FeCo alloys in-situ formed in Co/Co2P/N-doped carbon as a durable catalyst for boosting bio-electrons-driven oxygen reduction in microbial fuel cells

Non-noble metal catalyst with high catalytic activity and stability towards oxygen reduction reaction (ORR) is critical for durable bioelectricity generation in air-cathode microbial fuel cells (MFCs). Herein, nitrogen-doped (iron-cobalt alloy)/cobalt/cobalt phosphide/partly-graphitized carbon ((FeCo)/Co/Co₂P/NPGC) catalysts are prepared by using cornstalks via a facile method. Carbonization temperature exerts a great effect on catalyst structure and ORR activity. FeCo alloys are in-situ formed in the catalysts above 900 °C, which are considered as the highly-active component in catalyzing ORR. AC-MFC with FeCo/Co/Co₂P/NPGC (950 °C) cathode shows the highest power density of 997.74 ± 5 mW m^?2, which only declines 8.65% after 90 d operation. The highest Coulombic efficiency (23.3%) and the lowest charge transfer resistance (22.89 Ω) are obtained by FeCo/Co/Co₂P/NPGC (950 °C) cathode, indicating that it has a high bio-electrons recycling rate. Highly porous structure (539.50 m² g^?1) can provide the interconnected channels to facilitate the transport of O₂. FeCo alloys promote charge transfer and catalytic decomposition of H₂O₂ to ?OH and ?O₂^?, which inhibits cathodic biofilm growth to improve ORR durability. Synergies between metallic components (FeCo/Co/Co₂P) and N-doped carbon energetically improve the ORR catalytic activity of (FeCo)/Co/Co₂P/NPGC catalysts, which have the potential to be widely used as catalysts in MFCs.     

Co-Fe/MIL-101(Cr) hybrid catalysts: Preparation and their electrocatalysis in oxygen reduction reaction

The development of highly efficient electrocatalysts with low cost for oxygen reduction reaction (ORR) is urgently required for metal-air batteries and fuel cells. In this work, FeCo/MIL-101(Cr) with various molar ratios of Fe/Co as hybrid catalysts was prepared by a facile and mild impregnation method. MIL-101(Cr) increased the specific surface areas of the hybrid catalysts, thus improving the dispersion of Fe and Co species at their surfaces. The effects of Fe and Co species on ORR activity of the hybrid catalysts were investigated. It is found that the synergistic effects between the well-dispersed Fe and Co species contribute mainly to ORR activity. More specifically, Fe species exert a partial-charge-transfer-activation effect on Co ones, which reduces the charge transfer resistance and thus improves the catalytic activity. As a result, FeCo/MIL-101(Cr) showed the excellent ORR activity, in which Co₅₀Fe₅₀/MIL-101(Cr) exhibited the superior ORR activity to the other prepared hybrid catalysts.     

Synergistic effect of Co alloying and surface oxidation on oxygen reduction reaction performance for the Pd electrocatalysts

The synergistic effect of Co alloying and oxidation treatment induced progressive enhancement on oxygen reduction reaction (ORR) activities of Pd/C catalysts is studied. Based on the XPS characterization, a new term, degree of surface oxidation (DSO), is proposed to illustrate their relationship between ORR activity and surface oxidation extent. TPR characterization also provides the evolution of surface species within the topmost region. It can be obviously found the optimal temperature for the promotion of ORR activity on various oxidized samples is 520 K. On the other hand, various heat treatment atmospheres (H₂ and CO) are applied on Pd-Co system without changing their particle size. It is clearly evident that the oxidized catalysts can exhibit the superior performance relative to that of the non-oxidized ones, confirming the improved ORR activity is solely ascribed to the formation of surface PdO species with 100% DSO value rather than large particle size effect. Moreover, an explainable model is demonstrated to illustrate the promotional effect of ORR performance on the oxidized PdCo/C catalysts.     

