CO2 Reduction Products Research Articles

Chromic hydroxide-decorated palladium nanoparticles confined by amine-functionalized mesoporous silica for rapid dehydrogenation of formic acid.

Formic acid (FA), one of the products of biomass conversion and CO2 reduction, has attracted much attention as a renewable liquid hydrogen carrier with a high hydrogen content (4.4wt%). Searching for efficient catalysts to realize hydrogen evolution from FA are highly desired but challenging. Herein, ultrafine and mono-dispersed Pd-Cr(OH)3 nanoparticles (1.3nm) loaded on amine-functionalized mesoporous silica (AFMS) have been prepared and applied as an effective catalyst for rapid hydrogen production from additive-free FA. The as-synthesized Pd-Cr(OH)3/AFMS catalysts exhibited efficient catalytic activity and 100% hydrogen selectivity and conversion toward FA dehydrogenation reaction without additives, giving an initial TOF value of 3112h-1 at 323K, which is comparable to most of the highly efficient heterogeneous catalysts reported so far under similar reaction conditions. This work provides a feasible idea for the design metal hydroxide-modified Pd-based efficient heterogeneous catalyst, which is expected to enhance the application of FA in fuel cells.

Rare-earth metal-N6 centers in porous carbon for electrocatalytic CO2 reduction.

Single-atom catalysts fabricated using rare earth elements have emerged for electrocatalytic carbon dioxide reduction, but they need to be studied systematically and intensively. Herein, density functional theory was employed to determine the electrocatalytic CO2 reduction activity of rare earth-N6 porous carbon (Re = Ce, Nd, Sm, Eu, Gd, Tb, Er, Tm, Yb, and Lu) single-atom catalysts. The results revealed that the binding energy of the rare-earth atoms to the N6C monolayers in the ten studied Re-N6C monatomic catalysts is much more negative than the cohesion energy of the bulk rare-earth metal, which makes rare-earth atoms stably dispersed in the N6C skeleton. CO is the primary chemical product of electrocatalytic CO2 reduction by Ce, Eu, and Lu. The primary product of the six monatomic species, i.e., Nd, Sm, Tb, Er, Tm, and Yb, is HCOOH. The dominant product of Gd is CH4. The limiting potentials of these catalysts are in the range of 0.31-0.786 V and their overpotentials are in the range of 0.06-0.707 V, all of which are relatively low, showing that they are potential and promising electrocatalysts for CO2 reduction. Subsequently, Eu-N6C was experimentally synthesized and used for electrocatalytic CO2 reduction to obtain CO products, and the overpotential showed good agreement with the theoretically calculated values.

Carbon monoxide separation: past, present and future.

Large amounts of carbon monoxide are produced by industrial processes such as biomass gasification and steel manufacturing. The CO present in vent streams is often burnt, this produces a large amount of CO2, e.g., oxidation of CO from metallurgic flue gasses is solely responsible for 2.7% of manmade CO2 emissions. The separation of N2 from CO due to their very similar physical properties is very challenging, meaning that numerous energy-intensive steps are required for CO separation, making the CO separation from many process streams uneconomical in spite of CO being a valuable building block in the production of major chemicals through C1 chemistry and the production of linear hydrocarbons by the Fischer-Tropsch process. The development of suitable processes for the separation of carbon monoxide has both industrial and environmental significance. Especially since CO is a main product of electrocatalytic CO2 reduction, an emerging sustainable technology to enable carbon neutrality. This technology also requires an energy-efficient separation process. Therefore, there is a great need to develop energy efficient CO separation processes adequate for these different process streams. As such the urgency of separating carbon monoxide is gaining greater recognition, with research in the field becoming more and more crucial. This review details the principles on which CO separation is based and provides an overview of currently commercialised CO separation processes and their limitations. Adsorption is identified as a technology with the potential for CO separation with high selectivity and energy efficiency. We review the research efforts, mainly seen in the last decades, in developing new materials for CO separation via ad/bsorption and membrane technology. We have geared our review to both traditional CO sources and emerging CO sources, including CO production from CO2 conversion. To that end, a variety of emerging processes as potential CO2-to-CO technologies are discussed and, specifically, the need for CO capture after electrochemical CO2 reduction is highlighted, which is still underexposed in the available literature. Altogether, we aim to highlight the knowledge gaps that could guide future research to improve CO separation performance for industrial implementation.

