Catalysts for electrochemical CO
The invention relates to an electrocatalyst for reduction of CO 2 to produce multi-carbon compounds, comprising a multi-metal material comprising a primary metal being copper and at least one enhancer metal selected from germanium, gallium, tin, silicon, silver, gold, zinc and aluminium. The invention also relates to a process for electrochemical production of a multi-carbon compound from CO 2 using such an electrocatalyst.
1. An electrocatalyst for reduction of CO 2 to produce multi-carbon compounds, wherein the electrocatalyst comprises a multi-metal material comprising a primary metal being copper and at least one enhancer metal being aluminum, so the electrocatalyst comprises a multi-metal Cu—Al material being formed, as a catalytic layer and comprises a surface region having a thickness between 1 nm and 3 nm as determined by Auger electron spectroscopy, and in that at least the surface region is nanoporous and comprises an Al content of 3 wt % to 30 wt % and a Cu content of 70 wt % to 97 wt %.
2. The electrocatalyst according to claim 1 , wherein the multi-metal Cu—Al material is a de-alloyed material.
3. The electrocatalyst according to claim 1 , wherein the multi-metal Cu—Al material:
comprises from 1 wt % to 50 wt % of Al based on the total weight of the multi-metal Cu—Al material, preferably from 3 wt % to 30 wt %; and/or
comprises from 50 wt % to 99 wt % Cu based on the total weight of the multi-metal Cu—Al material, preferably from 70 wt % to 97 wt % Cu.
4. The electrocatalyst according to claim 1 , wherein the electrocatalyst comprises a gas diffusion membrane.
5. The electrocatalyst according claim 1 , wherein the catalytic layer has a thickness between 10 nm and 5000 nm, as determined by cross-sectional scanning electron microscopy.
6. The electrocatalyst according to claim 1 , wherein:
the multi-metal Cu—Al material comprises Al-terminated pores; or
the Al is ion-implanted into the Cu.
7. The electrocatalyst of claim 1 , wherein at least the surface region has pores that have pore diameters ranging from 1 nm to 100 nm, as determined by HRTEM and HAADF analysis, or from 5 nm to 20 nm.
8. The electrocatalyst of claim 1 , wherein at least the surface region has a homogeneous distribution of Al and Cu; and/or at least the surface region consists of Cu and Al.
9. The electrocatalyst of claim 1 , wherein the Cu in at least the surface region is Cu (111).
10. The electrocatalyst of claim 1 , wherein the Cu in at least the surface region is Cu (100).
11. A process for electrochemical production of a multi-carbon compound from CO 2 , comprising:
contacting CO 2 gas and an electrolyte with an electrode comprising the electrocatalyst according to claim 1 , such that the CO 2 contacts the electrocatalyst;
applying a voltage to provide a current density to cause the CO 2 gas contacting the electrocatalyst to be electrochemically converted into the multi-carbon compound; and
recovering the multi-carbon compound.
12. The process of claim 11 , wherein the current density provided in the current collection structure is predetermined for selective electrochemical conversion of the CO 2 into a target multi-carbon compound.
13. The process of claim 11 , wherein the target multi-carbon compound is ethylene or an alcohol; and/or in that the electrolyte comprises an alkaline compound.
14. The process of claim 11 , wherein the electrolyte comprises an alkaline solutions.
15. The process of claim 11 , conducted in a three-electrode flow-cell.
16. A system for CO 2 electro reduction to produce multi-carbon hydrocarbons, comprising:
an electrolytic cell configured to receive a liquid electrolyte and CO 2 gas;
an anode;
a cathode comprising an electrocatalyst as defined in claim 1 ; and
a voltage source to provide a current density to cause the CO 2 gas contacting the electrocatalyst to be electrochemically converted into the multi-carbon hydrocarbon.
17. A method of manufacturing an electrocatalyst for reduction of CO 2 to produce multi-carbon compounds, the method comprising:
a multi-metal material comprising Cu and Al; and
subjecting the multi-metal material to chemical etching to remove a portion of the Al from a surface region of the multi-metal material to produce a de-alloyed Cu—Al material.
18. The method of claim 17 , wherein the chemical etching comprises immersing the multi-metal material comprising Cu and Al into an acidic solution to remove Al.
19. The method of claim 17 , wherein the step of producing a multi-metal material comprising Cu and Al comprises co-evaporation of Al and Cu to form a Cu—Al alloy; with preference the multi-metal material comprising Cu and Al form a layer having a thickness ranging from 200 to 1000 nm, as determined by cross-sectional scanning electron microscopy.
20. A method of manufacturing an electrocatalyst for reduction of CO 2 to produce multi-carbon compounds, the method comprising ion-implanting Al into Cu, wherein the electrocatalyst comprises a multi-metal material comprising a primary metal being copper and at least one enhancer metal being aluminum, so the electrocatalyst comprises a multi-metal Cu—Al material being formed as a catalytic layer and comprises a surface region having a thickness between 1 nm and 3 nm, as determined by Auger electron spectroscopy, and in that at least the surface region is nanoporous and comprises an Al content of 3 wt % to 30 wt % and a Cu content of 70 wt % to 97 wt %.