Oxygen Reduction Reaction Activity Research Articles

Engineering Proton‐Coupled Electron Transfer to Break Activity‐Stability Trade‐Off of Oxygen Electroreduction Catalysts for Temperature‐Adaptive Zn–Air Battery

AbstractSingle‐atom catalysts (SACs) are regarded as effective electrocatalysts for oxygen reduction reaction (ORR). However, integrating high active and long‐term durability on SACs is still challenging due to the severe limitations of the activity‐stability trade‐off. Herein, we report an integrative electrocatalyst combining isolated Fe sites and MoC nanoparticles (MoC/Fe─NC). MoC nanoparticles accelerate ORR kinetics via the proton‐feeding effect and optimize Fe site microstructure. Thus, MoC/Fe─NC exhibits a high alkaline ORR activity with half‐wave potential (E1/2) of 0.916 V versus the reversible hydrogen electrode, and exceptional durability of 50k cycles with 5 mV E1/2 loss. The observed ORR performance is further verified in a zinc–air battery (ZAB) with a high peak power density of 316 mW cm−2 and operational stability over 1000 h. Moreover, the fabricated temperature‐adaptive quasi‐solid‐state ZAB can cycle stably for 150 h under alternating temperatures. Theoretical calculations and experiment characterizations, involving scanning electrochemical microscopy techniques and distribution of relaxation times analysis, reveal that the excellent capabilities of MoC/Fe─NC arise from accelerated proton‐coupled electron transfer, weakened *OH adsorption, and strengthened Fe─N bonds fueled by MoC nanoparticles. This work sheds light on breaking the activity‐stability trade‐off barrier of SACs for energy‐conversion applications.

Engineering Proton-Coupled Electron Transfer to Break Activity-Stability Trade-Off of Oxygen Electroreduction Catalysts for Temperature-Adaptive Zn-Air Battery.

Single-atom catalysts (SACs) are regarded as effective electrocatalysts for oxygen reduction reaction (ORR). However, integrating high active and long-term durability on SACs is still challenging due to the severe limitations of the activity-stability trade-off. Herein, we report an integrative electrocatalyst combining isolated Fe sites and MoC nanoparticles (MoC/Fe─NC). MoC nanoparticles accelerate ORR kinetics via the proton-feeding effect and optimize Fe site microstructure. Thus, MoC/Fe─NC exhibits a high alkaline ORR activity with half-wave potential (E1/2) of 0.916V versus the reversible hydrogen electrode, and exceptional durability of 50k cycles with 5mV E1/2 loss. The observed ORR performance is further verified in a zinc-air battery (ZAB) with a high peak power density of 316mW cm-2 and operational stability over 1000h. Moreover, the fabricated temperature-adaptive quasi-solid-state ZAB can cycle stably for 150h under alternating temperatures. Theoretical calculations and experiment characterizations, involving scanning electrochemical microscopy techniques and distribution of relaxation times analysis, reveal that the excellent capabilities of MoC/Fe─NC arise from accelerated proton-coupled electron transfer, weakened *OH adsorption, and strengthened Fe─N bonds fueled by MoC nanoparticles. This work sheds light on breaking the activity-stability trade-off barrier of SACs for energy-conversion applications.

Structure Preferred Spinel Ferrite on Polypyrrole Derived N‐Doped Carbon Nanofibers as Bifunctional Electrocatalyst for Zn‐Air Battery

AbstractThe explorationof noble metal free bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is very important for Zn‐air batteries (ZABs). Spinel ferrites are famous bifunctional ORR/OER electrocatalysts. Herein, to further improve their ORR and OER activities, we anchor CoFe2O4 on N‐doped carbon nanofibers (NCNF) derived from polypyrrole (PPy) and obtain CoFe2O4 loaded NCNF (CoFe2O4@NCNF). In its structure, CoFe2O4 particles with small size distribute evenly on NCNF. The combination of CoFe2O4 and NCNF generates excellent ORR activity with typical four‐electron character in both alkaline and neutral electrolyte. In OER, the activity of CoFe2O4@NCNF is also excellent. A rechargeable ZAB is constructed with CoFe2O4@NCNF as cathode material. The specific capacity and energy density of this ZAB reach 807.4 mAh g−1 and 963.6 Wh kg−1 at 10 mA cm−2, respectively. ZAB can keep stable after continuous charge/discharge test for 120 h. This work not only provides an efficient and low cost cathode material for ZABs, but also clarifies the structure‐activity relationship in ORR/OER for spinel ferrites.

