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Cu catalysts are most apt for reducing CO(2) to multi‐carbon products in aqueous electrolytes. To enhance the product yield, we can increase the overpotential and the catalyst mass loading. However, these approaches can cause inadequate mass transport of CO(2) to the catalytic sites, which will then lead to H2 evolution dominating the product selectivity. Herein, we use a MgAl LDH nanosheet 'house‐of‐cards' scaffold to disperse CuO‐derived Cu (OD‐Cu). With this support‐catalyst design, at −0.7 VRHE, CO could be reduced to C2+ products with a current density (jC2+) of −1251 mA cm−2. This is 14× that of the jC2+ shown by unsupported OD‐Cu. The current densities of C2+ alcohols and C2H4 were also high at −369 and −816 mA cm−2 respectively. We propose that the porosity of the LDH nanosheet scaffold enhances CO diffusion through the Cu sites. The CO reduction rate can thus be increased, while minimizing H2 evolution, even when high catalyst loadings and large overpotentials are used. [ABSTRACT FROM AUTHOR]

Coupling renewable energy with the electrochemical conversion of CO2 to chemicals and fuels has been proposed as a strategy to achieve a new circular carbon economy and help mitigate the effects of anthropogenic CO2 emissions. Liquid‐like Nanoparticle Organic Hybrid Materials (NOHMs) are composed of polymers tethered to nanoparticles and are previously explored as CO2 capture materials and electrolyte additives. In this study, two types of aqueous NOHM‐based electrolytes are prepared to explore the effect of CO2 binding energy (i.e., chemisorption versus physisorption) on CO2 electroreduction over a silver nanoparticle catalyst for syngas production. Poly(ethylenimine) (PEI) and Jeffamine M2070 (HPE) are ionically tethered to SiO2 nanoparticles to form the amine‐containing NOHM‐I‐PEI and ether‐containing NOHM‐I‐HPE, respectively. At less negative cathode potentials, PEI and NOHM‐I‐PEI‐based electrolytes produce CO at higher rates than 0.1 molal. KHCO3 due to favorable catalyst‐electrolyte interactions. Whereas at more negative potentials, H2 production is favored because of the carbamate electrochemical inactivity. Conversely, HPE and NOHM‐I‐HPE‐based electrolytes display poor CO2 reduction performance at less negative potentials. At more negative potentials, their performance approached that of 0.1 molal. KHCO3, highlighting how the polymer functional groups of NOHMs can be strategically selected to produce value‐added products from CO2 with highly tunable compositions. [ABSTRACT FROM AUTHOR]

Electrocatalytic carbon monoxide reduction has been previously reported to yield a range of carbonaceous products including alcohols, hydrocarbons and carboxylic acids. However, esters, an important family of organic compounds, have not been formed. Herein, we report the electrosynthesis of C3 to C6 acetate esters (H3C−(C=O)−O−R) from carbon monoxide using copper catalysts in a membrane electrode assembly cell. Ethyl acetate and propyl acetate could be produced with an unprecedented total Faradaic efficiency (FE) of ∼22 % and with a current density of up to −55 mA cm−2, alongside minor quantities of methyl acetate and butyl acetate. The esters are produced via the addition reaction of ethenone (H2C=C=O) and alcohols produced during CO reduction. We show that the near water‐free reaction conditions and the high local pH play key roles in the formation of the esters. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 (eCO2RR) is a potentially sustainable approach for carbon‐based chemical production. Despite significant progress, performing eCO2RR economically at scale is challenging. Here we report meeting key technoeconomic benchmarks simultaneously through electrolyte engineering and process optimization. A systematic flow electrolysis study ‐ performing eCO2RR to CO on Ag nanoparticles as a function of electrolyte composition (cations, anions), electrolyte concentration, electrolyte flow rate, cathode catalyst loading, and CO2 flow rate ‐ resulted in partial current densities of 417 and 866 mA/cm2 with faradaic efficiencies of 100 and 98 % at cell potentials of −2.5 and −3.0 V with full cell energy efficiencies of 53 and 43 %, and a conversion per pass of 17 and 36 %, respectively, when using a CsOH‐based electrolyte. The cumulative insights of this study led to the formulation of system design rules for high rate, highly selective, and highly energy efficient eCO2RR to CO. [ABSTRACT FROM AUTHOR]

