Carbon-based Oxygen Reduction Reaction Catalysts Research Articles

Engineering rich defects in nitrogen-doped porous carbon to boost oxygen reduction reaction kinetics

Metal-free carbon-based materials offer a promising alternative to Pt-based catalysts for the oxygen reduction reaction (ORR). However, challenges persist due to its sluggish kinetics and poor acid ORR performance. Here, we introduce a novel nitrogen-doped porous carbon with rich defects sites (such as pentagons, edge and vacancy defects) (PV/HPC) via a simple etching strategy. The PV/HPC demonstrates long-term stability and exceptional catalytic activity with half-wave potential of 0.9 V and average electron transfer number of 3.98 in alkaline solution while 0.78 V and 3.78 in acidic solution, indicating its efficiency and robustness as an ORR catalyst. Additionally, it achieves a higher kinetic current density of 91.9 mA cm−2 at 0.8 V, which is 1.75 times that of Pt/C (52.5 mA cm−2). Furthemore, it enables Al-air battery to attain a maximum power density of 487 mW cm−2, compared to 477 mW cm−2 for the Pt/C catalyst. Density functional theory (DFT) calculations elucidate that the introduction of multifunctional defects in nitrogen-doped porous carbon collectively reduces the reaction energy barrier of the departure of OH* and boosts the oxygen reduction reaction kinetics. This work presents a simple method to design durable and effective carbon-based ORR catalysts.

Co-Adjusting d-Band Center of Fe to Accelerate Proton Coupling for Efficient Oxygen Electrocatalysis.

The problem in d-band center modulation of transition metal-based catalysts for the rate-determining steps of oxygen conversion is an obstacle to boost the electrocatalytic activity by accelerating proton coupling. Herein, the Co doping to FeP is adopted to modify the d-band center of Fe. Optimized Fe sites accelerate the proton coupling of oxygen reduction reaction (ORR) on N-doped wood-derived carbon through promoting water dissociation. In situ generated Fe sites optimize the adsorption of oxygen-related intermediates of oxygen evolution reaction (OER) on CoFeP NPs. Superior catalytic activity toward ORR (half-wave potential of 0.88V) and OER (overpotential of 300mV at 10mA cm-2) express an unprecedented level in carbon-based transition metal-phosphide catalysts. The liquid zinc-air battery presents an outstanding cycling stability of 800h (2400 cycles). This research offers a newfangled perception on designing highly efficient carbon-based bifunctional catalysts for ORR and OER.

Fe, N, S co-doped carbon network derived from acetate-modified Fe-ZIF-8 for oxygen reduction reaction

In this work, potassium acetate (KAc) was added during the synthesis of a Zn-Fe based metal-organic framework (Fe-ZIF-8) to increase the fixed amount of Fe while simultaneously enhancing the number of pores. Electrospinning was utilized to embed KAc-modified Fe-ZIF-8 (Fe-ZIF-8-Ac) into the polyacrylonitrile nanofiber mesh, to obtain a network composite (Fe@NC-Ac) with hierarchical porous structure. Fe@NC-Ac was co-pyrolyzed with thiourea, resulting in Fe, N, S co-doped carbon electrocatalyst. The electrochemical tests indicated that the prepared catalyst displayed relatively remarkable oxygen reduction reaction (ORR) catalytic activity, with an onset potential (Eonset) of 1.08 V (vs. reversible hydrogen electrode, RHE) and a half-wave potential (E1/2) of 0.94 V, both higher than those of the commercial Pt/C (Eonset = 0.95 V and E1/2 = 0.84 V), respectively. Assembled into Zn-air batteries, the optimized catalyst exhibited higher open circuit voltage (1.698 V) and peak power density (90 mW cm−2) than those of the commercial 20 wt% Pt/C (1.402 V and 80 mW cm−2), respectively. This work provided a straightforward manufacturing strategy for the design of hierarchical porous carbon-based ORR catalysts with desirable performance.

