Metal-Organic Diffusion Layer （MODL） in Electrocatalytic Carbon Dioxide Reduction Chemistry

Zhiyuan Xing; Wenjun Yang; Haoqi Shi; Yang Peng

doi:10.7536/PC20250719

Progress in Chemistry ›› 2026, Vol. 38 ›› Issue (1) : 116-129 DOI: 10.7536/PC20250719

review-article

Scan to read & Share

Metal-Organic Diffusion Layer （MODL） in Electrocatalytic Carbon Dioxide Reduction Chemistry

Author information +

History +

PDF

Abstract

Electrochemical CO₂ reduction （eCO₂R）， as one of the pivotal technologies for achieving carbon neutrality strategic goals， demonstrates significant application potential in renewable energy storage and high-value chemical synthesis. The electrode-electrolyte interfacial electric double layer （EDL）， serving as the highly active reaction zone， profoundly governs the overall system performance by coupling reaction kinetics at catalytic sites with interfacial mass transport processes. Conventional solid/liquid EDL systems suffer from limitations imposed by one-dimensional regulatory mechanisms relying on electric field-driven effects and static interfacial configurations， resulting in restricted ion spatial distributions and insufficient dynamic regulation dimensions. This inherent constraint hinders the synergistic optimization of interfacial reaction kinetics and mass transport processes. To address these challenges， we propose the construction of a "Metal-Organic Diffusion Layer" （MODL） architecture. Through molecular design strategies incorporating functionalized organic components （e.g.， amphiphilic molecules， coordinating and charged polymers）， this approach leverages their abundant functional groups and dynamic interfacial characteristics to precisely regulate the hierarchical condensed-phase structures within the MODL at the near-field microscopic scale （e.g.， electrode crystallinity， reaction pathways）， far-field mesoscopic scale （e.g.， interfacial electric field， water molecular configuration）， and macroscopic scale （e.g.， interfacial wettability， mass transport channels）， achieving precise regulation of spatial partitioning of electrode interfaces. This work will systematically analyze the organic-mediated dynamic coupling mechanism between the near-field catalytic core and far-field mass transport environment， elucidating their synergistic interplay in regulating CO₂ conversion pathways and interfacial kinetics. The established multi-dimensional MODL interfacial model provides a theoretical framework for deciphering intricate structure-performance relationships in electrochemical interfaces， laying scientific foundations for the rational design of efficient and stable eCO₂R catalytic systems.

Contents

1 Introduction

2 Linking metal-organic diffusion layer configurations to eCO2R performance

2.1 Near-field interfacial engineering： organic component-induced reactive crystalline surface exposure and reaction path modulation

2.2 Far-field mesoscale regulation： organic-mediated structural expansion of diffusion layer and gradient microenvironment reconstruction

2.2.1 Far-field regulated water/electric field structures，local pH

2.2.2 Far-field modulation of substance transport

3 Conclusion and outlook

Graphical abstract

Keywords

metal-organic diffusion layer / electrocatalysis / carbon dioxide / condensed-state structure / organic substances

Cite this article

Download citation ▾

Zhiyuan Xing, Wenjun Yang, Haoqi Shi, Yang Peng. Metal-Organic Diffusion Layer （MODL） in Electrocatalytic Carbon Dioxide Reduction Chemistry. Progress in Chemistry, 2026, 38(1): 116-129 DOI:10.7536/PC20250719

登录浏览全文

4963

注册一个新账户忘记密码

1 Introduction

Under the dual impetus of the accelerating global carbon neutrality process and the increasing cost-effectiveness of renewable energy, electrocatalytic carbon dioxide reduction (eCO₂R) technology, with its unique capability to directly convert CO₂ into high-value carbon-based fuels and chemicals (such as CO, formic acid, methanol, and multi-carbon compounds) under mild reaction conditions, has provided innovative solutions for revolutionizing conventional high-energy-consuming chemical carbon capture processes and addressing the missing carbon reduction step in industrial metabolic pathways^[1–2]. Despite significant breakthroughs achieved in recent years in catalytic material design and reactor engineering, the large-scale industrial application of eCO₂R still faces severe challenges^[3–5]. One of the core challenges lies at the catalyst level: although copper-based catalysts are regarded as the most promising electrocatalysts for generating high-value hydrocarbon products in eCO₂R, their reduction products are generally constrained by the close thermodynamic theoretical potentials of various reduction pathways and the strong correlations among the adsorption energies of key intermediates. This makes it difficult to achieve highly selective control over specific target products on a single active surface. Another critical challenge originates from the engineering application perspective: under industrial-scale high-current-density operating conditions, issues such as electrode flooding, salt precipitation, and ion-exchange membrane swelling severely limit the long-term operational stability of the system. Therefore, constructing stable gas–liquid–solid three-phase transport channels through microinterface engineering and precisely regulating interfacial mass transfer and charge transfer processes are considered key breakthroughs for addressing core challenges in eCO₂R, including product selectivity control, system durability enhancement, and scale-up engineering.

In eCO₂R, the three-phase microinterface composed of gaseous CO₂, liquid electrolyte, and solid catalyst constitutes the core region that determines reaction selectivity and stability. This interface serves as the critical site for CO₂activation, electron/proton transfer, and product formation; its microstructure and dynamic behavior directly govern the reaction pathway and efficiency. In the field of electrochemistry, the most classic and fundamental model for describing the electrode/electrolyte solution interface structure is the electrical double layer (EDL) model^［6］. The Gouy–Chapman–Stern (GCS) model provides a classical description of the EDL structure. This model characterizes the chemical composition and the distribution of electric potential and electric field as functions of distance near the electrode surface—typically within the nanoscale range. As shown in Figure 1a, extending outward from the electrode surface, the EDL consists of the inner Helmholtz plane (IHP), the outer Helmholtz plane (OHP), and the diffuse layer. Specifically, in the IHP, reactive molecules and solvent molecules are specifically adsorbed onto the electrode surface, making it the key region where electron transfer and electrochemical reactions occur. The properties of the electrode material are crucial factors influencing the kinetics of these processes. The OHP is defined as the electrical neutral plane formed by solvated counterions. At this plane, hydrated cations are closely arranged under electrostatic attraction, exhibiting a charge distribution similar to that of a parallel-plate capacitor relative to the negative charges on the electrode surface. The resulting local electric field can significantly modulate the adsorption behavior of ions and molecules in the IHP. The diffuse layer refers to the region extending from the OHP into the bulk solution. This model can describe macroscopic and mesoscopic electrochemical phenomena such as interfacial capacitance, potential distribution, and ion transport, thereby providing a foundational theoretical framework for understanding the overall characteristics of interfacial behavior^［7］.