The world emits over 14 gigatons of CO2 in excess of what can be remediated by natural processes annually, contributing to rising atmospheric CO2 levels and increasing global temperatures. The electrochemical reduction of CO2 (CO2RR) to value‐added chemicals and fuels has been proposed as a method for reusing these excess anthropogenic emissions. While state‐of‐the‐art CO2RR systems exhibit high current densities and faradaic efficiencies, research on long‐term electrode durability, necessary for this technology to be implemented commercially, is lacking. Previous reviews have focused mainly on the CO2 electrolyzer performance without considering durability. In this Review, the need for research into high‐performing and durable CO2RR systems is stressed by summarizing the state‐of‐the‐art with respect to durability. Various failure modes observed are also reported and a protocol for standard durability testing of CO2RR systems is proposed. [ABSTRACT FROM AUTHOR]

Novel electrodes for the electroreduction of CO2 were prepared by the electrodeposition of copper (I) oxide (Cu2O) catalytic films on a gas diffusion layer. Different electrodes were prepared by varying the deposition time, corresponding to catalyst loadings of 0.37, 0.74, 2.22, 3.70 mg cm−2 and a total charge density of 0.5, 1, 3, and 5 C cm−2, respectively. The electrodes were characterized with SEM, XRD, and UPD. The effect of catalyst loading on the selectivity towards ethylene was investigated in an alkaline flow electrolyzer under ambient conditions. The electrodes were found to be highly selective (>60 %) towards ethylene. The 1 C cm−2 electrode reached Faradaic efficiency values as high as 67 % at industrially relevant current densities of 183 mA cm−2, −0.8 V cathode overpotential and 36 % cell energy efficiency. This performance was attributed to the interplaying role of applied potential, local pH, availability of active sites, and reduced CO2 mass transport limitations. [ABSTRACT FROM AUTHOR]

Electrodeposition of CuAg alloy films from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor yields high surface area catalysts for the active and selective electroreduction of CO2 to multicarbon hydrocarbons and oxygenates. EXAFS shows the co-deposited alloy film to be homogeneously mixed. The alloy film containing 6% Ag exhibits the best CO2 electroreduction performance, with the Faradaic efficiency for C2H4 and C2H5OH production reaching nearly 60 and 25%, respectively, at a cathode potential of just -0.7 V vs RHE and a total current density of ~ - 300 mA/cm². Such high levels of selectivity at high activity and low applied potential are the highest reported to date. In situ Raman and electroanalysis studies suggest the origin of the high selectivity toward C2 products to be a combined effect of the enhanced stabilization of the Cu2O overlayer and the optimal availability of the CO intermediate due to the Ag incorporated in the alloy. [ABSTRACT FROM AUTHOR]

We introduce a gross-margin model to evaluate the technoeconomic feasibility of producing different C1-C2 chemicals such as carbon monoxide, formic acid, methanol, methane, ethanol, and ethylene through the electroreduction of CO2. Key performance benchmarks including the maximum operating cell potential ( Vmax), minimum operating current density ( jmin), Faradaic efficiency (FE), and catalyst durability ( tcatdur) are derived. The Vmax values obtained for the different chemicals indicate that CO and HCOOH are the most economically viable products. Selectivity requirements suggest that the coproduction of an economically less feasible chemical (CH3OH, CH4, C2H5OH, C2H4) with a more feasible chemical (CO, HCOOH) can be a strategy to offset the Vmax requirements for individual products. Other performance requirements such as jmin and tcatdur are also derived, and the feasibility of alternative process designs and operating conditions are evaluated. [ABSTRACT FROM AUTHOR]

Keywords: CO2 reduction; durability; gas diffusion electrode; membrane electrode assembly; stability B The Cover Feature b shows a gas diffusion electrode for electroreduction of CO SB 2 sb , while highlighting four possible mechanisms of physical or chemical degradation. CO2 reduction, durability, gas diffusion electrode, membrane electrode assembly, stability. [Extracted from the article]