Nanostrukturierte Materialien für die elektrokatalytische CO2-Reduktion und ihre Reaktionsmechanismen

Multimethod Approach to the Low-Overpotential Region of Micro- to Macro-Scale Working Electrodes of Sub-10 nm Gold Nanoparticles in the CO2 Reduction Reaction

The electrochemical carbon dioxide reduction reaction (CO2RR) over carbon-supported gold nanoparticles (AuNP) was investigated using a broad variety of (electro)analytical methods, including linear sweep voltammetry with a rotating disk electrode (LSV-RDE), sample-generation tip-collection mode of scanning electrochemical microscopy (SG/TC-SECM), as well as full cell tests with highly sensitive online gas chromatography (GC). In contrast to most other studies, this work focuses on the low-overpotential region (0 to -0.4 V vs RHE) where initial product formation is already detected and addresses micro- to macro-sized electrodes. The sub-10 nm AuNPs supported on three different carbon supports (CNTs and carbon blacks) were pretreated in H2/Ar to remove the stabilizer used during AuNP synthesis. LSV-RDE points toward different CO2RR mechanisms at the samples, additionally confirmed by the SG/TC-SECM and full cell tests with online GC. Besides H2 and CO, the AuNP supported on carbon nanotubes showed significant evolution of H2CO in contrast to the other two samples, which was additionally confirmed by accumulating the product during chronoamperometric RDE experiments followed by mass spectroscopic analysis. Surface analysis indicated a complete removal of residual thiolate stabilizer molecules exclusively at the AuNPs supported on carbon nanotubes, which may result in a change in the adsorption geometry or reaction mechanism at this sample. The results demonstrate the effectiveness of the combination of these multiple methods to investigate the CO2RR in the low-overpotential region.

Recent Advances of Core-Shell Cu-Based Catalysts for the Reduction of CO2 to C2+ Products

Copper is a key metal for carbon dioxide (CO₂ ) reduction reaction, which can reduce CO₂ to value-added products. The core-shell structure can effectively promote the C-C coupling process due to its strong synergistic effect originated from its unique electronic structure and interface environment. Therefore, the combination of copper and core-shell structure to design an efficient Cu-based core-shell structure catalyst is of great significance for electrocatalytic CO₂ reduction (CO₂ RR). In this review, we first briefly summarize the basic principle of CO₂ RR. In addition, we outline the advantages of core-shell structure for catalysis. Then, we review the recent research progresses of Cu-based core-shell structures for the selective reduction of multi-carbon (C₂₊ ) products. In the end, the challenges of using core-shell catalyst for CO₂ RR are described, and the future development of this field is prospected.

Surface and Interface Engineering for the Catalysts of Electrocatalytic CO2 Reduction

The massive use of fossil fuels releases a great amount of CO₂ , which substantially contributes to the global warming. For the global goal of putting CO₂ emission under control, effective utilization of CO₂ is particularly meaningful. Electrocatalytic CO₂ reduction reaction (eCO₂ RR) has great potential in CO₂ utilization, because it can convert CO₂ into valuable carbon-containing chemicals and feedstock using renewable electricity. The catalyst design for eCO₂ RR is a key challenge to achieving efficient conversion of CO₂ to fuels and useful chemicals. For a typical heterogeneous catalyst, surface and interface engineering is an effective approach to enhance reaction activity. Herein, the development and research progress in CO₂ catalysts with focus on surface and interface engineering are reviewed. First, the fundaments of eCO₂ RR is briefly discussed from the reaction mechanism to performance evaluation methods, introducing the role of the surface and interface engineering of electrocatalyst in eCO₂ RR. Then, several routes to optimize the surface and interface of CO₂ electrocatalysts, including morphology, dopants, atomic vacancies, grain boundaries, surface modification, etc., are reviewed and representative examples are given. At the end of this review, we share our personal views in future research of eCO₂ RR.

Nature of the Active Sites of Copper Zinc Catalysts for Carbon Dioxide Electroreduction

The electrochemical CO₂ reduction (CO₂ ER) to multi-carbon chemical feedstocks over Cu-based catalysts is of considerable attraction but suffers with the ambiguous nature of active sites, which hinder the rational design of catalysts and large-scale industrialization. This paper describes a large-scale simulation to obtain realistic CuZn nanoparticle models and the atom-level structure of active sites for C₂₊ products on CuZn catalysts in CO₂ ER, combining neural network based global optimization and density functional theory calculations. Upon analyzing over 2000 surface sites through high throughput tests based on NN potential, two kinds of active sites are identified, balanced Cu-Zn sites and Zn-heavy Cu-Zn sites, both facilitating C-C coupling, which are verified by subsequent calculational and experimental investigations. This work provides a paradigm for the design of high-performance Cu-based catalysts and may offer a general strategy to identify accurately the atomic structures of active sites in complex catalytic systems.