On the role of C4 and C5 products in electrochemical CO2 reduction via copper-based catalysts

We identify many larger organics as products of electrochemical CO2 reduction in high-current GDEs – most interestingly, C4 and C5 isomers. The analysis of selectivity trends allows for deduction of general hypotheses to build a detailed mechanism.

Anolyte Enhances Catalyst Utilization and Ion Transport Inside a CO2 Electrolyzer Cathode

Electrochemical CO2 reduction is a promising technology to capture and convert CO2 to valuable chemicals. High Faradaic efficiencies of CO2 reduction products are achieved with zero-gap alkaline CO2 electrolyzers with a supporting electrolyte at the anode (anolyte). Herein, we investigate the effect of anolyte on the electrode properties such as catalyst utilization, ionic accessibility etc. of a CO2 reduction cathode using electrochemical techniques and cell configurations that avoid the complexities related to co-electrolysis. Using 1M KOH as the anolyte and a Cu gas-diffusion-electrode with low Nafion content as the model CO2 reduction electrode, we find that electrode capacitance (proxy for electrochemically active surface area) and ionic conductivity inside the cathode increase approximately 4 and 447 times, respectively, in presence of KOH. Liquid anolyte wets the electrode’s pore structure more efficiently than capillary condensation of feed water vapor. The ionomer coverage is very low, and its distribution inside the electrode is highly fragmented. Surface ion conduction mechanisms inside the electrode are orders of magnitude lower than the bulk ion conduction in presence of anolyte. This study shows that when an anolyte (e.g., KOH) is used, catalyst utilization and ionic accessibility inside the electrode increase significantly.

Enabling technologies for the continuous electrically driven conversion of CO2 and water to multi-carbon products at high current densities

We report a soft-templating method for the synthesis of high surface area nickel phosphide catalyst (Ni2P). Ni2P exhibits a 40–50% CO2 reduction products selectivity over H2 formation at current densities ranging from 50–300 mA cm−2 in a flow cell.

Photocatalytic Reduction of Carbon Dioxide in Aqueous Suspensions of a Titania Semiconductor

The photocatalytic reduction reactions of CO2 in aqueous suspensions of titanium dioxide (TiO2) semiconductor with photodeposited Pt and Cu cocatalysts have been studied. It has been found that the composition and amount of CO2 reduction products significantly depend on the nature of the cocatalyst supported onto TiO2. A mechanism for the formation of CO2 reduction products has been proposed.

Iron/cobalt/nickel regulation for efficient photocatalytic carbon dioxide reduction over phthalocyanine covalent organic frameworks.

Using solar photocatalytic CO2 reduction to produce high-value-added products is a promising solution to environmental problems caused by greenhouse gases. Metal phthalocyanine COFs possess a suitable band structure and strong light absorption ability, making them a promising candidate for photocatalytic CO2 reduction. However, the relationship between the electronic structure of these materials and photocatalytic properties, as well as the mechanism of photocatalytic CO2 reduction, is still unclear. Herein, the electronic structure of three MPc-TFPN-COFs (M = Ni, Co, Fe) and the reaction process of CO2 reduction to CO, HCOOH, HCHO and CH3OH were studied using DFT calculations. The calculated results demonstrate that these COFs have a good photo response to visible light and are new potential photocatalytic materials. Three COFs show different reaction mechanisms and selectivity in generating CO2 reduction products. NiPc-TFPN-COFs obtain CO through the reaction pathway of CO2 → COOH → CO, and the energy barrier of the rate-determining step is 2.82 eV. NiPc-TFPN-COFs and FePc-TFPN-COFs generate HCHO through CO2 → COOH → CO → CHO → HCHO, and the energy barrier of the rate step is 2.82 eV and 2.37 eV, respectively. Higher energies are required to produce HCOOH and CH3OH. This work is helping in understanding the mechanism of photocatalytic reduction of CO2 in metallophthalocyanine COFs.