Atomic Layer Thickness Modulated the Catalytic Activity of Platinum for Oxygen Reduction and Hydrogen Oxidation Reaction.

Reducing platinum (Pt) usage and enhancing its catalytic performance in the hydrogen oxidation reaction (HOR) and the oxygen reduction reaction (ORR) are vital for advancing fuel cell technology. This study presents the design and investigation of monolayer and few-layer Pt structures with high platinum utilization, developed through theoretical calculations. By minimizing the metal thickness from 1 to 3 atomic layers, an atomic utilization rate ranging from 66.66% to 100% is achieved, in contrast to conventional multilayer Pt structures. This reduction resulted in a unique surface coordination environment. These thinner structures exhibited nonlinear fluctuations in key electronic characteristics-such as the d-band center, surface charge, and work function-as the atomic layer thickness decreased. These variations significantly impacted species adsorption and the Pt-H2O interfacial structure, which in turn affected the catalytic activity. Notably, 1-layer Pt exhibited the best performance for HOR, while 3-layer Pt showed high activity for both HOR and ORR. The findings establish a clear relationship between atomic layer thickness, surface characteristics, adsorption behavior, electric double-layer structure, and catalytic performance in Pt systems. This research contributes to a deeper understanding of precision atomic-structured electrocatalyst design and paves the way for the development of highly effective, low-loading Pt-based catalytic materials.

Fabrication and characterization of Ni-based electrodes for improved NiZn battery performance

In this study, a hydrothermal method was used to synthesize nickel hydroxide (Ni(OH)2) powders, which are active materials for use in nickel (Ni) electrodes located in nickel-zinc (NiZn) batteries. X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential, Brunauer-Emmett-Teller (BET), and electrochemical characterization were used to characterize the cathode material in the prepared Ni electrodes. These results showed a β-phase Ni(OH)2 nanosphere with a well-crystalline structure. The electrochemical test results indicated the Ni electrode has a stable cyclic cycle in the half-cell. Based on the electrochemical performance results, the Ni electrode with Ni(OH)2, which was synthesized at 70oC for 3h of aging time (Ni_pH 12_3h_70oC), was the best-performing metal oxide. Compared with nickel electrodes, the NiCoZn electrode exhibited high OER (oxygen evolution reaction) and ORR (oxygen reduction reaction) activities because the combination of cobalt and zinc oxides with nickel provides excellent electrolyte access capability and promotes effective ion transfer through the active material. The NiZn battery with NiCoZn electrode showed a high capacity of 192.7 mAh gactive−1 at 10 mA cm−2 and cycling durability (after cycling at 10 mA cm−2 for 70 cycles). Benefiting from the excellent interaction between Ni, Co, and Zn, NiCoZn exhibited high onset potential and current density, suggesting that the NiCoZn electrode is a promising candidate as a high-performance configuration for Ni-based electrodes in NiZn batteries.

Electron Donor-Acceptor Activated Anti-Fenton Property for the Ultradurable Oxygen Reduction Reaction.

Iron-nitrogen-carbon (Fe-N-C) materials are recognized as an effective category of catalysts that do not contain platinum (Pt) for the oxygen reduction reaction (ORR). Nonetheless, the long-term stability and effectiveness of these materials are significantly hindered by the dissolution and oxidation of Fe atoms. Microstructural engineering of Fe-N-C is a viable approach to enhancing ORR activity and stability. Herein, CuN5-single-atom nanozymes (SAzyme)-assisted Fe-N5 catalysts (SA-Fe-N5) were developed by introducing single-atom Cu to enhance Fe-N-C catalyst ORR performance. Electrochemical assessments indicated that SA-Fe-N5 exhibited excellent ORR activity in alkaline solutions, with a half-wave potential and a diffusion-limited current density similar to that of commercial Pt/C. Calculations based on density functional theory indicated that a single copper atom can function as an electron donor, enhancing the electron density at the iron sites. This modification improves the adsorption and desorption energies for intermediates involved in the ORR process, ultimately boosting the ORR performance of the single-atom Fe-N5 catalyst. Moreover, the introduction of the Cu site can be regarded as a catalase single-atom nanozyme (CAT-SAzyme), facilitating the decomposition of the byproduct H2O2 to H2O and thereby enhancing the anti-Fenton activity during the ORR process. Notably, as a cathode catalyst in a zinc-air battery, SA-Fe-N5 demonstrated an impressive power density of 217.8 mW cm-2 alongside a current density of 257.3 mA cm-2.