Carbon-Confined Indium Oxides for Efficient Carbon Dioxide Reduction in a Solid-State Electrolyte Flow Cell

Developing robust electrocatalysts and advanced devices is important for electrochemical carbon dioxide (CO₂ ) reduction toward the generation of valuable chemicals. We present herein a carbon-confined indium oxide electrocatalyst for stable and efficient CO₂ reduction. The reductive corrosion of oxidative indium to the metallic state during electrolysis could be prevented by carbon protection, and the applied carbon layer also optimizes the reaction intermediate adsorption, which enables both high selectivity and activity for CO₂ reduction. In a liquid-phase flow cell, the formate selectivity exceeds 90 % in a wide potential window from -0.8 V to -1.3 V vs. RHE. The continuous production of ca. 0.12 M pure formic acid solution is further demonstrated at a current density of 30 mA cm^-2 in a solid-state electrolyte mediated reactor. This work provides significant concepts in the parallel development of electrocatalysts and devices for carbon-neutral technologies.

CO2 Capture, Separation and Reduction on Boron-Doped MoS2 , MoSe2 and Heterostructures with Different Doping Densities: A Theoretical Study

Designing high-performance materials for CO₂ capture and conversion is of great significance to reduce the greenhouse effect and alleviate the energy crisis. The strategy of doping is widely used to improve activity and selectivity of the materials. However, it is unclear how the doping densities influence the materials' properties. Herein, we investigated the mechanism of CO₂ capture, separation and conversion on MoS₂ , MoSe₂ and Janus MoSSe monolayers with different boron doping levels using density functional theory (DFT) simulations. The results indicate that CO₂ , H₂ and CH₄ bind weakly to the monolayers without and with single-atom boron doping, rendering these materials unsuitable for CO₂ capture from gas mixtures. In contrast, CO₂ binds strongly to monolayers doped with diatomic boron, whereas H₂ and CH₄ can only form weak interactions with these surfaces. Thus, the monolayers doped with diatomic boron can efficiently capture and separate CO₂ from such gas mixtures. The electronic structure analysis demonstrates that monolayers doped with diatomic doped are more prone to donating electrons to CO₂ than those with single-atom boron doped, leading to activation of CO₂ . The results further indicate that CO₂ can be converted to CH₄ on diatomic boron doped catalysts, and MoSSe is the most efficient of the surfaces studied for CO₂ capture, separation and conversion. In summary, the study provides evidence for the doping density is vital to design materials with particular functions.

Highly Perfluorinated Covalent Triazine Frameworks Derived from a Low-Temperature Ionothermal Approach Towards Enhanced CO2 Electroreduction

Perfluorinated covalent triazine frameworks (F-CTFs) have shown unique features and attractive performance in separation and catalysis. However, state-of-the-art F-CTFs synthesized via the ZnCl₂ -promoted procedure have quite low fluorine contents due to C-F bond cleavage induced by chloride (a Lewis base) and the harsh conditions deployed (400-700 °C). Fabricating F-CTFs with high fluorine contents (>30 wt %) remains challenging. Herein, we present a low-temperature ionothermal approach (275 °C) to prepare F-CTFs, which is achieved via polymerization of tetrafluoroterephthalonitrile (TFPN) over the Lewis superacids, e.g., zinc triflimide [Zn(NTf₂ )₂ ] without side reactions. With low catalyst loading (equimolar), F-CTFs are afforded with high fluorine content (31 wt %), surface area up to 367 m²  g^-1 , and micropores around 1.1 nm. The highly hydrophobic F-CTF-1 exhibits good capability to boost electroreduction of CO₂ to CO, with faradaic efficiency of 95.7 % at -0.8 V and high current density (-141 mA cm^-2 ) surpassing most of the metal-free electrocatalysts.

