Nitrogen-doped Carbon Materials Research Articles

Microfluidic chemistry assisted synthesis of cobalt quantum dot embedded nitrogen doped carbon with oxidase-like properties toward ascorbic acid detection

Ascorbic acid (AA) is a powerful antioxidant in food safety and disease treatment. It is of great significance to develop a low-cost, high-stability, and easy-to-operate colorimetric method for quantitative detection of AA in food or human body. Although various nanozymes have been developed for the colorimetric detection of AA, the size regulation of the catalytic center of nanozymes remains a challenge. In this work, we propose a combined strategy of flow chemistry synthesis and pyrolysis to realize the controllable adjustment of the catalytic center size of nanozymes. Zinc-cobalt zeolitic imidazole frameworks (ZnCo-ZIFs) with different sizes are synthesized by flow chemistry. Nitrogen-doped carbon materials with different Co catalytic centers (80 nm–10 nm) are then obtained by pyrolysis of ZnCo-ZIFs precursors. Among them, cobalt quantum dot embedded nitrogen-doped carbon (Co QDs/N-C) exhibits excellent oxidase activity, with Vmax and Km of 4.19 × 10−7 M s−1 and 0.12 mM. Therefore, a simple, low-cost, and stable colorimetric method for the detection of AA is established with a good linear relationship (3–500 μM) and low detection limit (0.40 μM). This work has certain guiding significance for the size regulation of catalytic center of nanozyme, and the detection method has broad application prospects in biochemical sensing field.

Boosting Electrochemical CO2 Reduction to CO by Regulating the Porous Structure of Carbon Membrane.

Ni single-atom-decorated nitrogen-doped carbon materials (Ni-Nx-C) have demonstrated high efficiency in the electrochemical reduction of CO2 (CO2RR) to CO. In this study, Ni-Nx-C active sites were embedded within a carbon membrane via an electrospinning and pyrolysis process. The resulting self-supported carbon membrane hosting Ni-Nx-C sites could be directly utilized as an electrode for the CO2RR. To enhance the CO2RR performance of the carbon membrane, the porous structure of the carbon membrane was fine-tuned by incorporating a pore-forming agent. The optimized porous carbon membrane electrode, K0.66-Ni-NC, achieved an impressive CO faradaic efficiency (FECO) of over 90% within a wide potential range from -0.8 to -1.6 V vs RHE for CO2RR. Additionally, it maintained an FECO of above 90% at -0.8 V vs RHE throughout a 30 h durability test in an H-cell. Further analysis has revealed that the porous structure of the carbon membrane not only facilitates the mass transport of CO2 but also increases the level of exposure of active sites during the CO2RR.

Enhanced electrocatalytic removal of bisphenol a by introducing Co/N into precursor formed from phenolic resin waste

Bisphenol A (BPA) is a typical endocrine disruptor, which can be used as an industrial raw material for the synthesis of polycarbonate and epoxy resins, etc. Recently, BPA has appeared on the list of priority new pollutants for control in various countries and regions. In this study, phenolic resin waste was utilized as a multi-carbon precursor for the electrocatalytic cathode and loaded with cobalt/nitrogen (Co/N) on its surface to form qualitative two-dimensional carbon nano-flakes (Co/NC). The onset potentials, half-wave potentials, and limiting current densities of the nitrogen-doped composite carbon material Co/NC in oxygen saturated 0.5 mol H2SO4 were −0.08 V, −0.61 V, and −0.41 mA cm−2; and those of alkaline conditions were −0.65 V, −2.51 V, and −0.38 mA cm−2, and the corresponding indexes were improved compared with those of blank titanium electrodes, which indicated that the constructed nitrogen-doped composite carbon material Co/NC was superior in oxygen reduction ability. The catalysis by metallic cobalt as well as the N-hybridized active sites significantly improved the efficiency of electrocatalytic degradation of BPA. In the electro-Fenton system, the yield of hydrogen peroxide generated by cathodic reduction of oxygen was 4.012 mg L−1, which effectively promoted the activation of hydroxyl radicals. The removal rate of BPA was above 95% within 180 min. This work provides a new insight for the design and development of novel catalyst to degrade organic pollutants.