Turning photocatalytic H2 evolution into CO2 reduction of molecular nickel(II) complexes by using a redox–active bipyridine ligand

Two bis–NHC (NHC = N–heterocyclic carbene) Ni(II) complexes has been designed and synthesized as molecular catalysts in photocatalytic H2 evolution and CO2 reduction. The Ni(II) complex with a redox–innocent 1,2–bis(diphenylphosphaneyl)ethane ligand only generates H2 with a TON of 149 ± 5 and no product of CO2 reduction is found, while the other Ni(II) complex with a redox–active 4,4′–dimethyl–2,2′–bipyridine ligand can catalyze reduction of CO2 to CO with a TON of 41 ± 2 and 93.2% selectivity over H2 evolution. This finding shows a redox–active ligand is capable of boosting CO2 photoreduction of a molecular metal complex, which is helpful for designing molecular catalysts in CO2 photoreduction.

Controlling Fractional Free Volume, Transport, and Co-Transport of Alcohols and Carboxylate Salts in PEGDA Membranes.

Understanding multi-component transport through polymer membranes is critical for separation applications such as water purification, energy devices, etc. Specifically for CO2 reduction cells, where the CO2 reduction products (alcohols and carboxylate salts), crossover of these species is undesirable and improving the design of ion exchange membranes to prevent this behavior is needed. Previously, it was observed that acetate transport increased in copermeation with alcohols for cation exchange membranes consisting of poly(ethylene glycol) diacrylate (PEGDA) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and that the inclusion of poly(ethylene glycol) methacrylate (PEGMA) (n = 5, n represents the number of ethylene oxide repeat units) could suppress this behavior. Here, we further investigate the role of PEGMA in modulating fractional free volume and transport behavior of alcohols and carboxylates. PEGDA-PEGMA membranes of varied membranes are fabricated with both varied pre -polymerization water content at constant PEGMA (n = 9) content and varied PEGMA content at two pre -polymerization water contents (20 and 60 wt.% water). Permeability to sodium acetate also decreases in these charge-neutral PEGDA-PEGMA membranes compared to PEGMA-free films. Therefore, incorporation of comonomers such as PEGMA with long side chains may provide a useful membrane chemistry structural motif for preventing undesirable carboxylate crossover in polymer membranes.

Stability of In2O3 nanoparticles in PTFE-containing gas diffusion electrodes for CO2 electroreduction to formate

Electrocatalytic conversion of CO2 to fuels and chemicals can help mitigate climate change by reuse of the greenhouse gas. Formic acid is an interesting product of electrochemical CO2 reduction, because it can serve as a liquid hydrogen carrier. Indium-based electrodes show promising activity and selectivity towards formic acid formation during CO2 electroreduction. However, the low stability of such electrodes at high current density limits their implementation in industry. Herein, we optimize a gas diffusion electrode (GDE) containing ∼6 nm In2O3 nanoparticles obtained by flame spray pyrolysis. The catalyst exhibits high initial faradaic efficiency towards formate (> 80%) at current densities up to 200 mA/cm2. In situ Raman spectroscopy reveals that the In2O3 particles rapidly reduce under reaction conditions, demonstrating that metallic indium is the active phase for CO2 reduction. Degradation mechanisms of the catalyst during 50 h at high current density were studied using XPS, in situ Raman, TEM and SEM, and elemental analysis of the electrolyte. Catalyst reduction, sintering of the active phase and dissolution of indium could be excluded as a cause of the declining FE. Adding carbon and hydrophobic PTFE particles to the catalyst in the GDE improves CO2 supply and prevents early saturation of the GDE by liquid electrolyte. The optimized GDE configuration inhibits hydrogen evolution and demonstrates increased stability during 50 h of CO2 electroreduction.

