# US 12,180,600 B2 · Electrochemical conversion of carbon dioxide to form an organic acid

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- Number: US 12,180,600 B2
- Document ID: US12180600B2
- Status: Granted
- Kind: B2
- Application number: 17/568,594
- Filed: 2022-01-04
- Published: 2023-09-28
- Granted: 2024-12-31
- Earliest claimed: 2022-01-04
- Assignees: Uop LLC
- Applicants: Uop LLC
- Inventors: Richa Baronia; Jyoti Goel; Sachin Daulatgir Giri; Sagar Sopan Ghadage; Kuldeep Balram Mamtani
- Web page: https://patentgrep.com/patent/US12180600B2

## CPC

- C25B 3/07: Oxygen containing compounds
- C25B 3/23: Oxidation (halogenation C25B3/27)
- C25B 3/26: of carbon dioxide
- C25B 9/17: Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
- C25B 9/21: two or more diaphragms
- C25B 11/032: Gas diffusion electrodes
- C25B 11/042: Electrodes formed of a single material
- C25B 13/00: Diaphragms; Spacing elements
- C25B 13/08: based on organic materials
- C25B 11/075: consisting of a single catalytic element or catalytic compound
- C25B 11/081: the element being a noble metal
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)

## Abstract

A process for electrochemical conversion of carbon dioxide using a three-compartment cell provides low voltage requirements, high faradaic efficiencies, and high concentration of formic acid in product solutions. The applied voltage between anode and cathode should be less than 3.5V. Carbon dioxide may be converted to an organic acid.

## Claims

### Claim 1

An electrochemical process for carbon dioxide conversion comprising:
feeding an anode reactant comprising hydrogen to an anode comprising a quantity of anode catalyst;
feeding a cathode reactant comprising carbon dioxide to a cathode comprising a quantity of cathode catalyst;
feeding an inlet solution feed comprising a solution with a pH between about 6 to about 8 to a central flow compartment, wherein the central flow compartment comprises macroreticular resin dispersed within a void space, and wherein an average diameter of said macroreticular resin is greater than about 120% of and less than about 170% of the width of said void space;
applying a voltage of less than about 3.5V between the anode and cathode; and
recovering a product solution comprising formic acid from an outlet of said central flow compartment, wherein a concentration of the formic acid in the product solution is greater than about 9 wt % and less than about 50 wt %.

### Claim 2 (depends on 1)

The process of claim 1 further comprising an anion exchange membrane interposed between said central flow compartment and said cathode, wherein the anion exchange membrane comprises a KOH treated polybenzimidazolium.

### Claim 3 (depends on 2)

The process of claim 2 wherein an average current density at the anion exchange membrane is at least about 20 mA/cm2, wherein an area in denominator of the average current density is the area of the cathode on which the cathode catalyst is disposed.

### Claim 4 (depends on 3)

The process of claim 3 wherein a formate ion selectivity at the cathode is at least 50% at a cell potential difference of about 2.2 V.

### Claim 5 (depends on 1)

The process of claim 1, wherein the cathode catalyst comprises a metal selected from the group consisting of Au, Ag, Cu, Sn, Sb, Bi, Pb, Zn, In and combinations thereof.

### Claim 6 (depends on 5)

The process of claim 5 wherein the metal comprises Sn and Bi.

### Claim 7 (depends on 1)

The process of claim 1 wherein said macroreticular resin forms a single layer within said void space.

### Claim 8 (depends on 1)

The process of claim 1 wherein said anode catalyst is free of Ir.

### Claim 9 (depends on 1)

The process of claim 1 wherein the faradaic efficiency of the process is greater than about 70%.

### Claim 10 (depends on 1)

The process of claim 1 wherein an unitless ratio of anode reactant flow to cathode reactant flow is greater than about 0.5 and less than about 1.5.

### Claim 11 (depends on 1)

The process of claim 1 wherein a flow rate of said inlet solution feed is about 0.05 mL/min.

### Claim 12 (depends on 1)

The process of claim 1, wherein the voltage applied is greater than 2V.