Improved Oxygen Reduction Reaction Activity Research Articles

Strong Interaction between Titanium Carbonitride Embedded in Mesoporous Carbon Nanofibers and Pt Enables Durable Oxygen Reduction.

Platinum (Pt) supported on high surface area carbon has been the most widely used electrocatalyst in proton exchange membrane fuel cell (PEMFC). However, conventional carbon supports are susceptible to corrosion at high potentials, leading to severe degradation of electrochemical performance. In this work, titanium carbonitride embedded in mesoporous carbon nanofibers (m-TiCN NFs) are reported as a promising alternative to address this issue. Benefiting from the interpenetrating conductive pathways inside the one-dimensional (1D) nanostructures and the embedded TiCN nanoparticles (NPs), m-TiCN NFs exhibit excellent stability at high potentials and interact strongly with Pt NPs. Subsequently, m-TiCN NFs-supported Pt NPs deliver remarkably enhanced oxygen reduction reaction (ORR) activity and durability, with negligible activity decay and less than 5% loss of electrochemical surface area（ECSA） after 50000 cycles. Moreover, the fuel cell assembled by this catalyst delivers a maximum power density of 1.22W cm-2 and merely 3% loss after 30000 cycles of accelerated durability tests under U.S. Department of Energy (DOE) protocols. The improved ORR activity and durability are attributed to the superior corrosion resistance of the m-TiCN NF support and the strong interaction between Pt and m-TiCN NFs.

Intrinsic Defect‐Rich Carbon‐Supported Iron Phthalocyanine as Beyond‐Pt Oxygen Reduction Catalysts for Zinc–Air Batteries

Molecular iron phthalocyanine (FePc) bearing a single‐atom Fe–N4 moiety is a high‐profile non‐platinum catalyst toward the oxygen reduction reaction (ORR), but its unsatisfactory activity and inadequate stability hinder the practical application. Herein, a novel strategy by hybridizing FePc with fullerene‐derived intrinsic defect‐rich carbon to improve its ORR activity and stability is reported. Via alkali‐assisted thermal pyrolysis, C60 molecules are disintegrated into tiny fragments that then restructure into pentagon‐ and edge‐rich carbon (FC). Utilizing FC as a support of FePc leads to a significantly improved ORR activity compared to other supports including reduced graphene oxide and carbon nanotube that hold distinct structural features. The optimized FePc/FC with a Fe loading of 3 wt% presents a half‐wave potential of 0.917 V, far beyond that of Pt/C (0.846 V), via selective four‐electron ORR pathway and excellent stability under accelerated stress test. The practical applicability of FePc/FC is also demonstrated as a high‐performing cathode catalyst of aqueous zinc–air batteries. It is, for the first time, explicitly disclosed that strong interactions between FePc molecules and intrinsic carbon defects (e.g., pentagons and edges) not only strengthen the anchoring effect of supported FePc but also enhance the intrinsic ORR activity of single‐atom Fe–N4 sites.

Unveiling the resistance component on fuel cell electrodes by ionic liquid adsorbed PtCo/C catalyst through distribution of relaxation time

A majority of studies focus on developing oxygen reduction reaction (ORR) catalysts and cathode configurations to enhance the performance and durability of polymer electrolyte membrane fuel cells (PEMFCs). In this study, resistance analyses of the membrane electrode assembly (MEA) are conducted to elaborate on the performance and durability improvements induced by the adsorption of [MTBD][beti] ionic liquid (IL) on the commercial PtCo/C catalyst. The morphological changes caused by IL adsorption are observed on micro and macro scales via physicochemical methods. From the half-cell measurement, when the 4 wt% IL was adsorbed, a 15 mV improvement in ORR activity occurred, and as the adsorption amount increased, the activity decreased. The MEA using 8 wt% IL adsorbed catalyst outperforms 1.7 times higher current density at 0.8 V and 40 % lower charge transfer resistance. Distribution of relaxation time resistance analysis reveals that oxygen mass transfer resistance (Rmass), ORR charge transfer resistance (RORR), and proton charge transfer resistance (Rproton) decrease due to IL adsorption. During accelerated durability tests, IL 8 % MEA showed a 58 % increase in durability, and a lower degradation of RORR and Rproton encouraged improved durability. The resistance analyses in this study contribute to identifying the factors responsible for the performance and durability enhancement of PEMFC.

Synergistic Electronic Interaction of Nitrogen Coordinated Fe-Sn Double-Atom Sites: An Efficient Electrocatalyst for Oxygen Reduction Reaction.

