Cu Nanowire Networks with Well-Defined Geometrical Parameters for Catalytic Electrochemical CO₂ Reduction

Abstract

Three-dimensional, highly interconnected copper nanowire networks are designed and fabricated by electrodeposition in etched ion track polymer templates with interconnected nanochannels and subsequently applied as a catalyst for the electrochemical CO 2 reduction toward hydrocarbons and alcohols in an aqueous electrolyte. The specific surface area expressed by the nanowire networks can be adjusted by tailoring the wire length, wire diameter, and nanowire number density to values between 70 cm 2 and 300 cm 2 per cm 2 geometrical sample area. The conversion efficiency and selectivity of CO 2 reduction toward liquid-and gas-phase products are studied as a function of the applied potential. Before and after the CO 2 reduction reaction, the nanowire networks are characterized by scanning and transmission electron microscopy and by X-ray diffraction, evidencing their stability during CO 2 reduction in a potential region between −0.5 V and −0.93 V versus RHE.

Copper Nanowires for Electrochemical CO2 Reduction Reaction

“…However, the competing HER remained dominant. 57 In contrast, another investigation employing Cu NWs with smaller diameters (25 or 50 nm) on eCO 2 R demonstrated a Faradaic efficiency for C 2 product formation of 60% at −1.1 V vs RHE, highlighting the significant effect of diameter size on catalyst performance. 58 This work presents a systematic computational investigation of the growth process of ultrathin (nanometer-sized) Cu NWs structures and how their surface morphology affects their electrocatalytic CO 2 conversion properties.…”

“…Even though Cu NWs show higher activity than polycrystalline for CO 2 R, there are still limited research reports on Cu NWs for this application. , Therefore, a comprehensive study of the growth tendency of Cu NWs as well as their adsorption and activation and conversion properties toward CO 2 would be beneficial to understand their potential application as eCO 2 R electrocatalysts. While previous eCO 2 R studies using Cu nanowires focused on larger diameters (100–200 nm), like Cu nanowires synthesized by electrodeposition, such studies yielded a series of hydrocarbons and C 2+ products in a potential range between −0.5 and −0.93 V vs RHE. However, the competing HER remained dominant .…”

Cu/Au(111) Surfaces and AuCu Intermetallics for Electrocatalytic Reduction of CO2 in Ionic Liquid Electrolytes

“…While Au and Ag electrodes exhibit very high Faraday efficiencies for reducing CO 2 to CO at moderate onset potentials of about −1.06 V vs the standard hydrogen electrode (SHE), Cu electrodes are interesting because of their ability to catalyze CO 2 RR to hydrocarbons at overpotentials of ∼−1.00 V. , However, at Cu electrodes, also, reduction products like methanol and formate are formed simultaneously . Improved selectivity for CO 2 catalysis can be achieved through nanostructuring − of electrodes leading to a substantial increase of the active surface area and more favorable surface terminations. − Additional strategies like surface alloying and active use of beneficial electrolyte effects , can be applied to improve selectivity and efficiency for CO 2 electrocatalysis.…”

Copper-Nanowires Incorporated with Silver-Nanoparticles for Catalytic CO2 Reduction in Alkaline Zero Gap Electrolyzer

“…Networked nanomaterials are promising CO2RR environments because they have large active surface areas and unique nanostructures encouraging fast mass transfer, electron transfer, and ion transfer, in addition to high electrochemical activity and stability. One-dimensional (1D) materials, such as nanotubes and nanowires, are the building blocks to form nanonetworks, which connect metal-nanoparticles to further composite of a 2D or a 3D structure for electrochemical applications, such as batteries, fuel cells, and water electrolysis. − Metal-nanowires have become common materials to be used as a catalyst for CO 2 reduction reaction (CO2RR), where an H-type electrolytic cell or flow-electrolyte cell is used as the reactor. − Different from the H-type or flow-type cell reactors, the zero-gap cell (as electrolyte membrane, <40 μm) has been recognized as the highest efficiency reactor for electrochemical reduction of carbon dioxide, potentially meeting the electrolysis rate requirements of industrial production. ,− We designed a catalytic nanonetwork by incorporating Ag-nanoparticles into copper-nanowires to realize the highest catalytic activity, stability, electric conductivity, and fast mass transfer.…”