Influence of doping level on the electrocatalytic properties for oxygen reduction reaction of N-doped reduced graphene oxide

Reduced Graphene Oxide (rGO) doped with different nitrogen (N) concentrations (5, 10, and 15 parts in weight) were successfully synthesized via hydrothermal conditions, from graphene oxide (GO) and 3-amino-1,2,4-triazole (amitrole) to obtain N₅-rGO, N₁₀-rGO, and N₁₅-rGO. These N-doped materials were characterized and evaluated for the first time as catalysts for the oxygen reduction reaction (ORR). The physicochemical characteristics confirmed the simultaneous N-doping and reduction processes with a turbostratic re-stacking of graphene layers. Nitrogen was successfully introduced as a mix of pyridine-N, amine like-N, pyrrolic-N, and quaternary bonding species into the carbon lattice. The N content were 8.1, 9.9, and 10.5 at.% for N₅-rGO, N₁₀-rGO, and N₁₅-rGO. High catalytic activity was demonstrated in alkaline media with an onset potential of ~0.88 V and high current density (3.9 mA cm^?2) for N₁₅-rGO, leading the ORR via the 4-electron transfer pathway. The results demonstrated that the amine like-N species enhance the ORR catalytic activity in addition to pyridinic and quaternary.     

One-step synthesis of carbon-encapsulated nickel phosphide nanoparticles with efficient bifunctional catalysis on oxygen evolution and reduction

As a promising and cost-efficient alternative to noble metal catalysts, transition metal phosphides (TMPs) show highly catalytic performance toward oxygen reduction and evolution reactions (ORR and OER). Mesoporous carbon-coated nickel phosphide (NiP) nanoparticles were successfully synthesized by thermal decomposition at 500 °C under N₂/H₂ (95:5) atmosphere. The NiP/C hybrid exhibits excellent OER/ORR activity. It can generate an OER current density of 10 mA cm^?2 at the overpotential of 0.26 V with a low Tafel slope of 43 mV dec^?1, and produce a limited ORR current density of 5.10 mA cm^?2 at 1600 rpm with a half-wave potential of 0.82 V via a 4-electron pathway. In addition, the OER/ORR catalytic currents remain considerable stable without significant loss for more than 25 h polarization. This work will open up a new avenue to design a bifunctional catalyst with a superior OER/ORR activity and stability, and this cost-efficient strategy will pave the way for the industrial application of the renewable energy technologies.     

Atomically dispersed Fe-Nx sites doped mesopore-dominated carbon nanodisks towards efficient oxygen reduction

Rational design and synthesis of carbon nanostructures doped with atomically dispersed metal sites is an effective method to improve electrocatalytic oxygen reduction reaction (ORR) performance. Introducing mesopores into substrate carbon materials would help expose more active sites and improve mass/charge transfer in the microenvironments near active sites, thus accelerating ORR. Nonetheless, it is still challenging to construct atomically dispersed metal-nitrogen-carbon with mesoporous structures. Herein, we propose a facile strategy to synthesize atomically dispersed Fe-N_x sites doped mesopore-dominated carbon nanodisks catalysts (Fe–N/CNDs) using functionalized zeolitic imidazole frameworks (ZIF-D). The Fe–N/CNDs-900 catalyst exhibits outstanding ORR activity (E_o = 1.03 V, E_1/2 = 850 mV), as well as excellent long-term durability and methanol-tolerance, ascribed to synergistic effect of the Fe-N_x active sites and the surrounding mesoporous structures. This work presents a promising method to develop highly efficient metal-nitrogen-carbon ORR catalysts using functionalized MOFs.     

Ag nanoparticle-loaded to MnO2 with rich oxygen vacancies and Mn3+ for the synergistically enhanced oxygen reduction reaction

MnO₂ is considered to be one of the most promising electrocatalysts for oxygen reduction reactions (ORR) in alkaline media and can be applied to various electrochemical energy conversion and storage devices. However, it is limited by the relatively slow kinetics of the cathodic electrochemical reactions. In addition, it is difficult to control the presence state of Ag during the modification of MnO₂. To this end, an efficient ORR electrocatalyst of Ag nanoparticles supported by MnO₂ nanorods was successfully synthesized by using NH₃·H₂O as a complexing agent to inhibit the Ag⁺ intercalating into the tunnels of MnO₂. The half-wave potential (E_1/2) and limiting current density (J_lim) of the obtained Ag/MnO₂ electrocatalysts are 0.81 V and −5.6 mA cm⁻², respectively, showing comparable ORR catalytic activity to commercial Pt/C catalysts. The excellent catalytic performances can be attributed to the presence of abundant oxygen vacancies and Mn³⁺ species on the MnO₂ surface, as well as the synergistic effect between MnO₂ substrates and Ag nanoparticles. Among them, oxygen vacancies enhances the adsorption of O₂, Mn³⁺ facilitates the displacement of O₂²⁻/OH⁻, MnO₂ inhibits the accumulation of peroxide species to improving the oxygen environment on the Ag surface and Ag accelerates the electron transfer in the whole process. This work provides a useful guide for the design of efficient Mn-based ORR electrocatalysts.     