Ultra-low-loaded Ni-Fe Dimer Anchored to Nitrogen/Oxygen Sites for Boosting Electroreduction of Carbon Dioxide

Single-atom catalysts (SACs), as a novel emerging category in heterogeneous catalysis, have exhibited superb activity and selectivity within the scope of many catalytic reactions, originating from their nature of atomic dispersion. However, they are not appropriate for more complicated reactions that benefit from multi-metal promotion, such as the carbon dioxide reduction reaction (CO₂ RR). Atomic pair catalysts can provide a synergistic effect to break the intrinsic activity limit. Herein, inspired by theoretical prediction, a hetero-paired atomic-site catalyst (Ni/Fe-N/O-C) was developed for CO₂ RR. Typically, the trace-amount-loaded double-atom-site catalysts exhibited outstanding turnover frequencies (≈460 s^-1 ) surpassing reported ones by far. Interestingly, the loaded metal contents of the three M-N/O-C samples were extremely low, and Ni/Fe-N/O-C exhibited greatly improved durability compared with pure Ni-N/O-C or Fe-N/O-C and excellent CO selectivity above 80 % within a broad potential window of -1.4 to -1.7 V (vs. saturated calomel electrode, 99.8 % at -1.5 V). The superb performance of diatomic-site catalysts was attributed to the adjusted local environment and electron structure of the active center, which could decrease the reaction barrier of *COOH formation. This work presents new insights into manipulating electrocatalytic performance for the development of more sophisticated active sites.

Lewis-Basic EDTA as a Highly Active Molecular Electrocatalyst for CO2 Reduction to CH4

The most active catalysts so far successful in hydrogenation reduction of CO₂ are mainly heterogeneous Cu-based catalysts. The complex coordination environments and multiple active sites in heterogeneous catalysts result in low selectivity of target product, while molecular catalysts with well-defined active sites and tailorable structures allow mechanism-based performance optimization. Herein, we firstly report a single ethylenediaminetetraacetic acid (EDTA) molecular-level immobilized on the surface of carbon nanotube as a catalyst for transferring CO₂ to CH₄ with an excellent performance. This catalyst exhibits a high Faradaic efficiency of 61.6 % toward CH₄ , a partial current density of -16.5 mA cm^-2 at a potential of -1.3 V versus reversible hydrogen electrode. Density functional theory calculations reveal that the Lewis basic COO^- groups in EDTA molecule are the active sites for CO₂ reduction reaction (CO₂ RR). The energy barrier for the generation of CO from *CO intermediate is as high as 0.52 eV, while the further protonation of *CO to *CHO follows an energetic downhill path (-1.57 eV), resulting in the high selectivity of CH₄ . This work makes it possible to control the product selectivity for CO₂ RR according to the relationship between the energy barrier of *CO intermediate and molecular structures in the future.

Efficient Electroconversion of Carbon Dioxide to Formate by a Reconstructed Amino-Functionalized Indium-Organic Framework Electrocatalyst

We report an amino-functionalized indium-organic framework for efficient CO₂ reduction to formate. The immobilized amino groups strengthen the absorption and activation of CO₂ and stabilize the active intermediates, which endow an enhanced catalytic conversion to formate despite the inevitable reduction and reconstruction of the functionalized indium-based catalyst during electrocatalysis. The reconstructed amino-functionalized indium-based catalyst demonstrates a high Faradaic efficiency of 94.4 % and a partial current density of 108 mA cm^-2 at -1.1 V vs. RHE in a liquid-phase flow cell, and also delivers an enhanced current density of ca. 800 mA cm^-2 at 3.4 V for the formate production in a gas-phase flow cell configuration. This work not only provides a molecular functionalization and assembling concept of hybrid electrocatalysts but also offers valuable understandings in electrocatalyst evolution and reactor optimization for CO₂ electrocatalysis and beyond.

In Situ Bismuth Nanosheet Assembly for Highly Selective Electrocatalytic CO2 Reduction to Formate

The reduction of carbon dioxide (CO₂ ) into value-added fuels using an electrochemical method has been regarded as a compelling sustainable energy conversion technology. However, high-performance electrocatalysts for CO₂ reduction reaction (CO₂ RR) with high formate selectivity and good stability need to be improved. Earth-abundant Bi has been demonstrated to be active for CO₂ RR to formate. Herein, we fabricated an extremely active and selective bismuth nanosheet (Bi-NSs) assembly via an in situ electrochemical transformation of (BiO)₂ CO₃ nanostructures. The as-prepared material exhibits high activity and selectivity for CO₂ RR to formate, with nearly 94% faradaic efficiency at -1.03 V (versus reversible hydrogen electrode (vs. RHE)) and stable selectivity (>90%) in a large potential window ranging from -0.83 to -1.18 V (vs. RHE) and excellent durability during 12 h continuous electrolysis. In addition, the Bi-NSs based CO₂ RR/methanol oxidation reaction (CO₂ RR/MOR) electrolytic system for overall CO₂ splitting was constructed, evidencing the feasibility of its practical implementation.