Double-atom site catalysts (DASs) have emerged as a recent trend in the oxygen reduction reaction (ORR), thereby modifying the intermediate adsorption energies and increasing the activity. However, the lack of an efficient dual atom site to improve activity and durability has limited these catalysts from widespread application. Herein, the nitrogen-coordinated iron and tin-based DASs (Fe-Sn-N/C) catalyst are synthesized for ORR. This catalyst has a high activity with ORR half-wave potentials (E1/2 ) of 0.92V in alkaline, which is higher than those of the state-of-the-art Pt/C (E1/2 =0.83V), Fe-N/C (E1/2 =0.83V), and Sn-N/C (E1/2 =0.77V). Scanning electron transmission microscopy analysis confirmed the atomically distributed Fe and Sn sites on the N-doped carbon network. X-ray absorption spectroscopy analysis revealed the charge transfer between Fe and Sn. Both experimental and theoretical results indicate that the Sn with Fe-NC (Fe-Sn-N/C) induces charge redistribution, weakening the binding strength of oxygenated intermediates and leading to improved ORR activity. This study provides the synergistic effects of DASs catalysts and addresses the impacts of P-block elements on d-block transition metals in ORR.

Boosting Oxygen Reduction at Pt(111)|Proton Exchange Ionomer Interfaces through Tuning the Microenvironment Water Activity.

A proton exchange ionomer is one of the most important components in membrane electrode assemblies (MEAs) of polymer electrolyte membrane fuel cells (PEMFCs). It acts as both a proton conductor and a binder for nanocatalysts and carbon supports. The structure and the wetting conditions of the MEAs have a great impact on the microenvironment at the three-phase interphases in the MEAs, which can significantly influence the electrode kinetics such as the oxygen reduction reaction (ORR) at the cathode. Herein, by using the Pt(111)|X ionomer interface as a model system (X = Nafion, Aciplex, D72), we find that higher drying temperature lowers the onset potential for sulfonate adsorption and reduces apparent ORR current, while the current wave for OHad formation drops and shifts positively. Surprisingly, the intrinsic ORR activity is higher after properly correcting the blocking effect of Pt active sites by sulfonate adsorption and the poly(tetrafluoroethylene) (PTFE) skeleton. These results are well explained by the reduced water activity at the interfaces induced by the ionomer/PTFE, according to the mixed potential effect. Implications for how to prepare MEAs with improved ORR activity are provided.

Fluoropyridine-medicated zeolite templating method for N/F co-doped carbon with high electrocatalytic performance on oxygen reduction reaction

Heteroatom-doped carbons have attracted increasing attention in recent years as inexpensive high-performance electrocatalytic materials owing to their electrical properties. A precisely controlled synthesis method for heteroatom-doped carbons is important to improve their performance and expand their applications. In this study, we developed a fluoropyridine-medicated zeolite templating method for Nitrogen/Fluorine (N/F) co-doped carbons. The N/F co-doped carbons showed better catalytic performances for oxygen reduction reaction (ORR) than N-doped carbon prepared using pyridine. In particular, the optimized N/F co-doped carbon exhibited a higher half-wave potential (0.87 V vs. RHE) than commercial Pt-loaded carbon black and N/F co-doped carbons reported in the literature. The comparative studies using various N/F co-doped carbons revealed that semi-ionic bonded C-F might improve ORR activity. In contrast, the contribution from covalent or ionic C-F to improving ORR activity would be negligible.

Structural and compositional analysis of MOF-derived carbon nanomaterials for the oxygen reduction reaction.

The development of low-cost and efficient cathode catalysts is crucial for the advancement of fuel cells, as the oxygen reduction reaction (ORR) on the cathode is constrained by expensive commercial Pt/C catalysts and a significant energy barrier. Metal-organic frameworks (MOFs) are considered excellent precursors for synthesizing carbon nanomaterials due to their simple synthesis, rich structure and composition. MOF-derived carbon nanomaterials (MDCNM) inherit the morphology of their precursors at low dimensional scales, providing abundant edge defects, larger specific surface area, and excellent electron transport paths. Furthermore, the rich composition of MOFs enables the carbon nanomaterials derived from them to exhibit various physicochemical properties, including stronger electron gaining ability, oxygen affinity, and a higher degree of graphitization, resulting in excellent ORR activity. However, a more detailed analysis is necessary to understand the advantages and mechanisms of MDCNM in the field of the ORR. This review classifies and summarizes the structure and different chemical compositions of MDCNM in low dimensions, and provides an in-depth analysis of the reasons for their improved ORR activity. Additionally, the recent practical applications of MDCNM as cathode material in fuel cells are introduced and analyzed in detail, with a focus on the enhanced electrochemical performance.