2D/1D MoS2 /TiO2 Heterostructure Photocatalyst with a Switchable CO2 Reduction Product.

Regulating the transfer pathway of charge carriers in heterostructure photocatalysts is of great importance for selective CO2 photoreduction. Herein, the charge transfer pathway and in turn the redox potential succeeded to regulate in 2D MoS2 /1D TiO2 heterostructure by varying the light wavelength range. Several in situ measurements and experiments confirm that charge transfer follows either an S-scheme mechanism under simulated solar irradiation or a heterojunction approach under visible light illumination, elucidating the switchable property of the MoS2 /TiO2 heterostructure. Replacing the simulated sunlight irradiation with the visible light illumination switches the photocatalytic CO2 reduction product from CO to CH4. 13 CO2 isotope labeling confirms that CO2 is the source of carbon for CH4 and CO products. The photoelectrochemical H2 generation further supports the switching property of MoS2 /TiO2 . Unlike previous studies, density functional theory calculations are used to investigate the band structure of Van der Waals MoS2 /TiO2 S scheme after contact, allowing to propose accurate charge transfer pathways, in which the theoretical results are well matched with the experimental results. This work opens the opportunity to develop photocatalysts with switchable charge transport and tunable redox potential for selective artificial photosynthesis.

2D SnO/MoO3 van der Waals heterojunction with tunable electronic behavior for multifunctional applications: DFT calculations

Metal oxide van der Waals (vdW) heterostructures have attracted extensive attention in fundamental research and new-device design. The remarkable advantage of their tunable energy band structure makes it particularly important to develop versatile metal-oxide heterojunctions and to explore their mechanisms. Herein, 2D SnO/MoO3 vdW heterojunction is successfully constructed by first-principles calculations. Interestingly, the two layers are not limited by horizontal displacements when forming the heterojunction. The electronic structure of the SnO/MoO3 vdW heterojunction has been systematically investigated, and the underlying physical mechanism responsible for its band alignment has been further revealed. A Z-scheme charge transfer mechanism has been demonstrated in SnO/MoO3 with remarkable photocatalytic CO2 reduction capability. Most importantly, the band alignment can be efficiently tuned by varying the external electric field, indicating its multifunctional potential. Furthermore, the CO2 reduction reaction pathway and product selectivity occurring at the surface of 2D SnO/MoO3 vdW heterojunction can be optimized by adjusting the applied electric field. These findings will provide strong theoretical support for the design of novel multifunctional devices using SnO/MoO3 vdW heterojunctions.

Revealing the Mechanism of sp-N Doping in Graphdiyne for Developing Site-Defined Metal-Free Catalysts.

Due to the limited reserves of metals, scientists are devoted to exploring high-performance metal-free catalysts based on carbon materials to solve environment-related issues. Doping would build up inhomogeneous charge distribution on surface, which is an efficient approach for boosting the catalytic performance. However, doping sites are difficult to control in traditional carbon materials, thus hindering their development. Taking the advantage of unique sp-C in graphdiyne (GDY), a new N doping configuration of sp-hybridized nitrogen (sp-N), bringing a Pt-comparable catalytic activity in oxygen reduction reaction is site-defined introduced. However, the reaction intermediate of this process is never captured, hindering the understanding of the mechanism and the precise synthesis of metal-free catalysts. After the four-year study, the fabrication of intermediate-like molecule is realized, and finally sp-N doped GDY via the pericyclic reaction is obtained. Compared with GDY doped with other N configurations, the designed sp-N GDY shows much higher catalytic activity in electroreduction of CO2 toward CH4 production, owing to the unique electronic structure introduced by sp-N, which is more favorable in stabilizing the intermediate. Thus, besides opening the black-box for the site-defined doping, this work reveals the relationship between doping configuration and products of CO2 reduction.

