Charge Transport Pathways Research Articles

The Design of Intrinsically Conductive Metal‐Organic Frameworks for Thermoelectric Materials

Thermoelectric (TE) materials offer exciting promise in the development of sustainable, green energy alternatives. Ideal TE materials promote high electrical conductivity, whilst effectively scattering phonons for reduced thermal conductivity, thus giving the phonon‐glass electron‐crystal concept. Metal‐organic frameworks (MOFs) have emerged as a versatile class of materials that could meet these criteria. The high crystallinity of MOFs can offer effective pathways for charge transport whilst their intrinsic high porosity yields ultralow thermal conductivity. The high structural diversity of MOFs, owing to the versatile coordination of metal cation/cluster and linker offers the potential to systematically tune their properties for TE performance. This review examines the advancement in the design strategies that have thus far been implemented toward intrinsically conductive MOFs and how these should be tailored for application toward TE materials. By addressing the challenges and leveraging the unique properties of MOFs, future research can pave the way for innovative and efficient TE MOF materials.

Structural Control of Photoconductivity in a Flexible Titanium-Organic Framework.

The soft nature of Metal-Organic Frameworks (MOFs) sets them apart from other non-synthetic porous materials. Their flexibility allows the framework components to rearrange in response to environmental changes, leading to different states and properties. The work extends this concept to titanium frameworks, demonstrating control over charge transport in porous molecular crystals. MUV-35 is a two-fold catenated framework composed of heterometallic TiMn2 trimers and electron donor 4,4',4″-(benzo[1,2-b:3,4-b':5,6-b″]trithiophene-2,5,8-triyl)tribenzoic acid (H3BTTTB) linkers, forming a rare sit-c net topology that can fold to reduce its volume by ≈40% through a single-crystal transformation controlled by linker conformation in open, intermediate, and closed states. This process, driven by a free energy difference of ≈300kJmol-1, originates from the formation of a continuous network of non-covalent interactions that force the spontaneous loss of the solvent in the pores of the framework to establish charge transport pathways that afford photocurrents of 2.5 × 10-3Sm-1 under visible light for an ON/OFF ratio (∆R) of four orders of magnitude. This photoconductivity rivals the best conductivity values described for though-transport conductive MOFs while maintaining a porosity of ≈1.000m2g-1.

Enhanced Charge Transport through Ion Networks in Highly Concentrated LiSCN‐Polyethylene Carbonate Solid Polymer Electrolytes

Challenging the preference for bulky anions due to low binding energy with Li+ ion, the lithium thiocyanate‐polyethylene carbonate (LiSCN‐PEC) solid polymer electrolyte (SPE) demonstrates higher ionic conductivities (3.16 × 10−5 S cm−1) at polymer‐in‐salt concentration (100 mol%) compared to those with lithium bis(fluorosulfonyl)imide (LiFSI, 1.01 × 10−5 S cm−1) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, 1.72 × 10−7 S cm−1). Through the careful selection of PEC and LiSCN as components of SPE, the carbonyl stretching of PEC and the SCN− stretching band as vibrational reporters provide detailed structural insights into the Li+ ion transport channel. Spectroscopic investigations reveal that enhanced ion aggregation alters the solvation structure around the Li+ and diminishes the interaction between Li+ and polymer (PEC) with increasing LiSCN concentrations, promoting faster segmental motion as a major transport mechanism. However, the transition observed from subionic to superionic behavior in the Walden plot indicates the onset of segmental motion decoupled charge transport pathway. The SCN− vibrational spectrum elucidates the evolution from a Li–SCN–Li type chain‐like structure to a Li2 > SCN < Li2 type extended ion network with increasing LiSCN concentration, revealing that the ion network provides an alternative channel for Li+ ion transfer at higher concentrations, enhancing conductivity.

Aeration‐Free Photo‐Fenton‐Like Reaction Mediated by Heterojunction Photocatalyst toward Efficient Degradation of Organic Pollutants

