Co-doped Mesoporous Carbon Research Articles

Construction of an extraordinary stable mesoporous carbocatalyst in acetylene hydrochlorination via boric acid assistance

In recent years, metal-free carbon catalysts have garnered significant attention as substitutes for metal catalysts due to their cost-effectiveness and increased resistance to poisoning. However, the stability of metal-free carbon catalysts still lags behind that of metal catalysts, presenting a significant hurdle to industrialization. To enhance the catalytic stability of these catalysts, a boron-nitrogen co-doped mesoporous carbon (B, N-MC) catalyst was synthesized using polyacrylonitrile (PAN) as the carbon and nitrogen source, with boric acid serving as the electron regulator. The acetylene conversion on the B, N-MC(0.5) catalyst reached 62.8 % at 220 °C and gas hourly space velocity (GHSV) of C2H2 at 300 h−1, even high than 0.25%Au/AC catalyst (53.3 %). Importantly, the B, N-MC(0.5) catalyst exhibited excellent stability, maintaining its initial activity even after 500 h of evaluation. Experimental and theoretical analyses demonstrate that the B–N pairs, facilitated by the electronic regulation ability of boric acid, effectively inhibits the polymerization of acetylene molecules, mitigates the formation of carbon deposits, thereby enhancing the stability of the catalyst.

Nitrogen and sulfur co-doped mesoporous carbon as an efficient peracetic acid activator for the degradation of 4-chlorophenol: A nonradical mechanism dominated by singlet oxygen

Metal-free peracetic acid (PAA) activators are urgently required due to their low toxicity. Heteroatom doping is beneficial to improve the catalytic performance of carbon materials, but the activation performance of doped carbon materials on PAA and the underlying mechanism have not been reported. Herein, nitrogen and sulfur co-doped mesoporous carbons (NS-MC-x, with x representing the mass ratio of thiourea:mesoporous carbon) were fabricated and used as efficient PAA activators for 4-chlorophenol (4-CP) degradation. The NS-MC-1.0/PAA system can remove > 95 % of 4-CP within 10 min, far more than the MC/PAA system. Co-existing anions show no effect on the degradation of 4-CP, whereas humic acid has a certain degree of inhibition. Singlet oxygen (1O2) primarily drives the degradation of 4-CP, with a secondary contribution from a direct electron transfer process mediated by reactive surface complexes, while the contribution of radicals is minimal. In addition, NS-MC-1.0 exhibits excellent reusability for PAA activation, which is conductive to its practical application. This study facilitates further research on metal-free catalysts for PAA activation and offers fresh perspectives on the utilization of PAA in degrading emerging pollutants.

Functional separator with 1 T/2H-MoSe2 nanosheets decorated nitrogen and sulfur co-doped mesoporous hollow carbon spheres for high-performance Li-S batteries

Due to the dissolution, shuttling, and tardy kinetics conversion of lithium polysulfides (LiPSs) during cycling, there are serious defects in the utilization of active material and capacity retention ability for lithium-sulfur batteries (LSBs). To inhibit effectively the shuttling effect of LiPSs, herein, we propose the dual design strategies, using 1 T/2H mixed phase MoSe2 (1 T/2H-MoSe2) nanosheets uniformly growing on the external surface and inner wall of nitrogen and sulfur co-doped mesoporous hollow carbon spheres (MoSe2-NSHC) as both sulfur host and modified material of conventional polypropylene (PP) separator. The hollow structure of MoSe2-NSHC has a large specific surface area and internal space, which not only loads a large amount of sulfur, but also buffers severe volume expansion of sulfur during charge/discharge process. Meanwhile, 1 T/2H-MoSe2 and co-doped nitrogen and sulfur in the carbon skeleton effectively anchor LiPSs and accelerate the kinetics conversion of LiPSs by forming chemical bond. Density-functional theory calculations indicate the corresponding mechanisms. Based on these advantages, lithium-sulfur battery assembled with a MoSe2-NSHC/S cathode and a MoSe2-NSHC-PP separator delivers an initial discharge capacity of 1402 mAh/g at 0.2C, and also exhibits the first discharge capacity of 1155 mAh/g at 0.5C with a capacity retention rate of 79 % after 100 cycles. And after 800 cycles at 1C, the outstanding long-term cyclability with a low capacity decay per cycle of 0.039 % is also obtained. Notably, even in case of sulfur loading of 3.2 mg cm−2 and electrolyte/sulfur ratio of 6 μL mg−1, lithium-sulfur battery still exhibits a good electrochemical performance. Importantly, this work provides a feasible approach for commercial application of LSBs.