Boosting Production of HCOOH from CO2 Electroreduction via Bi/CeOx

Formic acid (HCOOH) is one of the most promising chemical fuels that can be produced through CO₂ electroreduction. However, most of the catalysts for CO₂ electroreduction to HCOOH in aqueous solution often suffer from low current density and limited production rate. Herein, we provide a bismuth/cerium oxide (Bi/CeO_x ) catalyst, which exhibits not only high current density (149 mA cm^-2 ), but also unprecedented production rate (2600 μmol h^-1  cm^-2 ) with high Faradaic efficiency (FE, 92 %) for HCOOH generation in aqueous media. Furthermore, Bi/CeO_x also shows favorable stability over 34 h. We hope this work could offer an attractive and promising strategy to develop efficient catalysts for CO₂ electroreduction with superior activity and desirable stability.

Heterostructure of ZnO Nanosheets/Zn with a Highly Enhanced Edge Surface for Efficient CO2 Electrochemical Reduction to CO

Electrochemical reduction of CO₂ to valuable chemicals or fuels is critical for closing the carbon cycle and preventing further deterioration of the environment. Here, we discover that by adopting the Zn foil as the substrate, a ZnO two-dimensional sheet array is in situ synthesized on the Zn foil by a facile hydrothermal method. The obtained ZnO sheet array/Zn foil exhibited an outstanding CO₂ reduction performance to CO, which showed the highest Faraday efficiency of 85% for CO at -2.0 V (vs Ag/AgCl) with a current density of 11.5 mA/cm² compared with the freestanding ZnO sheets and particles and excellent stability in the 0.1 M KHCO₃ electrolyte. The in situ vertical ZnO sheet array exposed with abundant exposed (11̅00) edge facets can accelerate the electron transfer and improve the number of active sites, which leads to the enhanced reduction performance. Alongside, the density functional theory simulation indicated that the vertical-grown ZnO sheet array possesses lower Gibbs free energy for the CO₂ activation, with a more exposed (11̅00) edge surface of ZnO.

Exfoliated Ultrathin ZnIn2 S4 Nanosheets with Abundant Zinc Vacancies for Enhanced CO2 Electroreduction to Formate

Electrocatalytic conversion of carbon dioxide (CO₂ ) is promising for balancing carbon cycles while producing value-added feedstocks. Herein, ultrathin ZnIn₂ S₄ nanosheets with abundant Zn vacancies are demonstrated for electrochemically reducing CO₂ to formate. Specifically, a partial current density of 245 mA cm^-2 with a near-unity faradaic efficiency of 94 % for formate generation was achieved over the ultrathin ZnIn₂ S₄ nanosheets in a flow cell configuration. Experimental and theoretical results revealed that abundant Zn vacancies in the ultrathin ZnIn₂ S₄ nanosheets with a high electrochemically active surface area synergistically optimized the intermediate binding energy and contributed to the boosted selectivity and activity. This work may provide useful understandings in designing efficient catalysts for selective CO₂ electroreduction.

Polyacrylamide-Mediated Silver Nanoparticles for Selectively Enhancing Electroreduction of CO2 towards CO in Water

Conversion of the greenhouse gas CO₂ to value-added products is an important challenge for sustainable energy research. Here, a durably nanohybrid composed of Ag nanoparticles and polyacrylamide was constructed for the selectively electroreduction of CO₂ to CO. The nanohybrid exhibited an outstanding CO faradaic efficiency of 97.2±0.2 % at -0.89 V_RHE (vs. the reversible hydrogen electrode) with a desirable CO partial current density of -22.0±2.3 mA cm^-2 and maintained the CO faradaic efficiency above 95 % over a wide potential range (-0.79 to -1.09 V_RHE ), showing excellent stability during a 48 h prolonged electrolysis. The origins of selective enhancement of CO₂ reduction over the nanohybrid stemmed from the activation of CO₂ via hydrogen bond and the low basicity of the amide. DFT calculations implied that the synergy of Ag nanoparticles and amide could better stabilize the key intermediate (*COOH) and effectively lower the overpotential of CO₂ reduction. These results establish the synergistic effects of organic/inorganic hybrid as a complementary method for tuning selectivity in CO₂ -to-fuels catalysis.