Controllable introduction of edged nitrogen sites in CVD-derived carbon materials for enhanced fenton-like reactions

Nitrogen doped carbon materials have great potential in the peroxymonosulfate based advanced oxidation processes due to their high efficiency. However, because of the limitation of prepared method, the doped N species are usually uncontrollable. In this work, a series of metal-free N-doped carbon materials are synthesized by chemical vapor deposition (CVD) with a CaO template and through regulating the deposition temperature we achieve the gradient control of the edged-N species. Taken phenol as the pollutant probe, the catalytic performances of N-doped carbon material are investigated, and 700 °C is determined to be the optimal deposition temperature for carbon material with a reaction rate constant of 0.335 min−1. After the analysis of kinetics and the N species, we demonstrate that the content of pyrrolic N has an exponential relationship with the activity. Radicals quenching experiments, electron paramagnetic resonance and electrochemical test are also employed to verify that O2•–, 1O2, and direct electron transfer are the dominated reactive oxidation species rather than typic hydroxyl and sulfate radicals. Overall，this doped strategy through CVD give a new insight of controlling doped species in carbon materials preparation.

N-doped carbon interwoven with carbon nanotubes as an accelerating polysulfide conversion interlayer for High-Performance lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are considered ideal for large-scale energy storage because of their high energy density and low cost, but it is necessary to solve their serious shuttle effects. In this paper, the melamine-formed nitrogen-doped carbon (NC) material is blended with carbon nanotubes (CNTs) to eventually form the composite material NC/CNT, which is coated on the separator to inhibit shuttle effects. The intertwined structure of NC/CNT forms a continuous conductive network, providing a fast transmission channel for Li+/e-. Additionally, NC/CNT effectively enhances the redox reaction kinetics and inhibits the shuttle effect of lithium polysulfides. Consequently, the cells incorporating NC/CNT exhibit excellent electrochemical performance, boasting a high reversible capacity of 611.5 mAh/g at 2C after 400 cycles, with a capacity decay rate of only 0.07%. These results underscore the considerable potential of the modified material for practical applications.

Design and assembly of ZIF@PPy-derived hierarchical structure CeCo-NxCC electrocatalyst towards oxygen reduction reaction

The research of high-performance catalysts for ORR is always a great challenge in the field of zinc-air batteries (ZABs) applications. Herein, a near-regular dodecahedral ZIF-67-derived nitrogen-doped carbon material (CeCo-NxCC-700) with abundant hollow nanospheres on the surface is successfully constructed by introducing Ce ions to replace part of the Co ions and polymerizing pyrrole on the surface of the polyhedrons. PPy-coating is beneficial to improving the electrochemical stability and increasing the number of Co-Nx active sites, especially the pyrrole N and pyridine N sites. Ce-doping adjusts the charge density around the active sites. Meanwhile, the pyrolysis at 700 °C during the preparation process does not cause the structural collapse of CeCo-NxCC. Based on their decent ORR/OER performance, ZABs have been further assembled with CeCo-NxCC-700, which exhibit a high specific capacity of 815.4 mAh·g (Zn)−1 and cycling stability of more than 80 h, indicating a great application potentiality in ZABs manufacturing.

FeNi alloy embedded in three-dimensional nitrogen-doped porous carbon as bifunctional oxygen electrocatalysts for rechargeable Zn-air batteries

Iron‑nickel (FeNi) alloy is one of the efficient bifunctional oxygen electrocatalysts for zinc-air batteries (ZABs). However, FeNi alloy nanoparticles prepared by traditional synthesis strategies are easy to agglomerate and have non-uniform sizes, which is not conducive to the improvement of catalytic activity and stability. Here, we have successfully encapsulated two different kinds of nitrogen-rich metal phthalocyanines (MPcs) in situ doping in zeolitic imidazolate framework (ZIF-8) homogeneously by the “double solvents” method. The ligand nitrogen and macrocyclic structure of MPcs encapsulated in ZIF-8 not only helps metal dispersion and enhances the metal-ligand‑nitrogen (M-Nx) structure, but also enhances the graphitisation of three-dimensional (3D) porous carbon after pyrolysis. Thus, a FeNi alloy uniformly embedded in 3D nitrogen-doped porous carbon materials (FeNi@NC) was constructed in the subsequent pyrolysis process and used as an efficient bifunctional oxygen reduction/evolution (ORR/OER) electrocatalyst for rechargeable ZABs. Impressively, the FeNi@NC catalyst carries high half-wave potential (0.850 V) in ORR and the low overpotential (291 mV) in OER, significantly better than Pt/C (0.830 V) and RuO2 (307 mV), respectively. In addition, the rechargeable ZAB assembled with FeNi@NC air cathode has a specific capacity of 649 mW cm−2 and shows no significant degradation after 240 h of charging and discharging cycles. This study provides a new design idea for the manufacture of carbon-supported non-noble metal alloy catalysts with bifunctional oxygen catalytic activity, and verifies the feasibility of regulating the composition of non-noble metals to construct a rechargeable ZABs with excellent performance.

