# US 2018/0023202 A1 · Electrolysis System for Carbon Dioxide

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- Number: US 2018/0023202 A1
- Document ID: US20180023202A1
- Status: Published application
- Kind: A1
- Application number: 15/548,618
- Filed: 2015-12-23
- Published: 2018-01-25
- Earliest claimed: 2015-02-06
- Assignees: Siemens Aktiengesellschaft
- Applicants: Siemens Aktiengesellschaft
- Inventors: Ralf KRAUSE; Christian RELLER; Guenter SCHMID; Elena VOLKOVA
- Web page: https://patentgrep.com/patent/US20180023202A1

## CPC

- C25B 3/25: Reduction
- B01J 29/106: {Y-type faujasite}
- C01B 32/50: Carbon dioxide
- C07C 47/04: Formaldehyde
- C25B 1/00: Electrolytic production of inorganic compounds or non-metals
- C25B 1/23: Carbon monoxide or syngas
- C25B 3/03: Acyclic or carbocyclic hydrocarbons
- C25B 3/07: Oxygen containing compounds
- C25B 3/26: of carbon dioxide
- C25B 15/08: Supplying or removing reactants or electrolytes; Regeneration of electrolytes
- C25B 15/083: {Separating products}
- C25B 15/085: {Removing impurities}
- C25B 15/087: {Recycling of electrolyte to electrochemical cell}
- C07C 1/2078: {by a transformation in which at least one -C(=O)-O- moiety is eliminated}
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The present disclosure relates to electrolysis systems and methods. The teachings thereof may be embodied in methods and systems for the utilization of carbon dioxide and production of carbon monoxide. For example, a method may include: passing an electrolyte and carbon dioxide in front of a cathode through a cathode chamber; and removing electrolysis byproducts from an electrolyte/electrolysis product mixture using a catalytic filter system. The cathode may include material to reduce carbon dioxide. The process may generate a hydrocarbon compound or carbon monoxide as the electrolysis product and a formate as an electrolysis byproduct. The filter system may include a functionalized complex or a functionalized support material which catalyzes a cleavage reaction of formates (a) to hydrogen and carbon dioxide, or (b) to water and carbon monoxide.

## Claims

### Claim 1

A method for carbon dioxide utilization by means of an electrolysis system, the method comprising:
passing an electrolyte and carbon dioxide in front of a cathode through a cathode chamber;
wherein the cathode comprises an electrode and/or catalyst material with which carbon dioxide is reduced;
wherein a hydrocarbon compound or carbon monoxide is generated as electrolysis product and a formate is generated as electrolysis byproduct; and
removing electrolysis byproducts from an electrolyte/electrolysis product mixture using a catalytic filter system comprising a functionalized complex or a functionalized support material which catalyzes a cleavage reaction of formates (a) to hydrogen and carbon dioxide, or (b) to water and carbon monoxide.

### Claim 2 (depends on 1)

The method as claimed in claim 1, further comprising:
guiding the electrolyte in a closed circuit; and
thermally regenerating the filter system.

### Claim 3

An electrolysis system for carbon dioxide utilization comprising:
an electrolysis cell having an anode in an anode chamber, a cathode in a cathode chamber, and a filter unit;
the cathode chamber takes up an electrolysis reactant comprising carbon dioxide and passes it in front of the cathode;
wherein the cathode comprises an electrode or catalyst material to reduce carbon dioxide to a hydrocarbon compound or to carbon monoxide as electrolysis product and a formate as electrolysis byproduct; and
wherein the filter unit comprises a catalytic filter system convert a formate to: (a) hydrogen and carbon dioxide, or (b) water and carbon monoxide.

### Claim 4 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the reactable formate is of the type R+HCOO− where R+ is a cation selected from the group consisting of: H+, Li+, Na+, K+, NH4+, Cs+, Sr+, Ba+, Mn+, and Cu+.

### Claim 5 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the catalytic filter system comprises transition metal complexes, including a metal from the eighth group of the periodic table or rhodium.

### Claim 6 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the catalytic filter system comprises transition-metal-functionalized zeolites.

### Claim 7 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the catalytic filter system comprises transition-metal-functionalized activated carbon or alumina as support materials.

### Claim 8 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the catalytic filter system comprises 3-aminopropyltrimethoxysilane-functionalized zeolites.

### Claim 9 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the catalytic filter system is at least partially immobilized on a surface of the cathode.

### Claim 10 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the filter unit comprises a through-flow filter with incorporated functionalized complexes or support materials as formate scavengers.

### Claim 11 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the filter unit comprises a reaction chamber separate from the electrolysis cell.

### Claim 12 (depends on 3)

The electrolysis system as claimed in claim 3, comprising a gas diffusion electrode functioning as a formate filter.

### Claim 13 (depends on 3)

The electrolysis system as claimed in claim 3, wherein the cathode comprises lead.