AbstractThe regulation of peroxymonosulfate (PMS) activation by photo‐assisted heterogeneous catalysis is under in‐depth investigation with potential as a replaceable advanced oxidation process in water purification, yet it remains a significant challenge. Herein, we demonstrate a strategy to construct polyethylene glycol (PEG) well‐coupled dual‐defect VO−M–Co3O4@CNx S‐scheme heterojunction to degrade organic pollutants without aeration, which dramatically provides abundant active sites, excellent photo‐thermal property, and distinct charge transport pathway for PMS activation. The degradation rate of VO−M−Co3O4@CNx in anaerobic conditions shows a higher efficient rate (4.58 min−1 g−2) than in aerobic conditions (1.67 min−1 g−2). Experimental evidence reveals that VO−M−Co3O4@CNx promotes more rapid redox conversion of photoexcited electrons induced by defects with PMS under anaerobic conditions compared to aerobic conditions. Additionally, in situ experiments and DFT provide mechanistic insights into the regulation pathway of PMS activation via synergistic defect‐induced electron, revealing the competitive effect between O2 and PMS over VO−M−Co3O4@CNx during the reaction process. The continuous flow reactor and flow cytometry results demonstrated that the VO−M−Co3O4@CNx/PMS/Vis system has remarkably enhanced stability and purification capability for removing organic pollutants. This work provides valuable insights into regulating the heterologous catalysis oxidation process without aeration through the photoexcitation synergistic PMS activation.

Aeration-Free Photo-Fenton-Like Reaction Mediated by Heterojunction Photocatalyst toward Efficient Degradation of Organic Pollutants.

The regulation of peroxymonosulfate (PMS) activation by photo-assisted heterogeneous catalysis is under in-depth investigation with potential as a replaceable advanced oxidation process in water purification, yet it remains a significant challenge. Herein, we demonstrate a strategy to construct polyethylene glycol (PEG) well-coupled dual-defect VO-M-Co3O4@CNx S-scheme heterojunction to degrade organic pollutants without aeration, which dramatically provides abundant active sites, excellent photo-thermal property, and distinct charge transport pathway for PMS activation. The degradation rate of VO-M-Co3O4@CNx in anaerobic conditions shows a higher efficient rate (4.58 min-1 g-2) than in aerobic conditions (1.67 min-1 g-2). Experimental evidence reveals that VO-M-Co3O4@CNx promotes more rapid redox conversion of photoexcited electrons induced by defects with PMS under anaerobic conditions compared to aerobic conditions. Additionally, in situ experiments and DFT provide mechanistic insights into the regulation pathway of PMS activation via synergistic defect-induced electron, revealing the competitive effect between O2 and PMS over VO-M-Co3O4@CNx during the reaction process. The continuous flow reactor and flow cytometry results demonstrated that the VO-M-Co3O4@CNx/PMS/Vis system has remarkably enhanced stability and purification capability for removing organic pollutants. This work provides valuable insights into regulating the heterologous catalysis oxidation process without aeration through the photoexcitation synergistic PMS activation.

Enhancing the electrochemical efficiency of metal-organic frameworks through integration of chromium nitride interfacial layer for efficient hybrid supercapacitors

Transition metal nitrides are highly stable and electrochemically efficient, making them a promising material for supercapacitor electrodes. Herein, for assessing the synergistic effects of metal-organic framework via transition metal nitrides, we synthesized chromium nitride electrode using magnetron sputtering followed by the deposition of copper-trimesic acid. Electrochemical testing in half and full cell configurations reveals that chromium nitride/copper-trimesic acid has the lowest charge transfer resistance, indicating its quick charge transport pathways, leading to an increased specific capacity (1651C/g at 1.5 A/g) and notable rate capability. Persuaded by the exceptional capacitive and charge storage potential, a two-cell mode-based hybrid supercapacitor was fabricated using activated carbon and chromium nitride/copper-trimesic acid. This combination demonstrated the highest energy density of 94.5 Wh/kg, maximum power density of 7750 W/kg while functioning at 1.6 V with cycling stability of 97.9 % after 3000 galvanostatic charge discharge cycles. Additionally, for examining the diffusive and capacitive behaviors of devices, two different semi-empirical models were further used and compared, which shed light on the special characteristics and implementation of supercapattery device.

Enhanced photocatalytic performance of SnS2/ZnO Z-scheme composite photocatalysts for efficient environmental remediation

Photocatalysts based on zinc oxide (ZnO) are promising for environmental applications, but their weak photoresponse and low photocarrier separation efficiency limit their practical use. To tackle this issue, we constructed Z-scheme composite photocatalysts of ZnO to boost its photocatalytic performance. We achieved the Z-scheme structure by hydrothermal modification of SnS2 nanoparticles onto ZnO microspheres. Its photocatalytic performance was evaluated through the degradation of Rhodamine B (RhB) under visible light with the assistance of magnetic stirring. The composite photocatalyst exhibited superior performance compared to individual ZnO and SnS2, achieving an optimal degradation rate of 0.0706 min⁻¹. This rate was 15.08 times higher than that of individual ZnO and 10.51 times higher than individual SnS2. Free radical trapping experiments showed that ·O2⁻ and ·OH radicals played a key role in RhB degradation. The Z-scheme composite structure established novel charge transport pathways, guided the migration of photogenerated carriers, and improved spatial separation, thereby enhancing photocatalytic performance. This study provides valuable insights into the design of highly efficient photocatalysts for environmental remediation, offering a promising solution for addressing challenges in pollution control and wastewater treatment.