Boron-doped rGO electrocatalyst for high effective generation of hydrogen peroxide: Mechanism and effect of oxygen-enriched air

Different B-doped rGO catalysts were prepared and their 2e- oxygen reduction reaction (ORR) performance was investigated. It was found that the 2e- ORR selectivity of B-doped rGO was related to the B content and oxygen mass transfer conditions. The synthesized catalyst exhibited high 2e- ORR selectivity of 95–98.6%, and the H2O2 yield reached up to 95.63 mg cm−2 h−1 at a current density of 200 mA cm−2. Moreover, increasing the oxygen concentration in the gas supplied to the B-doped rGO modified gas diffusion electrode (GDE) only to 30–40% resulted in almost the same H2O2 yield as using pure oxygen. Experimental analysis and theoretical calculations indicated that the isolated B dopant acts as active site for the 2e- ORR. Furthermore, B-doped rGO modified GDE was applied to the electro-Fenton system to continuously degrade organic pollutants. This work will be beneficial for the study and application of carbon-based ORR catalysts.

Nitrogen-doped carbon/graphitic CQDs composites with 98.8% microporosity as a highly stable electrocatalyst for oxygen reduction

Designing micropore-rich carbon materials with large specific surface area (SSA) as a carbon-based oxygen reduction reaction (ORR) electrocatalyst is still frontier but remains challenging in catalysis of zinc-air batteries. Here we propose a new strategy for synthesis of nitrogen atoms co-doped carbon sheets and carbon quantum dots (N-C@CQDs) with an SSA of 1485.3 m2 g−1 and 98.8 % micro-porosity from α-cellulose via using a complex salt (ZnCl2-NH4Cl) with low eutectic point (179 °C) as a pore regulator and K2FeO4 as a graphitization catalyst, which can serve as an active and stable carbon-based ORR electrocatalyst. The role of K2FeO4 not only promotes graphitization but also oxidizes the large-sized graphitic carbon particles into a huge amount of uniformly distributed CQDs. This catalyst has exhibited a comparable ORR activity and superior stability to the Pt/C, but a Zn-air battery assembled with the former has delivered a higher peak power density (214 mW cm−2) and a larger gravimetric energy density (ED) of (959 Wh kgZn-1), especially in which it also displays an outstanding catalytic durability with 98.7 % ED retention during a ∼110 h continuous discharge. This work provides a new pathway for design of high-performance carbon-based ORR catalysts in various energy devices.

Metal-Free Electrocatalysts for the Selective 2 e- Oxygen Reduction Reaction: A Never-Ending Story?

Hydrogen peroxide (H2 O2 ) electrosynthesis via the 2e- Oxygen Reduction Reaction (ORR) represents a highly challenging, environmentally friendly and cost-effective alternative to the current anthraquinone-based technology. Various lightweight element hetero-doped carbon nanostructures are promising and cheap metal-free electrocatalysts for H2 O2 synthesis, particularly those containing O-functionalities. The exact role of O-containing functional groups as electroactive sites for the process remains debated if not highly controversial. Herein, we have reported on the covalent exohedral functionalization of the outer surface of extra-pure multi-walled carbon nanotubes (MWCNTs) with discrete O-functional groups as a unique approach to prepare selective electrocatalysts for the process. This kind of decoration has added fundamental tiles to the puzzling structure/reactivity relationship of O-containing carbon-based catalysts for ORR, clearing doubts on the controversial role of hydroxyl/phenol groups as key functionalities for the design of more performing 2e- ORR electrocatalysts.