Interfacial oxygen atom modification of a PdSn alloy to boost oxygen reduction in zinc-air batteries

Modifying the surface of a catalyst with heteroatoms can regulate the interfacial atomic valence state and adjust the charge distribution, which is promising for obtaining desirable platinum carbon catalyst (Pt/C)-matched oxygen reduction reaction (ORR) catalytic performance. Here, we developed an efficient method to access O-rich crystalline interfacial-exposed palladium-tin alloy (111) crystal surfaces [Pd3Sn (111)] for highly efficient ORR via direct reduction of Pd/Sn metal salt species that are well dispersed in a nitrogen, phosphorus-doped carbonaceous (NPC) substrate. In addition to the other materials, preembedded Pd/Sn metal salt species in NPC control the release of metal sources upon reduction in the liquid phase, resulting in the grafting of an as-prepared PdSn alloy with many merits, such as efficient electron conduction, short-range crystallinity and increased crystal interface exposure. The presence of a considerable quantity of oxygen atoms at the interface of small-sized PdSn alloys on NPC substrates has been methodically verified by powder X-ray diffraction, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy characterizations. The PdSn-O sample exhibited excellent ORR activity, achieving an onset potential of ∼0.99 V and a half-wave potential of ∼0.88 V at 1600 rpm in O2-saturated 1.0 M KOH. Density functional theory simulations of pure Pd, Pd-O, the PdSn alloy and PdSn-O suggest that interfacial oxygen atom modification is responsible for the significantly improved ORR activity. The assembled zinc-air battery provides a high specific power of 218.9 mW cm−2 and a specific capacity of 810.6 mAh gZn-1. Our approach has the potential to stimulate the preparation of O-rich crystalline interfacial-exposed alloy compounds for other energy conversion applications.

MoOy-Pt(CuNi)x heterojunction nanostructured catalyst for promoting the oxygen reduction reaction activity property

The catalyst intrinsic area-specific activity for the oxygen reduction reaction (ORR) was constrained by the scaling relations governing the adsorption of reaction intermediates. In this study, we strategically modified the electronic band structures of Pt(CuNi)x alloy nanoparticles by varying their composition, resulting in a specific activity trend resembling a volcano shape. The introduction of MoOy shattered the existing scaling relations, leading to a significant enhancement in ORR activity of Pt alloys, surpassing the activity of Pt(CuNi)x catalysts. These findings proved the effectiveness of MoOy deposition on Pt(CuNi)x in disrupting the scaling relations, ultimately improving ORR activity.

Improving Oxygen Reduction Reaction Activity through Defect Engineering of Atomically Dispersed Iron Electrocatalysts for Proton Exchange Membrane Fuel Cells

Atomically dispersed and nitrogen-coordinated iron catalysts(Fe-N-Cs) have the potential as an alternative to platinum-group metal catalysts for the oxygen reduction reaction (ORR). However, in the context of practical proton exchange membrane fuel cell (PEMFC) applications, the membrane electrode assembly (MEA) performances of Fe-N-Cs remain unsatisfactory. To address this issue, a defect engineering strategy has been developed to prepare high-performance PEMFC MEAs using atomically dispersed Fe-N-C catalysts. This strategy involves the use of a zeolitic imidazolate framework (ZIF)-derived nitrogen-doped carbon with additional CO2 activation to create atomically dispersed iron sites with a controlled number of defects. By adjusting the extent of defect formation in the carbon plane using CO2 activation, it is anticipated that changes in the oxidation state and spin state of the Fe center will modify the electronic structure of the Fe-N4 active sites. The Fe-N-C species with the optimal number of defect sites exhibit excellent ORR performance with a high half-wave potential of 0.83 V in 0.5 M H2SO4. Fine-tuning the number of defects can be optimized the ORR activity by adjusting the contribution of the Fe d-orbitals to the reaction intermediate binding energies. The resulting MEA based on the defect-engineered Fe-NC catalyst exhibits remarkable peak power densities in both H2/O2 and H2/air fuel cells, making it one of the most active atomically dispersed catalyst materials at the MEA level.