Fe/N-doped porous carbon materials derived from corn stalks as ORR electrocatalysts for DMFC

For the development of cheap and efficient catalysts, the Fe/N co-doped mesoporous carbon material catalyst (Fe5-PANI/C-MCS) was prepared by using corn stalks with polyaniline and melamine. The ORR performance of Fe5-PANI/C-MCS under alkaline conditions (0.1 M KOH) showed excellent stability, tolerance to methanol and catalytic activity with Eonset at 1.09 V and E1/2 at 0.85 V, comparison with commercial Pt/C. The electron transfer and material transport become easy since the rich pore structure of Fe5-PANI/C-MCS. The Fe5-PANI/C-MCS (1.56 mW cm−2) has a higher power density than Pt/C (1.4 mW cm−2) at 50 °C as a DMFC cathode catalyst. This work offered practical application for the development of ORR electrocatalysts using biomass carbon materials based on agroforestry waste.

Cooperative regulation of hard template and emulsion self-assembly to the synthesis of N/O co-doped mesoporous hollow carbon nanospheres for supercapacitors

Hollow carbon nanospheres have attracted more and more attention as supercapacitor materials due to their excellent electrical conductivity, high theoretical surface area, high accumulation and rapid ion transfer and diffusion. In this work, we employed the Stöber method to create silica as a template, and then applied self-assembly and dopamine polymerization on the surface of the template to form SiO2@TMB-F127-PDA micelles. Then the nitrogen-doped mesoporous hollow carbon nanospheres (N-MHCNs) were prepared by carbonization and etching on the formed carbon precursors. The effect of dopamine amount on the structure and properties of N-MHCNs was systematically studied. Microstructural characterization results reveal that the morphology of N-MHCNs can be changed from sheet to sphere, and the particle size of N-MHCNs can be 33.8–225.7 nm, the specific surface area is distributed in the range of 175.9–430.1 m2 g−1. Due to the N,O heteroatomic co-doping and Porous spherical structure (with a small particle size of 33 nm, and a large specific surface area of 430.1 m2 g−1), typical sample N-MHCNS-2 shows excellent electrochemical performance in supercapacitors. And it has the highest specific capacitance (241 F g−1) at 0.5 A g−1 current density, excellent rate performance (capacity retention rate of 79 % when current density increases from 0.5 to 10 A g−1) and good cycling ability (capacity retention rate of 90.4 % after 3000 cycles), indicating that it shows great potential in energy storage. This approach provides new opportunities for the controllable synthesis of hollow mesoporous nanospheres and it can be extended to other systems such as hollow metals, metal oxide nanomaterials and carbon-based hybrids.

Nitrogen and sulfur co-doped mesoporous hollow carbon spheres for high rate sodium ion storage

Nitrogen and sulfur co-doped mesoporous hollow carbon spheres for high rate sodium ion storage

Nonradical activation of peroxydisulfate over Fe/N doped mesoporous carbon for selective removal of organic pollutant

Mesoporous carbon materials are promising catalysts for peroxydisulfate (PDS) activation for degrading aqueous organic pollutants but limited by the intrinsic inertness. Herein, co-doping of iron and nitrogen into the mesoporous carbon framework was performed via thermal conversion of metal-polyphenol coordination polymers (Fe-TA) to synthesize Fe/N co-doped mesoporous carbon for efficient PDS activation. Owing to the large surface area, high graphitization degree and defective configurations, the Fe/N co-doped mesoporous carbon (Fe/N-MCs) exhibited superior catalytic performance toward the degradation of organic pollutants. Electron paramagnetic resonance tests, chemical quenching experiments, electrochemical analysis and spectra measurements revealed that the degradation of organic pollutants over the Fe/N-MCs followed a nonradical oxidation pathway based on electron transfer process. Graphite nitrogen and hydroxyl (C-OH) groups on the defective edges of Fe/N-MCs were proved to be possible active sites for PDS activation. PDS catalyzed by the Fe/N-MCs exhibited strong anti-interference capability to surrounding inorganic ions (such as Cl–, CO32–, NO3– and SO42–) and natural organic matters, making it a promising candidate for the degradation of organic pollutants. This work provides a new prospect for developing highly active mesoporous carbon materials via heteroatom doping for PDS activation for wastewater decontamination.