However, in gas/liquid/solid three-phase interfacial eCO₂R catalytic systems involving multiple electron transfers, multi-path competition, and heterogeneous microenvironments, the analytical solutions of classical models need to be further extended to account for the specific characteristics of the system. Since the CO₂reduction process involves the migration and coupling behaviors of various intermediates, its reaction pathways are highly dependent on the atomically resolved anisotropic features of the catalyst surface (such as crystallographic facet differences, defect sites, and step edges). These microscopic structural features exert a decisive influence on the catalytic performance^［8-15］. For instance, if traditional models simplify the electrode surface into an idealized, structureless homogeneous plane, they fail to accurately capture the heterogeneity of solid-state electrode surfaces—including atomic-scale roughness, facet-specific properties, and defect distributions—and the resulting local electric field distortions caused by their dynamic evolution. Moreover, interfacial structures at different length scales have a profound impact on gas/liquid mass transport in eCO₂R, directly determining the kinetic behavior of the reaction. Due to the inherent nanoscale spatial constraints of the conventional EDL model, it cannot describe how macroscopic-scale gas enrichment at the interface, hydrophobic treatment of electrodes, and mesoscopic-scale modifications of the water network can significantly affect the electrode–electrolyte interfacial structure, the local mass transfer environment, and the distribution of reactant concentrations^［16-22］. Furthermore, while traditional EDL models primarily rely on linear coupling between electrostatic potential and ion concentration for regulation, in eCO₂R systems, the synergistic interactions among chemical adsorption configurations, interfacial water networks, and mass transfer microenvironments necessitate consideration of additional control dimensions.

Building upon the conventional planar EDL model, this paper introduces an organic dielectric layer—comprising organic molecules or polymeric materials—as an interfacial functional layer, thereby proposing a modulation strategy known as "Metal–Organic Diffusion Layer (MODL) Interface Engineering." As illustrated in Figure 1b, the incorporation of the organic dielectric layer leverages its hydrophilicity/hydrophobicity, molecular polarity, and steric hindrance, among other multidimensional tuning parameters, to actively modulate the interfacial microenvironment. This includes restructuring hydrogen-bonding networks, buffering local pH, and optimizing proton-transfer pathways, thus enabling synergistic co-regulation across multiple length scales—from nanoscale active sites to micrometer-scale mass-transport channels (>1 μm)—and across multiple physical fields (electric field, concentration field, and chemical-gradient field). This strategy initially focuses on regulating the internal interfaces within the catalyst, aiming to establish an intrinsic correlation between spatial anisotropy at the electrode surface and its dynamic evolution (e.g., exposure of specific crystal facets and formation of defect sites) on one hand, and the kinetics of key species formation and charge-exchange efficiency within the interfacial Helmholtz plane (IHP) on the other. Subsequently, by precisely introducing the organic dielectric layer, the overall microenvironmental structure of the EDL can be actively controlled and optimized. To elucidate the dynamic mechanisms underlying the MODL interface, this study deeply integrates the concept of "near-/far-field synergistic regulation" into the framework of this interface engineering approach, adopting a spatially resolved, dynamic perspective to reexamine the electrode–electrolyte interface. By examining two spatially distinct regions—the near field and the far field—we comprehensively investigate the dynamic evolution of the MODL interface and its intrinsic relationships with the reaction rate, product selectivity, and catalyst stability in eCO₂R processes. Through the integration of the core principles of "near-/far-field regulation" with the spatial partitioning model of the EDL, we endeavor to construct a unified, high-spatial-resolution research framework. From the standpoint of condensed-phase chemistry, this framework aims to provide novel theoretical foundations and design principles for systematically understanding how organic functional groups reshape the microenvironment at the electrode surface, ultimately facilitating efficient and stable electrochemical conversion of CO₂.

2 The Relationship Between Metal–Organic Diffusion Layer Structure and eCO₂R Performance

2.1 Near-field Interface Engineering: Organic Component-Induced Active Facet Exposure and Reaction Pathway Regulation

Catalyst near-field (inner interface) structure and property precise control is the primary cornerstone for constructing high-efficiency reaction interfaces. This layer directly corresponds to the electrode surface (metal intrinsic inner interface) and the tightly adsorbed IHP region, where atomic/molecular-scale arrangement and dynamic behavior profoundly govern CO₂ initial adsorption activation, key intermediate formation, and subsequent reaction pathway branching. The MODL interface engineering near-field regulation strategy focuses on how organic components act as powerful “interface sculptors” and “pathway guides,” by inducing preferential exposure of specific active crystal facets or directly regulating key reaction intermediates, thereby achieving reshaping of the spatial anisotropy of the electrode surface (Figure 2a).

In eCO₂R, the specific crystal facets exposed on the surface of metal catalysts have a decisive impact on both reactivity and selectivity. Through sophisticated nanosynthesis techniques, it is possible to precisely modulate the distribution and degree of exposure of highly active crystal facets on the electrode surface, thereby directing the reaction pathway and significantly optimizing the selectivity and efficiency toward the desired products. For example, our team^［23］has achieved 97% CO selectivity by precisely synthesizing Ag/Au nanoarchitectures enriched with specific grain boundaries and defects, shifting the rate-determining step of CO₂R to the hydrogenation process. Furthermore, by epitaxially depositing Cu domains under high strain and leveraging interfacial electronic effects to break the linear relationship in C—C coupling, they obtained a Faraday efficiency (FE) of 77% for C₂H₄. In addition, precise control over Cu’s active crystal facets—for instance, Cu(100) promoting C—C coupling while Cu(111) favors hydrogenation—can direct the *CO adsorption configuration and modulate the reaction energy barriers, making this one of the core strategies for enhancing the selectivity of target products, particularly high-value multi-carbon species. However, conventional methods for facet modulation, such as synthesizing nanoparticles with specific morphologies, often encounter challenges related to surface reconstruction under electrochemical operating conditions, leading to instability in the crystal facet structure, and they struggle to finely tune the reaction pathways at the molecular level. To overcome these limitations, the “MODL interface engineering” strategy introduces organic components, greatly enriching and innovating the means and dimensions of facet regulation. These organic molecules or ligands can serve as “structure-directing agents,” inducing and stabilizing the preferential exposure of specific highly active crystal facets during synthesis or in situ electrochemical processes, thus mitigating surface reconstruction issues. For instance, based on an organic–inorganic synergistic induction strategy, our team has collaborated with conductive MOF precursors such as Cu₃(HITP)₂and carbon-based matrices to regulate charge distribution, thereby selectively constructing Cu microcrystals rich in grain boundaries and defects^［24］(Figure 2b, c). The resulting polycrystalline structure enhances *CO adsorption within the IHP, promotes C—C coupling, and suppresses hydrogen evolution. Meanwhile, the —NH groups in the organic ligands activate CO₂via hydrogen bonding, ultimately enabling stable, highly selective conversion of CO₂to C₂H₄within a broad potential window (60%–70%) (Figure 2d). Similarly, we have recently employed organic ligands such as biphenyl and bipyridine to precisely control the restructuring behavior of Cu species confined within MOFs, achieving fine-tuned directional control over eCO₂R product selectivity^［25］. Specifically, bipyridine ligands tend to induce the formation of small-sized Cu⁰nanocrystals, whose exposed facets are more conducive to efficient hydrogenation and methane production (Figure 2e–g). In contrast, biphenyl ligands promote the assembly of large-sized Cu₂O aggregates, which favor C—C coupling and result in highly selective generation of C₂₊products (Figure 2h–j).

