Copper catalysts for electrochemical CO2 reduction to C2+ products

Patent metadata

Field	Value
Publication number	US-11708641-B2
Application number	US-202117393151-A
Country	US
Kind code	B2
Filing date	Aug 3, 2021
Priority date	Aug 3, 2020
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

An electrochemical method includes performing anodic halogenation of Cu foils, performing subsequent oxide-formation in a KHCO3 electrolyte, and performing an electroreduction in neutral KHCO3 to generate a copper catalyst.

First claim

What is claimed is:

1. An electrochemical method comprising:
performing anodic halogenation of Cu foils; wherein the anodic halogenation comprises 60-100 s at 1.1 V (vs. Ag/AgCl) for KCI, 60-90 s at 0.18 V (vs. Ag/AgCl) for KBr, or 1-10 s at −0.2 V (vs. Ag/AgCl) for KI;
performing subsequent oxide-formation in a KHCO 3 electrolyte; and
performing an electroreduction in neutral KHCO 3 to generate a copper catalyst comprising cubic structures of Cu and a surface roughness of less than 30; the catalyst capable to provide a faradaic efficiency ≥50% for C 2 H 4 generation.

2. The electrochemical method of claim 1 wherein the electroreduction in neutral KHCO 3 is by linear sweep voltammetry (LSV).

3. The electrochemical method of claim 1 wherein performing anodic halogenation of Cu foils comprises applying an oxidative potential to electropolished Cu foils immersed in an electrolyte containing halide ions.

4. The electrochemical method of claim 1 , further comprising:
prior to performing the anodic halogenation of the Cu foils;
mechanically polishing the Cu foils;
rinsing the polished the Cu foils;
electropolishing the Cu foils by chronoamperometry in 85% phosphoric acid at 1.5 V with a Cu counter electrode in a two-electrode configuration;
rinsing the electropolished Cu foils;
cutting the electropolished Cu foils into 2×0.5 cm 2 pieces;
flattening the electropolished Cu foils;
covering a back side and part of a front side of the flattened electropolished Cu foils with polyimide (PI) tape to define a geometric area of a working electrode; and
wrapping the working electrode in PTFE tape to prevent detachment of the PI tape, exposing an area of 0.35 cm 2 .

5. The electrochemical method of claim 4 , further comprising:
dissolving KCl, KBr, and KI in de-ionized (DI) water to a concentration of 0.1 M; and
performing the anodic halogenation on an electropolished Cu foil immersed in 0.1 M KCl, KBr, and KI, respectively, in a three-electrode configuration using a potentiostat.

6. The electrochemical method of claim 5 wherein a counter electrode is Pt gauze.

7. The electrochemical method of claim 6 wherein a reference electrode was Ag/AgCl (saturated KCl) electrode.

8. The electrochemical method of claim 7 wherein open circuit potentials of electropolished Cu in 0.1 M KCl, KBr, and KI are −0.115 V, −0.134 V, and −0.315 V vs. Ag/AgCl.

Assignees

• Univ Brown

Inventors

• Palmore G Tayhas R
• Kim Taehee

Classifications

• C25F7/00 Primary

  Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects (for both electrolytic coating and removal C25D); Servicing or operating · CPC title

• C25B3/26

  of carbon dioxide · CPC title

• C25B11/061

  Metal or alloy · CPC title

• C25D11/34

  of metals or alloys not provided for in groups C25D11/04 - C25D11/32 · CPC title

• C25D21/12

  Process control or regulation (controlling or regulating in general G05) · CPC title