Adsorption of antibiotics from wastewater by cabbage-based N, P co-doped mesoporous carbon materials

Research on low-polluting, economical, and reliable antibiotic adsorption materials is of great significance for reducing pollution in the pharmaceutical and aquaculture industries. Herein, N, P co-doped carbon material (PCC500) with a high specific surface area of 1400 m2/g and a high mesoporous ratio of 89.9% were prepared from cabbage waste by H3PO4 hydrothermal combined with activation. PCC500 showed good adsorption performance for various antibiotics, including chloramphenicol (CHL), tetracycline (TC), ofloxacin (OFX) and erythromycin (ERY). 99% removal efficiency and 247 mg/g adsorption capacity of TC on PCC500 were obtained at 298 K (C0 = 50 mg/L), and 471 mg/g of the maximum adsorption capacity of was achieved at 318 K. The adsorption kinetics and thermodynamic analysis indicated that there was chemisorption during the adsorption process. A series of characterizations including SEM, EDS, N2 adsorption and desorption, FTIR, XPS showed that the abundant pore structure and P, N functional groups are important factors affecting the adsorption performance, and the graphite-N and C3-PO structures in PCC500 could be the important active sites responsible for antibiotic chemisorption. Moreover, PCC500 exhibits good resistance to impurity ions and cyclic stability.

Ultra-fine Co nanoparticles in-situ anchored on porous conductive nanosheets as efficient electrocatalysts for promoting sulfur redox reaction kinetics

Lithium-sulfur (Li-S) batteries are considered as one of the most promising energy storage devices due to their high theoretical energy density. However, the sluggish conversion kinetics and the polysulfides shuttling cause terrible capacity attenuation, impeding the practical developments. Herein, the Co/N co-doped mesoporous carbon nanosheet is developed after the pyrolysis of metal organic framework on graphene oxide layer, which is further explored as kinetics promotor towards advanced Li-S batteries. In this structure, the mesoporous carbon nanosheets with large specific surface area serve as the polysulfide trappers by physical constraint and the ultra-fine Co nanoparticles provide chemical adsorption and electrocatalytic capability for polysulfides, thus effectively suppressing the shuttle effect and accelerating the reaction kinetics. As a result, the Li-S batteries with modified kinetic modulation separators exhibit a high capacity of 585.3 mAh g−1 after 500 cycles at 1.0 C and excellent rate capability (511.2 mAh g−1 at 3 C).

Pyrolysis-Free Mechanochemical Conversion of Small Organic Molecules into Metal-Free Heteroatom-Doped Mesoporous Carbons for Efficient Electrosynthesis of Hydrogen Peroxide

The synthesis of heteroatom-doped porous carbons for efficient electrochemical production of hydrogen peroxide (H2O2) through two-electron (2e–) oxygen reduction reaction (ORR) has attracted increasing research attention since it offers a promising renewable substitute for the traditional complex energy-intensive anthraquinone process. Herein, a novel pyrolysis-free mechanochemical approach was developed for straightforward conversion of small organic molecules into metal-free heteroatom-doped mesoporous carbons (HMCs), where the uniqueness of this one-pot ball-milling technique not only exceeds the limit of volatilities of traditional carbonaceous precursors but also eliminates the need for any additional mesoporous templates. The abundance of molecular precursors (up to 23 different molecules) provides a facile means to introduce a wide variety of heteroatoms (B, N, O, P, S, F, Cl, etc.) into the resultant carbon materials, accompanied by in situ formation of rich mesopores. As a result, the resulting N/O co-doped mesoporous carbon with the highest Brunauer–Emmett–Teller (BET) surface area of 1238 m2 g–1 exhibits exceptional H2O2 selectivity of 95.2% in 0.1 M KOH solution at 0.70 V (vs. reversible hydrogen electrode, RHE) and a large H2O2 production rate of ca. 265 mmol gcat.–1 h–1, ranking at the top among all metal-free carbonaceous electrocatalysts. We anticipate our findings will facilitate new possibilities for the development of mesoporous carbons for electrocatalytic applications.

Fast-Charging Sodium-Ion Batteries Enabled by Molecular-Level Designed Nitrogen and Phosphorus Codoped Mesoporous Soft Carbon.

