with an electrode comprising the multilayer CO 2 reduction composite catalyst according to claim 1 , such that the CO 2 gas diffuses through the hydrophobic gas-diffusion layer and contacts the catalyst layer;
b) applying a voltage to provide a current density in the current collection structure of the multilayer CO 2 reduction composite catalyst to cause the CO 2 gas contacting the catalyst layer to be electrochemically converted into the hydrocarbon product; and
c) recovering the hydrocarbon product.
15. The method according to claim 14 , characterized in that the current density provided in the current collection structure is at least 100 mA/cm 2 for selective electrochemical conversion of the CO 2 into a target hydrocarbon product being ethylene.
16. The method according to claim 14 , wherein the electrolyte comprises KOH.
17. A method of reducing flooding of a CO 2 gas-diffusion membrane used in a CO 2 reduction composite catalyst comprising a metal catalyst and a current collection material for converting CO 2 into chemical compounds, the method comprising decoupling the CO 2 gas-diffusion membrane from the current collection material, characterized in that the CO 2 reduction composite catalyst is according to claim 1 .
18. A method of manufacturing a composite multilayer CO 2 reduction catalyst according to claim 1 , comprising:
depositing a catalyst material onto a hydrophobic gas-diffusion layer to provide a catalyst layer thereon;
affixing current collection material to the catalyst layer to form a current collection structure thereon, wherein the current collection structure and the hydrophobic gas-diffusion layer are decoupled such that the hydrophobic gas-diffusion layer maintains hydrophobicity during operation.
19. The method according to claim 18 , further comprising:
coating an exposed surface of the catalyst layer with a conductive stabilization material to form a stabilization layer that is electrically connected to the catalyst material; and
affixing a conductive material to an exposed surface of the stabilization layer to provide a current collection layer thereon, such that the current collection structure comprises the stabilization layer and the current collection layer.
20. The method according to claim 18 , characterized in that the step of depositing the catalyst material onto the hydrophobic gas-diffusion layer is performed using a physical deposition method.
21. The method according to claim 18 , characterized in that:
the hydrophobic gas-diffusion layer is composed of an electrically insulating material which is a polymeric material.
22. The method according to claim 18 , characterized in that the current collection material is or comprises graphite and in that graphite is applied to the catalyst layer to form a single graphite layer as the current collection structure.