Kinds Of Carbon Materials Research Articles

Fabrication of Zwitterionic Polymer-Functionalized Onion-like Carbon Nanoparticles as Aqueous Lubricant Additives.

Onion-like carbon (OLC) is a kind of carbon material with a graphene-like structure and large interlayer spacing, favorable to a good lubricating performance. Herein, a facile method is presented for the preparation of functionalized OLC nanoparticles from candle soot with surface modification. The OLC nanoparticles are collected from combustion soot with candle burning via a simple heat treatment, and then the zwitterionic polymer (polyethylenimine-quaternized derivative, PEIS) can self-assemble onto the OLC surface with epigallocatechin gallate via Michael addition and Schiff-base reaction, thus obtaining PEIS-functionalized OLC nanoparticles (PEIS@OLC). The grafting zwitterionic polymer PEIS endows the OLC nanoparticles with good hydrophilic performance, so the as-obtained PEIS@OLC exhibits outstanding dispersion and lubricating property as a water-based lubricant additive. Compared to pure water, the average coefficient of friction decreases to 0.110 from 0.512, and the corresponding wear volume is reduced by 61.02% with 1.5 wt % addition. The improved lubricating property is mainly due to the synergetic effect of the protective film induced by the tribochemical reaction and the hydration film of zwitterionic polymer PEIS. Besides, the OLC nanoparticles could also display the nanoscale rolling and repairing effects at the friction contact interface, resulting in reduction of friction and wear.

Li-decorated B-doped biphenylene network for reversible hydrogen storage

Hydrogen energy is the mainstream alternative to fossil fuels in the future. However, finding safe and efficient hydrogen storage materials has become a key obstacle to achieving a sustainable hydrogen economy. This paper proposes that exploring hydrogen storage property of synthesized biphenylene network (Fan et al., Science, 372:852-6 (2021)) is an effective way to overcome the obstacle. In this work, Li-decorated biphenylene networks with different proportions of B were systematically constructed. The structures, thermal stability, diffusion barriers, and hydrogen storage characteristics were explored. The electron-deficient B can significantly enhance the Li binding energy, and increase the diffusion energy barrier to prevent metal aggregation, which is better than N doping. The hydrogen adsorption energies are just within the ideal range to facilitate hydrogen desorption. When the pressure is 0.1 MPa, the critical temperature is 230–310 K. The hydrogen storage capacities of Li-decorated B-doped biphenylene network change from 6.30 wt% to 19.22 wt% with the increase of Li atomic concentration from 7.69 % to 25.00 %, exceeding the ultimate onboard hydrogen storage goal set by DOE. Considering the hydrogen storage density and metal polymerization, Li-decorated B-doped BPNs have excellent hydrogen storage properties compared with transition metal-decorated carbon material systems and alkali metal-decorated N-doped BPN systems. Therefore, Li-decorated B-doped BPNs are a kind of carbon material with great potential for hydrogen storage.

The effect of different carbon reductants on the production of ferrosilicon 75% on an industrial scale in an electric arc furnace

Ferrosilicon production is based on the carbothermal reduction of silica and iron oxide in submerged electric arc furnaces. The reducing process of iron oxide and silicon oxide is carried out by the carbon contained in carbon materials such as coal, charcoal, semi-coke, and all types of coke. Based on its inherent and functional characteristics, the kind of carbon material can be effective in the ferrosilicon production process and furnace energy consumption. Therefore, in this work, which was performed by Iran Ferrosilice company, in a long period of 5 years, the effects of seven combinations of different carbon materials on the electrical and metallurgical performance of the process were investigated. The results showed that the minimum value of energy coefficient per ton (8.46 MWh/ton) was obtained using combination 5 (consisting of 55% coal, 30% semi-coke, 5% charcoal, and wood chips). The use of wood chips reduced the energy consumption by 3.03 MWh/ton. The composition consisting of 50% coal, 35% semi-coke, 15% charcoal, and wood chips had the highest Si% of 73.64% and the lowest Al% of 1.54%. Finally, by evaluating all the results, especially the reduction of energy consumption and recovery of Si, compound 5 was introduced as the optimal compound in the ferrosilicon production process.

Recent advances of bifunctional catalysts for zinc air batteries with stability considerations: from selecting materials to reconstruction.