Based on the precise regulation of the active crystal facets on the electrode surface, the core value of the “MODL interfacial engineering” strategy is further manifested in the directional guidance and enhancement of key reaction pathways. Organic components are by no means merely structural modifiers; their deeper role lies in serving as powerful “reaction pathway guides.” Through molecular-level modification of the intrinsic metal–electrolyte interface and the adjacent IHP region, they directly intervene in the subsequent evolution pathways of critical intermediates (such as *CO). By finely tuning the local electronic structure, providing a specific spatial microenvironment, or participating in intermediate stabilization, the organic layer can selectively lower the activation energy barriers of target reaction pathways (e.g., C—C coupling or specific hydrogenation steps) while suppressing undesired competitive pathways (such as over-hydrogenation or the hydrogen evolution reaction [HER]). This proactive “regulation” of reaction energy barriers enables us to overcome the limitations imposed by thermodynamic preferences alone, achieving precise control over reaction pathways and thereby efficiently directing the synthesis toward the desired product (Figure 3, Fig. 3).For example, our team recently filled Cu-MOF pores with short-chain polyaniline (PANI) and polypyrrole (PPy) via in-situ polymerization, followed by electrochemical reconstruction to obtain copper nanoparticles (3–5 nm) embedded within N-containing polymers for use in eCO₂R^[10]. The pore filling combined with chemical reconstruction resulted in metal particles being tightly encapsulated by short-chain polymers, thereby enabling modulation of the near-field environment. Performance tests revealed that the reconstructed Cu/PANI exhibited a C₂H₄ Faraday efficiency (FE) as high as 67.5%, whereas the primary product of the Cu/PPy-catalyzed reaction was CH₄ (FE = 55.5%) (Fig. 3 b–e). The markedly different catalytic selectivities of these two composite materials primarily stem from the differing basicities of the —NH groups in PANI and PPy, which lead to distinct interactions with reaction intermediates and consequently alter the reaction pathways. Specifically, the —NH group in aniline within PANI possesses stronger basicity, allowing it to adsorb protons on the Cu surface and suppress the formation of *H intermediates, while simultaneously providing hydrogen to react with *CO to form the *COH intermediate. The relatively high coverage of *CO on the Cu surface, coupled with the rapid generation of *COH, facilitates C—C coupling; hence, the main catalytic product of Cu/PANI is C₂H₄. In contrast, the —NH group in pyrrole within PPy exhibits weaker basicity and cannot preferentially bind protons. Instead, it merely participates in water splitting catalyzed by Cu to generate *H. This *H undergoes selective inner-sphere transfer to the carbon atom of CO (as the pyrrole —NH blocks the oxygen atom of CO via hydrogen bonding), thereby promoting the formation of the *CHO intermediate. The reaction pathway dominated by *CHO ultimately leads to CH₄ as the principal product in the Cu/PPy system. This work demonstrates that introducing organic functional groups with distinct functionalities into the MODL IHP to synergistically catalyze CO₂ conversion at the electrode surface can effectively modulate both the catalytic pathways and product selectivity.

In addition to regulating product selectivity, organic small molecules can also enhance the conversion efficiency of specific products by modulating the electronic properties of metal electrodes within the IHP and stabilizing key reaction intermediates. For example, Wang’s team^［26］proposed an in-situ molecular modification strategy. By electrochemically reconstructing a tannic acid (TA)–Cu²⁺complex, they prepared a TA-modified Cu catalyst (TA-Cu) (Figure 3f), which significantly improved the catalytic performance for CO₂electroreduction to C₂H₄. The electrochemical reconstruction enabled direct anchoring of TA molecules onto the surface of Cu nanorods, thereby achieving precise control over Cu atoms within the IHP and key adsorbed intermediates. Under alkaline conditions, the C₂H₄selectivity of TA-Cu reached 63.6% (Figure 3g), which is 6.5 times that of the pristine Cu catalyst. Mechanistic studies revealed that the hydroxyl oxygen of TA coordinates with Cu, stably maintaining Cu ^δ ^⁺sites under reducing potentials and lowering the energy barrier for C—C coupling. Meanwhile, the hydroxyl groups of TA stabilize the *COH intermediate via hydrogen bonding. The synergistic effect between the stabilized Cu ^δ ^⁺/Cu⁰interface and hydrogen bonding promotes C—C coupling between CO and *COH, thereby enhancing the selectivity toward C₂H₄.

CO₂molecule's efficient activation at the IHP is a critical step in regulating the electrocatalytic reaction pathway, directly determining the kinetics of key intermediate formation. Traditional strategies rely on the electrostatic polarization effect of alkali metal cations, but their activation efficiency is limited by electric field strength and ionic hydration structures. Recent studies, however, have demonstrated that organic cations can directly participate in CO₂activation through short-range chemical bonding interactions. For example, Professor Zhuang Lin's team at Wuhan University^［27］designed molecules to anchor a series of cations—trimethylammonium (TMA⁺), piperidinium (Pip⁺), pyridinium (Py⁺), 1-methylimidazolium (Meim⁺), 1-hexylimidazolium (Hexim⁺), and 1-methylbenzimidazolium (Beim⁺)—onto a polymer backbone (pTPN). They investigated the effects of these organic components on the eCO₂R performance of Cu electrodes (Figure 3h). Among them, the system involving Beim⁺exhibited the most outstanding CO₂reduction activity. Mechanistic studies revealed that, under reduction potentials, Beim⁺captures electrons to form a highly active radical species, which then reacts with CO₂to generate the Beim-CO₂ ^‒adduct, thereby directly cleaving the C

̿

O bond. Consequently, this electrode achieved a C₂₊selectivity as high as 75.9% under neutral conditions and, under CO₂/pure water co-electrolysis, realized efficient production of C₂H₄at an industrial-scale current density of 331 mA/cm²(Figure 3i). These findings demonstrate that organic components can directly activate CO₂molecules via chemical bonding, offering a new paradigm for molecular-level interface engineering.