Dealloying kinetic and catalytic applications of hierarchical porous copper via hot-dip galvanization and subsequent vapor phase dealloying

Hierarchical porous copper (HPC) was synthesized using a Cu-Zn liquid phase alloyed on a Cu tube followed by vapor pressure dealloying. This study demonstrates that HPC with ligament sizes of 0.61–1.97 µm and residual Zn contents of 29–2 at% can be synthesized with a dealloying time of 0.5–30 min and temperature of 773–973 K. The coarsening exponent of 4.099 suggested that the ligament formation and coarsening are attributable to surface diffusion. At the same time, the activation energy of 0.29 eV further confirmed that the Cu atoms diffused on the Cu surface dominated the coarsening of Cu ligaments in this vapor phase dealloying system. The double-layer capacitance of the HPC tube is 34 times higher than that of the electropolished Cu tube. Further, the current density of the CO2 reduction reaction for HPC is two times that of the electropolished Cu tube. With the interaction of Cu and Zn and the use of HPC as an electrocatalyst, the CO2 reduction products transformed from formic acid to carbon monoxide and ethanol.

Electrocatalytic CO2 Reduction at Pyridine Functionalized Au Nanoparticles Supported by NanoCOT Electrode

CO2 reduction reaction (CO2RR) is a promising technique for mitigating global warming and storing renewable energy if it can be obtained with a highly selective, efficient, and durable electrocatalyst. Here, we report CO2RR catalyzed by Au nanoparticles (NPs) stabilized by pyridines and pyrimidines (e.g., 2-mercaptopyridine (2Mpy), 4-mercaptopyridine (4Mpy), and 2-mercaptopyrimidine (2Mpym)) on a nanostructured carbon-doped TiO2 nanowire (NanoCOT) electrode, which has been previously reported by our team for electrocatalytic water oxidation. An online gas chromatography (GC) set-up with improved gaseous product sensitivity with real-time pressure monitoring is used to quantify CO and hydrogen products from the Au NP-modified NanoCOT electrode. High CO selectivity is observed at Au-2Mpy coated NanoCOT electrode. CO2 reduction products are not observed at bare NanoCOT suggesting CO2 is reduced at the Au nanoparticle sites of the electrode. Moreover, CH3OH is not detected at the Au-Mpy/Mpym NPs during rotating ring disk electrode (RRDE) analysis which implies pyridine attached to the Au NPs has no catalytic effects on CO2RR as claimed by others in the literature. A durable complete H-cell using a NanoCOT anode and Au NP-NanoCOT cathode electrodes is assembled for complete water splitting, CO2RR, and stability test.

In Situ Surface-Enhanced Raman Spectroscopy Analysis for Estimation of the Role of Pyridinic Nitrogen on Nitrogen-Doped Carbon Catalyst in CO2 Electroreduction