With the growing depletion of traditional fossil energy resources and ongoing enhanced awareness of environmental protection, research on electrochemical energy storage techniques like zinc-air batteries is receiving close attention. A significant amount of work on bifunctional catalysts is devoted to improving OER and ORR reaction performance to pave the way for the commercialization of new batteries. Although most traditional energy storage systems perform very well, their durability in practical applications is receiving less attention, with issues such as carbon corrosion, reconstruction during the OER process, and degradation, which can seriously impact long-term use. To be able to design bifunctional materials in a bottom-up approach, a summary of different kinds of carbon materials and transition metal-based materials will be of assistance in selecting a suitable and highly active catalyst from the extensive existing non-precious materials database. Also, the modulation of current carbon materials, aimed at increasing defects and vacancies in carbon and electron distribution in metal-N-C is introduced to attain improved ORR performance of porous materials with fast mass and air transfer. Finally, the reconstruction of catalysts is introduced. The review concludes with comprehensive recommendations for obtaining high-performance and highly-durable catalysts.

Effect of Single-Walled Carbon Nanotube Sub-carbon Additives and Graphene Oxide Coating for Enhancing the 5 V LiNi0.5Mn1.5O4 Cathode Material Performance in Lithium-Ion Batteries

High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cathode material for next-generation lithium-ion batteries (LIBs), but its poor cycle performance has impeded its commercialization. In this study, we developed highly stable LNMO cathode materials having an octahedral morphology through a solid-state high-energy ball-mill–cum–spray-drying method. We also developed a novel strategy for modifying this cathode material with two kinds of carbon materials, thereby improving the electrochemical cycling performance. Introducing single-walled carbon nanotubes (SWCNTs) as a sub-carbon conductive additive during the slurry preparation process improved the conductivity of electrons between the particles of the cathode material. The LNMO electrode modified with the SWCNT sub-carbon additives exhibited an average Coulombic efficiency of 99.4% after 500 cycles at 1C, compared with 98.9% for the pristine LNMO-based electrode. Furthermore, we used a wet-chemical method to coat graphene oxide (GO) onto the post-sintered LNMO cathode material to act as a protective layer, preventing corrosion induced by HF in the electrolyte. The capacity retention of the GO-coated LNMO electrode after 500 cycles at 1C (91.8%) was higher than that of the pristine LNMO (52.5%). The corresponding dual-modification strategy, combining the SWCNTs and GO, provided LNMO cathode materials exhibiting superior rate performance and cyclability, with an average Coulombic efficiency of 99.3% and capacity retention of 92.9% after 500 cycles at 1C. Thus, the LNMO cathode materials prepared in this study possessed excellent electrochemical properties favoring their marketability, applicability, and competitiveness for application in high-voltage LIBs.

A novel and durable oxygen reduction reaction catalyst with enhanced bio-energy generation in microbial fuel cells based on Ag/Ag2WO4@f-MWCNTs

• Ag/Ag 2 WO 4 @f-MWCNTs was fabricated with a scalable, high efficiency, energy-saving, and time-saving strategy. • Ag/Ag 2 WO 4 @f-MWCNTs catalyst enriches oxygen diffusion and facilitates oxygen reduction reaction in MFCs. • The Ag/Ag 2 WO 4 @f-MWCNTs catalyst indicates high cathodic oxygen reduction reaction rate with 4e – pathway. • The Ag/Ag 2 WO 4 @f-MWCNTs has the potential to be an alternative to Pt/C-based oxygen reduction reaction catalysts. • The usage of this catalyst can substantially improves power production and enables broader applications of MFCs. Microbial fuel cell, as a promising technology, utilizes microorganisms to break down and oxidize the organic matter for harvesting energy. Progress in creating specific compositional functionalities of electrodes that are catalytically active, durable, cost-effective, and energy-recovery efficient is exclusively challenging for microbial fuel cell operation because of its bio-compatibility requirement. The electrodes composition impresses the oxidation-reduction reaction and electron charge-discharge rates. This study explores the use of silver/silver tungstate supported on different kinds of carbon materials, as cathode material for microbial fuel cells. The as-prepared catalysts were synthesized by a simple, environment-friendly, and self-developed surfactant-less method. Among proposed catalysts, the Ag/Ag 2 WO 4 @f-MWCNTs upgraded the oxygen reduction reaction to a four-electron pathway. As well, the optimal catalyst Ag/Ag 2 WO 4 @f-MWCNTs, exhibited excellent oxygen reduction reaction performance activity and stability with onset potential of -0.037 V and kinetic current density of 17.66 mA cm −2 compared with other synthesized catalysts and even the standard Pt/C catalyst. Owing to the more active sites, larger surface, and faster charge transfer, the microbial fuel cell equipped Ag/Ag 2 WO 4 @f-MWCNTs device delivered a high power density and current density of 0.965 W m –2 and 6.43 A m –2 , respectively. Consequently, Ag/Ag 2 WO 4 @f-MWCNTs is an effective catalyst that has the potential to be an alternative to Pt/C-based oxygen reduction reaction catalysts. The usage of this Ag/Ag 2 WO 4 @f-MWCNTs catalyst can therefore substantially improves power production and enable broader applications of microbial fuel cells for renewable electricity generation using waste materials.

