Co-doped Carbon Research Articles

Preparation of Co[sbnd]N co-doped carbon nanosheets electrocatalyst for efficient oxygen reduction reaction in zinc-air battery

It is very vital that there be a high-activity and serviceable catalyst for the oxygen reduction reaction (ORR) in the Zn-air Battery. Herein, utilizing g-C3N4 as a self-sacrifice template and Cobalt-His framework as the precursor, a simple strategy was developed to synthesize Co/N co-doped carbon nanosheets (CoNC 800) as a metal electrocatalyst for ORR. Due to the Co/N co-doped CoNX site and large specific surface area, the acquired materials show a preeminent ORR catalytic activity with an initial potential (~0.96 V) and half-wave potential (E1/2) of 0.85 V (vs. RHE) in an alkaline medium. Most importantly, the material has superior long-term stability and methanol tolerance than Pt/C. Furthermore, we assembled the Zn-air battery employing catalyst as an air cathode catalyst, demonstrating maximum power densities of 144 mWcm−2, a specific capacity of 821.50 Wh·kg−1, and charge/discharge cycle stability of more than 140 h. The nanosheet structure electrocatalysts derived from the Cobalt-His framework and g-C3N4 provide an innovative and instructive approach to the design of diverse nanomaterials.

Fluoropyridine-medicated zeolite templating method for N/F co-doped carbon with high electrocatalytic performance on oxygen reduction reaction

Heteroatom-doped carbons have attracted increasing attention in recent years as inexpensive high-performance electrocatalytic materials owing to their electrical properties. A precisely controlled synthesis method for heteroatom-doped carbons is important to improve their performance and expand their applications. In this study, we developed a fluoropyridine-medicated zeolite templating method for Nitrogen/Fluorine (N/F) co-doped carbons. The N/F co-doped carbons showed better catalytic performances for oxygen reduction reaction (ORR) than N-doped carbon prepared using pyridine. In particular, the optimized N/F co-doped carbon exhibited a higher half-wave potential (0.87 V vs. RHE) than commercial Pt-loaded carbon black and N/F co-doped carbons reported in the literature. The comparative studies using various N/F co-doped carbons revealed that semi-ionic bonded C-F might improve ORR activity. In contrast, the contribution from covalent or ionic C-F to improving ORR activity would be negligible.

Hf and Co Dual Single Atoms Co-Doped Carbon Catalyst Enhance the Oxygen Reduction Performance.

Single-atom metal-doped M-N-C (M═Fe, Co, Mn, or Ni) catalysts exhibit excellent catalytic activity toward oxygen reduction reactions (ORR). However, their performance still has a large gap considering the demand for their practical applications. This study reports a high-performance dual single-atom doped carbon catalyst (HfCo-N-C), which is prepared by pyrolyzing Co and Hf co-doped ZIF-8 . Co and Hf are atomically dispersed in the carbon framework and coordinated with N to form Co-N4 and Hf-N4 active moieties. The synergetic effect between Co-N4 and Hf-N4 significantly enhance the catalytic activity and durability of the catalyst. In an acidic medium, the ORRhalf-wave potential (E1/2) of the catalyst is up to 0.82V , which is much higher than that of the Co-N-C catalyst without Hf co-doping (0.80V). The kinetic current density of the catalyst is up to 2.49Acm-2 at 0.85V , which is 1.74 times that of the Co-N-C catalyst without Hf co-doping. Moreover, the catalyst exhibits excellent cathodic performance in single proton exchange membrane fuel cells and Zn-air batteries. Furthermore, Hf co-doping can effectively suppress the formation of H2O2, resulting in significantly improved stability and durability.

