Flow-through reactor for electrocatalytic reactions

1. A method of reducing CO 2 , the method comprising:

contacting CO 2 with a cathode housed in a flow-through electrolysis cell;

wherein the cathode comprises a hierarchical nanoporous metal;

wherein the flow-through electrolysis cell comprises an anode and an ion-exchange membrane, wherein the anode comprises a metallic mesh;

wherein the CO 2 is dissolved in an electrolyte;

wherein contacting CO 2 with the cathode comprises flowing the electrolyte through the cathode; and

wherein the cathode comprises a first face and an opposite facing second face, the flow-through electrolysis cell further comprising a first electrolytic fluid input proximal to the first face and a first electrolytic fluid output proximal to the second face, wherein the electrolyte is flowed substantially perpendicular to the first face of the cathode that is substantially parallel to the ion-exchange membrane.

2. The method of claim 1 further comprising collecting a reduction product comprising a hydrocarbon, an aldehyde, an alcohol, a ketone, a carboxylic acid, or a mixture of any two or more thereof.

3. The method of claim 2 , wherein the method further comprises monitoring the reduction product via gas chromatography mass spectrometry (GCMS).

4. The method of claim 1 further comprising collecting a reduction product comprising ethylene, methane, or a mixture thereof.

5. The method of claim 1 , wherein flowing comprises applying a pressure gradient across the cathode.

6. The method of claim 5 , wherein the pressure gradient is from about 0.1 atm to about 10 atm.

7. The method of claim 1 , wherein the electrolyte flows through the cathode at a velocity of less than about 1 cm/s.

8. The method of claim 1 , wherein the cathode is between an electrolyte-in line and an electrolyte-out line of the flow-through electrolysis cell.

9. The method of claim 1 , wherein the hierarchical nanoporous metal comprises one or more of copper, platinum, silver, gold, nickel, iron, and zinc.

10. The method of claim 1 , wherein the hierarchical nanoporous metal is hierarchical nanoporous copper.

11. The method of claim 10 , wherein the hierarchical nanoporous copper is a dealloyed aluminum-copper alloy.

12. The method of claim 1 , wherein the hierarchical nanoporous metal is a dealloyed metal alloy.

13. The method of claim 1 , wherein the hierarchical nanoporous metal comprises nanopores with an average diameter of about 10 nm to about 500 nm and macropores with an average diameter of about 500 nm to about 10 6 nm.

14. The method of claim 1 , wherein the metallic mesh comprises one or more of platinum, palladium, carbon and boron-doped carbon/diamond.

15. The method of claim 1 , wherein:

the cathode is between an electrolyte-in line and an electrolyte-out line; and

the hierarchical nanoporous metal is a catalytic metal for reduction of a reactant which contacts the hierarchical nanoporous metal.