For carbon-neutral transition, technologies are required which enable the efficient conversion of CO2 into valuable feedstocks for chemicals and fuels (e.g., CO, methane, and ethylene). Electrochemical reduction of CO2 (CO2ER) is one of the most promising pathways due to its high product selectivity as well as high activity at mild temperature and pressure, powered by electricity from renewable sources. Among the CO2 reduction products with high selectivity through CO2ER, CO is a useful feedstock to produce methane, methanol, and olefins through conventional catalytic reactions. It is reported that noble metal CO2ER catalysts such as Au and Ag exhibit high CO selectivity[1]. Toward social implementation of CO2ER technology on a commercial scale, earth-abundant elements are more favorable as a catalyst. In recent years, nitrogen (N)-doped carbon materials have attracted much attention for their high CO selectivity comparable to Au and Ag. Previous studies indicate the N-doped carbon catalysts with high content of pyridinic N show high CO generation activity[2]. However, the specific role of pyridinic N (how N contributes to the activity during CO2ER) is still unclear. To establish a design strategy for the efficient N-doped carbon catalyst, the catalytic mechanism involving the pyridinic N must be clarified. In this study, carbon nanotube (CNT) is selected as a model carbon material whose commercial-scale production methods are relatively advanced among carbon materials. With electrochemical and spectroscopic measurements, the local pH dependence of the CO2ER catalytic performance of N-doped CNT (NCNT) was investigated, and the role of the pyridinic N on the CO2ER activity was discussed.The NCNT was prepared by pyrolysis of 1,10-phenanthroline on a multi-walled carbon nanotube as previously reported[2]. CO generation activity was examined in two types of electrochemical systems; the liquid phase electrolysis using an H-cell with a three-electrode system including 4 cm2 NCNT-loaded glassy carbon as a working electrode, and the gas phase using a polymer electrolyte fuel-cell type reactor including membrane-electrode assembly (MEA) with 5 cm2 active area. In the liquid phase electrolysis with CO2 gas bubbling, NCNT showed high faradaic efficiencies toward CO in 1.0 M KHCO3 electrolyte (pH 7.37), while no CO was detected in 1.0 M KHSO4 (pH 0.55) at any applied potentials. In the case of the gas phase reaction, NCNT loaded on a carbon paper (a gas diffusion electrode) with a Nafion® ionomer (Nafion® DE2020CS, The Chemours Company, Delaware, U.S.) showed poor CO selectivity at any cell voltage in both cases using a proton and an anion exchange membrane, while the ionomer substitution to Sustainion® XA-9 (Dioxide Materials, Inc., Florida, U.S.), an anion exchange type, increased the faradaic efficiency toward CO remarkably. From those results, it was confirmed that the local pH near the catalyst surface affects the CO generation activity of NCNT.The local pH dependence on the CO generation activity could be attributed to the CO2 concentration in the electrolyte as well as the protonation of the pyridinic N of the catalyst as previously reported in the system of O2 electroreduction[3]. To observe changes in the local pH and the chemical state of pyridinic N directly, spectroscopic analyses were conducted. We applied our previously reported in situ surface-enhanced Raman spectroscopy measurement system[4] to this reaction to detect the local pH near NCNT surface in the liquid phase as well as the adsorbate species. Surface X-ray photoelectron spectroscopy was also performed to study the changes in the chemical state of N. Those spectroscopic analyses suggested that the factor which affects the CO2ER activity is not only the difference in dissolved CO2 concentration induced from the less acidic condition but also the change in the pyridinic N state.

Coupled CO2 reduction and Alcohol Oxidation for Fuel Synthesis and CO2 Utilization

Electro-conversion CO2 to fuels like formic acid, methanol, and ethanol is an attractive method to recycle CO2 and close the carbon cycle associated with these fuels, which could benefit the environment, national energy security Many CO2 electrolyzers oxidize water or hydroxyl ions as a counter reaction which releases oxygen. However, this can lead to a large cell potential due to oxygen’s large, positive reduction potential. Further, oxygen is a relatively low-value product. These systems also use an ion exchange membrane to prevent crossover of CO2 reduction products to the anode while conducting ions between the electrodes.Instead of oxygen evolution, the partial oxidation of alcohols could serve as the anodic counter reaction to synthesize oxygenated fuel additives. Partial alcohol oxidation could be coupled with CO2 reduction which could regenerate the alcohol. Coupling the anodic and cathodic reactions in this way could preclude the need for an ion exchange membrane, and lower required energy input by decreasing the thermodynamic cell voltage. Our system is also capable of high-pressure operation, which could allow higher concentrations of CO2 in the electrolyte. This study examines the use of alcohol/water mixtures as a working fluid for a CO2 electrolyzer, and the effect of pressure and catalyst composition on the current density and product selectivity. Linear sweep voltammetry and chronoamperometry will be used to evaluate the current densities and cell voltages for different catalysts at pressures up to 90 bar. Gas and liquid products will be analyzed following chronoamperometry studies to determine the faradaic efficiencies. Noble and transition metal catalysts will be used at the cathode and anode based on their purported ability to drive CO2 reduction to alcohol and partial oxidation of alcohols.