Fe doped Co9S8 nanoparticles embedded in N, S co-doped porous carbon as an efficient bifunctional electrocatalyst for rechargeable Zn-air batteries

Transition metal sulfides embedded in co-doped porous carbon materials with nitrogen and sulfur are a promising catalyst that can effectively solve the problem of slow oxygen reduction reaction (ORR) kinetics. However, monometallic sulfides consisting of a single active component only have monofunctional catalytic activity and cannot effectively increase the rate of oxygen evolution reaction (OER), thus limiting the energy conversion efficiency of Zn-air batteries (ZAB). Herein, a unique silica template assisted in situ pyrolysis strategy is used to synthesize iron (Fe)-doped cobalt sulfide (Co9S8) nanoparticle embedded in a honeycomb nitrogen (N), sulphur (S) co-doped porous carbon (Fe/Co9S8@NSC) electrocatalyst. The introduction of Fe increases the active component of the catalyst and further enhances the catalytic ability of Co9S8 by optimizing the electronic structure through charge transfer effect. Therefore, the rich active sites of Fe/Co9S8 nanoparticles anchored in N, S co-doped carbon materials with rich pore structure enable the catalysts to have good bifunctional catalytic activities of ORR and OER. In particular, the Fe/Co9S8@NSC has a high half-wave potential of 0.82 V for catalytic ORR and only needs low overpotential of 332 mV at a current density of 10 mA cm−2 for catalytic OER. In addition, the Fe/Co9S8@NSC catalyst based rechargeable ZAB also exhibits a significant specific capacity of 734 mAh g−1 and prolonged stability of 270 h, which outperforms the bulk of recently reported catalysts based on transition metal sulfides-based catalysts. This research offers a workable method for producing metal sulfides catalysts with bifunctional catalytic activity.

ZnSe/SnSe Heterostructure Incorporated with Selenium/Nitrogen Co-Doped Carbon Nanofiber Skeleton for Sodium-Ion Batteries.

Effective strategies toward building exquisite nanostructures with enhanced structural integrity and improved reaction kinetics will carry forward the practical application of alloy-based materials as anodes in batteries. Herein, a free-standing 3D carbon nanofiber (CNF) skeleton incorporated with heterostructured binary metal selenides (ZnSe/SnSe) nanoboxes is developed for Na-ion storage anodes, which can facilitate Na+ ion migration, improve structure integrity, and enhance the electrochemical reaction kinetics. During the carbonization and selenization process, selenium/nitrogen (Se/N) is co-doped into the 3D CNF skeleton, which can improve the conductivity and wettability of the CNF matrices. More importantly, the ZnSe/SnSe heterostructures and the Se/N co-doping CNFs can have a synergistic interfacial coupling effect and built-in electric field in the heterogeneous interfaces of ZnSe/SnSe hetero-boundaries as well as the interfaces between the CNF matrix and the selenide heterostructures, which can enable fast ion/electron transport and accelerate surface/internal reaction kinetics for Na-ion storage. The ZnSe/SnSe@Se,N-CNFs exhibit superior Na-ion storage performance than the comparative ZnSe/SnSe, ZnSe and SnSe powders, which deliver an excellent rate performance (882.0, 773.6, 695.7, 634.2, and 559.0mAhg-1 at current rates of 0.1, 0.2, 0.5, 1, and 2Ag-1) and long-life cycling stability of 587.5mAhg-1 for 3500 cycles at 2Ag-1.

Li3V2(PO4)3 particles embedded in N and S Co-doped porous carbon cathode for high performance lithium storage：An experimental and DFT study

Li3V2(PO4)3 (LVP)-coated with N and S co-doped carbon (NSC) is investigated by DFT calculation, suggesting that NSC significantly enhances electronic conductivity and lowers Li+ migration energy barrier in comparison to...

Urea and ammonium fluoride di-nitrogen and Cu & Fe bi-metal co-doped carbon felt as cathode for electro-Fenton degradation of norfloxacin: 1O2-dominated oxidation pathway

Dual nitrogen source co-doped carbon with copper and iron induces 1O2 degradation of norfloxacin.

Hetero-structured Ru-Mo2C nanoparticles loaded on N,P co-doped carbon for a pH universal hydrogen evolution reaction.