Low-temperature plasma modified Vulcan XC72R as a support to enhance the methanol oxidation performance of Pt nanoparticles

Vulcan XC72R as a kind of carbon material is widely used as a support to deposit metal catalysts. However, its low pore size, the difficulty of dispersion, and the rare sites have limited its application. In this work, we modified the surface of Vulcan XC72R by low-temperature plasma. It is detected that its original morphology and structure have been greatly changed by longtime plasma irradiation. The pore size increased and the specific surface area decreased with the increasing treatment time, while the pore volume initially increased and then decreased. Meanwhile, the outside surfaces of Vulcan XC72R were exfoliated to ultra-thin nanosheets and grafted with the oxygen-containing functional groups. Compared with the untreated Vulcan XC72R, Pt nanoparticles supported on treated Vulcan XC72R with smaller size exhibited higher catalyst activity and longer cyclic stability for the methanol oxidation reaction. This study demonstrates that plasma is an efficient approach to tuning the pore size and functionalizing the surface of Vulcan XC72R.

Facial Synthesis of Adsorbent from Hemicelluloses for Cr(VI) Adsorption.

It is challenging work to develop a low-cost, efficient, and environmentally friendly Cr(VI) adsorbent for waste water treatment. In this paper, we used hemicelluloses from chemical fiber factory waste as the raw material, and prepared two kinds of carbon materials by the green hydrothermal method as adsorbent for Cr(VI). The results showed that hemicelluloses hydrothermally treated with citric acid (HTC) presented spherical shapes, and hemicelluloses hydrothermally treated with ammonia solution (HTC-NH2) provided spongy structures. The adsorption capacity of the samples can be obtained by the Langmuir model, and the adsorption kinetics could be described by the pseudo-second-order model at pH 1.0. The maximum adsorption capacity of HTC-NH2 in the Langmuir model is 74.60 mg/g, much higher than that of HTC (61.25 mg/g). The green hydrothermal treatment of biomass with ammonia solution will provide a simple and feasible way to prepare adsorbent for Cr(VI) in waste water treatment.

Three-dimensional porous carbon derived from different organic acid salts for application in electrochemical sensing.

Three-dimensional porous carbon materials were synthesized by the one-step pyrolysis of organic salts with different numbers of hydroxyl groups on the side chain (sodium tartrate, sodium malate and sodium succinate). Further, the formation of these porous carbon materials was explored. And then, three kinds of carbon materials were used for constructing electrochemical sensors for nitrite detection, respectively. Porous carbon derived from sodium tartrate (PCST) showed the highest electrocatalytic ability for nitrite oxidation among all three materials. The PCST-based sensors allow for rapid detection of nitrite in a wide linear range of 0.1–100 μM with a low detection limit of 0.043 μM. The sensor was applied to detect nitrite in meat samples and the results tested by the developed sensor were consistent with the results obtained by HPLC. We envision that PCST-based electrochemical sensor is promising as an alternative choice for the development of electrochemical analysis.

Effect of temperature on composite films made with activated carbon, graphite, or graphene oxide (GO) in a gelatin matrix

Activated carbon, graphite, and GO/gelatin composite films were prepared by the blending method. The properties of composites were characterized by tensile strength (TS), elongation at break (EB), water vapour permeability (WVP), water-absorption ability, contact angle, scanning electron microscopy (SEM), and moisture at different temperatures. The properties of GO/gelatin composite films were better when each of three kinds of carbon materials were used as reinforcement phases and added into the matrix gelatin. The results showed that EB and TS of GO/gelatin composite films were both excellent. The moisture of GO/gelatin composite films was greater than the others. SEM micrographs showed that GO had better compatibility and dispersibility with gelatin than activated carbon and graphite. The water absorption of GO/gelatin composite films were low, at 15 °C and 25 °C, and the WVP was low at 35 °C. The WVP of GO/gelatin composite films was lower than the others at different temperatures. The contact angle of GO/gelatin composite films was larger than the others.