Role of macrocyclic salen-type Schiff base ligands in one-dimensional Co(II) complexes for superior activities toward oxygen reduction/evolution reactions

Developing high activities, stable, non-precious metal based bi-functional electrocatalysts oxygen evolution/reduction reactions (OER/ORR) in rechargeable metal-air batteries and regenerative fuel cell technologies is essential for future energy conversion and storage. In this work, the potential of utilizing the synthesized one-dimensional transition metal salen-type complexes (TM-SCs) as bi-functional electrocatalysts of ORR and OER is systematically explored by computational screening approach. The results demonstrate that different types of macrocyclic ligands, including N₂O₂, N₃O and N₄ as donor groups around the active sites, govern the OER/ORR catalytic performances. Co–SCs with N₂O₂ ligands exhibit the highest bifunctional catalytic activities. In particular, low limiting overpotentials of 0.22 V for OER and 0.33 V for ORR can be observed on Co sites, which are even superior to those of noble metal catalysts. Analyzing the linear relationships between the adsorption strength of intermediates and the overpotentials shows that the origin of excellent electrocatalytic performance is the smaller slope (0.86) for OOH1 vs OH1 on TM-SCs compared to metal surfaces, resulting in strengthened binding of the OOH1 intermediate. Besides, the adsorption energies of the intermediates bound on Co–N₂O₂ are close to the ideal values, while too strong on the Co–N₃O and Co–N₄ catalysts. By applying external strains, the adsorption strengths of reaction intermediates can be further modulated due to the tunable d-band centers, and the resulting ORR/OER activities are further boosted. Considering that the Co salen-based chain has been synthesized experimentally, this work highlights the excellent electrocatalytic performances of this new material and devises novel strategy by straining for catalyst optimizations.     

ZrO2 anchored core-shell Pt–Co alloy particles through direct pyrolysis of mixed Pt–Co–Zr salts for improving activity and durability in proton exchange membrane fuel cells

Highly active and durable Pt-based catalysts for oxygen reduction reaction (ORR) are very important and necessary for the proton exchange membrane fuel cells (PEMFCs). In this paper, we report the preparation and performance study of ORR catalysts composed of core-shell Pt–Co alloy nanoparticles (NPs) on multi-walled carbon nanotubes (MWCNTs) anchored with ZrO₂ NPs (denoted as Pt–Co–ZrO₂/MWCNTs). Thanks to the unique three-phase structure, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR at 0.9 V versus reversible hydrogen electrode (RHE) is1577 mA mg_Pt^?1, which is ～6.6-fold higher than that of the commercial Pt/C (238 mA mg_Pt^?1). After 50,000 cycles for durability test, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR remained 88% of its initial value. In stark contrast, that of Pt/C kept only about 56.3% of its initial value. More importantly, its catalytic performance was fully observed/verified in a H₂-air PEMFC single cell test. When the Pt loading of Pt–Co–ZrO₂/MWCNTs loaded cathode was one fourth of that with commercial Pt/C as the cathode catalyst, comparable cell performance was achieved. More impressively, the MEA with Pt–Co–ZrO₂/MWCNTs underwent only 24.5% degradation in maximum power density after 30,000 accelerated durability tests (ADTs). However, the MEA with Pt/C after 30,000 ADTs exhibited 39.6% performance loss in maximum power density. The enhanced mass activity and catalytic durability of Pt–Co–ZrO₂/MWCNTs could be attributed to the core-shell Pt–Co alloy NPs with Pt-rich surface and the interface effect between Pt–Co alloy NPs and oxygen vacancy-rich ZrO₂ NPs. In addition, this research also provided a solution to the durability issue of cathodes without sacrificing ORR mass activity, which would promote practical application of PEMFCs.     