Unveiling the Effect of Flue Gas Contaminants on Electrochemical Reduction of CO2 to Methyl Formate in Dual Methanol/Water Electrolysis System

Exploiting renewable energy sources to drive CO2 reduction electrochemically into value-added products has gained tremendous attention towards reducing the greenhouse effect. Upstream processes for capturing and purifying the CO2 raise the overall cost of the electrolysis system. Direct reduction of flue gas into value-added C2+ products has attained much consideration in recent years. However, the sensitivity of the cathode catalyst performance in the presence of flue gas contaminants, particularly O2, and strong competition from the hydrogen evolution reaction in aqueous electrolyte are major challenges for such an approach. Herein, the influence of flue gas contaminants on electrochemical reduction of CO2 in acidic nonaqueous methanol to a methyl formate product has been investigated on a Pb-catalyzed electrode in conjunction with aqueous anolyte for the promotion of a sustainable water oxidation half-reaction. The presence of 4% O2, 0.05% SO2, and 0.05% NO is shown to have minimal effect on the total faradaic efficiency of CO2 reduction products. CO2 concentration-dependent measurements reveal declining CO2 reduction faradaic efficiencies corresponding to the decrease in partial pressure, which is attributed to CO2 mass transfer limitations to the electrode surface. XPS analysis displays the relative stability of the Pb working electrode before and after the electrochemical operation during exposure to flue gas components, which further highlights the promising tolerance of this system for direct flue gas conversion. Figure 1

High Surface Area 3D Copper Nanowire Networks for High-Throughput Electrochemical CO2 Reduction

An attractive solution towards net-zero carbon emission is the electrocatalytic CO2 reduction with its ability to convert the greenhouse gas CO2 with renewable electricity and appropriate catalytic materials to useful chemicals and fuels to store energy. Depending on the number of electrons transferred a variety of oxygenates and hydrocarbons can be obtained. Among used catalytic materials, such as metals, alloys or composites, copper has shown the unique property to electrocatalytically convert CO2 into a wide variety of valuable C2+ products such as ethylene or alcohols.Apart from the high potential to reshape our carbon economy the electrocatalytic CO2 reduction is still in its early development stage compared to the more mature water electrolysis, with high-throughput operation at practical current densities as well as long-term stability of the catalysts being only scarcely demonstrated. Additionally, selectivity towards high-value (beyond C1) products using copper catalysts has proven to be challenging and many research efforts are directed towards improving product selectivity. For this purpose, mainly nanostructured porous Cu electrodes either based on randomly ordered nanoparticles loaded on porous (carbon-based) supports or low-surface area metal foams, meshes or felts with high porosity are commonly used. While the former electrode architecture typically shows poor long-term stability with often weak adhesion between the nanoparticles and the porous support, the latter electrodes have a low electrochemical surface area and hence are not suitable for high-throughput CO2 reduction at high current densities.In this work we present novel high-surface area porous copper electrodes, so-called copper nanomeshes, that are regular 3D-networks of interconnected Cu nanowires. These unique few µm-thin electrodes show a large surface area enhancement (compared to planar Cu) by a factor of ~80, while providing a high porosity of ~70% together with sufficient mechanical stability, an important aspect towards their practical implementation in electrocatalytic flow cells. Cu nanomesh electrodes with a thickness of 4µm were fabricated through electrochemically plating in 3D-porous anodic aluminum oxide templates and show a mixed surface texture of (111), (100) and (110) Cu. We demonstrate the high potential toward high-throughput CO2 electrolysis of these novel electrodes in comparison to planar copper electrodes in various CO2-containing electrolyte solutions. The CO2 reduction product analysis showed a significant difference in selectivity between planar (polycrystalline or with preferential 111 or 200 texture) and the polycrystalline Cu nanomesh electrodes with CO or C2H4 as major reduction products depending on the potential applied. The beneficial effect of the high electrochemical surface area was demonstrated by a significant increase in the current density on the nanostructured Cu electrodes. Additionally, we characterized the copper nanomesh electrodes before, during and after CO2 reduction with complementary techniques to gain insights on the reaction mechanism and on the electrode stability. Figure 1