The above-mentioned study has sufficiently demonstrated that organic components can penetrate deep into the electrode surface (the intrinsic metal–electrolyte interface) and reach the near-field region of the tightly adsorbed inner Helmholtz plane. Within this critical interfacial zone, organic constituents not only induce the selective exposure of active crystal facets on the metal substrate, thereby optimizing its intrinsic catalytic sites, but also directly participate in and precisely regulate the reaction pathway through rich interactions with CO₂ reaction intermediates at the metal surface. This near-field regulation of the reaction microenvironment at the molecular level provides a robust platform for synergistically catalyzing CO₂ conversion while rationally controlling both the reaction rate and selectivity. Notably, to maximize such near-field synergistic catalytic effects, it is essential to develop specific synthetic methodologies capable of constructing structurally precise and controllable metal–organic composite interfaces.

2.2 Far-field mesoscopic regulation: diffusion layer expansion mediated by organic layers and microenvironment gradient reconstruction

In traditional solid/liquid EDL models, the control targets are typically confined to the nanoscale spatial region (0–10 nm) at the solid–liquid two-phase interface. The two-dimensional planar nature of this interface, combined with simple boundary conditions at the solid–liquid contact, significantly simplifies the complexity of the interfacial microenvironment. However, in the eCO₂R system—a typical gas–liquid–solid three-phase interfacial system—the three-dimensional topological structure of the reaction domain causes the actual EDL to exhibit dynamic, cross-scale characteristics. As a result, the control region has expanded from the two-dimensional nanoscale interface in conventional models to a micrometer-scale three-dimensional space. In particular, in the cathode of a membrane electrode assembly (MEA) without liquid electrolyte, where the catalyst layer is in direct contact with the ion-exchange membrane, mass transport processes at the reaction interface (CO₂mass transfer, transport of liquid products, and release of gaseous products), ionic flux management (proton transport, counterion migration, and interfacial charge compensation), and water management (arrangement of interfacial water molecules, transmembrane water transport, and water balance control) all heavily rely on the synergistic multi-physics field regulation within the micrometer-scale gap at the membrane–catalyst interface. At this interface, processes such as CO₂adsorption activation, molecular rearrangement of interfacial water, and proton–electron coupled transfer involve cross-scale interactions spanning several micrometers. These phenomena have far exceeded the scope of conventional EDL physical explanations, necessitating the establishment of a “far-field regulation” paradigm to break through the inherent boundary limitations of traditional EDLs. In light of this, the “far-field regulation” concept proposed in this paper introduces functionalized organic dielectric layers to achieve strategic “expansion” and multidimensional modulation of the EDL structure. The core objective of this “far-field regulation” is to break through the physical boundaries of the traditional EDL, significantly extending the controllable scale to the micrometer level. By leveraging the rich physicochemical properties of organic components—such as hydrophilicity/hydrophobicity, charge state, molecular polarity, and steric hindrance—it introduces a series of novel, finely tunable “regulation variables.” Through actively shaping the chemical microenvironment of the far-field region (e.g., enriching CO₂concentration, optimizing the interfacial water structure to facilitate proton transport, buffering local pH fluctuations, and constructing gradient electric fields), it not only independently improves mass transport and charge distribution but also forms deep synergy with near-field regulation (at the metal intrinsic inner interface and the IHP), thereby systematically enhancing the efficiency and selectivity of eCO₂R catalytic performance. This section will systematically elaborate on the scientific connotations of far-field chemical microenvironment regulation, its key strategies, and the cross-scale optimization mechanisms by which it enhances eCO₂R performance.

2.2.1 Water/Electric Field Structures, Hydrogen-Bond Networks, and Local pH in Far-Field Regulation

The EDL composed of alkali metal cations is a necessary condition for efficient eCO₂R. Studies have shown that the addition of high-concentration alkali metal salts to acidic electrolytes is required to activate the CO₂reduction reaction. The underlying mechanism is as follows: hydrated alkali metal cations are densely packed and stabilized within the OHP, inducing an ultra-high interfacial electric field that promotes CO₂activation. Simultaneously, electrostatic repulsion suppresses H⁺ migration, thereby weakening HER. However, alkali metal cations tend to combine with CO₃ ^2‒, leading to salt precipitation that blocks gas transport channels and compromises the stability of the electrolytic reaction. By constructing a MODL structure containing organic cations in the far-field region, it is possible to both replace alkali metal cations to maintain efficient eCO₂R performance and avoid the salt precipitation effect, significantly enhancing electrolytic stability (Figure 4a).

Recently, our team^［28］effectively enhanced the efficiency and stability of electrocatalytic CO₂reduction to C₂₊products by in-situ electrospinning a quaternized polyvinyl alcohol film on a Cu electrode (Figure 4b, c). In an alkaline electrolyte, the quaternary ammonium cations on the surface of this film repel hydrated potassium ions in the electrolyte, thereby achieving a directional reconstruction of the interfacial electric field. The cationic density on the polymer film directly determines the strength of the interfacial electric field. By controlling the grafting ratio of quaternary ammonium ions within the polymer, we found that as the grafting amount increased from 0% to 54%, the selectivity for C₂₊products effectively rose by approximately 13%, reaching 83%, with an FE of 55% for ethylene (Figure 4d). Combined with in-situ characterization, it was revealed that the introduction of quaternary ammonium groups effectively promoted the polarization of interfacial water. These results indicate that increasing the density of organic quaternary ammonium cations can effectively strengthen the local electric field, thereby facilitating the dissociation of water molecules and the electrostatic capture of OH^‒anions, ultimately leading to a higher local pH value in the far-field environment (Figure 4e), which in turn promotes eCO₂R. Furthermore, the organic cations can effectively prevent the contact between K⁺ions in solution and CO₃ ^2‒on the electrode surface through electrostatic repulsion, thus alleviating the salting-out issue in the electrolytic system. The polymer-modified Cu electrode can operate continuously at a current density of 300 mA/cm²for up to 300 hours, with

F E C 2 H 4

showing almost no decay (Figure 4f).