Highly active Ni/CeO2 for the steam reforming of acetic acid using CTAB as surfactant template

A series of CTAB-templated Ni/Ce catalysts were synthesized by adding CTAB during the hydrothermal synthesis of ceria to improve the pore structure of catalysts. Their catalytic performance was evaluated in the steam reforming of acetic acid and the effects of CTAB concentration on the porous structures, reducibilities, morphology, and activity of catalysts were studied. The catalysts were characterized by BET, XRD, H₂-TPR, XPS, HRTEM, in-situ DRIFTS, DTG, FTIR, and temperature-programmed reaction to elucidate the structure-activity relationship of the catalyst. The results showed that owing to the CTAB assistance, a high surface area of ceria could be achieved, which induced a better Ni dispersion with a smaller Ni size, strengthened the interaction between Ni and CeO₂, and promoted the reducibility of Ni, obtaining higher activity and lower methane yield than Ni/Ce. Among these prepared samples, Ni/Ce–C6 showed the highest surface area and the best catalytic performance with a hydrogen yield of up to 82.5% even at a low temperature (550 °C). Owing to the stronger Ni-ceria interaction of Ni/Ce–C6, the lattice oxygen in ceria migrates easily to the Ni surface, interacts with the reaction intermediates, and thus improves the CO₂/CO ratio in the products. Much more CO and CO₂ and less CH₄ were observed over Ni/Ce–C6 during the temperature-programmed reaction, indicating its high activity. In-situ DRFITS characterization demonstrated that the two types of catalysts had similar reaction intermediates but various adsorption and conversion abilities toward the acetic acid. More reaction intermediates were adsorbed at low temperatures and a higher conversion was obtained over Ni/Ce–C6 owing to its better Ni dispersion. The CTAB assistance inhibited the formation of amorphous carbon but facilitated the formation of graphitic carbon at ～637 °C which did not induce catalyst deactivation.     

Systematically theoretical investigation the effect of nitrogen and iron-doped graphdiyne on the oxygen reduction reaction mechanism in proton exchange membrane fuel cells

Developing economical electrocatalysts as alternatives to platinum for oxygen reduction reaction (ORR) to develop the applications of green energy devices like proton exchange membrane fuel cells (PEMFCs) is of paramount importance. In the current study, a different ratio of nitrogen-doped graphdiyne (GDY) with Fe single-site is reported to be more cost-effective and efficient for PEMFCs. The current study also demonstrates the design principle to improve the ORR activity associated with catalysts using Fe single-site with a greater Fe charge, which is controlled through the coordinated structure of the active center. Based on the simulation results, the formation of N₂-doped GDY and N₂-doepd Fe-GDY are more lucrative compared to the formation of Nx-doped GDY (x > 2) in terms of energy. O₂ molecules have a direct dissociation on the N₂-doepd Fe-GDY via Eley-Rideal (ER) mechanism, which involves the formation of H₂O by reacting with H+ from the electrolyte. Moreover, N₂-doepd Fe-GDY exhibits better performance as an ORR catalyst in an acidic medium because of its low overpotential of 0.488 V. However, N₂-doped GDY follows the OOH1 formation pathway, showing a higher overpotential for ORR. Furthermore, in the structure under study, the thermodynamic favorability of ORR is observed since the reaction energies calculated at each reaction step are exothermic and the energy profile of all reaction steps are downhill. The results of the current work provide new insights into the construction of extremely efficient heterogeneous catalysts in electrochemical energy technologies.     

Well-dispersed Co–Co3O4 hybrid nanoparticles on N-doped carbon nanosheets as a bifunctional electrocatalyst for oxygen evolution and reduction reactions

Bifunctional catalysts are vital for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in metal-air batteries. In this work, Co–Co₃O₄/N-doped carbon nanosheets (NCNs) were developed as highly efficient bifunctional oxygen catalysts via the pyrolysis of a hybrid ZIF-67/CNs precursor. It is found that the introduced CNs play important roles. On one hand, the introduced CNs can tune the surface contents of Co, N and/or O species that are closely correlated with OER and ORR activity. On the other hand, they also facilitate to achieve high specific surface areas for the catalysts. In addition, the introduced CNs helps the formed Co–Co₃O₄ hybrid nanoparticles with uniform and small sizes to be well-distributed on the NCNs substrates. Despite such important roles, it should be noted that a moderate content of the introduced CNs is required to achieve optimal oxygen catalytic activity. As a result, the optimized ZIF-67/CNs(1)-600 exhibits a low value of η₁₀ (~350 mV) for OER and a high value of E_1/2 (~0.85 V) for ORR. Its overall bifunctional activity (ΔE) is as low as ~0.73 V, which is comparable to the recent reported Co-based catalysts.     