Transforming bio-oil into nitrogen-doped hierarchical porous carbons: Excellent oxygen reduction electrocatalysts for Zn-air batteries

Nitrogen-doped hierarchical porous carbons are considered as important substitutes for noble metal electrocatalysts for the oxygen reduction reaction (ORR) in green-energy devices. Herein, bio-oil, the liquid product of biomass pyrolysis, and urea were used as the carbon and nitrogen source based on a simple MgO template approach. The obtained carbons exhibited a micro-/meso-/macroporous structure, considerable specific surface area and abundance of Graphitic and Pyridinic nitrogen species, leading to the excellent ORR catalytic performance with a half-wave potential of 0.84 V. The assembled primary Zn-air battery displayed a maximum power density of 239.36 mW cm−2 and consistent discharging stability. This work verified the great potential of bio-oil as a sustainable and low-cost precursor of advanced functional carbon materials and was conducive to the large-scale production of efficient carbon-based ORR catalysts.

Insights into Nitrogen-doped Carbon for Oxygen Reduction: The Role of Graphitic and Pyridinic Nitrogen Species.

Nitrogen-doped carbons (N/Cs) manifest good catalytic performance for oxygen reduction reaction (ORR) for fuel cell systems. However, to date, controversies remain on the role of active sites in N/Cs. In the present study, ORR test was conducted on three N/Cs in O2 -saturated 0.1 M KOH aqueous solution, where apparent linear correlation between graphitic N contents and ORR activity was observed. Theoretical calculations demonstrated that graphitic N doping is energetically more favorable than that of pyridinic N doping for ORR and the pyridinic N leads to more preferential with 2 e- ORR pathway. These results reveal that graphitic N plays a key role in N/Cs mediated ORR activity. This work lays a solid foundation on identifying the active sites in heteroatom-doped carbons and can be exploited for rational design and engineering of effective carbon-based ORR catalysts.

Water-regulated and bioinspired one-step pyrolysis of iron-cobalt nanoparticles-capped carbon nanotubes/porous honeycombed nitrogen-doped carbon composite for highly efficient oxygen reduction

To achieve commercial applications of green fuel cells and rechargeable metal-air batteries, rational design and synthesis of low-cost, high-efficiency and ultra-stable transition metal-based electrocatalysts are of significant importance for alkaline oxygen reduction reaction (ORR). In this work, iron-cobalt (FeCo) nanoparticles-capped carbon nano-tubes/-porous nitrogen-doped honeycombed carbon composite (FeCo-CNTs/NHC-800) is synthesized by a water-regulated and bioinspired one-step pyrolysis method at 800 °C, where l-histidine behaves as the C and N sources combined by working as a chelating agent of Fe/Co. The formation mechanism is discussed by adjusting the pyrolysis temperature and water amount. The resultant FeCo-CNTs/NHC-800 exhibits a positive onset potential (Eonset = 1.091 V) and half-wave potential (E1/2 = 0.88 V), showing promising ORR activity, outperforming home-made controls and many lately reported catalysts. The hierarchically porous honeycombed structures have fascinating open porous spaces for fast diffusion of active species, large specific surface area, high conductivity, and stable sites for anchoring FeCo nanoparticles (NPs). Moreover, the N-doped carbon nanotubes coupling with homogeneous FeCo NPs greatly improve the catalytic activity and stability of ORR. This work provides some valuable insights to prepare hierarchical, reliable, and high-efficiency carbon-based ORR catalysts for new energy-correlated devices.

Red Blood Cells-Derived Iron Self–Doped 3D Porous Carbon Networks for Efficient Oxygen Reduction

In addition to C, H and O, some biomass is also rich in mineral elements. The recovery and utilization of special mineral elements is of great significance to prepare functional materials and alleviate the current energy shortage. Herein, we describe a facile strategy for making full use of the chemical composition (C, Fe) and special structure of red blood cells (RBCs) from waste pig blood to fabricate a dual metal (Fe, Co)-nitrogen (N)-doped porous carbon catalyst by pyrolysis of a mixture of RBCs biomass, cobaltous acetate, and melamine. The porous catalyst displays a comparable activity for oxygen reduction reaction (ORR) to that of commercial Pt/C catalyst, with a half-wave potential of 0.821 VvsRHE in alkaline media and 0.672 VvsRHE in acid electrolyte. Especially, the as-prepared catalyst shows excellent methanol tolerance and stability in both acidic and alkaline electrolytes, which is superior to commercial Pt/C catalysts. The excellent ORR activity of FeCo-N/C(RBC) can be ascribed to the porous morphology and the cooperation between metal and nitrogen species. This work provides a novel idea of exploiting the composition of renewable biomass to modulate the activity and stability of carbon-based ORR catalysts.