Although the enhanced electric field can accelerate CO₂ reduction kinetics, it also intensifies water molecule polarization within the OHP, thereby promoting H₂O dissociation and exacerbating the hydrogen evolution side reaction, which ultimately leads to a decrease in overall product selectivity. Therefore, based on quaternary ammonium polymers, we designed and introduced hydroxyl groups that can stabilize the water network. Raman spectroscopy studies revealed that, unlike conventional EDLs, MODLs containing organic cations exhibit almost no M⁺·H₂O complexes within the OHP, indicating that organic cations can repel alkali metal ions and reshape the OHP structure. Furthermore, water molecules in the OHP predominantly adopt a four-hydrogen-bonded configuration (4-BH·H₂O). This is attributed to the hydroxyl groups in polyvinyl alcohol materials, which strengthen the hydrogen-bonding network and promote the regular arrangement of H₂O molecules into stable tetrahedral coordination (Figure 4g). Such an ordered water network reduces water-splitting activity, significantly inhibits HER activity on Cu electrodes, and enhances eCO₂R performance.

We assembled the quaternary ammonium polymer-modified Cu electrode into an MEA with pure water as the electrolyte and successfully operated it continuously at a current of 1 A for more than 20 hours, achieving a

F E C 2 H 4

efficiency of up to 54.4%. The eCO₂R experimental results in the pure water system validated the inducing effect of organic cations on the interfacial electric field.

The MODL structure containing organic cations can also achieve efficient eCO₂R under purely acidic conditions. Typically, in an acidic environment, hydrated hydrogen ions (H₃O⁺) accumulate at the cathode surface to form the OHP layer; however, their excessively high concentration can lead to severe hydrogen evolution and electrode corrosion. Meanwhile, the rapid consumption of H⁺results in insufficient interfacial electric field strength, thereby inhibiting CO₂reduction efficiency. Based on this, Sargent’s research team^［29］coated a Cu electrode surface with a benzimidazole-cation-containing (Aemion) ionomer to form a MODL structure incorporating organic cations, and investigated its eCO₂R performance under acidic conditions (Figure 4h). Using COMSOL, they predicted the interfacial electric field within the EDL and confirmed that the cationic ionomer in this MODL could generate an interfacial electric field comparable in magnitude to that produced by K⁺, effectively stabilizing CO₂reduction intermediates (Figure 4i). Performance tests demonstrated that the ionomer-modified Cu electrode is capable of achieving eCO₂R under purely acidic conditions. Compared with the pure Cu/K⁺system, the cations in the MODL inhibited the migration rate of protons toward the Cu surface, thereby increasing the pH within the IHP and raising the

F E C 2 H 4

from less than 1% to 27%. The team further demonstrated that ionomers with high cation densities can induce stronger interfacial electric fields, leading to higher CO₂reduction selectivity (Figure 4j).

In addition to Cu electrodes, some research teams have also utilized Ag electrodes modified with cationic ionomers to achieve stable CO₂ reduction to CO under acidic conditions. For example, Li’s research group^［30］ prepared an Ag electrode modified with a mixed layer of a cationic polymer (diallyldimethylammonium chloride) and graphene oxide (PDDA-GO) (Figure 4k, l). The pyrrolidinium quaternary ammonium cations in PDDA can replace alkali metal cations to establish an interfacial electric field. This MODL structure can prevent salt precipitation and promote the stable CO₂ R process in acidic media. Through comparative experiments, the team found that for an EDL composed of alkali metal cations and an acidic electrolyte, the FE for CO gradually decreased to 0% over a 16-hour electrolysis period, and carbonate crystals were observed in the cathodic cold trap. In contrast, the PDDA-GO-modified Ag gas-diffusion electrode (GDE), in an acidic MEA electrolyzer without alkali metal cations, was able to maintain a current density of 100 mA/cm² for 50 hours, with the FE for CO decreasing only slightly from 70% to 60%, and no carbonate precipitates formed on the electrode surface (Figure 4m).

Based on the far-field dielectric modulation strategy, a directional interfacial electric field is constructed by anchoring organic cations to the polymer backbone, while hydrogen-bonding functional groups are introduced to dynamically regulate the arrangement of water molecules at the electrode surface. This non-migratory organic dielectric layer not only circumvents the diffusion and loss of traditional alkali metal ions in pure acid/pure water systems but also completely eliminates the salting-out effect due to the water-soluble nature of the corresponding carbonates. Through the synergistic action of chemical and electric field effects, this remote dielectric modulation mechanism maintains CO₂ activation while achieving a self-adaptive dynamic equilibrium of the interfacial microenvironment, thereby providing a novel paradigm for efficient and stable CO₂ electroreduction in acidic/pure water media.

2.2.2 Material Transport in the Far Field

The diffuse layer in the EDL connects the OHP with the bulk solution and serves as a transition region where the concentration gradient of species changes at the electrode/electrolyte interface. Since the concentration difference is the primary driving force for mass transport apart from the electric field, the structure of the diffuse layer directly influences the mass transport rate within the EDL. In the MODL, the organic dielectric layer can reshape the species distribution on the electrode surface through its intrinsic physical properties, thereby extending the transition zone of the concentration gradient beyond the nanometer scale to span the entire organic dielectric layer and further reach the organic dielectric layer/electrolyte interface (micrometer scale). Consequently, in the MODL model, the presence of the organic dielectric layer broadens both the spatial range and the mechanisms of species transport toward the electrode surface, thus altering the eCO₂R performance of the electrode (Figure 5a).