Mixed Conductive Materials to Improve the Conductive Path of All-Solid-State Battery Composite Electrodes

Lithium-ion Batteries (LIBs) function as energy-storage devices in various electronic applications. However, the use of flammable liquid electrolytes raises significant safety concerns, including the risk of fire or explosion. To mitigate these safety issues, all-solid-state batteries (ASSBs) have emerged as a promising alternative as they are composed of solid electrolytes instead of liquid ones. Li7La3Zr2O12 (LLZO) stand out as a highly promising garnet-type solid electrolyte, known for its chemically and electrochemically stable characteristics, making it suitable for ASSBs. However, LLZO suffers from high interfacial resistance, leading to decreased ion conductivity. In particular, the formation of voids during composite electrode fabrication interrupts ion conduction paths, resulting in a significantly increased resistance. Consequently, the high interfacial resistance arising from solid-state contacts can significantly impair the electrochemical performance and hinder practical cell operation. For these reasons, ASSBs typically use an excess of 10 wt.% or more solid electrolytes during electrode manufacturing, leading to a decrease in the active material fraction. Therefore, conducting research on electrode design aimed at optimizing the content of inactive components, such as the use of conductive additives and solid electrolytes, is necessary to improve the performance of ASSBs. In addition, novel approaches are needed to address the above-mentioned issues by reducing the interfacial resistance within composite electrodes containing solid electrolytes and maximizing electrochemical reactions.This study aims to improve the performance of ASSBs by incorporating carbon nanotubes (CNTs) as a conductive additive with the solid electrolyte LLZO to establish an efficient charge transport pathway and improve interfacial resistance. When using CNT@LLZO as a conductive additive, the internal voids within the electrode are minimized, and an effective Li-ion conduction pathway is formed, resulting in improved electrochemical performance. Further details will be presented in the meeting.

A Helicene-Based Single-Molecule Inductor and Capacitor with Frequency-Dependent Charge-Transport Pathways.

Despite extensive studies has been explored on single-molecule switches and rectifiers, the design of single-molecule inductors has not been explored due to the experimental challenges in the investigation of frequency-dependent charge transport at the single-molecule scale. In this study, we synthesized a helicene-based helical molecular wire and carried out meticulous single-molecule conductance measurements, combined with current-voltage (IV) studies with varying frequencies using the scanning tunneling microscope break junction (STM-BJ) technique. Our results reveal the formation of a single-molecule junction and highlight the unique behavior of the molecular wire in response to different alternating current (AC) varying frequencies. The transport of charges occurs selectively either through the coiled backbone of the conjugated helical structure or vertically via π-π stacking, depending on the frequency of the applied AC. Notably, our investigation demonstrates the functionality of the wire as an inductor at low frequencies, and a capacitor at high frequencies. This work lays the foundation for a systematic approach to designing, fabricating, and implementing single-molecule logic devices such as inductors and wave filters.

Impact of Dilute DIO Additive on Local Microstructure of Fluorinated, pNDI-Based Polymer Solar Cells.

The performance of all-polymer solar cells is often enhanced by incorporating solvent additives during solution processing. In particular, blends based on the model all-polymer system PBDBT:N2200 have been shown to have increased short-circuit current and fill factor when processed with dilute diiodooctane (DIO). However, the morphological mechanism that drives the increase in performance is often not well understood due to limitations in common characterization techniques. In this study, it is shown that a combination of X-ray techniques with cryogenic high-resolution transmission electron microscopy (HRTEM) analysis can provide a quantitative and spatially resolved picture of polymer chain orientation and alignment in all-polymer blends. It is found that DIO induces vertical phase separation in PBDBT-2F:F-N2200 and increases donor crystallite thickness in the pi-stacking direction leading to an acceptor-rich film surface. However, it is also shown that DIO does not disrupt the formation of face-on donor-acceptor interfaces. These findings suggest that dilute DIO primarily affects crystalline domain formation in single component regions as opposed to mixed regions; thus, dilute DIO can impact vertical charge transport pathways without sacrificing donor-acceptor interfacial connectivity.