Formate-Selective CO2 Electrochemical Reduction with a Hydrogen-Reduction-Suppressing Bronze Alloy Hollow-Fiber Electrode

Electroreduction carbon dioxide into formate has been regarded as a hopeful measure to relieve global warming. Copper-based hollow fibers demonstrated good performances on converting carbon dioxide in previous researches. Herein Cu-Sn alloy hollow fibers were synthesized in an innovative way, combining the structure advantages of hollow fiber and high selectivity towards formate on η' bronze. Tests under different gas injection conditions were conducted to analyze the contribution of the hollow fiber structure on suppression of hydrogen evolution and promotion on kinetics. Strikingly, Cu-Sn_45 % hollow fiber, the optimal catalyst in this work, achieved a highest faradaic efficiency towards formate of 90.96 % at a lower potential of -0.75 V vs. RHE than most non-noble catalysts, and the FE of H₂ was below 4 %.

Engineering Heterostructured Nanocatalysts for CO2 Transformation Reactions: Advances and Perspectives

As a conceivable route to achieving anthropological carbon looping, carbon capture and utilization (CCU) technologies employ waste CO₂ as an accessible C1 building block to generate upgraded chemicals or fuels, thereby simultaneously remedying environmental issues and energy crises. However, efficient CO₂ conversion is disfavored by both its thermodynamics and its kinetics. Heterostructured materials with well-controlled interfaces have great potential for enhanced catalytic performance in various CO₂ transformation reactions, owing to the synergistic effects among components, numerous interfacial and/or surface active sites, increased CO₂ adsorption capacity, promoted charge transfer efficiency, and unique physicochemical properties. This Review highlights the state of the art in typical heterostructures, such as core-shell, yolk-shell, Janus, hierarchical (branched and hollow), and 2D/2D layered structures, applied for CO₂ conversion with various energy inputs (radiation, electricity, heat). Fabrication methods of different heterostructures and structure-composition-performance relationships are also discussed concisely. Finally, a brief summary and prospective research directions are provided. The motivation of this Review is to offer instructive information on the applicability of inorganic heterostructures for CO₂ transformation reactions, and it is hoped that further enlightening studies in this field could emerge in the future.

Ordered-Mesoporous-Carbon-Confined Pb/PbO Composites: Superior Electrocatalysts for CO2 Reduction

CO₂ electroreduction has gained significant interest. However, fabricating cost-effective nonprecious-metal electrocatalysts that can selectively convert CO₂ to a specific product remains highly challenging. Herein, Pb-based materials consisting of Pb⁰ and PbO confined in ordered mesoporous carbon (OMC) (Pb/PbO@OMC) were constructed for CO₂ electroreduction to CO. Interestingly, the activity and selectivity of the Pb/PbO@OMC varied with the molar ratio of Pb⁰ /PbO. The material calcined at 800 °C (Pb/PbO@OMC-800) with a Pb⁰ /PbO ratio of 0.58 provided the best result with CO as the only carbon-based product, and the Faradaic efficiency of CO reached 98.3 % at a high current density of 41.3 mA cm^-2 . Detailed studies indicated that Pb⁰ , PbO, and OMC co-operated well to enhance the performance of Pb/PbO@OMC-800, which mainly originated from the good interface between Pb⁰ and PbO, higher electrochemical active surface area, and faster electron transfer to form the CO₂ ^⋅- intermediate.

Electrochemical Conversion of CO2 to CO by a Competent FeI Intermediate Bearing a Schiff Base Ligand

Iron complexes with a N₂ O₂ -type N,N'-bis(salicylaldehyde)-1,2-phenylenediamine salophen ligand catalyze the electrochemical reduction of CO₂ to CO in acetonitrile with phenol as the proton donor, giving rise to 90-99 % selectivity, faradaic efficiency up to 58 %, and turnover frequency up to 10³  s^-1 at an overpotential of 0.65 V. This novel class of molecular catalyst for CO₂ reduction operate through a mononuclear Fe^I intermediate, with phenol being involved in the process with first-order kinetics. The molecular nature of the catalyst and the low cost, easy synthesis and functionalization of the salophen ligand paves the way for catalyst engineering and optimization. Competitive electrodeposition of the coordination complex at the electrode surface results in the formation of iron-based nanoparticles, which are active towards heterogeneous electrocatalytic processes mainly leading to proton reduction to hydrogen (faradaic efficiency up to 80 %) but also to the direct reduction of CO₂ to methane with a faradaic efficiency of 1-2 %.