Considering the extensive research studies on Ru and Mo2C for the hydrogen evolution reaction (HER), the construction of heterostructure catalysts containing both Ru and Mo2C nanoparticles can further improve the catalytic activity by the synergistic effect of different species. In this work, we report the synthesis of N,P co-doped carbon coated Ru and Mo2C nanoparticles for the HER using a ZnMo metal-organic framework (MOF) as the precursor. The addition of phosphomolybdic acid during the synthesis of a Zn-MOF not only provides a Mo source for the formation of Mo2C, but also induces a nano-bowl structure. After anchoring RuCl3 in the ZnMo-MOF and thermal annealing, Ru and Mo2C nanoparticles encapsulated in N,P doped carbon (Ru-Mo2C@NPC) were synthesized and the nano-bowl morphology was well preserved. Due to the co-existence of the highly active catalytic species Ru and Mo2C, a large specific surface area owing to the evaporation of Zn during the calcination process, and the nano-bowl-like morphology that boosts mass transfer, Ru-Mo2C@NPC exhibits good catalytic activity for the HER over a wide pH range, with overpotentials of 62, 64 and 170 mV in 0.5 M H2SO4, 1 M KOH and 1 M PBS solution at 10 mA cm-2, surpassing the values for many Ru and Mo2C based catalysts. This work provides a feasible route for designing high performance HER catalysts.

Bio-based poly(benzimidazole-co-amide)-derived N, O co-doped carbons as fast-charging anodes for lithium-ion batteries.

Lithium-ion batteries (LIBs) that can be charged faster while delivering high capacity are currently in significant demand, especially for electric vehicle applications. In this context, this study introduces a less-explored subject: nitrogen and oxygen dual-doped carbons derived from bio-based copolymers, specifically poly(benzimidazole-co-amide). The synthesis involved varying proportions of benzimidazole to amide, namely, 8.5 : 1.5, 7 : 3, and 5 : 5. The copolymers were pyrolyzed under a nitrogen atmosphere to obtain co-doped carbons, wherein the copolymers acted as single sources of carbon, nitrogen, and oxygen, with the nitrogen content ranging between 12.1 and 8.0 at% and oxygen doping between 11.8 and 25.0 at%, and were named as pyrolyzed polybenzimidazole-co-amide 8.5-1.5, 7-3, and 5-5. Coin cells were fabricated and rate studies were conducted for all three samples, wherein PYPBIPA8.5-1.5 outperformed all others, especially at higher current densities. Intrigued by these interesting results, when long-cycling studies were performed at a high current density of 4.0 A g-1, pyrolysed polybenzimidazole-co-amide 8.5-1.5 showed a delithiation capacity of 135 mA h g-1 compared to pyrolysed polybenzimidazole-co-amide 7-3 and 5-5 with a delithiation capacity of 100 mA h g-1 and 60 mA h g-1, respectively, with a capacity retention of 90% even after 3000 cycles. Furthermore, a full cell (2025-coin cell) was fabricated using the PYPBIPA8.5-1.5 anode and LiNi0.80 Co0.15Al0.05O2 (LiNCAO) cathode.

The Mott–Schottky Co2P/Co heterocatalyst encapsulated by N,P-doped graphene/carbon nanotubes as high-efficiency trifunctional electrocatalysts for cable-type flexible Zn–air batteries and water splitting

The novel Mott–Schottky Co2P/Co encapsulated by N,P co-doped graphene and carbon nanotubes is prepared and employed it as superior catalyst for zinc–air batteries and water splitting application, making it a noteworthy advancement in the field.

Preparation and characterization of sulphur and zinc oxide Co-doped graphitic carbon nitride for photo-assisted removal of Safranin-O dye.