Efficient degradation of sulfamethoxazole by acetylene black activated peroxydisulfate

Acetylene black (AB), as a kind of carbon material with large specific surface area, low density, strong electron transferability, is supposed to have great potential for application in advanced oxidation processes (AOPs). In this study, AB was utilized as a peroxydisulfate (PDS) activator for the catalytic degradation of sulfamethoxazole (SMX) in aqueous media. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) techniques, zeta potential and Raman spectra were employed to characterize the features of AB. To verify the excellent performance of AB/PDS systems, a series of control experiments were carried out. Compared to graphite/PDS and biochar/PDS system, AB/PDS system could complete degradation of SMX within 15 min. Besides, the effects of key factors including AB dosage, PDS dosage, initial pH and SMX concentration on SMX degradation in AB/PDS system were elucidated systematically. Furthermore, through the radical quenching experiments, it was proved that singlet oxygen (1O2) was dominantly responsible for the degradation of SMX. Finally, based on the experiment results and comprehensive analysis, a probable reaction mechanism of AB/PDS system for SMX degradation was proposed. This work suggests that AB has a good potential for tackling the hazardous pollutants in environmental remediation.

Performance improvement of N-doped carbon ORR catalyst via large through-hole structure

N-doped carbon-based materials are crucial electrically conductive additives and non-metal electrocatalysts for the oxygen reduction reaction. At present, many pieces of research are focused on the effects of micropore, mesopore and hierarchical pore structure on the catalytic activity, however, there are few works concerning the role of large-dimension through-hole structure. Hence, in this work, we prepare two kinds of carbon materials with large through-hole structure, i.e. N-doped carbon hollow-spheres and hollow-tubes, as the oxygen reduction catalysts. The synthesis follows template-free morphology-controlled pyrolysis, which is more convenient than the preparation of conventional N-doped nanotubes and graphene. The resultant N-doped carbon hollow-spheres and hollow-tubes evidently enhanced their ORR catalytic activity, remarkable long-term stability and methanol resistance. The large-dimension through-hole structure is found to account for the increase in mass transfer.

Optical, Electronic Properties and Anisotropy in Mechanical Properties of "X" Type Carbon Allotropes.

Based on first-principle calculations, the mechanical anisotropy and the electronic and optical properties of seven kinds of carbon materials are investigated in this work. These seven materials have similar structures: they all have X-type structures, with carbon atoms or carbon clusters at the center and stacking towards the space. A calculation of anisotropy shows that the order of elastic anisotropy in terms of the shear modulus, Young’s modulus and Poisson’s ratio of these seven carbon materials with similar structure is diamond < supercubane < T carbon < Y carbon < TY carbon < cubane-diyne < cubane-yne. As these seven carbon materials exhibit cubic symmetry, Young’s modulus has the same anisotropy in some major planes, so the order of elastic anisotropy in the Young’s modulus of these seven main planes is (111) plane < (001) plane = (010) plane = (100) plane < (011) plane = (110) plane = (101) plane. It is also due to the fact that their crystal structure has cubic symmetry that the elastic anisotropy in the shear modulus and the Poisson’s ratio of these seven carbon materials on the seven major planes are the same. Among the three propagation directions of [100], [110], and [111], the [110] propagation direction’s anisotropic ratio of the sound velocity of TY carbon is the largest, while the anisotropic ratio of the sound velocity of cubane-diyne on the [100] propagation direction is the smallest. In addition, not surprisingly, the diamond has the largest Debye temperature, while the TY carbon has the smallest Debye temperature. Finally, TY carbon, T carbon and cubane-diyne are also potential semiconductor materials for photoelectric applications owing to their higher or similar absorption coefficients to GaAs in the visible region.