Towards Stable Helical Structures with Enhanced Molecular Conductance by Strengthening Through‐Space Conjugation

AbstractDeveloping long‐chain molecules with stable helical structures is of significant importance for understanding and modulating the properties and functions of helical biological macromolecules, but challenging. In this work, an effective and facile approach to stabilize folded helical structures by strengthening through‐space conjugation is proposed, using new ortho‐hexaphenylene (o‐HP) derivatives as models. The structure–activity relationship between the through‐space conjugation and charge‐transport behavior of the prepared folded helical o‐HP derivatives is experimentally and theoretically investigated. It is demonstrated that the through‐space conjugation within o‐HP derivatives can be strengthened by introducing electron‐withdrawing pyridine and pyrazine rings, which can effectively stabilize the helical structures of o‐HP derivatives. Moreover, scanning tunneling microscopy‐break junction measurements reveal that the stable regular helical structures of o‐HP derivatives open‐up dominant through‐space charge‐transport pathways, and the single‐molecule conductance is enhanced by more than 70 % by strengthening through‐space conjugation with pyridine and pyrazine. However, the through‐bond charge transport pathways contribute much less to the conductance of o‐HP derivatives. These results not only provide a new method for exploring stable helical molecules, but also provide a stepping stone for deciphering and modulating the charge‐transport behavior of helical systems at the single‐molecule level.

Towards Stable Helical Structures with Enhanced Molecular Conductance by Strengthening Through-Space Conjugation.

Developing long-chain molecules with stable helical structures is of significant importance for understanding and modulating the properties and functions of helical biological macromolecules, but challenging. In this work, an effective and facile approach to stabilize folded helical structures by strengthening through-space conjugation is proposed, using new ortho-hexaphenylene (o-HP) derivatives as models. The structure-activity relationship between the through-space conjugation and charge-transport behavior of the prepared folded helical o-HP derivatives is experimentally and theoretically investigated. It is demonstrated that the through-space conjugation within o-HP derivatives can be strengthened by introducing electron-withdrawing pyridine and pyrazine rings, which can effectively stabilize the helical structures of o-HP derivatives. Moreover, scanning tunneling microscopy-break junction measurements reveal that the stable regular helical structures of o-HP derivatives open-up dominant through-space charge-transport pathways, and the single-molecule conductance is enhanced by more than 70 % by strengthening through-space conjugation with pyridine and pyrazine. However, the through-bond charge transport pathways contribute much less to the conductance of o-HP derivatives. These results not only provide a new method for exploring stable helical molecules, but also provide a stepping stone for deciphering and modulating the charge-transport behavior of helical systems at the single-molecule level.

Chain rigidity controlled aggregation ability and solid-state microstructures for efficient stretchable conjugated polymer films

Stretchable conjugated polymer films with good electrical performance under mechanical deformation are highly desirable for soft electronics. However, the mechanical and electrical properties of these films, particularly in conjugated polymer:elastomer blends, are not fully understood at molecular level. This study explores the relationships among molecular structure, aggregation ability, film microstructure, and the electrical/mechanical properties of three diketopyrrolopyrrole -based conjugated polymers (P1, P2, P3) with decreasing backbone rigidity and their corresponding polymer:elastomer blends. The most flexible polymer P3 shows strong aggregation, which forms highly crystalline fibers to produce fragile neat film and produces large isolated crystallites restricting charge transport in blend film. As chain rigidity increases, the P1 and P2 polymers show weaker aggregation, and produce smaller crystallites in neat films with enhanced ductility. P1 and P2 based blend films display nanocrystallites polymer networks with dispersed elastomer domains. As a result, we achieved near-constant charge mobility before and after stretching under 50 % strain for P2-based blend films with well-controlled pathways for both charge transport and energy dissipation. This study demonstrates the critical role of backbone rigidity in regulating the properties of stretchable conjugated polymer films, paving the way for more reliable and deformable materials in soft electronics.

Architectural Design of a Multichannel Porous Carbon Fiber for Efficient Electromagnetic Microwave Absorption.