Soft carbons have attracted extensive interests as competitive anodes for fast-charging sodium-ion batteries (SIBs); however, the high-rate performance is still restricted by their large ion migration barriers and sluggish reaction kinetics. Herein, we show a molecular design approach toward the fabrication of nitrogen and phosphorus codoped mesoporous soft carbon (NPSC). The key to this strategy lies in the chemical cross-linking reaction between polyphosphoric acid and p-phenylenediamine, associated with pyrolysis induced in-situ self-activation that creates mesoporous structures and rich heteroatoms within the carbon matrix. Thanks to the enlarged interlayer spacing, reduced ion diffusion length, and plentiful active sites, the obtained NPSC delivers a superb rate capacity of 215 mAh g-1 at 10 A g-1 and an ultralong cycle life of 4,700 cycles at 5 A g-1. Remarkably, the full cell shows 99% capacity retention during 100 continuous cycles, and maximum energy and power densities of 191 Wh kg-1 and 9.2 kW kg-1, respectively. We believe that such a synthetic protocol could pave a novel venue to develop soft carbons with unique properties for advanced SIBs.

Nitrogen and fluorine co-doped mesoporous carbon as an efficient metal-free catalyst for selective oxidation of 2-methylnaphthalene

N/F co-doped carbon materials prepared with an aniline-type benzoxazine as a carbon precursor show a better catalytic performance for the selective oxidation of 2-methylnapthalene.

Coal-derived N,O co-doped mesoporous carbon as electrode material for high performance aqueous electric-double layer capacitors and zinc-ion hybrid supercapacitors

Carbon-based materials are widely used as electrode materials for electrochemical energy storage devices. However, achieving high performance carbon materials via facile preparation process with abundant precursors is still a huge challenge. Herein, a nitrogen/oxygen co-doped mesoporous coal-derived carbon (N/O-DMCC) is synthesized with raw coal as precursor through a facile pyrolysis treatment. The treatment endows the N/O-DMCC with high surface area, mesoporous structure, as well as rich heteroatom doping content. The combination of above features enhances the electrochemical capacitance of the as-synthesized N/O-DMCC by delivering a satisfactory value of 376.5 F g−1 (i.e., 376.5 C g−1) at 0.5 A g−1, which is superior to many state-of-the art coal-derived carbon materials in literature. A symmetric electric-double layer capacitor (EDLC) and a zinc-ion hybrid supercapacitor (ZHS) based on N/O-DMCC electrode are assembled to achieve high energy densities of 23.1 Wh kg−1 (at 500 W kg−1) and 347.0 Wh kg−1 (at 175.5 W kg−1), respectively, strongly demonstrating the huge potential of coal-derived carbon materials for energy storage devices.

Sulfur/Nitrogen Co-Doped Mesoporous Carbon for High-Performance Lithium-Ion Battery Anodes

Sulfur/Nitrogen Co-Doped Mesoporous Carbon for High-Performance Lithium-Ion Battery Anodes

Insights into high-efficient removal of tetracycline by a codoped mesoporous carbon adsorbent

Adsorbents with simple preparation and high surface area have become increasingly prevalent for the removal of organic contaminants. Herein, a carbon nanoplate codoped by Co and N elements with abundant ordered mesoporous (Co/N-MCs) was applied as an adsorbent for tetracycline removal. Taking integrated advantages of ordered mesopores on carbon-based structures and N-doping inducing the strengthened π–π dispersion and generation of pyridinic N, as well as cobaltic nanoparticles embedded in carbon nanoplates, the Co/N-MCs was tailored for high efficiently absorbing tetracycline via π-π interaction, Lewis acid-base interaction, metal complexation and electrostatic attraction. The Co/N-MCs had the advantages of high surface area, porous structure, plenty adsorption sites, and easy separation. As such, the as-prepared Co/N-MCs adsorbents significantly enhanced tetracycline removal performance with a maximum adsorption capacity of 344.83 mg·g −1 at pH 6 and good reusability, which was finally applied to removal tetracycline from tap water sample. Furthermore, the adsorption process towards tetracycline hydrochloride could be well attributed to the pseudo-second-order kinetic and Langmuir isotherm models. Compared with traditional carbon-based adsorbents, it owns a simpler synthesis method and a higher adsorption capacity, as well as it is a promising candidate for water purification.

N, O Co-Doped Mesoporous Coal-Derived Carbon Material with Enhanced Energy Storage Performance for Supercapacitors

N, O Co-Doped Mesoporous Coal-Derived Carbon Material with Enhanced Energy Storage Performance for Supercapacitors

Rational construction of yolk-shell CoP/N,P co-doped mesoporous carbon nanowires as anodes for ultralong cycle life sodium-ion batteries.