CARBON-BASED CATHODE CATALYSTS USED IN MICROBIAL FUEL CELLS FOR WASTEWATER TREATMENT AND ENERGY RECOVERY

In the past 20 years Microbial fuel cells (MFCs) have been extensively studied regarding the possibility of transforming organic waste directly into electricity. There are significant differences between MFCs and conventional low temperature Fuel Cells (FCs), which make MFCs attractive: biotic catalyst at the anode; the anodic fuel is complex organic waste; MFCs operate under mild reaction conditions (neutral pH, temperature and pressure), close to ambient levels as optimum. Like chemical fuel cells, MFCs are composed of anode and cathode. Oxygen is an ideal electron acceptor for MFCs because of its high redox potential, availability, and sustainability. However, the Oxygen Reduction Reaction (ORR) is kinetically sluggish, resulting in a large proportion of potential loss. Also, working conditions are quite different because of the type of complex media in which MFCs operate. In order to overcome these limitations, catalysts are often used to lower the overpotentials and accelerate the kinetics of the oxygen reduction reaction. One of the main challenges is the development of efficient and stable cathode catalysts for MFCs. By far, Pt and Pt-based catalysts (PGMs) have been extensively used, due to their catalytic efficiency in gas-diffusion electrodes. But the high cost and low durability have significantly lowered their utilization in MFCs. A variety of non-precious metal catalysts have been developed for MFC applications including carbon-based catalysts, carbon supported composite catalysts, Me-based catalysts and biocatalysts. It is supposed that the ORR catalyst used for wastewater treatment in MFCs is simple to synthesize, cost-effective, durable after long-term operation in wastewater, tolerant to poisoning and able to restore catalytic activity after cleaning. In this regard carbon-based catalyst may be the most promising candidate for practical applications. This study reviews different carbon-based ORR catalysts for MFC applications for wastewater treatment and energy recovery.

CoFe alloy embedded in N-doped carbon nanotubes derived from triamterene as a highly efficient and durable electrocatalyst beyond commercial Pt/C for oxygen reduction

For development of green and sustainable energy, it is of importance to search highly efficient and low-cost electrocatalysts of oxygen reduction reaction (ORR) in energy conversion devices. Herein, CoFe alloyed nanocrystals embedded in N-doped bamboo-like carbon nanotubes (CoFe@NCNTs) were facilely synthetized by one-step co-pyrolysis with the mixture of triamterene, metal chlorides and graphitic carbon nitride (g-C3N4). The resultant CoFe@NCNTs exhibited excellent ORR activity with the positive shifts in the onset potential (Eonset = 0.97 V) and half-wave potential (E1/2 = 0.88 V), outperforming commercial Pt/C (Eonset = 0.96 V; E1/2 = 0.84 V). Compared to metal organic frameworks (MOFs)-based strategy for synthesis of low-cost carbon-based ORR catalysts, this method is simple and convenient, coupled by avoiding the complicated synthesis of MOFs and its ligands. This work provides a promising route to fabricate advanced transition-metal-based carbon catalysts in the researches correlated with energy conversion devices.