Manipulating Oxygen Reduction Mechanisms of Platinum with Nonmetallic Phosphorus and Metallic Copper Synergistic Alloying.

Alloying of platinum (Pt) nanostructures with heteroelements, commonly including transition-metals and nonmetals, is an effective strategy to improve the electrocatalytic performance for oxygen reduction reaction (ORR). However, the distinct mechanisms by which metal/nonmetal alloying improves ORR activity remain unclear. Herein, based on the successful alloying of porous network Pt nanospheres (NSs) with metallic copper (Cu) and non-metallic phosphorus (P) and systematically integrating the electrochemical tests, density functional theory calculations, and in situ electrochemical Raman spectroscopy, this study reveals that the internal Cu-alloying is responsible for modulating the binding strength of oxygenated intermediates to lower the free energy barrier of the potential-determining step (PDS) along the ORR associative mechanism, while the further surface P-alloying can transform the ORR pathway to dissociative mechanism, in which the PDS has a quite low barrier. As a result, the carbon-supported P/Cu co-alloyed porous network Pt nanospheres (P-PtCuNSs/C) catalyst synthesized by confinement growth and post-phosphorization demonstrates excellent electrocatalytic ORR activity and stability compared to the commercial Pt/C catalyst both in half-cells and proton exchange membrane fuel cells. In particular, the hydrogen (H2)-oxygen (O2) single cell with P-PtCuNSs/C as the cathode catalyst achieves a high mass activity of 0.52 A mgPt -1 at the voltage of 0.90V, surpassing the U.S. Department of Energy's current activity target.

Constructing Pentagonal Topological Defects in Carbon Aerogels for Flexible Zinc-Air Batteries.

In the context of energy conversion, the design and synthesis of high-performance metal-free carbon electrocatalysts for the oxygen reduction reaction (ORR) is crucial. Herein, a one-step nitrogen doping/extraction strategy is proposed to fabricate 3D nitrogen-doped carbon aerogels (NCA-Cl) with rich pentagonal carbon topological defects. The NCA-Cl electrocatalyst exhibits superb ORR activity, displaying a half-wave potential of 0.89V vs RHE and 0.74V vs RHE under alkaline (0.1m KOH) and acidic (0.1m HClO4) media, respectively, thanks to the balanced *OOH intermediate adsorption and desorption induced by the pentagonal carbon topological defects and nitrogen dopants. The aqueous zinc-air battery (ZAB) equipped with the NCA-Cl cathode delivers a peak power density of 206.6mWcm-2, a specific capacity of 810.6mAhg-1, and a durability of 400h, and the flexible ZAB also performed convincingly. This work provides an effective strategy for the formation of topological carbon defects for the enhancement of the electrocatalytic activity of carbon-based catalysts.

Synergistic Catalysts with Fe Single Atoms and Fe3C Clusters for Accelerated Oxygen Adsorption Kinetics in Oxygen Reduction Reaction.

The design of cost-effective and efficient catalysts based on transition metal-based electrocatalysts for the oxygen reduction reaction (ORR) is crucial yet challenging for energy-conversion devices like metal-air batteries. In this work, we present a cost-effective strategy for preparing catalysts consisting of single-atomic Fe sites and Fe3C clusters encapsulated in nitrogen-doped carbon layers (FeSA-Fe3C/NC). The FeSA-Fe3C/NC electrocatalyst demonstrates outstanding ORR performance in alkaline electrolytes, achieving a high half-wave potential (E1/2=0.902V), 4e- ORR selectivity, and robust methanol tolerance. The exceptional ORR catalytic performance is credited to the relatively substantial specific surface area and the optimal arrangement of active sites, including atomically dispersed Fe-N sites and synergistic Fe3C clusters. In situ spectroelectrochemical characterization and theoretical calculations verify that Fe3C clusters disrupt the symmetric electronic structure of Fe-N4, optimizing 3d orbitals of Fe centers, thereby accelerating O─O bond cleavage in *OOH to boost ORR activity. Furthermore, a zinc-air battery constructed with FeSA-Fe3C/NC demonstrates excellent potential in energy storage application, yielding a maximum power density of 151.3mW cm-2 and robust cycling durability surpassing that of commercial Pt/C catalysts. This study establishes a cost-effective route for producing metal-based carbon electrocatalysts with exceptional performance using environmentally friendly raw materials.