For the eCO₂R reaction, the CO₂concentration at the electrode interface is the primary rate-limiting factor. Increasing the local CO₂concentration can effectively enhance the coverage of *CO₂intermediates on the electrode surface, thereby accelerating catalytic conversion. However, the low solubility of CO₂in water (33 mmol/L)^［18］greatly hinders the efficiency of eCO₂R. Therefore, it is necessary to introduce organic materials with strong CO₂adsorption capacity to enhance its solubility and diffusion rate in the electrolyte. Recently, our team^［31］fabricated a core–shell composite material by in-situ construction of a metalloporphyrin framework (Cu₂O@Cu-TCPP(Co)) on the Cu₂O surface via an epitaxial growth method, and applied it to eCO₂R (Figure 5b, c). In this MODL structure, the porous MOF shell efficiently enriches CO₂at the bulk solution level, increasing the CO₂concentration in the electrode region and greatly promoting the transport of CO₂toward the near-field. Notably, the MOF shell also facilitates the enrichment of CO generated during the reaction, slowing down its desorption from the electrode surface, thereby increasing the coverage of *CO species and fostering C–C coupling. Benefiting from the porous MOF layer’s regulation of CO₂and CO transport within the MODL, the Cu₂O@Cu-TCPP(Co) composite achieved a C₂H₄selectivity of 54% and a C₂₊selectivity of 69% under neutral conditions (Figure 5d). Similarly, Gewirth’s research group^［32］employed a co-electrodeposition strategy to deposit Cu nanoparticles together with a series of poly-N-(6-aminohexyl)acrylamide-derived polymers onto a gas diffusion layer substrate, thereby preparing a family of Cu catalysts modified by polyamine polymers (Figure 5e). The nucleophilic N atoms of the amines form N–C chemical bonds with the electrophilic C atoms of CO₂. This strong interaction enables the polyamine polymers to efficiently enrich CO₂from the bulk solution, significantly elevating the CO₂concentration in the bulk region and ensuring a continuous supply of CO₂to the near-field reaction zone. Thanks to this mass-transfer optimization mechanism, the Cu–polyamine catalysts achieved a C₂product selectivity as high as 90% in a 1 mol/L KOH electrolyte (Figure 5f).

The water–gas competitive transport at the electrode surface is another key factor determining the performance of eCO₂R. Hydrophilic electrode surfaces tend to form a dense water molecular coverage layer, leading to the accumulation of *H intermediates, whereas hydrophobic surfaces can effectively prevent aqueous-phase infiltration, thereby creating favorable conditions for CO₂mass transfer to dominate at the reaction interface and significantly promoting the enrichment of CO₂molecules on the catalyst surface. Consequently, reducing the water concentration at the electrode/electrolyte interface can effectively suppress the hydrogen evolution rate and enhance the selectivity of eCO₂R. For example, Li’s research team^［33］employed long-chain quaternary ammonium salt cationic surfactants as additives to self-assemble on the Ag electrode surface, thereby constructing a unique MODL structure (Figure 5g, h). These cationic surfactants, owing to the hydrophobicity of their long alkyl chains, are capable of disrupting the hydrated cation layer and forming numerous gas-philic/hydrophobic molecular channels spanning the MODL. Such gas-philic/hydrophobic channels not only effectively facilitate the transport of CO₂to the near-field region but also significantly reduce the overall water molecule concentration in the far field, inhibiting the diffusion of H₂O into the near field and hindering the formation of *H intermediates on the electrode surface, thereby substantially suppressing HER. By regulating the gas-philicity and hydrophobicity in the far field, these cationic surfactants increase the CO₂/H₂O ratio in the near field, greatly enhancing the selectivity for CO₂reduction to CO. In particular, the Ag electrode modified with hexadecyltrimethylammonium bromide (CTAB) exhibited an FE for HER that decreased from 83.0% to 4.3%, while the FE for CO increased from 16.8% to 96.2% compared with the unmodified Ag electrode (Figure 5i).

In the eCO₂R system, in addition to the mass-transfer gradients of the reactants (CO₂ and H₂O), the far-field mesoscopic regulation of ion transport at the cathode interface also plays a decisive role in reaction efficiency and product selectivity. Particularly in MEA systems, precise control over the transport pathways and concentration distributions of ionic species (such as H⁺, OH⁻, and K⁺) at the cathode surface directly determines the MODL structure and the local pH environment. Recently, our team^［34］developed a far-field regulation strategy based on an asymmetric porous bipolar membrane (BPM) (Figure 6a–c). This BPM consists of electrospun anion-exchange nanofibers (AENFs) and a planar cation-exchange membrane (CEM), which can synergistically optimize ion transport and reactant concentration distribution in acidic eCO₂R systems. Its performance advantages are primarily manifested in the following aspects: First, the porous AENFs layer forms highly efficient mass-transfer channels, significantly enhancing the CO₂ diffusion flux. Under conditions of 300 mA/cm² and 15 sccm (1 sccm = 1 cm³/min) of CO₂, the single-pass conversion rate reaches as high as 67%, three times that of conventional CEMs. Second, the unique interfacial configuration of the BPM dynamically suppresses the migration of H⁺/K⁺ ions, maintaining a locally high alkalinity at the cathode in acidic electrolytes (pH = 2) and reducing HER to its minimum level, thereby achieving a CO selectivity exceeding 90%. Furthermore, the fiber gaps promote the recirculation of CO₂/H₂O within the cathode region, effectively alleviating interfacial stress. Finally, the AENFs layer finely regulates the interfacial microenvironment through its hydrophobic/hydrophilic balance: on one hand, the Donnan exclusion effect reduces the migration rate of K⁺ ions by 42%, mitigating pore blockage caused by salt precipitation; on the other hand, it decreases cathodic flooding by 22%, sustaining a high CO₂ concentration at the reaction interface. These synergistic effects ultimately enable continuous stable operation for up to 325 hours under acidic conditions (Figure 6d, e). This work breaks through the limitations of the traditional EDL space, achieving global optimization of ion transport and reactant concentration at the far-field scale, and provides a breakthrough solution for the industrialization of acidic eCO₂R.

In the MODL system, the construction mechanism of the diffuse layer has undergone a fundamental transformation: its intrinsic formation mechanism has shifted from traditional metal-electrolyte interactions dominated by thermodynamics to far-field expansion regulation actively mediated by the organic dielectric layer. This "triple interaction" (metal–organic layer–electrolyte) facilitated by organic components expands the structural thickness of the diffuse layer from the nanoscale to the micrometer scale and endows it with cross-scale programmability. Consequently, the engineered far-field mass transport, achieved through the construction of hydrophobic microdomains as high-speed CO₂ channels and porous nucleophilic networks as active-species concentration fields, not only overcomes the mass-transfer limit bottleneck but also establishes dynamic steady-state synergy with near-field reactions—this is precisely the core value of the strategy of "extending the near-field catalytic steady state by supporting it with the far-field environment."

