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Indirect electroreduction route design a Direct reduction, and (b) indirect reduction of CO2 for high-purity ethylene production (2-bromoethanol: Br-EO). c FEethylene and FEH2 for electrochemical reduction of Br-EO over commercial Ag foil electrode (1 × 1 cm²) in 0.5 M KCl electrolyte containing 50 mM Br-EO, under CO2 bubbling (30 sccm). Error bars correspond to the Standard Deviation of three independent measurements. d Schematic illustration for the shielding effect of specific adsorbed thiol molecules (2-bromoethanol: Br-EO). e CV curves for Br-EO reduction (50 mM) in 0.5 M KCl electrolyte with and without thiol additive (50 μM). The scan rate is 10 mV s⁻¹.
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High-purity ethylene production from CO2 electroreduction (CO2RR) is a coveted, yet arduous feat because the product stream comprises a blend of unreacted CO2, H2, and other off-target CO2 reduction products. Here we present an indirect reduction strategy for CO2-to-ethylene conversion, one that employs 2-bromoethanol (Br-EO) as a mediator. Br-EO i...
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Most commonly, electrochemical CO2 reduction is performed in a three‐compartment setup employing gas diffusion electrodes (GDEs) to decrease mass transport limitations of the gaseous reactant CO2 to the reaction interface. However recently, there has been a rising number of investigations on suitable membrane electrode assemblies (MEAs) to overcome...
Citations
... Catholyte and anolyte are continuously circulated through the peristaltic pump. Moreover, CO 2 gas directly feeds into the cathode, significantly improving mass transport and boosting production rates [141][142][143][144] . As a result, the thermodynamics and kinetics of CO 2 RR in flow cells differ significantly from those in traditional H-type cells, making flow cells more favorable for large-scale commercial applications [145][146][147] . ...
Recent research on the electrocatalytic CO2 reduction reaction (eCO2RR) has garnered significant attention given its capability to address environmental issues associated with CO2 emissions while harnessing clean energy to produce high-value-added products. Compared to C1 products, C2+ products provide greater energy densities and are highly sought after as chemical feedstocks. However, the formation of the C-C bond is challenging due to competition with the formation of H-H and C-H bonds. Therefore, to elevate the selectivity and yield of C2+ fuels, it is essential to develop more advanced electrocatalysts and optimize the design of electrochemical cell configurations. Of the materials investigated for CO2RR, Cu-based materials stand out due to their wide availability, affordability, and environmental compatibility. Moreover, Cu-based catalysts exhibit promising capabilities in CO2 adsorption and activation, facilitating the formation of C2+ compounds via C-C coupling. This review examines recent research on both electrocatalysts and electrochemical cells for CO2 electroreduction to C2+ compounds, introducing the core principles of eCO2RR and the reaction pathways involved in generating C2+ products. A key focus is the categorization of Cu-based catalyst designs, including defect engineering, surface modification, nanostructure engineering, and tandem catalysis. By analyzing recent studies on eCO2RR with Cu-based catalysts, we aim to elucidate the mechanisms behind enhanced selectivity for C2+ compounds. Additionally, various types of electrolytic cells are discussed. Lastly, the prospects and limitations of utilizing Cu-based materials and electrocatalytic cells for CO2 reduction are highlighted for future research.
The synergistic effects in electrocatalysis can significantly enhance catalyst performance by improving catalytic activity, selectivity, and stability, and optimizing reaction mechanisms and electron transfer processes. This review summarizes recent advancements in the synergistic effects of the electrochemical reduction of CO2 (eCO2RR) to multi‐carbon (C2+) products. Starting with the fundamental principles of eCO2RR for C2+ product formation, the paper outlines the reaction mechanisms for producing C2, C3, C4, and C5 products. A comprehensive discussion is provided on the critical impact of synergistic effects on the structure–performance relationship in eCO2RR for the production of C2+ products. Subsequently, the synergistic effects observed are classified in various electrocatalysts with different properties, including single/dual‐atom catalysts, multi‐centric catalysts, single‐atom alloys, metal‐organic frameworks, and heterojunction catalysts. Finally, the challenges in achieving selective C2+ product formation in eCO2RR through synergistic effects are discussed, along with corresponding strategies to overcome the obstacles.