Adsorption Characteristics of Sulfamethazine on Three Typical Porous High-temperature Modified Solid Waste Materials

Three typical porous solid wastes, including livestock manure, crop straw, and coal mining waste, were used as raw materials to prepare cattle manure charcoal, straw charcoal, and coal gangue charcoal by low-oxygen controlling temperature carbonization and calcination. Batch adsorption experiments of sulfamethazine (SMZ) in water were carried out. Adsorption kinetics and isothermal adsorption equilibrium were used to investigate the adsorption characteristics of SMZ on cattle dung charcoal, straw charcoal, and coal gangue charcoal, and the adsorption mechanism was discussed by means of field-electron scanning electron microscope, Fourier transform infrared spectroscopy, Boehm titration, Brunauer-Emmett-Teller measurement, and zeta potentiometric titration. The results showed that the adsorption of SMZ on the three carbon materials reached equilibrium at 24 h. The adsorption kinetics of SMZ on three kinds of carbon materials agreed with the quasi-second-order kinetics equation. R2 ranged from 0.9968 to 0.9999, and the adsorption rate decreased with the decrease in effective adsorption sites on the surface of carbon materials. The adsorption process mainly consists of three steps:membrane diffusion, intraparticle diffusion, and the equilibrium stage. Both intraparticle diffusion and membrane diffusion control the adsorption rate. Isothermal adsorption is more consistent with the Freundlich model. R2 is between 0.9874 and 0.9997. It is mainly physical adsorption and spontaneous exothermic reaction. The maximum adsorption capacity of the three kinds of carbon materials was cattle dung carbon (19.64 mg·g-1) > coal gangue carbon (12.06 mg·g-1) > straw carbon (9.16 mg·g-1). The adsorption mechanism of SMZ on the three kinds of carbon materials mainly includes hydrogen bonding between molecules, surface electrostatic adsorption of multi-molecular layers, and pore filling. Of these, electrostatic adsorption is the main adsorption mechanism. The best adsorption performance of cattle manure charcoal may be due to its rich oxygen-containing functional groups, more negative charges, and larger specific surface area and pore volume.

Electrode materials derived from plastic wastes and other industrial wastes for supercapacitors

The present review not only devotes on the environmental consequences of plastic bag wastes and other industrial wastes observable in the landfills, in the oceans or elsewhere but also gives a new insight idea on conversion of them into worth material, carbon, for the best electrochemical supercapacitor. Transformation of plastic wastes into high-value materials is the incentive for plastic recycling, end-of-life handling case for plastic bag wastes in practice quite limited. The plastic recycling waste for reuse saves energy compared with manufacturing virgin materials. Herein, we identified several synthetic methods to convert plastic waste and other industrial wastes into carbon material for supercapacitor. Different kinds of carbon materials, including nanofiber, nanotube, graphene, mesoporous carbon, etc., have been derived from plastic waste, and thus give a superior potential for transforming trash into a “gold capacitor”. Finally, conclusions and future trends of high-voltage supercapacitors were made as well as the easy and mass production of high-performance electrode materials for supercapacitors. Our work offers a promising sustainable approach to handle plastic bags, waste, and other industrial wastes and provides a new avenue in supercapacitor applications and other areas.

Influence of reaction of Al2O3 and carbonaceous materials in Al2O3–C refractories on aluminum and carbon pick-up of iron

Carbon-containing Al2O3 refractory crucibles and pure Al2O3 refractory crucible were fabricated to study the effect of carbon-containing Al2O3–C refractories on aluminum and carbon pick-up of iron. Refractory crucibles with pure iron powder were placed in a vacuum induction furnace and heated at 1600 °C for regular time under flowing argon atmosphere. The Al and C contents of iron samples were analyzed, and iron samples were also investigated using a field scanning electron microscope equipped with energy-dispersive spectroscope. The results showed that carbon materials did affect the interaction of (Al2O3–C)/Fe system, carbothermal reduction in alumina occurred in the reaction system and the extent of reactions depended on the kinds of carbon materials.

Coupled Biphase (1T-2H)-MoSe2 on Mold Spore Carbon for Advanced Hydrogen Evolution Reaction.

Performance breakthrough of MoSe2 -based hydrogen evolution reaction (HER) electrocatalysts largely relies on sophisticated phase modulation and judicious innovation on conductive matrix/support. In this work the controllable synthesis of phosphate ion (PO43- ) intercalation induced-MoSe2 (P-MoSe2 ) nanosheets on N-doped mold spore carbon (N-MSC) forming P-MoSe2 /N-MSC composite electrocatalysts is realized. Impressively, a novel conductive N-MSC matrix is constructed by a facile mold fermentation method. Furthermore, the phase of MoSe2 can be modulated by a simple phosphorization strategy to realize the conversion from 2H-MoSe2 to 1T-MoSe2 to produce biphase-coexisted (1T-2H)-MoSe2 by PO43- intercalation (namely, P-MoSe2 ), confirmed by synchrotron radiation technology and spherical aberration-corrected TEM (SACTEM). Notably, higher conductivity, lower bandgap and adsorption energy of H+ are verified for the P-MoSe2 /N-MSC with the help of density functional theory (DFT) calculation. Benefiting from these unique advantages, the P-MoSe2 /N-MSC composites show superior HER performance with a low Tafel slope (≈51 mV dec-1 ) and overpotential (≈126 mV at 10 mA cm-1 ) and excellent electrochemical stability, better than 2H-MoSe2 /N-MSC and MoSe2 /carbon nanosphere (MoSe2 /CNS) counterparts. This work demonstrates a new kind of carbon material via biological cultivation, and simultaneously unravels the phase transformation mechanism of MoSe2 by PO43- intercalation.

