Process for making formic acid

1. A method for electrochemical production of at least formic acid, comprising:

(A) introducing water to a first compartment of an electrochemical cell, the first compartment including an anode;

(B) introducing carbon dioxide to a second compartment of the electrochemical cell, the second compartment including a solution of an electrolyte and a cathode, the cathode is selected from the group consisting of indium, lead, tin, cadmium, and bismuth, the electrolyte in the second compartment having a pH of between approximately 4 and 7;

(C) applying an electrical potential between the anode and the cathode in the electrochemical cell sufficient to reduce the carbon dioxide to formic acid; and

(D) maintaining a concentration of formic acid in the second compartment at or below approximately 500 ppm.

2. The method of claim 1 , wherein the solution of electrolyte includes at least one of potassium sulfate, potassium chloride, sodium chloride, sodium sulfate, lithium sulfate, sodium perchlorate, and lithium chloride.

3. The method of claim 1 , wherein the concentration of formic acid in the second compartment is maintained at or below approximately 500 ppm by removing formic acid from the second compartment.

4. The method of claim 1 , wherein the concentration of formic acid in the second compartment is maintained at or below approximately 300 ppm.

5. The method of claim 1 , further including:

introducing a concentration of divalent ions to the second compartment.

6. The method of claim 5 , where the concentration of divalent ions includes a concentration of at least one of magnesium ions, calcium ions, strontium ions, and barium ions.

7. The method of claim 1 , further comprising:

maintaining the pH of the electrolyte in the second compartment to between approximately 4.3 and approximately 5.5.

8. The method of claim 1 , wherein the second compartment further includes a heterocyclic aromatic amine selected from the group consisting of 4-hydroxy pyridine, adenine, a heterocyclic amine containing sulfur, a heterocyclic amine containing oxygen, an azole, benzimidazole, a bipyridine, furan, an imidazole, an imidazole related species with at least one five-member ring, an indole, methylimidazole, an oxazole, phenanthroline, pterin, pteridine, a pyridine, a pyridine related species with at least one six-member ring, pyrrole, quinoline, a thiazole, and mixtures thereof.

9. The method of claim 8 , wherein the heterocyclic aromatic amine is 4-hydroxy pyridine.

10. The method of claim 9 , further comprising:

producing at least one of methanol, acetone, and isopropanol in the electrolyte.

11. A method for electrochemical production of at least formic acid, comprising:

(A) introducing a liquid to a first compartment of an electrochemical cell, the first compartment including an anode;

(B) introducing carbon dioxide to a second compartment of the electrochemical cell, the second compartment including a solution of an electrolyte and a cathode, the electrolyte in the second compartment having a pH which provides a concentration of hydrogen ions, the carbon dioxide, and water at a surface of the cathode to favor reduction of the carbon dioxide at the cathode;

(C) applying an electrical potential between the anode and the cathode in the electrochemical cell sufficient for the cathode to reduce the carbon dioxide to at least formic acid; and

(D) maintaining a concentration of formic acid in the second compartment at or below approximately 500 ppm.

12. The method of claim 11 , wherein the cathode includes at least one of lead, tin, cadmium, bismuth, and indium.

13. The method of claim 12 , wherein the cathode comprises indium.

14. The method of claim 11 , wherein the liquid is water.