Tuning Coal into Graphene-Like Nanocarbon for Electrochemical H2O2 Production with Nearly 100% Faraday Efficiency

Electrochemical reduction of O2 to produce H2O2 provides the most promising alternative to the current anthraquinone process, whereas an electrocatalyst that is cost-effective and has rich resources, excellent oxygen reduction reaction (ORR) activity, and dominant two-electron (2e–) selectivity is highly required. Herein, by using inexpensive and earth-abundant anthracite coal as the precursor along with the KOH activation method, a defective graphene-like carbon (DGLC) nanomaterial has been successfully constructed. The as-prepared DGLC material features a graphene-like morphology, a hierarchical porous structure, a high surface area, abundant defects/edges, and a high content of ether functional groups, which endow it with excellent ORR activity, dominant 2e– selectivity, and high stability toward H2O2 synthesis in alkaline media. Remarkably, when employed as the electrocatalyst in H-cell, it can achieve a high H2O2 production rate of 355.0 mmol L–1 h–1 cm–2 gcat–1 with nearly 100% Faraday efficiency, which is superior to most carbon-based ORR catalysts. Experimental and theoretical studies describe that such high ORR activity and selectivity of DGLC are highly associated with its defect degree and ether groups (C–O–C) content, respectively, which contribute together to boost the superior 2e– ORR performance. This finding will be very helpful for designing a carbon-based 2e– ORR electrocatalyst toward H2O2 synthesis.

Inside-out dual-doping effects on tubular catalysts: Structural and chemical variation for advanced oxygen reduction performance

Dual-doping of carbon, especially the combination of nitrogen and a secondary heteroatom, has been demonstrated efficient to optimize the oxygen reduction reaction (ORR) performance. However, the optimum dual-doping is still not clear due to the lack of strong experimental proofs, which rely on a reliable method to prepare carbon materials that can rule out the interference factors and then emphasize only the doping effects. In this work, an inside-out doping method is reported to prepare carbon submicrotubes (CSTs) as a material to study the principles of designing dual-doping catalysts for ORR. The interference factors including the metal impurities and doping gradient in the bulk phase are excluded, and the doping effects including the structural and chemical variation of carbon are studied. P-doping exhibited a higher pore-forming ability to perforate carbon and a lower doping content, but a higher ORR catalytic activity as compared with S- and B-doped N-CSTs, demonstrating the N,P co-doping is more efficient in making carbon-based catalysts for ORR. First-principle calculations reveal that the edge C situated around the oxidized P site nearby a graphitic N atom is the active site that shows the lowest ORR overpotential comparable to Pt-based catalysts. This study suggests that the catalytic activity of dual-heteroatoms-doped carbons not only depends on the intrinsic chemical bonding between heteroatoms and carbon, but also is affected by the structural variation generated by introducing different atoms, which can be extended to the study of other kinds of functionalization of carbon and potential reactions besides ORR.

Etching engineering on controllable synthesis of etched N-doped hierarchical porous carbon toward efficient oxygen reduction reaction in zinc–air batteries

Low-cost, high-performance oxygen reduction reaction (ORR) catalysts greatly determine the practical application of advanced energy storage and conversion systems, including fuel cells and metal–air batteries. Precise design and controllable preparation of cutting-edge ORR catalysts demonstrate much meaningful to their electrochemical performance. Herein, etching engineering is applied on polypyrrole-derived carbon to controllably prepare etched N-doped hierarchical porous carbon (ENHPC–t, t means etching time) by using ammonia as an etching source. By systematical characterization and analysis, we find altering etching time exerts a profound effect on the morphology, structure, and composition of ENHPC–t. In spite of relatively lower defect density than the counterparts, the obtained ENHPC–5 with unique hierarchical porous structure, much larger specific surface area, and more optimized N configurations, display significantly improved ORR performance in both basic and acid media. When constructed as a cathode catalyst for zinc–air batteries, it also presents competitive performance to commercial Pt/C catalysts. Undoubtedly, our adopted etching strategy provides good guidance on a controllable synthesis of low-price but high-performance carbon-based ORR catalysts.