High content pyridine nitrogen-doped carbon nanosheets derived from ZIF-L as anode materials of lithium-ion batteries with excellent capacity and rate performance

The precise control of nitrogen doping types in carbon materials is crucial for optimizing energy storage devices. In this study, we synthesize nitrogen-doped carbon nanosheets (NCS) using ZIF-L as a precursor. Comparatively, the two-dimensional crystal structure of ZIF-L provides several advantages over ZIF-8 as a precursor in terms of nitrogen doping efficiency, achieving a higher doping level (14.56 %) and an increased ratio of pyridinic nitrogen (53.60 %). Consequently, NCS display a greater capacity for pseudocapacitive lithium storage. Furthermore, by adjusting the carbonization temperature, we precisely tailor the graphite-nitrogen doping level of NCS within the range of 16.80–31.22 %. Remarkably, when employed as an anode material in lithium-ion batteries, NCS-800 demonstrates exceptional cycling stability, with a capacity retention of 1078 mAh g−1 after 500 cycles at a current density of 0.5 A g−1, as well as excellent rate capability (735 mAh g−1 at 5 A g−1). This study not only compares the impact of precursor crystal structure modifications on nitrogen doping and lithium storage performance but also introduces a novel synthesis methodology for highly nitrogen-doped carbon materials, offering new avenues for future research in this field.

Co-N-C axially coordination regulated H2O2 selectivity via water medicated recombination of solute •OH: A new route

The cobalt, earth abundant transition metal, embedded in nitrogen doped carbon material as single atom site (Co-N-C) has been manifested as promising electrochemical oxygen reduction reaction (ORR) catalyst, however the unsatisfying production selectivity has hampered its widespread applications. Herein, the H2O2 selectivity of Co-N-C catalyst has been tailored with Co axial functional groups. Thermodynamically, the selectivity is regulated due to the fine-tuning of the adsorption of the key reaction intermediates (ΔG*OOH), and five functional groups, including −O, –OH, –CN, −CH3 and −SO3, endow the Co-N-C catalyst with superior H2O2 selectivity. Importantly, we unravel a new water medicated recombination of solute •OH reaction pathway for H2O2 production, which was the result of dissociation of *HOOH in explicit water environment. That is, two •OH species reaction in the liquid environment which originated from the creaking of *OOH intermediates due to the weakened O-O bond by the interaction with surrounding water. This study provides foundational understanding for the ORR catalytic mechanism at the electrochemical interface and opens up new avenues for rational design of targeted high efficiency electrocatalysts.

The electrocatalytic activity of pomelo peel-derived nitrogen-doped carbon material for oxygen reduction reaction

Exploring the non-precious metal catalysts of oxygen reduction reaction (ORR) becomes the key to promote the industrialization of new energy devices such as fuel cells and metal-air batteries because of the sluggish kinetics of ORR. Three-dimensional N-doped carbon (NC-900) material was obtained using the high-temperature pyrolysis of pomelo peel waste. The prepared NC-900 catalyst possesses an ultra-high specific surface area of 1631.3 m2·g−1, high content of 57.7 ± 0.9% pyrrolic-N, and three-dimensional porous structure. As the ORR catalyst, NC-900 has a onset potential of 0.992 V and half-wave potential of 0.859 V, comparable to 0.988 and 0.872 V of Pt/C. The typical 4-electron pathway of ORR process is occupied by the surface of NC-900. The ORR catalytic activity of NC-900 was almost unaffected by methanol. After 8 h of continuous operation, the reduction current on the surface of NC-900 was decreased only 2.7% of the initial current. Based on these outstanding ORR performances, the pomelo peel-derived NC-900 can serve as a strong competitor for the substitute of Pt/C to promote the potential industrialization of new energy devices.

Low-cost pyrolysis of biomass-derived nitrogen-doped porous carbon: Chlorella vulgaris replaces melamine as a nitrogen source.