An ingenious microstructure of electromagnetic microwave absorption materials is crucial to achieve strong absorption and a broad bandwidth. Herein, one-dimensional (1D) carbon fibers with implantation of zero-dimensional (0D) ZIF-8-derived carbon frameworks and construction of a three-dimensional (3D) microcosmic multichannel porous structure are fabricated by electro-blown spinning, solvent-thermal reaction, and high-temperature pyrolysis techniques. The 1D carbon fiber skeleton with a multichannel structure provides a direct axial conductive pathway for charge transport, which plays an important role in dielectric loss. The 0D surface carbon frameworks offer plenty of heterogeneous interfaces to trigger intensive interfacial polarization loss and act as dihedral angles for microwave scattering. The 3D microcosmic multichannel pores can not only generate multiple reflections as much as possible to dissipate electromagnetic microwave energy but also supply huge interior cavities to improve impedance matching. Thanks to the synergistic effect of a strong electrically conductive pathway for enhancing the conductive loss, a plenteous heterogeneous interface for triggering intensive interfacial polarization loss, microcosmic multichannel pores for generating multiple reflections and improving impedance matching, and N and O atom doping for inducing dipole polarization, the optimal sample with an ingenious microstructure delivers an excellent absorption performance of a minimum reflection loss of -35.5 dB at a thickness of 5.0 mm and an effective absorption bandwidth of 6.72 GHz (10.96-17.68 GHz) at a thickness of 2.0 mm. Such a well-designed multichannel porous carbon fiber may pave the way for the exploitation of high-performance microwave absorbing materials.

Stepwise Curing Induced All-Stretchable Thermoelectric Generator of High Power Density.

In this study, a wearable and highly stretchable organic thermoelectric (TE) generator with a notable power density is developed. A highly stretchable and solution-processable TE/electrode pattern is realized by stepwise-curing elastomeric and conducting network. Significant advances in the TE or electrical properties are obtained for these stretchable patterns through post-activation treatment, which creates long-range charge transport pathways without degrading pre-established elastomeric networks. The TE and electrode patterns are solution-processed to a stretchable template, so that all-stretchable TE generator is realized. The fabricated TE generator maintains 90% of its maximum TE power output at 40% stretching stress and shows a stable TE power output after 200 stretching cycles. The TE generator maintains its stretchability in highly densified patterns, as the highly stretchable TE/electrode patterns enable good stretchability with little aid of the stretchable template. So, the TE generator has a high power density of 0.32 nW cm-2 K-2, one of the highest values among stretchable TE generators to date.

Covalent Immobilization of Mediators on Photoelectrodes for NADH Regeneration.

The reduced nicotinamide adenine dinucleotide (NADH) is a vital biomolecule involved in many biocatalytic processes, and the high cost makes it significant to regenerate NADH in vitro. The photoelectrochemical approach is a promising and environmentally friendly method for sustainable NADH regeneration. However, the free Rh-based mediator ([Cp*Rh (bpy)H2O]2+) in the electrolyte suffers from low efficiency due to the sluggish charge transfer controlled by the diffusion process. Herein, we report an efficient and facile covalent bonding of the Rh-based mediator with the Si-based photocathode for NADH regeneration. The bipyridine-containing covalent organic framework (BpyCOF) layer ensures the even distribution of mediators throughout the surface of the photoelectrode. The graphene interlayer provides a pathway for charge transport and prevents silicon from corrosion. Furthermore, during the synthesis of BpyCOF, it functions as a substrate to promote the growth of the oriented BpyCOF film. The imitated contact between the components of the photocathode favors the charge transfer to the surface to participate in a chemical reaction, thus improving the catalytic performance and the NADH regeneration efficiency, which is four times higher than the reported photocathode modified by the Rh-based mediator. This study offers a new strategy for the construction of photoelectrochemical solar energy conversion devices.

Carbon Doping Regulates Charge Transfer Paths via a Type-II to S-Scheme Transformation to Improve Photocatalytic Performance.

Designing S-scheme heterojunctions with enhanced interfacial interaction is an effective strategy for promoting the separation of photocarriers while maintaining strong photoredox capabilities. However, precisely tailoring the interfacial charge transport pathways between two contacted semiconductors remains a significant challenge due to the similar band alignment in type-II and S-scheme heterostructures. Herein, we report a facile and low-cost carbon doping strategy to smartly tune the charge transfer pathway via a type-II to S-scheme transformation for efficient photocatalytic H2 evolution and H2O2 synthesis. Density functional theory calculations combined with in situ XPS studies demonstrate that the Fermi level of MoO2 shifts from being higher than that of C3N4 to being lower after carbon doping, which drives the inversion of the internal electric field (IEF) direction between MoO2 and C3N4, thus enabling a transition from type-II MoO2/C3N4 heterojunctions to S-scheme C-MoO2/C3N4 heterojunctions. As a result, the optimal S-scheme C-MoO2/C3N4 heterojunctions exhibit a high H2 evolution rate of 16.2 mmol g-1 h-1 and a H2O2 production rate of 877 μmol g-1 h-1, notably surpassing those of the original C3N4 and type-II MoO2/C3N4 heterojunctions. This work provides valuable insights into the fabrication of C3N4 heterostructures and the control of electron migration pathways, thereby creating new possibilities for photocatalysis and optoelectronics applications.