Synergistic Catalysts with Fe Single Atoms and Fe3C Clusters for Accelerated Oxygen Adsorption Kinetics in Oxygen Reduction Reaction

AbstractThe design of cost‐effective and efficient catalysts based on transition metal–based electrocatalysts for the oxygen reduction reaction (ORR) is crucial yet challenging for energy‐conversion devices like metal–air batteries. In this work, we present a cost‐effective strategy for preparing catalysts consisting of single‐atomic Fe sites and Fe3C clusters encapsulated in nitrogen‐doped carbon layers (FeSA‐Fe3C/NC). The FeSA‐Fe3C/NC electrocatalyst demonstrates outstanding ORR performance in alkaline electrolytes, achieving a high half‐wave potential (E1/2 = 0.902 V), 4e− ORR selectivity, and robust methanol tolerance. The exceptional ORR catalytic performance is credited to the relatively substantial specific surface area and the optimal arrangement of active sites, including atomically dispersed Fe–N sites and synergistic Fe3C clusters. In situ spectroelectrochemical characterization and theoretical calculations verify that Fe3C clusters disrupt the symmetric electronic structure of Fe–N4, optimizing 3d orbitals of Fe centers, thereby accelerating O─O bond cleavage in *OOH to boost ORR activity. Furthermore, a zinc–air battery constructed with FeSA‐Fe3C/NC demonstrates excellent potential in energy storage application, yielding a maximum power density of 151.3 mW cm−2 and robust cycling durability surpassing that of commercial Pt/C catalysts. This study establishes a cost‐effective route for producing metal‐based carbon electrocatalysts with exceptional performance using environmentally friendly raw materials.

Engineering the coordination environment of Ni and Pd dual active sites for promoting the oxygen reduction reaction

Precisely regulating active sites is vital for promoting the oxygen reduction reaction (ORR) activity. Here we reported highly active Ni-Pd co-doped N-coordinated graphene towards ORR achieved by edge termination and O doping. Our first-principles calculations demonstrated that edge termination effectively boost the ORR activity, and armchair-edge termination was energetically more favorable than zigzag-edge termination. Notably, after O doping Ni-Pd active center, armchair edge-terminated Ni-Pd active site exhibited better ORR activity, and the lowest overpotential was only 0.31 V. This improvement in activity was attributed to the shift of the d-band center of Ni atom toward the Fermi-level and the shift of the d-band center of Pd atom away from the Fermi-level, thus regulating the *OH adsorption strength. This work paves the way for developing highly active graphene-based dual-atom catalysts for ORR through edge and doping engineering.

Understanding the Mechanism of Fe-N-C Catalyst Oxygen Reduction Reaction Performance Enhancement: The Impact of Iron Valence State and Nitrogen Content.

Optimizing non-noble catalysts for the oxygen reduction reaction (ORR) is crucial for advancing energy storage and conversion technologies. This study investigates the influence of iron valence states and nitrogen precursor contents on the physicochemical properties and electrochemical performance of lignin-based Fe-N-C catalysts. Catalysts are synthesized using different valence iron sources and varying pyrrole contents. The results reveal that iron(II) doping increases microporosity and specific surface area, while iron(III) doping enhances mesoporous and iron contents of the carbon materials. XPS and Raman spectroscopy confirm the successful incorporation of Fe-Nx active sites in the as-prepared LFeIIIPx catalysts. Electrochemical tests demonstrate that LFeIIIP10 exhibits the highest ORR activity, surpassing commercial Pt/C in half-wave potential (E1/2) and limiting current density (JL). The direct formate fuel cell (DFFC) with an LFeIIIP10 air cathode achieves a maximum power density of 24.7 mW cm-2, 32% higher than that with a Pt/C cathode. This study highlights the critical role of tailoring iron valence states and nitrogen levels to develop high ORR performance, cost-effective Fe-N-C catalysts, providing valuable insights for the future design of non-noble metal catalysts in energy applications.