Porous carbon generated from biomass has a rich pore structure, is inexpensive, and has a lot of promise for use as a carbon material for energy storage devices. In this work, nitrogen-doped porous carbon was prepared by co-pyrolysis using bagasse as the precursor and chlorella as the nitrogen source. ZnCl2 acts as both an activator and a nitrogen fixer during activation to generate pores and reduce nitrogen loss. The thermal weight loss experiments showed that the pyrolysis temperatures of bagasse and chlorella overlap, which created the possibility for the synthesis of nitrogen-rich biochar. The optimum sample (ZBC@C-5) possessed a surface area of 1508 m2g-1 with abundant nitrogen-containing functional groups. ZBC@C-5 in the three-electrode system exhibited 244.1F/g at 0.5A/g, which was extremely close to ZBC@M made with melamine as the nitrogen source. This provides new opportunities for the use of low-cost nitrogen sources. Furthermore, the devices exhibit better voltage retention (39%) and capacitance retention (96.3%). The goal of this research is to find a low cost, and effective method for creating nitrogen-doped porous carbon materials with better electrochemical performance for highly valuable applications using bagasse and chlorella.

Mn-modulated Co–N–C oxygen electrocatalysts for robust and temperature-adaptative zinc-air batteries

Flexible zinc-air batteries (FZABs) are featured with safety and high theoretical capacity and become one of the ideal energy supply devices for flexible electronics. However, the lack of cost-effective electrocatalysts remains a major obstacle to their commercialization. Herein, we synthesized a porous dodecahedral nitrogen-doped carbon (NC) material with Co and Mn bimetallic co-embedding (CoxMn1−x@NC) as a highly efficient oxygen reduction reaction (ORR) catalyst for ZABs. The incorporation of Mn effectively modulates the electronic structure of Co sites, which may lead to optimized energetics with oxygen-containing intermediates thereby significantly enhancing catalytic performance. Notably, the optimized Co4Mn1@NC catalyst exhibits superior E1/2 (0.86 V) and jL (limiting current density, 5.96 mA cm−2) compared to Pt/C and other recent reports. Moreover, aqueous ZAB using Co4Mn1@NC as a cathodic catalyst demonstrates a high peak power density of 163.9 mW cm−2 and maintains stable charging and discharging for over 650 h. Furthermore, FZAB based on Co4Mn1@NC can steadily operate within the temperature range of −10 to 40 °C, demonstrating the potential for practical applications in complex climatic conditions.

Ligin-derived graphene-like ultrathin carbon materials for ORR catalysis

Low-cost nitrogen-doped carbon materials with graphene-like structures were designed and prepared from extensive renewable biomass waste lignin. The obtained carbon materials exhibited well-designed ultrathin two-dimensional structures with high specific area and mesoporous characteristics. Benefiting from the well-designed structures with extensive catalytic active sites and efficient mass transfer and diffusion, as well as the modified electronic characteristics from nitrogen doping, the lignin-derived carbon materials exhibited pronounced ORR catalytic activity and methanol tolerance. Considering these, the lignin-derived carbon materials hold great application potentials as ORR catalysts and catalyst supports.

Toward boosted alkaline hydrogen evolution reaction: Covalent organic framework-derived N-doped carbon for highly dispersed cobalt nanoparticles

The preparation of renewable hydrogen via electrocatalytic water splitting is a burgeoning strategy in developing sustainable energy. However, it is still a great challenge to prepare an efficient non-precious metal based electrocatalyst for hydrogen evolution in alkaline electrolysis. Herein, we describe a functional hydrogen evolution reaction (HER) electrocatalyst by the combination of soaking metal ions in covalent organic framework (COF) and high temperature calcination. Especially, the 2Co-NC-700 catalyst possesses large specific surface area, appropriate defective nature and structural distortion, thus it embodies outstanding HER catalytic activity with only an overpotential of 303 mV at the current density of 10 mA cm−2 in the solution of 1.0 M KOH. Moreover, the kinetics and durability are also confirmed. Theoretical calculations not only indicates that the stable configuration combined small-sized cobalt nanoparticles and nitrogen-doped carbon but also reveals the synergistic effect of multiple active sites, while the optimal active location that shows the lowest hydrogen adsorption free energy is a major contributor for excellent HER. This work not only offers a highly efficient HER catalyst in alkaline environment but also provides a novel approach to develop non-precious metal nitrogen-doped carbon materials derived from COF as HER electrocatalysts in alkaline media.