Recently, there has been significant interest in photocatalytic reactions involving graphitic carbon nitride (g-C3N4) due to its sp2-hybridized carbon and nitrogen content and it is an ideal candidate for blending with other materials to enhance performance. Here, we have synthesized and analyzed both doped and undoped g-C3N4 nanoparticles. Specifically, we co-doped sulfur (S) into g-C3N4, integrated it with ZnO particles, and investigated the photocatalytic potential of these nanocomposites to remove Safranin-O dye. The initial step involved the preparation of pure g-C3N4 through calcination of urea. Subsequently, S-g-C3N4 was synthesized by calcining a mixture of urea and thiourea with a 3 : 1 ratio. Finally, the ZnO-S-g-C3N4 composite was synthesized using the liquid exfoliation technique, with distilled water serving as the exfoliating solvent. These samples were characterized by advanced techniques, including UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), energy dispersive X-ray (EDX) and scanning electron microscopy (SEM), to assess their crystallinity, morphology, optical properties, and phase purity. Subsequently, these nanocomposites were employed in catalytic and photocatalytic processes to remove the Safranin-O dye (SO). The results highlighted the formation of Z-scheme junction responsible for ZnO-S-g-C3N4's significant performance improvement. The comparison of results demonstrated that S-g-C3N4 and ZnO-S-g-C3N4 composites revealed an effective removal of Safranin-O dye in the presence of UV-light as compared to pure g-C3N4, as it was attributed to the phenomenon of improved separation of photogenerated charge carriers as a result of heterojunction formation between S-g-C3N4 and ZnO interfaces. In addition to improving photocatalytic performance, this study presents a facile route for producing ZnO-S-g-C3N4 composite with superior adsorption capabilities and selectivity.

Preparation of carbon quantum dots and their application in the detection of vitamin B2.

A novel metal-doped carbon quantum dot, zinc-chlorine co-doped carbon quantum dots (Zn/Cl-CQDs), has been developed for the fluorescent probe detection of vitamin B2 and the analysis of the correlation properties of this carbon quantum dot and vitamin B2. Stability experiments demonstrate that Zn/Cl-CQDs possess good fluorescence properties under alkaline conditions. However, when vitamin B2 is added into Zn/Cl-CQDs, the fluorescence intensity decreases sharply, indicating that the fluorescence sensor shows rapid and sensitive detection of vitamin B2 under the static quenching. Lastly, the use of Zn/Cl-CQDs in the detection of vitamin B2 tablets and vitamin B2-rich fruits resulted in recovery rates of 98.2% and 100.6%, respectively. Therefore, this method can be well applied to the detection and analysis of vitamin B2, and has great development prospects in the pharmaceutical industry and food monitoring fields.

Na and O Co-doped Carbon Nitride for Efficient Photocatalytic Hydrogen Evolution

Na and O Co-doped Carbon Nitride for Efficient Photocatalytic Hydrogen Evolution

‘MoS2-coated nitrogen/oxygen co-doped carbon nanocages composite as active material for supercapacitor electrodes

Nitrogen/oxygen co-doped carbon nanocages (NOCN) have been deemed as promising materials in renewable energy-storage applications. Herein, we report a facile one-pot hydrothermal approach for formation of three-dimensional (3D) flower-like MoS2 nanoflakes/NOCN composite (MoS2@NOCN) with excellent storage properties as anode for supercapacitor. As a result, ultrathin MoS2 nanosheets were vertically grown onto the surface of NOCN, which can prevent sheet aggregation and provide a rapid pathway for electron transfer. The as-prepared MoS2@NOCN composites were characterized by electrochemical measurements to demonstrate the supercapacitor performance. The results indicate that MoS2@NOCN-3 exhibited a high specific capacitance (240.8 F g−1 at 0.5 A g−1) and excellent rate performance (approximately 46.4 % from 1 A g−1 to 10 A g−1). The as-obtained composites demonstrated their potential applications in supercapacitor electrode materials.