Magnesium oxide anchored into a hollow carbon sphere realizes synergistic adsorption and activation of CO2 for electrochemical reduction

We report the synergistic adsorption and activation of CO₂ by using magnesium oxide anchored into a hollow carbon sphere (MgO/HCS) as an efficient catalyst for electrochemical reduction of CO₂ (ERC). The MgO/HCS catalyst exhibits a high selectivity for CO production with a faradaic efficiency of 81.7% at -1.0 V vs. RHE and a partial current density (PCD) of 16.7 mA cm^-2 in aqueous electrolyte.

The Origin of the Electrocatalytic Activity for CO2 Reduction Associated with Metal-Organic Frameworks

There has been a rapid growth in the use of metal-organic framework (MOF) materials as electrocatalysts. However, simple anodic stripping analysis reveals that some well-known previously reported stable MOFs are in fact unstable at the negative potentials used to catalytically reduce CO₂ in aqueous electrolyte media. Thus, it is the resulting metal nanoparticles derived from reduction of the MOFs rather than the MOFs themselves that are the electrocatalysts. The results reported herein therefore suggest that stability data and the origin of the activity for MOF electrocatalysts may need careful re-evaluation and that suitable strategies are needed to ensure that stable MOF electrocatalysts have been synthesized. The use of the readily accessible stripping analysis method provides a powerful tool to assess MOF stability under turnover conditions.

Electrochemically Driven Formation of Sponge-Like Porous Silver Nanocubes Toward Efficient CO2 Electroreduction to CO

Electrochemical conversion of CO₂ into valuable products by utilizing renewable electricity is a thriving research field. For electrochemical reduction of CO₂ to CO, uniform sponge-like porous Ag nanocubes (SPC-Ag) integrated on carbon paper are prepared by using an electrochemically driven method. The SPC-Ag has a 3 D porous structure and a large specific surface area, which affords abundant active sites for the CO₂ reduction reaction (CO₂ RR), as well as reducing impedance to accelerate the CO₂ RR kinetics. This distinctive organization affords SPC-Ag with outstanding electrocatalytic performance for CO₂ reduction to CO. High faradaic efficiency (>90 %) and large partial current density for CO with excellent durability are observed in a wide potential window, with a maximum value of 93 % at -0.9 V versus reversible hydrogen electrode.

Electrochemical Reduction of CO2 to CO by N,S Dual-Doped Carbon Nanoweb Catalysts

Converting CO₂ into useful chemicals through an electrocatalytic process is an attractive solution to reduce CO₂ in the atmosphere. However, the process suffers from high overpotential, low activity, or poor product selectivity. In this study, N,S dual-doped carbon nanoweb (NSCNW) materials were proposed as an efficient nonmetallic electrocatalyst for CO₂ reduction. The NSCNW catalysts preferentially and rapidly converted CO₂ into CO with a high Faradaic efficiency of 93.4 % and a partial current density of -5.93 mA cm^-2 at a low overpotential of 490 mV. A small Tafel slope value (93 mV dec^-1 ) was obtained, demonstrating a high rate for CO₂ reduction. Moreover, the catalysts also exhibited a quite stable current-density profile during 20 h with a high CO Faradaic efficiency above 90 % throughout the electrolysis reaction. The high catalytic performance of the catalysts for CO₂ reduction could be attributed to synergistic effects associated with the structural advantages of 3 D carbon nanoweb structures and effective S doping of the carbon materials with the highest ratio of thiophene-like S to oxidized S species.

Enhanced Ethanol Production from CO2 Electroreduction at Micropores in Nitrogen-Doped Mesoporous Carbon

Efficient formation of valuable multicarbon products in CO₂ electrochemical reduction is challenging, owing to the difficulty of C-C coupling. Medium micropores embedded in the channel walls of nitrogen-doped ordered mesoporous carbon are found to capably promote ethanol production from CO₂ electroreduction. By scaling up the medium micropore content, the yield of ethanol is increased to 2.3 mmol g_cat ^-1  h^-1 , far outperforming previously reported state-of-the-art electrocatalysts. The intrinsically higher activity is attributed to the desolvation effect induced by the medium micropores, facilitating the coupling reaction of C₁ intermediates to form ethanol.