Preparation of nitrogen-doped carbon pyrolyzed from ZIF-8 and its performance in electrocatalytic oxygen reduction to hydrogen peroxide

As an environment-friendly strategy, electrocatalytic hydrogen peroxide (H2O2) generation via two-electron oxygen reduction reaction (2e– ORR) has attracted significant scientific and technological attention. Nevertheless, limited to the low catalytic activity and high cost of noble metal-containing catalysts, forging desired electrocatalysts with high catalytic activity, low cost, and sustainability is still challenging. In this work, nitrogen doped porous carbon materials named p-ZIF-800 and p-ZIF-950 were obtained by pyrolysis of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals at 800 °C and 950 °C, respectively. Then, they were employed as a catalytic layer in the gas diffusion electrodes p-ZIF-n/Ni/CB (n = 800 °C or 950 °C, CB = acetylene black). The production rates of H2O2 are up to 1.18 mg h−1 cm−2 and 1.25 mg h−1 cm−2 for p-ZIF-800/Ni/CB and p-ZIF-950/Ni/CB, respectively. Noticeably, although p-ZIF-800 had a lower degree of graphitization the difference in catalytic activity between p-ZIF-800 and p-ZIF-950 is negligible. This can be construed as a higher total nitrogen and richer mesoporous structure in p-ZIF-800 than in p-ZIF-950. Under optimized conditions of an electrode spacing of 3 cm, a pH value of 6.5, and a current density of 7.5 mA cm−2, the H2O2 production rate of p-ZIF-800/Ni/CB in the “floating-cathode” cell is up to as high as 2.09 mg h−1 cm−2, which is about 3.3 times higher than that of the cell with the “submerged-cathode” under aeration and stirring. Also, the p-ZIF-800/Ni/CB cathode demonstrates remarkable stability, it maintains its structure without losing catalytic activity after 5 catalytic cycle experiments. These results indicate that the state-of-the-art pyrolysis-based nitrogen-doped porous carbon materials exhibit a high potential for the advanced electrocatalyst of H2O2 electrogeneration.

Catalytic Hydrogenolysis by Atomically Dispersed Iron Sites Embedded in Chemically and Redox Non-innocent N-Doped Carbon.

Atomically dispersed first-row transition metals embedded in nitrogen-doped carbon materials (M-N-C) show promising performance in catalytic hydrogenation but are less well-studied for reactions with more complex mechanisms, such as hydrogenolysis. Their ability to catalyze selective C-O bond cleavage of oxygenated hydrocarbons such as aryl alcohols and ethers is enhanced with the participation of ligands directly bound to the metal ion as well as longer-range contributions from the support. In this article, we describe how Fe-N-C catalysts with well-defined local structures for the Fe sites catalyze C-O bond hydrogenolysis. The reaction is facilitated by the N-C support. According to spectroscopic analyses, the as-synthesized catalysts contain mostly pentacoordinated FeIII sites, with four in-plane nitrogen donor ligands and one axial hydroxyl ligand. In the presence of 20 bar of H2 at 170-230 °C, the hydroxyl ligand is lost when N4FeIIIOH is reduced to N4FeII, assisted by the H2 chemisorbed on the support. When an alcohol binds to the tetracoordinated FeII sites, homolytic cleavage of the O-H bond is accompanied by reoxidation to FeIII and H atom transfer to the support. The role of the N-C support in catalytic hydrogenolysis is analogous to the behavior of chemically and redox-non-innocent ligands in molecular catalysts based on first-row transition metal ions and enhances the ability of M-N-Cs to achieve the types of multistep activations of strong bonds needed to upgrade renewable and recycled feedstocks.

Defective nitrogen doped carbon material derived from nano-ZIF-8 for enhanced in-situ H2O2 generation and tetracycline hydrochloride degradation in electro-Fenton system

Tetracycline hydrochloride (TC) accumulates in large quantities in the water environment, causing a serious threat to human health and ecological environment safety. This research focused on developing cost-effective catalysts with high 2e- selectivity for electro-Fenton (EF) technology, a green pollution treatment method. Defective nitrogen-doped porous carbon (d-NPC) was prepared using the metal-organic framework as the precursor to achieve in-situ H2O2 production and self-decomposition into high activity ·OH for degradation of TC combined with Co2+/Co3+. The d-NPC produced 172.1 mg L−1 H2O2 within 120 min, and could degrade 96.4% of TC in EF system. The self-doped defects and graphite-nitrogen in d-NPC improved the oxygen reduction performance and increased the H2O2 yield, while pyridine nitrogen could catalyze H2O2 to generate ·OH. The possible pathway of TC degradation was also proposed. In this study, defective carbon materials were prepared by ball milling, which provided a new strategy for efficient in-situ H2O2 production and the degradation of pollutants.