3 Conclusion and Outlook

For eCO₂R, this paper innovatively proposes the MODL theoretical framework based on the traditional EDL model. The core innovation of this framework lies in the introduction of a dynamic interface hypothesis, which broadens the regulatory scale of the EDL and enriches the interface description parameters (Table 1). Specifically, the framework presents a spatially resolved MODL interface engineering regulation strategy. At its core, this strategy optimizes the electrode MODL structure through a near-field/far-field synergistic mechanism: in the near-field region, organic coordination is employed to induce the exposure of active crystal facets and precisely regulate the reaction pathways of key intermediates via electrostatic interactions; in the far-field region, immobilized organic functional groups achieve triple synergistic regulation—reconstructing the interfacial water/electric field structure, dynamically compensating for pH/electric field gradient fluctuations, and constructing cross-scale mass transport channels to regulate reactant/ion concentrations. This strategy breaks through the rigid framework of the traditional EDL. Its core innovation resides in flexibly defining the near-field reaction core and the far-field regulation boundary, thereby realizing dynamic adaptation across spatial scales and proactive coordination of the microenvironment.

The effectiveness of the MODL framework depends on the rational design of its organic components based on spatial functional partitioning. For the near-field region of MODL, which primarily involves nanoscale site modification to regulate microscopic reaction pathways, it is necessary to select small molecules or short-chain polymers (such as bipyridine and polyaniline) that can establish strong interactions (e.g., coordination or hydrogen bonding) with metal surfaces or reaction intermediates. Through in-situ electrochemical reconstruction and self-assembly techniques, molecular-level precise positioning can be achieved, thereby directly controlling the reaction pathways. For the far-field region, which mainly concerns micrometer-scale interface structure reconstruction to optimize mesoscopic mass transport efficiency and environmental regulation, polymers or framework materials capable of forming extended structures should be chosen (such as quaternized polymers and MOFs). By employing methods like electrospinning and coating film formation, three-dimensional porous structures can be created to enhance ion/reactant transport and modulate the interfacial electric field, thus minimizing mass transfer resistance to the greatest extent.

It is noteworthy that the interfacial challenges addressed by the MODL framework are common across various electrocatalytic systems. For example, in the nitrogen reduction reaction (NRR), the severe hydrogen evolution side reaction necessitates interfacial energy selectivity to suppress proton transport and enrich reactants. Meanwhile, the kinetics of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are profoundly influenced by interfacial water structure, proton transfer, and local pH variations. The near-field reaction pathway modulation and far-field interface reconstruction methods established in this study provide a universal design strategy for addressing these common challenges. This cross-system applicability underscores the potential of MODL as a general-purpose interfacial design tool.

However, the MODL framework still faces several key challenges in transitioning from conceptualization to precise design. First, it is necessary to balance functional regulation with mass-transfer resistance under high current densities by conducting quantitative studies on parameters such as organic layer thickness and porosity to construct a "high-throughput" interface. Second, the current screening of organic components relies more on qualitative principles; in the future, it will be essential to integrate theoretical calculations with high-throughput experiments to establish rational design guidelines that move from qualitative to quantitative approaches. Furthermore, the long-term stability of organic components under harsh conditions and their degradation mechanisms also require in-depth investigation using advanced characterization techniques to enhance their practical applicability.

In summary, the MODL framework, through its explicit organic component selection and construction theory, has provided a new paradigm for the rational design of complex electrochemical interfaces. Future research should focus on advancing this theory from qualitative principles to quantitative models, overcoming challenges related to mass transport, design, and stability, ultimately enabling broader applications in various energy conversion reactions.

References

Publishing order | Descend order by publishing year | Descend order by cited within

[1]	De Luna P， Hahn C， Higgins D， Jaffer S A， Jaramillo T F， Sargent E H. Science， 2019， 364（6438）: eaav3506.

[2]	Chu S， Majumdar A. Nature， 2012， 488（7411）: 294.

[3]	Ozden A， García de Arquer F P， Huang J E， Wicks J， Sisler J， Miao R K， O’Brien C P， Lee G， Wang X， Ip A H， Sargent E H， Sinton D. Nat. Sustain.， 2022， 5（7）: 563.

[4]	Lees E W， Mowbray B A W， Parlane F G L， Berlinguette C P. Nat. Rev. Mater.， 2022， 7（1）: 55.

[5]	Chen Q， Wang X， Zhou Y， Tan Y， Li H， Fu J， Liu M. Adv. Mater.， 2024， 36（5）: 2303902.

[6]	Gebbie M A， Liu B C， Guo W X， Anderson S R， Johnstone S G. ACS Catal.， 2023， 13（24）: 16222.

[7]	Yu J L， Yin J W， Li R C， Ma Y B， Fan Z X. Chem Catal.， 2022， 2（9）: 2229.

[8]	Song D Q， Lian Y B， Wang M， Su Y H， Lyu F L， Deng Z， Peng Y. eScience， 2023， 3（2）: 100097.

[9]	Zhu D D， Liu J L， Qiao S Z. Adv. Mater.， 2016， 28（18）: 3423.

[10]	Cheng J， Chen L， Xie X L， Feng K， Sun H， Qin Y Z， Hua W， Zheng Z Y， He Y， Pan W Y， Yang W J， Lyu F L， Zhong J， Deng Z， Jiao Y， Peng Y. Angew. Chem. Int. Ed.， 2023， 62（44）: e202312113.

[11]	Ross M B， De Luna P， Li Y F， Dinh C T， Kim D， Yang P D， Sargent E H. Nat. Catal.， 2019， 2（8）: 648.

[12]	Nitopi S， Bertheussen E， Scott S B， Liu X Y， Engstfeld A K， Horch S， Seger B， Stephens I E L， Chan K R， Hahn C， Nørskov J K， Jaramillo T F， Chorkendorff I. Chem. Rev.， 2019， 119（12）: 7610.

[13]	Yang B Y， Chen L， Xue S L， Sun H， Feng K， Chen Y F， Zhang X， Xiao L， Qin Y Z， Zhong J， Deng Z， Jiao Y， Peng Y. Nat. Commun.， 2022， 13: 5122.

[14]	Yang P P， Gao M R. Chem. Soc. Rev.， 2023， 52（13）: 4343.

[15]	Xiong L K， Zhang X， Chen L， Deng Z， Han S， Chen Y F， Zhong J， Sun H， Lian Y B， Yang B Y， Yuan X Z， Yu H， Liu Y， Yang X Q， Guo J， Rümmeli M H， Jiao Y， Peng Y. Adv. Mater.， 2021， 33（32）: 2101741.