Biomass-derived Co, N and P co-doped 3D porous carbon as an effective electrocatalyst for oxygen reduction reaction

Fuel cells are an important and promising energy system which has attracted lots of attention. The research on non precious metal catalysts is extremely important for the development of fuel cells. In this work, we fabricated metal organic hybrids (MOH) from chitosan, phytic acid, and CoCl2 through a simple chemical method, and further obtained the Co, N, and P co-doped 3D porous carbon material, with the Co atoms exhibiting good monodispersity on the surface. Due to the size effect brought by the single atom doping of Co and the influence of N and P doping on the microenvironment of the active center, the obtained Co-NPC-6 M exhibits excellent catalytic performance for ORR in the alkaline aqueous electrolyte solution.

Effective construction of Cu, S-CQDs/BiVO4 composites through a facile and efficient route

Monoclinic bismuth vanadate (m-BiVO4) is a well-known photocatalytic material. However, its poor charge transport and photogenerated electron hole rapid recombination limit the application of m-BiVO4. In this paper, we successfully constructed a novel copper-sulfur co-doped carbon quantum dots (Cu, S-CQDs)/BiVO4 nanocomposite through a facile and efficient route, which significantly improved the photocatalytic performance of BiVO4. The physicochemical properties of Cu, S-CQDs and Cu, S-CQDs/BiVO4 samples were studied by various characterization. It was concluded from the degradation experiments that the photocatalytic degradation rate of rhodamine B reaches 99% in 60 min under natural light. The degradation curve compounds the quasi-primary kinetic model, and the kinetic coefficient of degradation is 0.07831 min−1, which is 5.37 times than that of pure BiVO4. Moreover, the free radical scavenging experiments reveal that the hole and superoxide radicals play a major role in the photocatalysis process. After four cycles, the activity of photocatalyst exhibits high stability, which is extremely important for the photocatalytic process. In the summery, the prepared Cu, S-CQDs/BiVO4has many advantages, such as environmental-friendly, low cost and a wide range of applications.

Manganese-Doped Bimetallic (Co,Ni)2P Integrated CoP in N,S Co-Doped Carbon: Unveiling a Compatible Hybrid Electrocatalyst for Overall Water Splitting.

Rational design of highly efficient noble-metal-unbound electrodes for hydrogen and oxygen production at increased current density is crucial for robust water-splitting. A facile hydrothermal and room-temperature aging method is presented, followed by chemical vapor deposition (CVD), to create a self-sacrificed hybrid heterostructure electrocatalyst. This hybrid material, (Mn-(Co,Ni)2P/CoP/(N,S)-C), comprises manganese-doped cobalt nickel phosphide (Mn-(Co,Ni)2P) nanofeathers and cobalt phosphide (CoP) nanocubes embedded in a nitrogen and sulfur co-doped carbon matrix (N,S)-C on nickel foam. The catalyst exhibits excellent performance in both the hydrogen evolution reaction (HER; η10 = 61mV) and oxygen evolution reaction (OER; η10 = 213mV) due to abundant active sites, high porosity, and enhanced hetero-interface interaction between Mn-(Co2P-Ni2P) CoP, and (N,S)-C supported by significant synergistic effects observed among different phases through density functional theory (DFT) calculations. Impressively, (Mn-(Co,Ni)2P/CoP/(N,S)-C (+,-) shows an extra low cell voltage of 1.49 V@10mA cm-2. Moreover, the catalyst exhibits remarkable stability at 100 and 300mA cm-2 when operating as a single stack cell electrolyzer. The superior electrochemical activity is attributed to the enhanced electrode-electrolyte interface among the multiple phases of the hybrid structure.

Advances in Atomically Dispersed Metal and Nitrogen Co-Doped Carbon Catalysts for Advanced Oxidation Technologies and Water Remediation: From Microenvironment Modulation to Non-Radical Mechanisms.