Solar‐driven photothermal chemical transformations are regarded as green processes to reduce energy consumption and are expected to utilize unique light‐induced activation mechanisms to improve reaction kinetics. Halide perovskites and their derivatives, due to unique optoelectronic properties and compositional flexibility, are allowed for the precise regulation of energy band structures and surface electronic states, showing potentials as photoactivated catalysts with photo‐thermal synergistic effects. However, the photothermal catalytic performance of halide perovskites is still unsatisfied with low conversion (<0.2%). Herein, Cs3BixSb2‐xBr9 is designed as a novel and effective photothermal catalyst for light‐driven degradation of ester under room temperature, achieving a near‐unity conversion of ≈99% without external heating. Photothermal catalytic process shows the remarkable enhancementup to 796% and 200% compared with that in the single thermocatalysis or photocatalysis. The stable catalyst shows superior light‐driven cyclic performance, as well. Mechanistic studies combined with in situ characterizations and theoretical calculations show that photon‐bismuth hotspot with the synergy of photoinduced charge transfer process (photochemistry) significantly reduce the activation energy, light‐to‐heat effects (thermochemistry) elevate the local temperature, and bismuth active site promotes the C─O bond activation (surface adsorption), which together contribute to excellent solar‐driven conversion efficiency on the perovskite derivative.
Electrosynthesis of high‐purity carbon monoxide (CO) from captured carbon dioxide (CO₂) remains energy‐intensive due to the unavoidable CO₂ regeneration and post‐purification stages. Here, we propose a direct high‐purity CO electrosynthesis strategy employing an innovative electrolyte, termed porous electrolyte (PE), based on "porous water". Zeolite nanocrystals within PE provide permanent pores in the liquid phase, enabling physical CO₂ adsorption through an intraparticle diffusion model, as demonstrated by molecular dynamics simulations and in‐situ spectral analysis. Captured CO₂ spontaneously desorbs under applied reductive potential, driven by the interfacial CO₂ concentration gradient, and is subsequently reduced electrochemically. The high CO₂ concentration in PE enhances mass transfer, and surface ion exchange between Si–OH groups and K⁺ ions on the zeolite surface generates a stronger interfacial electric field, promoting electron transfer steps. This optimized kinetics for mass and electron transfer confers heightened intrinsic activity toward CO₂ electroreduction. The PE‐based electrolysis system demonstrated superior CO Faradaic efficiency and partial current density compared to the conventional CO₂‐fed system. A circular system using PE and a Ni‐N/C cathode realized continuous production of high‐purity CO (97.0 wt%) from dilute CO2 (15%) and maintained > 90.0 wt% under 150 mA cm‐2, with significantly reduced energy consumption and costs.
Electrosynthesis of high‐purity carbon monoxide (CO) from captured carbon dioxide (CO2) remains energy‐intensive due to the unavoidable CO2 regeneration and post‐purification stages. Here, we propose a direct high‐purity CO electrosynthesis strategy employing an innovative electrolyte, termed porous electrolyte (PE), based on “porous water”. Zeolite nanocrystals within PE provide permanent pores in the liquid phase, enabling physical CO2 adsorption through an intraparticle diffusion model, as demonstrated by molecular dynamics simulations and in situ spectral analysis. Captured CO2 spontaneously desorbs under applied reductive potential, driven by the interfacial CO2 concentration gradient, and is subsequently reduced electrochemically. The high CO2 concentration in PE enhances mass transfer, and surface ion exchange between Si−OH groups and K⁺ ions on the zeolite surface generates a stronger interfacial electric field, promoting electron transfer steps. This optimized kinetics for mass and electron transfer confers heightened intrinsic activity toward CO2 electroreduction. The PE‐based electrolysis system demonstrated superior CO Faradaic efficiency and partial current density compared to the conventional CO2‐fed system. A circular system using PE and a Ni−N/C cathode realized continuous production of high‐purity CO (97.0 wt %) from dilute CO2 (15 %) and maintained >90.0 wt % under 150 mA cm⁻², with significantly reduced energy consumption and costs.
This review explores the latest developments in CO 2 electroreduction based systems, including coupling reaction systems, co-reduction reaction systems, cascade systems, and integrated capture and conversion systems.
Ethylene (C2H4) electrosynthesis from the electrocatalytic CO2 reduction process holds enormous potential applications in industrial production. However, the sluggish kinetics of C─C coupling often result in low yield and poor selectivity for C2H4 production. Herein, the performance of Cu catalysts of varying sizes is investigated, prepared via a cryo‐mediated liquid phase exfoliation technique, for the electrochemical CO2 reduction to C2H4. The activity and selectivity of C2H4 gradually increase as the size of the Cu catalysts decreases from tens of nanometers to a few nanometers. Impressively, the 5 nm Cu quantum dots (Cu‐5) achieve a maximum C2H4 Faradaic efficiency (FE) of 81.5% and a half‐cell cathodic energy efficiency (CEE) of 42.2% with a large partial current density of 1.1 A cm⁻² at −0.93 V versus the reversible hydrogen electrode. Structural characterization and in situ spectroscopic analysis reveal that the Cu‐5 quantum dots, dominated by the (100) facet, provide an abundance of active sites that enhance CO2 adsorption and activation, promoting the formation of *CO intermediates. The accumulation of *CO intermediates on the Cu active sites facilitates the CO‐CHO coupling reaction, thus enhancing the C2H4 production rate.