Microalgal cycling in the cathode of microbial fuel cells (MFCs) induced oxygen reduction reaction (ORR) and electricity: A biocatalytic process for clean energy

Development in electricity generation technologies is necessary to ensure a safe and sustainable future. Catalytic activity of oxygen reduction reaction (ORR) is still the key challenge in microbial fuel cells (MFCs) which has not improved significantly even upon the application of catalysts. In this study, microalgae as biocatalysts (i.e., availability of electron acceptors and maintain ORR) were applied for spontaneous bioelectricity generation. Microalgal cycling was performed at various concentrations (5, 10, 15, and 20 % vv−1) in the cathode whereas, 2 % fat, oil, and grease (FOG) were added in the anode. Electrochemical and next-generation sequencing (NGS) analyses along with biological parameters were studied to fully understand the anodic and cathodic behavior towards electrogenesis. Continuous microalgal cycling resulted in the highest power density (21.0 mW m−2) and current density (245 mA m−2) in the reactor loaded with 2 % FOG + 15 % vv−1 microalgae. Electrochemical analysis showed the potential of 2 % FOG + 15 % vv−1 microalgae via exhibiting Ohmic resistance of 34. 9 Ω and charge transfer resistance of 100 Ω with improved ORR activity. NGS revealed that Clostridium (7–16.5 %), Bacteroidetes (4.54–12.87 %), and Geobacter (6.5–22.7 %) were the dominant species involved in the electron transport mechanism. CoA ligase, acetyl-CoA C-acetyltransferase, and acetate kinase were the major enzymes involved in β-oxidation and electrogenesis. This study demonstrated the baseline for the use of microalgae as biocatalyst in cathode of MFCs to improve the catalytic efficiency of ORR.

Effectively boosting hydration capacity and oxygen reduction activity of cobalt-free perovskite cathode by K+ doping strategy for protonic ceramic fuel cells

Development of triple-conducting cathode can extend the electrochemically active region to the entire cathode to more effectively promoting oxygen reduction reaction (ORR). Herein, a cobalt-free perovskite Sr1.75K0.25Fe1.5Mo0.5O6−δ (SKFM) was developed as a single-phase triple-conducting cathode material for protonic ceramic fuel cells (PCFCs). Introduction of K into Sr-site leads to a 21.54 % increase in the hydration capacity compared to the undoped Sr2Fe1.5Mo0.5O6−δ (SFM). The bulk diffusion coefficient and surface exchange coefficient of SKFM are 3.8 and 5.2 times higher than those of SFM at 550 °C, respectively. XAS and EPR results demonstrate that the average valence state of Fe and the concentration of surface oxygen vacancies in SKFM are higher than those in SFM. The polarization resistances (Rp) value of SKFM cathode in wet air is 0.06 Ω cm2 at 700 °C, while it is 0.11 Ω cm2 for SFM cathode, which is reduced by 45.5 %, indicating significantly improved ORR activity. The Rp is dominated by the adsorption and diffusion process of oxygen associated with low-frequency part in wet air. The single cell with a configuration of Ni-BZCY4/21-μm-thick BZCY4/SKFM delivers a power output of 1000.8 mW cm−2 in wet H2 at 700 °C and steady operation at 600 °C for a total of 100 h.

Bypassing Formation of Oxide Intermediate via Chemical Vapor Deposition for the Synthesis of an Mn-N-C Catalyst with Improved ORR Activity.

A significant barrier to the commercialization of proton exchange membrane fuel cells (PEMFCs) is the high cost of the platinum-based oxygen reduction reaction (ORR) cathode electrocatalysts. One viable solution is to replace platinum with a platinum-group metal (PGM) free catalyst with comparable activity and durability. However, PGM-free catalyst development is burdened by a lack of understanding of the active site formation mechanism during the requisite high-temperature synthesis step, thus making rational catalyst design challenging. Herein we demonstrate in-temperature X-ray absorption spectroscopy (XAS) to unravel the mechanism of site evolution during pyrolysis for a manganese-based catalyst. We show the transformation from an initial state of manganese oxides (MnOx) at room temperature, to the emergence of manganese-nitrogen (MnN4) site beginning at 750 °C, with its continued evolution up to the maximum temperature of 1000 °C. The competition between the MnOx and MnN4 is identified as the primary factor governing the formation of MnN4 sites during pyrolysis. This knowledge led us to use a chemical vapor deposition (CVD) method to produce MnN4 sites to bypass the evolution route involving the MnOx intermediates. The Mn-N-C catalyst synthesized via CVD shows improved ORR activity over the Mn-N-C synthesized via traditional synthesis by the pyrolysis of a mixture of Mn, N, and C precursors.