Fe7C3 nanoparticles with in situ grown CNT on nitrogen doped hollow carbon cube with greatly enhanced conductivity and ORR performance for alkaline fuel cell

Reasonable design of the porous metal-organic frameworks (MOFs) to convert a burgeoning carbon-based catalysts with high oxygen reduction reaction (ORR) activity are still challenging in energy conversion, storage and transport. Herein, Fe7C3-doped in-situ grown carbon nanotubes and N-doped hollow carbon (Fex-CNT@NHC) are prepared by using a simple and robust preparation method, which is used cubic ZIF-8-derived zinc oxide cubes as a template for secondary MOFs re-growth followed by the final carbonization. In the 0.1 M KOH, the as-pyrolyzed Fe0.1-CNT@NHC electrocatalyst displays the value of half-wave potential is 0.92 V and the value of diffusion-limited current density is 6.08 mA cm−2, respectively, which are close to the corresponding electrochemical values of the standard commercial Pt/C (0.89 V and 5.89 mA cm−2). Meanwhile, the material has passed relevant tests on its long-term stability and methanol tolerance in alkaline media, showing that it has excellent ORR activity and efficient stability under electrocatalysis. Furthermore, the Fe0.1-CNT@NHC materials catalyze a Zn-air battery that delivers a performed peak power density of 105.9 mW cm−2. The impressive catalytic activity of Fe0.1-CNT@NHC stems from the effective synergy between efficient Fe and N co-doping, large specific surface area, and high electrical conductivity. This preparation route for carbon nanomaterials will provide a new synthetic strategy to synthesize high-performance non-noble metal carbon-based ORR catalysts for practical energy-related applications.

ZIF67@MFC-Derived Co/N-C@CNFs Interconnected Frameworks with Graphitic Carbon-Encapsulated Co Nanoparticles as Highly Stable and Efficient Electrocatalysts for Oxygen Reduction Reactions.

Development of nonprecious metal catalysts for oxygen reduction reaction (ORR) to reduce or eliminate Pt-based electrocatalysts is of great importance for fuel cells. Herein, Co/N-codoped carbon with carbon nanofiber (CNF) interconnected three-dimensional (3D) frameworks and graphitic carbon-encapsulated Co nanoparticles were designed and successfully prepared via the in situ growth of zeolitic imidazolate framework-67 (ZIF67) with biomass nano-microfibrillar cellulose (MFC) and then pyrolysis. The catalyst (Co/N-C@CNFs) exhibited outstanding long-term catalytic durability with 92.7% current retention after 70 000 s, which was much higher than that of commercial Pt/C in alkaline media. The support and connection of CNFs to Co/N-C frameworks and the protection of Co nanoparticles by graphite layers contribute to their impressive long-term catalytic stability. Meanwhile, Co/C-N@CNFs displayed excellent ORR catalytic performance (E0 = 0.952 V vs RHE, E1/2 = 0.852 V vs RHE, and n: 4.2) in alkaline media. This strategy provides new insights into developing advanced nonprecious metal carbon-based catalysts for ORR.

Nitrogen and sulfur co-doped fibrous-like carbon electrocatalyst derived from conductive polymers for highly active oxygen reduction catalysis

Carbon-based electrocatalysts hold great promise towards the development of clean renewable energy conversion and storage technologies. Herein, we present the preparation of a nitrogen (N) and sulfur (S) co-doped fibrous-like carbon electrocatalyst through sequential polymerization of conjugated poly(3,4-ethylenedioxythiophene) and polyaniline polymers onto silica nanoparticles, followed by carbonization. The morphological characterization of the material reveals a highly entangled fibrous-like carbon structure after etching away of the silica nanoparticles. The as-obtained N and S co-doped entangled fibrous-like carbon electrocatalyst demonstrates excellent oxygen reduction reaction (ORR) activity with an onset potential of 0.94 V vs. RHE, comparable to the onset potential 1.0 V vs. RHE of benchmark Pt/C (20 wt%) and outperforming single heteroatom (N/S) doped carbon in alkaline medium. The catalyst also shows excellent stability and resistance towards methanol poisoning effects. This study demonstrates the facile synthesis of N and S co-doped fibrous-like carbon-based catalysts for ORR derived from conjugated polymers as a potential alternative to precious metal-based catalysts.