Pt-Based Ternary Alloy on Nanohoneycomb Nitrogen-Doped Carbon Support for Highly Active and Stable Oxygen Reduction Reaction

Pt-Based Ternary Alloy on Nanohoneycomb Nitrogen-Doped Carbon Support for Highly Active and Stable Oxygen Reduction Reaction

Tailoring Oxygen Electrocatalytic Performance via Construction of Iron‐Cobalt Oxides and FeN4 Sites on Hierarchical Carbon Fibers for Efficient Zinc–Air Batteries

AbstractThe design and fabrication of non‐precious metal materials for bifunctional oxygen electrocatalytic properties with reversible oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been a research hotspot in the field of zinc–air batteries. Herein, a hierarchical carbon nanofiber immobilized with iron cobalt oxide particles (FeCoOx) and Fe‐Nx sites catalyst is synthesized through electrostatic spinning and the in situ polymerization of pyrrole coupled with pyrolysis. The FeCoOx/Fe─N─C demonstrates a superior bifunctional electrocatalytic performance (E1/2 = 0.91 V, η10 = 350 mV). Liquid zinc–air batteries employing FeCoOx/Fe─N─C exhibit a high power of 184.8 mW cm−2 and more than 580 cycles of stable cycling ability. Additionally, the incorporation of iron cobaltite introduces extra electrons and optimizes the adsorption capacity for oxygen intermediates, effectively boosting the inherent ORR activity. The experimental results illustrate that the special geometrical structure of spinel ferrite provides excellent OER catalytic performance. Theoretical calculations indicate that the incorporation of FeCoOx shifts the d‐band center of iron closer to the Fermi level (Ef), thereby modulating the hybridization between Fe 3d and O 2p orbitals. This work offers an effective approach to constructing coupling catalysts that have single atoms coexisting with oxide particles for efficient bifunctional catalysis.

Interfacial metal-coordinated bifunctional PtCo for practical fuel cells.

Platinum (Pt) has been documented as the top-tier fuel cell catalyst, yet it faces a notable challenge regarding its poor CO tolerance and sluggish oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), particularly when using CO-contaminated blue and gray H2. Here, we present an interfacial metal coordination strategy to design a bifunctional platinum-cobalt (PtCo) intermetallic catalyst integrated with a tin-nitrogen-carbon (Sn-N-C) support, which forms Pt-Sn-N bonds that substantially boost both ORR activity and CO tolerance. The PtCo/Sn-N-C-made fuel cell achieves a topmost peak power density of 2.11 watts per square centimeter in 100 parts per million (ppm) of CO-containing H2, surpassing all previously reported PEMFCs. In addition, it operates stably at a rated voltage for over 710 hours in 100 ppm of CO/H2-air. This work demonstrates the feasibility of fuel cells directly using CO-contaminated gray & blue H2, paving the way for PEMFC-driven energy vehicles.

Influence of Commercial Ionomers and Membranes on a PGM-Free Catalyst in the Alkaline Oxygen Reduction.

Hitherto, research into alkaline exchange membrane fuel cells lacked a commercial benchmark anionomer and membrane, analogous to Nafion in proton-exchange membrane fuel cells. Three commercial alkaline exchange ionomers (AEIs) have been scrutinized for that role in combination with a commercial platinum-group-metal-free Fe-N-C (Pajarito Powder) catalyst for the cathode. The initial rotating disc electrode benchmarking of the Fe-N-C catalyst's oxygen reduction reaction activity using Nafion in an alkaline electrolyte seems to neglect the restricted oxygen diffusion in the AEIs and is recommended to be complemented by measurements with the same AEI as used in the alkaline exchange membrane fuel cell (AEMFC) testing. Evaluation of the catalyst layer in a gas-diffusion electrode setup offers a way to assess the performance in realistic operating conditions, without the additional complications of device-level water management. Blending of a porous Fe-N-C catalyst with different types of AEI yields catalyst layers with different pore size distributions. The catalyst layer with Piperion retains the highest proportion of the original BET surface area of the Fe-N-C catalyst. The water adsorption capacity is also influenced by the AEI, with Fumion FAA-3 and Piperion having equally high capabilities surpassing Sustainion. Finally, the choice of the membrane influences the ORR performance as well; particularly, the low hydroxide conductivity of Fumion FAA-3 in the room temperature experiments mitigates the ORR performance irrespective of the AEI in the catalyst layer. The best overall performance at high current densities is shown by the Piperion anion exchange ionomer matched with Sustainion X37-50 membrane.

Influence of Hemilabile Arm and Amide Functionality in the Ligand Backbone on Chemical and Electrochemical Dioxygen Reduction Catalyzed by Mononuclear Copper(II) Complexes.