[16]	Wang J L， Tan H-Y， Qi M Y， Li J Y， Tang Z R， Suen N T， Xu Y J， Chen H M. Chem. Soc. Rev.， 2023， 52（15）: 5013.

[17]	Dong Y， Ma M T， Jiao Z Y， Han S， Xiong L K， Deng Z， Peng Y. Chin. Chem. Lett.， 2024， 35（7）: 109049.

[18]	Chen C J， Jin H Y， Wang P T， Sun X G， Jaroniec M， Zheng Y， Qiao S Z. Chem. Soc. Rev.， 2024， 53（4）: 2022.

[19]	Kim C， Bui J C， Luo X Y， Cooper J K， Kusoglu A， Weber A Z， Bell A T. Nat. Energy， 2021， 6（11）: 1026.

[20]

Li F W， Thevenon A， Rosas-Hernández A， Wang Z Y， Li Y L， Gabardo C M， Ozden A， Dinh C T， Li J， Wang Y H， Edwards J P， Xu Y， McCallum C， Tao L Z， Liang Z Q， Luo M C， Wang X， Li H H， O’Brien C P， Tan C S， Nam D H， Quintero-Bermudez R， Zhuang T T， Li Y C， Han Z J， Britt R D， Sinton D， Agapie T， Peters J C， Sargent E H. Nature， 2020， 577（7791）: 509.

[21]	Wang J C， Cheng T， Fenwick A Q， Baroud T N， Rosas-Hernández A， Ko J H， Gan Q， Goddard W A， Grubbs R H. J. Am. Chem. Soc.， 2021， 143（7）: 2857.

[22]	Li W Z， Yin Z L， Gao Z Y， Wang G W， Li Z， Wei F Y， Wei X， Peng H Q， Hu X T， Xiao L， Lu J T， Zhuang L. Nat. Energy， 2022， 7（9）: 835.

[23]	Xiong L K， Zhang X， Yuan H， Wang J， Yuan X Z， Lian Y B， Jin H D， Sun H， Deng Z， Wang D， Hu J P， Hu H M， Choi J， Li J， Chen Y F， Zhong J， Guo J， Rümmerli M H， Xu L， Peng Y. Angew. Chem. Int. Ed.， 2021， 60（5）: 2508.

[24]	Sun H， Chen L， Xiong L K， Feng K， Chen Y F， Zhang X， Yuan X Z， Yang B Y， Deng Z， Liu Y， Rümmeli M H， Zhong J， Jiao Y， Peng Y. Nat. Commun.， 2021， 12: 6823.

[25]	Song D Q， Yang W J， Ma M T， Hua W， Zheng Z Y， Wei Z H， Chen M Z， Cheng J， Zhong J， Deng Z， Peng Y. Energy Lab， 2024， 2（3）: 240010.

[26]	Chen S H， Ye C L， Wang Z W， Li P， Jiang W J， Zhuang Z C， Zhu J X， Zheng X B， Zaman S， Ou H H， Lv L， Tan L， Su Y Q， Ouyang J， Wang D S. Angew. Chem. Int. Ed.， 2023， 62（50）: e202315621.

[27]	Xue L W， Gao Z Y， Ning T S， Li W Z， Li J M， Yin J L， Xiao L， Wang G W， Zhuang L. Angew. Chem. Int. Ed.， 2023， 62（46）: e202309519.

[28]	Cheng J， Chen L， Zhang Y Z， Wang M， Zheng Z Y， Jiang L， Deng Z， Wei Z H， Ma M T， Xiong L K， Hua W， Song D Q， Huo W X， Lian Y B， Yang W J， Lyu F L， Jiao Y， Peng Y. Nat. Commun.， 2025， 16: 3743.

[29]	Fan M Y， Huang J E， Miao R K， Mao Y， Ou P F， Li F， Li X-Y， Cao Y F， Zhang Z S， Zhang J Q， Yan Y， Ozden A， Ni W Y， Wang Y， Zhao Y， Chen Z， Khatir B， O’Brien C P， Xu Y， Xiao Y C， Waterhouse G I N， Golovin K， Wang Z Y， Sargent E H， Sinton D. Nat. Catal.， 2023， 6（9）: 763.

[30]	Fan J， Pan B B， Wu J L， Shao C C， Wen Z Y， Yan Y C， Wang Y H， Li Y G. Angew. Chem. Int. Ed.， 2024， 63（9）: e202317828.

[31]	Ma M T， Xiong L K， Dong Y， Bai Q Q， Hua W， Zheng Z Y， Lyu F L， Lian Y B， Wei Z H， Yuan H H， Jiao Z Y， Cheng J， Song D Q， Wang M， Xing Z Y， Zhong J， Han S， Deng Z， Peng Y. Adv. Funct. Mater.， 2024， 34（25）: 2315667.

[32]	Chen X Y， Chen J F， Alghoraibi N M， Henckel D A， Zhang R X， Nwabara U O， Madsen K E， Kenis P J A， Zimmerman S C， Gewirth A A. Nat. Catal.， 2021， 4（1）: 20.

[33]	Ge W X， Chen Y X， Fan Y， Zhu Y H， Liu H L， Song L， Liu Z， Lian C， Jiang H L， Li C Z. J. Am. Chem. Soc.， 2022， 144（14）: 6613.

[34]	Liu P， Lyu F， Yang X， Zheng Z， Hua W， Mei S， Ma M， Wang H， Ge X， Wu L， Xu T， Deng Z， Peng Y. EES Catal.， 2025， 3: 1117.

Funding

the National Natural Science Foundation of China(22571222)

the Natural Key R&D Program of China(2024YFA1509300)

PDF (4309KB)

312

Accesses

Citation

Detail

Sections

Recommended

Abstract

Graphical abstract

Keywords

Cite this article

1 Introduction

2 The Relationship Between Metal–Organic Diffusion Layer Structure and eCO2R Performance

2.1 Near-field Interface Engineering: Organic Component-Induced Active Facet Exposure and Reaction Pathway Regulation

2.2 Far-field mesoscopic regulation: diffusion layer expansion mediated by organic layers and microenvironment gradient reconstruction

2.2.1 Water/Electric Field Structures, Hydrogen-Bond Networks, and Local pH in Far-Field Regulation

2.2.2 Material Transport in the Far Field

3 Conclusion and Outlook

References

Funding

RIGHTS & PERMISSIONS

2 The Relationship Between Metal–Organic Diffusion Layer Structure and eCO₂R Performance