Mechanochemical regulation of microcrystalline in coal-derived disordered carbon for improved sodium storage: Metamorphic grade

Coals are common precursors of the disordered carbon anodes for sodium ion batteries. In order to hinder the long-range ordered development of coal precursors during thermal conversion, the acid reagents and calcination under air atmosphere have been adopted in the pre-oxidation procedure, not in accordance with the demand of green energy storage. Herein, the mechanochemical pretreatment was employed to break the aromatic structures and generate the edge defects and oxygen functional groups on the coal surface, which would suppress the long-range ordered tendency and promote the introduction of nitrogen heteroatoms during following calcination. With the increasing metamorphic grades, the molecular rigidity of coal precursors increases owing to more highly polycondensed aromatic structures and less interior buffer space. The aromatic structures in the highest-ranked anthracite are broken most heavily during the mechanochemical process. Thus the nitrogen-doped anthracite-based carbon materials have the most disordered carbon structures and deliver a high reversible capacity of 323 mA h g−1 under 0.03 A/g after 90 cycles. This work provides a facile and green solution to fabricate the highly disordered carbon anodes with low cost and high performance from the industrial raw materials.

The in-situ generation of ClO• by single- and dual-atom catalysis of chloride ions to degrade sulfonamide antibiotics: A DFT study

Single- (SACs) and dual-atom catalysts (DACs) are recognized as promising electrochemical materials. However, their application potential in the water treatment with the presence of chloride ions (the most common water matrice) still needs to be investigated. Thus, the first-principles calculation was used to investigate the electrocatalytic activation of Cl− and micropollutant degradation mechanisms by four kinds of metal-embedded nitrogen-doped carbon materials (M-N-C). The results show that the average Cl− adsorption energies (Eads) in different configurations follow the order of M2N6-a < M2N8 < MN4 < M2N6-b. The average Eads of SACs and DACs doped with different metal atoms follow the order of Fe < Co < Ni and Fe2 < FeNi < FeCo < CoNi ≈ Co2 < Ni2, respectively. The chlorine evolution reactions (CER) on the FeN4 and Fe2N6-a in neutral water were revealed as Cl− → *Cl → HClO* → free HClO, and HClO will rapidly generate ClO• to degrade target pollutants. The generated ClO• exhibits high reactivity towards sulfanilamide antibiotics (SAs) with the reaction rate constants of 1.78 × 108–6.86 × 109 M−1 s−1, indicating the high feasibility of ClO• in SAs purification from wastewater. This study provides mechanistic insights into the electrocatalytic generation of ClO• and its application in removing contaminants of emerging concern in M-N-C-supported electrochemical advanced oxidation processes.

Porphyrin-based frameworks and derivatives for the oxygen reduction reaction

The global energy crisis and environmental pollution issues caused by the continuous consumption of fossil fuels are increasingly becoming severe. Developing clean and sustainable hydrogen (H2) energy and corresponding storage and conversion devices have attracted increasing attention. The utilization of H2 energy highly depends on the fuel cell (FC). However, the slow kinetics of oxygen reduction reaction (ORR) on the cathode of FC cannot be improved without efficient catalysts. Currently, precious metal platinum (Pt) and its alloys are commonly used catalysts for ORR process. However, the scarcity and high cost of Pt hinder their large-scale practical application. To replace typical Pt-based catalysts, non-precious metal electrocatalysts have been investigated for ORR. Inspired by the catalytic ORR active center Fe porphyrin of cytochrome c oxidase in nature, metalloporphyrin-based frameworks and their derivatives have become promising electrocatalysts due to their abundant conjugated electronic structure, tunable functional groups, and large specific surface area. First, this review briefly introduces porphyrins and catalytic ORR mechanisms. Second, recent progress on porphyrin-based ORR catalysts including porphyrin-based frameworks, framework@substrate composites, and framework-based derivatives was summarized. Porphyrin-based frameworks mainly include metal-organic frameworks (MOFs), covalent organic frameworks (COFs), hydrogen-bonded organic frameworks (HOFs), and polymers constructed with porphyrin building blocks. Porphyrin-based framework@substrate composites were usually assembled and constructed to improve the electron transfer rate of frameworks. To further improve the conductivity, framework-based derivatives, usually named metal, nitrogen-doped carbon (M-N-C) materials, were synthesized through pyrolyzing frameworks at high temperatures. Finally, research challenges and directions of porphyrin-based electrocatalysts for ORR were discussed. This review is meaningful and enlightening for designing and developing other porphyrin-based electrocatalysts for ORR.