Quantum Confinement and End-Sealing Effects for Highly Sensitive and Stable Nitrogen Dioxide Detection: Homogeneous Integration of Ti3C2Tx-Based Flexible Gas Sensors.

The real-time and room-temperature detection of nitrogen dioxide (NO2) holds significant importance for environmental monitoring. However, the performance of NO2 sensors has been hampered by the trade-off between the high sensitivity and stability of conventional sensitive materials. Here, we present a novel fully flexible paper-based gas sensing structure by combining a homogeneous screen-printed titanium carbide (Ti3C2Tx) MXene-based nonmetallic electrode with a MoS2 quantum dots/Ti3C2Tx (MoS2 QDs/Ti3C2Tx) gas-sensing film. These precisely designed gas sensors demonstrate an improved response value (16.3% at 5 ppm) and a low theoretical detection limit of 12.1 ppb toward NO2, which exhibit a remarkable 3.5-fold increase in sensitivity compared to conventional Au interdigital electrodes. The outstanding performance can be attributed to the integration of the quantum confinement effect of MoS2 QDs and the conductivity of Ti3C2Tx, establishing the main active adsorption sites and enhanced charge transport pathways. Furthermore, an end-sealing effect strategy was applied to decorate the defect sites with naturally oxygen-rich tannic acid and conductive polymer, and the formed hydrogen bonding network at the interface effectively mitigated the oxidative degradation of the Ti3C2Tx-based gas sensors. The exceptional stability has been achieved with only a 1.8% decrease in response over 4 weeks. This work highlights the innovative design of high-performance gas sensing materials and homogeneous gas sensor techniques.

Molecular interaction induced dual fibrils towards organic solar cells with certified efficiency over 20%

The nanoscale fibrillar morphology, featuring long-range structural order, provides abundant interfaces for efficient exciton dissociation and high-quality pathways for effective charge transport, is a promising morphology for high performance organic solar cells. Here, we synthesize a thiophene terminated non-fullerene acceptor, L8-ThCl, to induce the fibrillization of both polymer donor and host acceptor, that surpasses the 20% efficiency milestone of organic solar cells. After adding L8-ThCl, the original weak and less continuous nanofibrils of polymer donors, i.e. PM6 or D18, are well enlarged and refined, whilst the host acceptor L8-BO also assembles into nanofibrils with enhanced structural order. By adapting the layer-by-layer deposition method, the enhanced structural order can be retained to significantly boost the power conversion efficiency, with specific values of 19.4% and 20.1% for the PM6:L8-ThCl/L8-BO:L8-ThCl and D18:L8-ThCl/L8-BO:L8-ThCl devices, with the latter being certified 20.0%, which is the highest certified efficiency reported so far for single-junction organic solar cells.

Engineering of active site coupling to facilitate interatomic charge transfer for bifunctional oxygen electrocatalysis

Interatomic charge transfer emerges as a robust technique for enhancing catalytic efficacy in key energy reactions, specifically the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Despite its potential, advancing simultaneous improvements in reversible oxygen catalysis pose considerable challenges. Herein, we detailed an active site coupling engineering method to create a CoCu@NSC bifunctional oxygen electrode. In this configuration, OER-active Cu sites were alloyed with ORR-active Co within a N/S-doping carbon nanobox. This arrangement yielded a half-wave potential of 0.924 V for ORR, alongside an overpotential of η10 = 356 mV for OER. The fabricated CoCu@NSC cathode yielded a discharge capacity of 768 mAh/gZn, a peak power density of 295 mW/cm2, and extensive cycling durability. Work function assessments indicated that the chemical integration of Co and Cu components at the atomic level promoted interfacial charge redistribution, effectively optimizing the adsorption-desorption dynamics of intermediates at the active sites, thereby substantially enhancing the catalytic performance for both OER and ORR. Additionally, doping with N/S species enhanced the conductivity of the hollow carbon matrix, facilitating more effective mass and charge transport pathways. These insights illuminate a compelling approach for the design and synthesis of effective bifunctional oxygen electrodes that is pivotal for advanced energy storage advice.