Four mononuclear copper(II) complexes, [(DPA-OH)Cu(CH3OH)(ClO4)](ClO4) (1), [(DPA-OMe)Cu(CH3OH)(ClO4)](ClO4) (2), [(6-Amide-DPA-OMe)Cu](ClO4)2 (3) and [(6-Amide2-DPA-OMe)Cu](ClO4)2 (4), of flexidentate ligands bearing hemilabile (hydroxy)methoxyethyl and/or amide group on DPA (di(2-picolyl)amine) backbone were isolated to explore their potency in catalyzing chemical and electrochemical oxygen reduction reaction (ORR). The role of a hemilabile arm, as well as amide functionality on the ligand backbone in affecting the rate-determining step (RDS) of the overall catalytic cycle has been explored and compared with that of the analogous [(tmpa)Cu](ClO4)2 (tmpa = tris(2-pyridylmethyl)amine) and [(PV-tmpa)Cu](ClO4)2 (PV-tmpa = bis(pyrid-2-ylmethyl){[6-(pivalamido)pyrid-2-yl]methyl}-amine) complexes. The hemilabile arm in these complexes results in an overall third-order rate, with kcat values ranging from 103 to 104 M-2s-1 during dioxygen reduction catalysis. All the complexes except complex 4 selectively reduce dioxygen via the 4e-/4H+ reduction pathway to water (H2O) using decamethylferrocene (Fc*) as a sacrificial reductant in acidic acetone at 298 K. In contrast, altering the reaction conditions from a chemical to an electrochemical ambiance in phosphate buffer displays a reverse order of ORR activity of the complexes while maintaining the same product selectivity as observed in chemical ORR catalysis in acetone.

CeO2 Boosted Fe‐N5 Electrocatalyst via Relay Catalysis for Modulating Oxygen Reduction Reaction in Al‐Air Batteries

AbstractAtomically dispersed iron‐nitrogen‐carbon (Fe‐N‐C) catalysts have demonstrated promising oxygen reduction reaction (ORR) activity. It poses a formidable challenge to simultaneously optimize the adsorption energies of multiple intermediates at a single active site. In addition, the lack of long‐term stability remains a significant problem due to the unavoidable 2‐electron by‐product hydrogen peroxide (H2O2). Here, multiple active sites are achieved to modulate the adsorption energy of intermediates while removing the by‐product of the reaction by growing the second active site CeO2 nanoparticles in situ on the surface of the hollow‐structured Fe‐N5, thus improving the efficiency and stability of the Fe‐N5/CeO2. Density functional theory (DFT) calculations are employed to probe into the synergistic catalytic interaction between Fe‐N5 and CeO2, proposing a relay catalytic mechanism underlying the enhanced catalytic activity. Furthermore, the catalyst stability is enhanced due to the ability of CeO2 to scavenge the reaction by‐product and inhibit its destructive effects on the Fe‐N5 active site. Additionally, the liquid Al – air batteries equipped with Fe‐N5/CeO2 display a higher power density. This work proffers an innovative vista for the conception and refinement of multi‐active‐site catalysts with excellent catalytic performance and prolonged lifespan.

Turn the Harm into A Benefit: Axial Cl Adsorption on Curved Fe-N4 Single Sites for Boosted Oxygen Reduction Reaction in Seawater.

Seawater electrocatalysis is urgently needed for various energy storage and conversion systems. However, the adsorption of chloride ions (Cl-) to the active sites can degrade the oxygen reduction reaction (ORR) activity and stability, thus reducing the catalytic performance. In this paper, a curved FeN4 single atomic structure is designed by utilizing curvature engineering, which can turns the harmful Cl adsorption into a benefit on the Fe single site that changes the rate determining step of ORR and reduces the overall energy barrier according to density functional theory (DFT) calculation. Experimental studies reveal the prepared highly-curved single-atom iron catalyst (HC-FeSA) exhibits excellent ORR activity in different electrolytes, with half-wave potentials of 0.90 V in 0.1 M KOH, 0.90 V in simulated seawater, and 0.75 V in natural seawater, respectively. This work opens up an avenue for the synthesis of high-performance seawater-based single-atom ORR catalysts through regulating the local atomic curvature.

Nitrogen and boron coordinating atoms adjust single-atom catalyst anchored on divacancy defect graphene for highly efficient electrochemical oxygen reduction

Nitrogen and boron coordinating atoms adjust single-atom catalyst anchored on divacancy defect graphene for highly efficient electrochemical oxygen reduction