Catalytic combustion of methane conducted on La–B–O–C (BCo,Mn, Fe) composites: The effects of B-sites cation properties

The novel La–B–O–C composites were fabricated as catalysts for methane catalytic combustion at low temperature, and considering the effect of newly C–O bond on B-site ions as active sites, three metal ions (Co, Mn, Fe) were selected for experiment. XRD, N₂-physisorption, XPS and H₂-TPR measurements were used to characterize the physicochemical properties of catalysts, which showed that the newly established C–O–B bond reduced the ionic valence of the B-site, and the redox capacities were increased or decreased to different degrees, respectively. Catalytic tests showed that T₅₀ of La–Co–C–O composites (LC-C) and La–Fe–C–O composites (LF-C) are 377 °C and 482 °C, much lower than that of unmodified catalyst, respectively. But T₅₀ of La–Mn–C–O composites (LM-C) increases to 507 °C from 493 °C. The superior performance of LC-C could be attributed to the high oxygen vacancies and enhanced redox property, and the better performance of LF-C was mainly benefited from the increase in lattice oxygen. For LM-C, the sacrifice of Mn⁴⁺ weakened the catalytic activity. There are more obvious mechanistic differences for different B-site elements in the La–B–O–C. The study will bring innovative insights into the design of excellent composites catalysts for methane oxidation.     

H2-induced thermal treatment significantly influences the development of a high performance low-platinum core-shell PtNi/C alloyed oxygen reduction catalyst

In the purpose of maximizing the utilization of noble metal Pt in oxygen reduction catalysts, we illustrate a synthesis method of preparing the low-platinum PtNi/C alloyed oxygen reduction reaction (ORR) catalyst, which is developed through the H₂-induced treatment to a glucose reduced PtNi/C alloy. After post-treatment with H₂/N₂ mixture gases, this catalyst displays excellent ORR catalytic activity and durability for the synergetic influences of electronic and geometry effects on catalysts during the alloying. Specifically, the as-prepared PtNi/C (350°C-6 h) sample delivers preponderant ORR activity with only 53.5% Pt usage than the commercial Pt/C. The specific activity and mass activity are corresponding 7.49 times and 3.5 times to the commercial Pt/C. This catalyst exhibits excellent ORR catalytic activity after 10 000 potential cycles in acid, which benefits from the well alloyed core-shell structure of PtNi/C. H₂-induced thermal treatment has significant effects on the development of high performance low-platinum PtNi/C alloy catalyst, and plays the significant role in the formation of well-alloyed core-shell structures. The lowered d-band center is believed to facilitate ORR catalysis through weakening the adsorption of intermediate oxygen species on the alloyed Pt surface. Therefore, PtNi/C(350°C-6 h) alloyed catalyst possesses outstanding ORR catalytic activity with much lower Pt loading.     

Comparative investigation on the properties of carbon-supported cobalt-polypyrrole pyrolyzed at various conditions as electrocatalyst towards oxygen reduction reaction

A series of non-precious metal catalysts named as Co-PPy-TsOH/C towards oxygen reduction reaction (ORR) were synthesized by pyrolyzing carbon supported cobalt-polypyrrole at various temperatures for diverse durations. The catalytic activity of these catalysts was evaluated with electrochemical techniques of cyclic voltammetry, rotating disk electrode and rotating ring-disk electrode. Physicochemical techniques, such as XRD, TEM and XPS, were employed to characterize the structure/morphology of the catalysts in order to understand the effects of pyrolysis conditions on the ORR activity. The results showed that both pyrolysis temperature and the duration have essential effects on the structure/morphology as well as ORR activity of the Co-PPy-TsOH/C catalysts, pyrolyzing the precursor at 800 °C for 2 h is the optimal condition to synthesize the catalyst with the best ORR performance.     