Atomically dispersed metal and nitrogen co-doped carbon catalysts (M-N-C) have been attracting tremendous attentions thanks to their unique MNx active sites and fantastic catalytic activities in advanced oxidation technologies (AOTs) for water remediation. However, precisely tailoring the microenvironment of active sites at atomic level is still an intricate challenge so far, and understanding of the non-radical mechanisms in persulfate activation exists many uncertainties. In this review, latest developments on the microenvironment modulation strategies of atomically dispersed M-N-C catalysts including regulation of central metal atoms, regulation of coordination numbers, regulation of coordination heteroatoms, and synergy between single-atom catalysts (SACs) with metal species are systematically highlighted and discussed. Afterwards, progress and underlying limitations about the typical non-radical pathways from production of singlet oxygen, electron transfer mechanism to generation of high-valent metal species are well demonstrated to inspire intrinsic insights about the mechanisms of M-N-C/persulfate systems. Lastly, perspectives for the remaining challenges and opportunities about the further development of carbon-based SACs in environment remediation are also pointed out. It is believed that this review will be much valuable for the further design of active sites in M-N-C/persulfate catalytic systems and promote the wide application of SACs in various fields.

Acid-base encapsulation prepared N/P co-doped carbon-coated natural graphite for high-performance lithium-ion batteries

The incorporation of natural graphite as an anode material effectively enhances the lithium storage capacity of lithium-ion batteries. However, the lower specific capacity of graphite anodes and the slow dynamics limit the application of fast charging in daily life. In this work, we proposed an acid-base neutralization strategy to prepare N/P co-doped carbon coated natural graphite for high-performance lithium-ion batteries. Electrochemical testing shows that the prepared NG-PN@C electrode has a first discharge specific capacity of 429.61mAh/g and a high initial Coulombic efficiency (ICE) of 87.39 %, exhibiting a capacity three times higher than that of the commercial natural graphite at a rate of 3C. The enhanced performance can be attributed to the synergistic interplay between N/P co-doping and carbon coating. This interplay heightens the chemical reactivity of the graphite surface, an appropriate introduction of heteroatom into graphite (carbon) hosts is beneficial for Li heterogeneous nucleation and thus renders a uniform Li deposition. In addition, the stable carbon layer of about 3 nm can mitigate the volume expansion throughout cycling and improve rate capability and long-term cycling performance. This simple and low-cost acid-base neutralization strategy not only provides an eco-friendly method for the modification of graphite anodes, achieving doping of N/ P and coating a carbon layer on graphite but also offers inspiration for the advancement of alternative nanocomposites dedicated to improving their electrochemical properties.

Hydrogen-Bonded Organic Framework Derived 2D N, O Co-Doped Carbon Nanobelt with Tunable Pseudocapacitive Contribution for Efficient Capacitive Deionization.

Defect engineering is recognized as an attractive method for modulating the electronic structure and physicochemical characteristics of carbon materials. Exploiting heteroatom-doped porous carbon with copious active sites has attracted great attention for capacitive deionization (CDI). However, traditional methods often rely on the utilization of additional heteroatom sources and strong corrosive activators, suffering from low doping efficiency, insufficient doping level, and potential biotoxicity. Herein, hydrogen-bonded organic frameworks (HOFs) are employed as precursors to synthesize N, O co-doped porous carbon via a simple and green reverse defect engineering strategy, achieving controllable heavy doping of heteroatoms. The N, O co-doping triggers significant pseudocapacitive contribution and the surface pore structure supports the formation of the electric double layer. Therefore, when HOF-derived N, O co-doped carbon is used as CDI electrodes, a superior salt adsorption capacity of 32.29±1.42mgg-1 and an outstanding maximum salt adsorption rate of 10.58±0.46mgg-1min-1 at 1.6V in 500mgL-1 NaCl solution are achieved, which are comparable to those of state-of-the-art carbonaceous electrodes. This work exemplifies the effectiveness of the reverse nitrogen-heavy doping strategy on improving the carbon structure, shedding light on the further development of rational designed electrode materials for CDI.