Improved DMFC water management via superwetting, high-performance catalyst synthesized by nanocapsule method

In this paper, an effective water management structure for direct methanol fuel cell (DMFC) is designed based on the super-hydrophilicity of nitrogen-doped carbon aerogel which functions as the support of Pt catalyst. Considering the case where Pt nanoparticles deposited into the nanopores of the support are difficult to contact with the ionomer, the catalyst is synthesized by nanocapsule method, and the experimental results prove that a favorable improved oxygen reduction reaction activity of the prepared catalyst has been achieved. The produced hydrophilic catalyst is used to construct a two-layered cathode catalyst layer (CCL) with hydrophilic inner layer and hydrophobic outer layer as water management structure, since a single-layered hydrophilic CCL shows poor performance due to serious water flooding. A mathematical model is developed to study the influence of two-layered CCL, and its effect on cell performance is also analyzed by polarization tests. For the improved liquid-feed DMFCs, high hydraulic pressure is formed in CCL to promote water recovery and inhibit methanol crossover. For the improved vapor-feed DMFC, the enhanced water recovery secures the water required for the anodic oxidation reaction, which increases the output performance and stability greatly. This study provides a new method for the optimization of DMFC.

Boosting Oxygen Reduction through Microenvironment Modulation to Enhance Mass Transportation

Electroreduction of oxygen driven by renewable electricity holds significant promise for the sustainable production of value‐added hydrogen peroxide (H2O2). While water is a desirable source of protons and electrons for this reaction, its low gas solubility often limits the transportation of gas molecules and consequently leads to large concentration overpotential, resulting in unsatisfactory energy efficiencies. Herein, a facile and effective strategy to promote the 2e− oxygen reduction reaction (ORR) through microenvironment modulation is presented. In this work, it is specifically aimed to facilitate oxygen transportation at the reaction interface, particularly at high rates. To achieve this, hydrophobic polytetrafluoroethylene (PTFE) particles are introduced into a catalyst layer containing amino‐group‐functionalized carbon nanotube (CNT‐NH2) as the ORR catalyst for H2O2 production. As a result, the PTFE‐modified CNT‐NH2‐based gas‐diffusion electrode (GDE) substantially improves ORR activity. At 100 mA cm−2, the PTFE‐modified CNT‐NH2 achieves a high cathodic energy efficiency of 92%, 1.5 times higher than the pristine CNT‐NH2‐based GDE (63%). Detailed kinetic analysis reveals that this enhanced ORR performance is indeed due to the enhanced oxygen transportation induced by the persistent hydrophobic microenvironment created by the PTFE‐modified catalyst layer, reducing the concentration overpotential during ORR.

Nitrogen sites prevail over textural properties in N-doped carbons for the oxygen reduction reaction

Nitrogen-doped carbon-based electrodes are among the most promising alternatives to platinum-based electrodes in the cathode of fuel cells and metal-air batteries, where the oxygen reduction reaction (ORR) takes place. Among the approaches for improving ORR activity, nitrogen functionalities and well-developed textural properties have proved very effective. Nonetheless, the question of which between nitrogen active sites or textural properties are more crucial in N-doped carbon materials remains unanswered. This work proposes a comparative and critical approach through the selective functionalization of four commercial activated carbons with different textural properties. This study highlights the greater importance of N-doping in relation to the textural properties of carbon materials, and provides fundamental insights for conclusively addressing the ongoing debate within the carbon community about the significance of these two factors in the context of ORR.

Molecular catalysts with electronic axial stretching for high-performance lean-oxygen seawater batteries

A dissolved-oxygen seawater battery (SWB) can generate electricity by reducing dissolved oxygen and sacrificing the metal anode at different depths and temperatures in the ocean, acting as the basic unit of spatially underwater energy networks for future maritime exploration. However, most traditional oxygen reduction reaction (ORR) catalysts are out of work at such ultralow dissolved oxygen concentration. Here, we proposed that the electronic axial stretching of the catalyst is essentially responsible for enhancing the catalyst’s sensitivity to dissolved oxygen. By modulating the lattice of iron phthalocyanine (FePc) as a model catalyst, the unique electronic axial stretching in the z-direction of planar FePc molecules was realized to achieve a boosted adsorption and electron transfer and result in a much improved ORR activity in lean-oxygen seawater environment. The peak power density of a homemade SWB using a practical carbon brush electrode decorated by the FePc is estimated to be as high as 3 W L−1. These results provide inspiring insights into the interaction between the catalyst and complicated seawater environment, and propose the electronic axial stretching as an effective indicator for the rational design of catalysts to be used in extremely lean-oxygen environment.