Understanding active sites and mechanism of oxygen reduction reaction on FeN4–doped graphene from DFT study

First-principle density functional theory (DFT) calculations are performed to study the active sites in FeN₄G electrocatalysts, as well as ORR activity and mechanism. The possible intermediates and transition states existing in the possible reaction paths from Langmuir-Hinschelwood (LH) mechanism are investigated. The results show that the associative pathways of OOH1 formation is prior to that of O₂1 dissociation. The condition of proton adsorbed on top N sites (T2) is more beneficial to the reduction of O-contained species adsorbed on top Fe site (T1) compared to the conditions of proton adsorbed on top C sites (T3). However, the dissociation of O₂1, OOH1 and H₂O₂1 is more likely to occur on the paired T1-T3 sites, since their lower energy barriers compared to other paired sites. The most favorable four-electron reduction pathway follows the mechanisms: O₂1→ OOH1→ O1+H₂O→ OH1+H₂O→ 2H₂O. The rate determining step for ORR on FeN₄G is the reduction of O1 into OH1 (barrier, 0.47 eV). The most feasible pathway for ORR is downhill at a high electrode potential (0.76 V vs. SHE at pH = 0) according to the free energy diagram. Compared to the ideal catalyst, the adsorption energy of OOH1 on FeN₄G is much lower in free energy, while those of OH1 and O1 are slightly higher. Additionally, the elementary reaction rate for OOH1→O1+H₂O is much larger than that of OOH1→H₂O₂ based on the parameter of activation barrier. Therefore, the formation of H₂O₂ (l) is unfavorable on FeN₄G catalysts.     

Hollow NH2-MIL-101@TA derived electrocatalyst for enhanced oxygen reduction reaction and oxygen evolution reaction

Non-precious metal-based electrocatalysts with excellent activity and stability are highly desired for the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, a tannic acid (TA) etching strategy is used to inhibit the metal aggregation and achieve muti-metal doping. The hollow NH₂-MIL-101@TA derived Fe–N–C catalyst exhibits superior ORR catalytic activity with an E_1/2 of 0.872 V and a maximum output power density of 123.4 mW cm⁻² in Zn-air battery. Since TA can easily chelate with metal ions, Fe/Co–N–C and Fe/Ni–N–C are also synthesized. Fe/Ni–N–C manifests exceptional bifunctional activity with an E_j = 10 of 1.67 V and a potential gap of 0.833 V between E_j = 10 and E_1/2 in alkaline electrolyte, which is 45 mV smaller than Pt/C–IrO₂. The improvement of ORR and OER performance of the catalysts via the simple TA etching and chelation method provides a novel strategy for the design and synthesis of efficient electrocatalysts.     

Crystal facet-dependent activity of α-Mn2O3 for oxygen reduction and oxygen evolution reactions

Electrocatalysts with different morphologies and specific exposed facets usually exhibit distinguished activities. In this work, two α-Mn₂O₃ with different morphologies and crystal facets were successfully prepared by solvothermal method and investigated as ORR/OER bifunctional catalysts for the first time. The results showed that the catalytic performance is affected by the crystal facet of α-Mn₂O₃, and the α-Mn₂O₃-cubic has better bifunctional activity than α-Mn₂O₃-octahedra. As revealed by catalyst characterization, the enhanced activity is originated with the nature of the exposed α-Mn₂O₃ (100) facet. The (100) facet with abundant low-coordinated surface oxygen sites makes the formation of more oxygen vacancies, which can improve the charge transfer and optimize the adsorption energies for intermediates, thereby enhancing the bifunctional activity for ORR/OER. This work highlights the correlation between OER/ORR activities and exposed crystal planes of α-Mn₂O₃ catalysts and it may deepen the understanding of facetdependent activity of α-Mn₂O₃ and points out a strategy to improve their catalytic activity by crystal facet engineering.     

Graphitic-N-rich N-doped graphene as a high performance catalyst for oxygen reduction reaction in alkaline solution

As a front runner to substitute for Pt as oxygen reduction reaction (ORR) catalysts, the N species in N-doped carbon materials have an important effect on their ORR activity. Herein, we report a nitrogen-doped graphene sheets (NrGO) rich in graphitic-N prepared through a thermal pyrolysis process of a mixture of polyaniline and graphene oxide. The electrochemical result of this novel graphitic N-rich NrGO exhibits excellent catalytic performance for oxygen reduction reaction with onset potential of 0.99 V and half-wave potential of 0.84 V. The transferred electron number of the oxygen reduction reaction process is 3.92, indicating a typical 4 electron path. This new NrGO sheet catalyst also exhibits outstanding durability and methanol resistance superior to Pt/C. This paper can provide a basis for the research of the effect of nitrogen species on their ORR catalytic activity in N-doped carbon materials.