Recent advances in carbon-based electrocatalysts for oxygen reduction reaction

Fuel cells are one of the most promising clean energy devices to substitute for fossil fuel in the future to alleviate energy crisis and environmental pollution. As the key reaction on the cathode in the fuel cells, oxygen reduction reaction (ORR) still requires efficient noble metal catalysts such as the commercial Pt/C to boost the reaction for its sluggish kinetics. Therefore, it is critical to design earth-abundant carbon-based catalysts with high efficiency and long-term stability to replace the noble metal-based catalysts. This review focuses on the recent progress about carbon-based ORR catalysts including non-metal doped carbon materials, transition metal-nitrogen-carbon species, transition metal carbides/carbon, single atom catalysts, and other carbon hybrids. And we further infer that the excellent ORR performances can be achieved by the balance of geometric and electronic structures of catalysts such as conductivity, surface area, hierarchical porous structure, defect and doping effect. Additionally, the perspective development trend is also proposed to guide the rational designation of carbon-based catalysts for ORR and even extend to other energy storage and conversion fields in the future.

First-Principles Prediction of Activated Carbon Nanostructures for Catalyzing Oxygen Reduction

Fuel cells are important energy conversion devices that provide an alternative energy source for transport, stationary and portable applications. Electricity is generated by harnessing coupled oxidation-reduction reactions of various chemistries, in each case limited by the sluggish oxygen reduction reaction (ORR) performed at the fuel cell cathode. Currently, platinum on carbon (Pt/C) is the standard material applied as the catalyst for ORR. However, Pt is expensive and scarce, drawing much interest in developing non-Pt catalysts. Carbon nanomaterials, including fullerenes, carbon nanotubes (CNTs), graphene, and their composites, have been actively studied as a potential candidate to replace Pt/C. Carbon-based ORR catalysts have been demonstrated to be competitive with Pt/C in electrochemical efficiency and durability, particularly in alkaline fuel cells (AFC). These sp 2-bonded carbon nanostructures are inherently constituted by extended p-conjugation systems, making them essentially unreactive toward molecular oxygen (O2) in their pristine forms. However, the conjugated p-systems can be significantly disrupted with localized p electrons through dopant incorporation, defect creation, and/or local lattice distortions. The doped, defective and distorted carbon structures are currently thought to be responsible for O2 adsorption/activation and thus ORR, but the active sites and the exact mechanisms are still uncertain. Using density functional theory (DFT) calculations, we have identified a novel method for the activation of graphene-like structures. This modification creates quasi-localized electron states in the π-conjugated system which are vulnerable to oxidation via O2. The result is favorable O2 adsorption, which despite being necessary for ORR activity is not predicted for previously proposed active sites. We have identified the importance of using proper solvation models at the solid-liquid interface. While many previous DFT studies were modeled in the gas phase where O2 adsorption is consistently predicted to be endothermic on carbon, our study clearly demonstrates that a more accurate description of interactions at the carbon-solvent interface is necessary to properly describe O2 adsorption. In addition we have found that more detailed descriptions of charge injection are necessary at carbon-based catalysts, where polarization of the carbon electrode is significant. Ab-initio MD simulations were performed with an explicit solvent model to outline a full reaction mechanism identifying elementary reaction steps. The rate limiting step of the ORR in this system is predicted to be desorption of the final reduction products for which we predict a moderate but surmountable activation barrier. Excitingly, we predicted overpotentials for the elementary reaction step of the modified carbon structures within the range of 0.4-1.1 eV, indicating our model can be used to design materials to compete with Pt/C. Using our model of the carbon-solvent interface, we revisited the prevalent types of activated carbon, including doping and plane edge structures, providing an improved description of the ORR activity. Our study provides insight into molecular mechanisms underlying the superior ORR activity of nanostructured carbon materials and also guidelines for the rational design and development of high-efficiency, cost-effective carbon-based ORR catalysts for fuel cell applications.