Ta2O5 Catalyst Support for Polymer Electrolyte Fuel Cells

The platinum electrocatalysts widely used in polymer electrolyte fuel cells (PEFCs) cause oxidative degradation of the carbon support especially under start-stop cycling conditions at the cathode. In addition, the potential fluctuations caused by load cycling promote Pt particle size growth, thereby decreasing their catalytic activity. In this work we investigate the use of tantalum oxide (Ta2O5) as a thermochemically stable electrocatalyst support under strongly-acidic and high voltage conditions, as a means to suppress carbon corrosion. Pt-Co alloy nanoparticles decorated on Ta2O5 in turn supported on a mesoporous carbon (MC) scaffold were synthesized and used in the electrocatalyst layer. Microstructural observation confirmed that both Ta2O5 and Pt-Co alloy particles were loaded within the carbon scaffold mesopores. The resulting electrocatalysts displayed significantly improved oxygen reduction reaction activity in half-cell measurement, as well as improved start-stop and load cycle durability by the prevention of carbon corrosion and ripening.

Do Melamine and Melamine-Formaldehyde Surface Modifiers Improve Fuel Cell Activity and Durability?

Precious group metal-based catalysts based on Pt- and Pt-alloys are currently used as catalysts for the kinetically sluggish Oxygen Reduction Reaction (ORR) on the cathode of fuel cells. The activity of Pt or Pt-alloy catalysts towards ORR is severely compromised by the adsorption of spectator-species such as sulfonate anions from perfluorosulfonic acid (PFSA) ionomer or Pt-O(H)ad via water activation. Considering recent evidence pointing to the improvement in ORR activity via the use of melamine organic molecule or melamine-formaldehyde copolymeric additives as surface blocking agents for the prevention of sulfonate or Pt-OHad adsorption, we evaluated these additives in fuel cells. The catalysts were modified with either of these additives and characterized using ex situ and in situ methods to verify successful adsorption and eventual performance in fuel cells. These surface modifying agents were found to suppress Pt-OHad formation as well as suppress ORR activity. There was no evidence to point out that these additives improved ORR activity and H2/air polarization performance in a fuel cell MEA on supported, polycrystalline Pt catalyst.

Zn-Induced Synthesis of Porous Fe-N,S-C Electrocatalyst with Iron-Based Active Sites Containing Sulfides, Oxides and Nitrides for Efficient Oxygen Reduction and Zinc-Air Batteries.

There is an urgent need to design and synthesize non-noble metal electrocatalysts (NNMEs) for the replacement of platinum-based electrocatalysts to enhance the sluggish oxygen reduction reaction (ORR) for Zn-air batteries and fuel cells. Herein, Fe-N,S-C materials were fabricated through two steps: first, reprecipitating hemin by adjusting the pH and, then, decorating it with melamine and cysteine in the presence of Zn2+. The resulting Fe-N,S-C-950 (Zn) was prepared after pyrolysis at 950 °C. Using this method, abundant iron-based active species with good dispersion were obtained. The fabrication of more micropores in Fe-N,S-C-950 (Zn) plays a positive role in the improvement of ORR activity. On comparison, Fe-N,S-C-950 (Zn) outperforms Fe-N,S-C-950 and Fe-N-C-950 (Zn) with respect to the ORR due to its larger specific surface area, porous structure, multiple iron-based active sites and N- and S-doped C. Fe-N,S-C-950 (Zn) achieves outstanding ORR performances, including a half-wave potential (E1/2) of 0.844 V and 0.715 V versus a reversible hydrogen electrode (RHE) in 0.1 M KOH and 0.1 M HClO4 solution, respectively. In addition, Fe-N,S-C-950 (Zn) shows an outstanding Zn-air battery performance with an open-circuit voltage (OCV) of 1.450 V and a peak power density of 121.9 mW cm-2, which is higher than that of 20 wt% Pt/C. As a result, the as-prepared electrocatalyst in this work shows the development of the Zn-assisted strategy combined with the assembly of porphyrins as NNMEs for the enhancement of the ORR in both alkaline and acidic solutions.