Porous Electrodeposited Cu as a Potential Electrode for Electrochemical Reduction Reactions of CO2

Abstract

In the present study, a systematic investigation is performed to assess the relationship between electroplating parameters, pore morphology and internal surface area of copper deposits which are promising to serve as electrodes for electrochemical reduction reactions of carbon dioxide (CO2). A set of porous copper deposits are fabricated with the dynamic hydrogen bubble template method. The microstructural and Brunauer–Emmett–Teller (BET) analysis demonstrate that current density, deposition time, and bath composition control pore size, strut size, and hence surface area which could be as high as 20 m2/g. Selected sets of porous copper electrodes are then employed in the electrochemical reduction reaction test to determine their conversion performance in comparison to a monolithic copper surface. From the gas chromatography (GC) and nuclear magnetic resonance (NMR) analysis, porous copper is shown to provide higher rates of production of some important chemicals, as compared to copper foil electrodes. Porous copper with fern-like morphology serves as a promising electrode that yields relatively high amounts of acetaldehyde, acetate and ethanol. The study thus presents the opportunities to enhance the electrochemical reduction reaction of CO2 through microstructural engineering of the copper surface, which benefits both CO2 reduction and generation of chemical products of high value.

Roughness Factors of Electrodeposited Nanostructured Copper Foams

“…For copper foams deposited from acidic electrolytes with a Cl − additive, roughness factors of ~ 400 Specific surface areas of the copper foams amount to 3.4 and 5.9 m 2 •g −1 for Cu f and Cu f,Cl samples with 10 s deposition time and do not depend significantly on the foam thickness. The specific surface area values are close to the specific surface areas obtained for similar copper foams using the BET method (~4 m 2 •g −1 ) [49]. This demonstrates that under the chosen experimental conditions, diffusion limitations in the pores of the copper deposits are efficiently minimized, and the whole surface area is accessible for the UPD process, which is an indication of the reliability of the RSA estimates derived from the Pb UPD measurements.…”

Direct Deposition of Copper Atoms onto Graphitic Step Edges Lowers Overpotential and Improves Selectivity of Electrocatalytic CO2 Reduction

“…19,24 However, challenges persist when using Cu in the form of foils or large nanoparticles, as over 95% of the atoms are located below the surface and remain unutilised in the reaction. 25,26 This underscores the urgent need to advance the field of CO2 reduction towards single metal atoms and sub-5 nm nanoparticles to maximise atom utilization efficiency and enhance selectivity control through the well-defined nature of catalytically active sites.…”

Highly selective Ag foam gas diffusion electrodes for CO2 electroreduction by pulsed hydrogen bubble templation

“…2,3 An efficient, fast and solvent-free electrochemical deposition method to produce highly porous 3D structured foam electrodes is the dynamic hydrogen bubble templation (DHBT). [4][5][6] This technique takes advantage of the parasitic hydrogen evolution reaction (HER) by which metal foam electrodes can be produced within seconds in a very controlled fashion. Metal ions are reduced and electrochemically deposited by applying sufficiently high overpotentials, while simultaneously the hydrogen bubbles originating from the HER detach from the substrate and work as a negative template for the formation of macro-porous layers and nanoscale interconnecting foam walls.…”

“…[7][8][9][10] Most of the electrodes fabricated by DHBT are tested in H-cell configurations and evaluated for CO 2 RR in aqueous electrolyte, saturated with CO 2 . [4][5][6][11][12][13][14][15][16][17][18][19] Here, the successful design of the DHBT foam electrodes and its effects on the CO 2 RR performance can be studied very effectively. A significant drawback in aqueous-fed systems is the limited CO 2 solubility, resulting in long diffusion pathways of CO 2 within the bulk electrolyte.…”