Owing to the natural abundance and low-cost of sodium, sodium-ion batteries offer advantages for next-generation portable electronic devices and smart grids. However, the development of anode materials with long cycle life and high reversible capacity is still a great challenge. Herein, we report a yolk-shell structure composed of N,P co-doped carbon as the shell and CoP nanowires as the yolk (YS-CoP@NPC) for a hierarchically nanoarchitectured anode for improved sodium storage performance. Benefitting from the 1D hollow structure, the YS-CoP@NPC electrode exhibits an excellent cycling stability with a reversibly capacity of 211.5 mA h g-1 at 2 A g-1 after 1000 cycles for sodium storage. In-depth characterization by ex situ X-ray photoelectron spectroscopy and work function analysis revealed that the enhanced sodium storage property of YS-CoP@NPC might be attributed to the stable solid electrolyte interphase film, high electronic conductivity and better Na+ diffusion kinetics.

Molten Salts Strategy for the Synthesis of CoP Nanoparticles Entrapped, N,P Co-doped Mesoporous Carbons as Electrocatalysts for Hydrogen Evolution

Molten Salts Strategy for the Synthesis of CoP Nanoparticles Entrapped, N,P Co-doped Mesoporous Carbons as Electrocatalysts for Hydrogen Evolution

Surface Engineering of Carbon via Coupled Porosity Tuning and Heteroatom‐Doping for High‐Performance Flexible Fibrous Supercapacitors

AbstractFlexible fibrous supercapacitors (FFS) are considered the next‐generation wearable energy storage devices because they provide reliable safety, eco‐friendliness, and high power density. In particular, the FFS is desirable for application to wearable electronics because it can overcome disadvantages of the lithium‐ion battery (LIB), such as the hazard of explosion and the complex manufacturing process. Nevertheless, the practical application of the FFS continues to be inhibited by the poor energy storage performance due to the limited specific surface area, poor electrical properties, and low wettability of the carbon fiber electrode. Herein, for the first time, the surface engineering of an FFS using nitrogen and fluorine codoped mesoporous carbon fibers (FFS‐NFMCF) is described, and the synergistic effect of porosity tuning and heteroatom codoping upon the electrochemical performance is demonstrated. The resultant supercapacitor shows a high specific capacitance of 243.9 mF cm−2 at a current density of 10.0 µA cm−2 and good ultrafast cycling stability with capacitance retention of 91.3% for up to 10 000 cycles at a current density of 250.0 µA cm−2. More interestingly, the FFS‐NFMCF exhibits good mechanical properties and remarkable safety in practical application, thus demonstrating its feasibility for use in wearable electronic textiles.

(Invited) Electrospun Carbon Nanofibers for Applications in Fuel Cells and Li-Metal Batteries

Carbon nanofibers (CNFs) have been widely utilized in energy conversion and storage devices owing to their excellent electrical conductivities, large surface areas, structural and chemical stabilities. In fuel cells and water electrolyzers, CNFs can be used as a durable support for precious metal nanoparticle catalysts and also as a catalyst itself by being incorporated with nitrogen and transition metals. For lithium (Li) metal anode of rechargeable batteries, CNFs can serve as a interlayer to suppress the formation of Li dendrites.In this talk, CNFs prepared by electrospinning polyacrylonitrile (PAN) and carbonization are presented for applications in fuel cells and Li-metal batteries. For fuel cell applications, transition metal precursors were added to the electrospinning solution to form the active sites for the oxygen reduction reaction [1]. To make mesoporous CNFs, silica nanoparticles polyvinyl acetate were added to the electrospinning solution [2]. To enhance the Li-ion adsorption on CNFs, metal nanoparticles were added to the spinning solution [3].[1] M. Kim, D.-H. Nam, H.-Y. Park, C. Kwon, K. Eom, S. Yoo, J. Jang, H.-J. Kim, E.A. Cho, H. Kwon, Journal of Materials Chemistry A, 3, 14284-14290 (2015)[2] M. J. Kim, J. H. Lim, J. Bak, D. H. Song, S. K. Oh, E. A. Cho "Fe and N Codoped Mesoporous Carbon Nanofiber as a Nonprecious Metal Catalyst for Oxygen Reduction Reaction and a Durable Support for Pt Nanoparticles", ACS Sustainable Chem. Eng., 7(20), 17544-17552 (2019)[3] H. Kang, MS Thesis, KAIST (2020) Figure 1