Effects of the π-electrons in fused polycyclic aromatic hydrocarbons on positron annihilation

The mesoporous phenol-formaldehyde resins (PFR) were synthesized using formaldehyde, phenol, F127 template as raw materials by high temperature hydrothermal method under different temperatures. Nitrogen doped mesoporous PFR were synthesized in the same way with another additional raw material HMTA. Two series of carbon materials PCs and PCNs were obtained after calcinating PFR at 700, 800, 900 °C. N2 adsorption analysis indicates that both the two kind of carbon materials have relatively large specific surface area (325–619 cm2/g for PCs and 431–580 cm2/g for PCNs). TEM and XRD analyses prove highly ordered mesoporous structure of the samples. Both the elemental analysis and IR results suggest a high carbon content and the abundant fused-ring structure of the test materials. The positron annihilation spectra show that the corresponding intensity I3 of the longest lifetime component τ3 is less than 2%, indicating that the π electrons in the fused rings with low ionization energy are capable of trapping positrons and inhibiting the formation of o-Ps.

The impact of carbon additives on lithium ion diffusion kinetic of LiFePO4/C composites

Introduction: LiFePO4/C composites were synthesized via physical mixing assisted solvothermal process. Different kinds of carbon materials were investigated including 0D (carbon Ketjen black), 1D (carbon nanotubes) and 2D (graphene) materials. X-rays diffraction patterns of carbon coated LiFePO4 synthesized by solvothermal was indexed to pure crystalline phase without the emergence of second phase. LiFePO4 platelets and rods were in range size of 80-200 nm and dispersed well in carbon matrix. The lithium ion diffusion kinetics was evaluated through the calculated diffusion coefficients to explore the impact of carbon mixing.&#x0D; Methods: In this work, we studied the structure, morphologies and the lithium ion diffusion kinetic of LiFePO4/C composites for Li-ion batteries. Different characterization methods were used including powder X-rays (for crystalline structure); Transmission Electron Microscopy (for particle and morphologies observation) and Cyclic voltammetry (for electrochemical kinetic study).&#x0D; Results: The study indicated LiFePO4/C composites were successfully obtained by mixing process and the electrochemical performance throughout the calculated diffusion coefficient was significantly improved by adding the carbon types.&#x0D; Conclusion: The excellent ion diffusion was obtained for composites LiFePO4/Ketjen black (KB) and LiFePO4/CNT compared to LiFePO4/Graphene. KB could be a potential candidate for large-scale production due to low-cost, stable and high electrochemical performance.&#x0D;

The construction of porous graphene tri-doped with B, N and Co for enhanced oxygen reduction reaction

Graphene-based materials are promising nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR). However, this kind of carbon materials are usually suffering from layer stacking and intrinsically lack of highly-efficient active sites for ORR. At present, it is still a huge challenge to develop porous multi-doped graphene. Herein, the B, N and Co tri-doped graphene with hierarchical pores is successfully synthesized via a first hydrothermal reaction of graphene oxide (GO) with Co(II) nitrate, 2-methylimidazole (2MI) and boric acid, subsequent pyrolysis and final acid leaching. The morphology, structure and components of a series of samples are systematically investigated. The as-obtained products possess abundant macro/mesopores and ORR active sites including B-bonded C (CB), pyridinic N, graphitic N, CoNC and defects owing to the formation and decomposition of the Co layered double hydroxides (Co-LDHs). After optimizing hydrothermal temperature, pyrolytic temperature and the amount of GO, the sample exhibits an excellent ORR performance in 0.1 M KOH solution. The activity, durability and methanol tolerance are comparable or even superior to those of the commercial Pt/C catalyst (20 wt%). This work provides a new strategy to construct porous multi-doped graphene as nonprecious ORR catalyst.