Nitrogen-doped Mesoporous Carbon Research Articles

Nitrogen-doped carbon quantum dots as a novel treatment for black fungal bone infections (Mucormycosis): in vitro and in vivo study

Most fungal bone and joint infections (arthritis) are caused by Mucormycosis (Mucor indicus). These infections may be difficult to treat and may lead to chronic bone disorders and disabilities, thus the use of new antifungal materials in bone disorders is vital, particularly in immunocompromised individuals, such as those who have contracted coronavirus disease 2019 (COVID-19). Herein, we reported for the first time the preparation of nitrogen-doped carbon quantum dots (N/CQDs) and a nitrogen-doped mesoporous carbon (N/MC) using a quick micro-wave preparation and hydrothermal approach. The structure and morphology were analysed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and surface area analyser. Minimum inhibitory concentration (MIC), disc diffusion tests, minimum fungicidal concentration (MFC) and antifungal inhibitory percentages were measured to investigate the antifungal activity of N/CQDs and N/MC nanostructures. In addition to the in vivo antifungal activity in rats as determined by wound induction and infection, pathogen count and histological studies were also performed. According to in vitro and in vivo testing, both N/CQDs with small size and N/MC with porous structure had a significant antifungal impact on a variety of bone-infecting bacteria, including Mucor infection. In conclusion, the present investigation demonstrates that functional N/CQDs and N/MC are effective antifungal agents against a range of microbial pathogenic bone disorders in immunocompromised individuals, with stronger and superior fungicidal activity for N/CQDs than N/MC in vitro and in vivo studies.

Encapsulating Sulfur into a Gel-Derived Nitrogen-Doped Mesoporous and Microporous Carbon Sponge for High-Performance Lithium-Sulfur Batteries.

The practical application of Li-S batteries (LSBs) has long been impeded by the inefficient utilization of sulfur and slow kinetics. Utilizing conductive carbonaceous frameworks as a host scaffold presents an efficient and cost-effective approach to enhance sulfur utilization for redox reactions in LSBs. However, the interaction of pure carbon materials with lithium polysulfide intermediates (LiPSs) is limited to weak van der Waals forces. Hence, the development of an economical method for synthesizing heteroatom-doped carbon materials for sulfur fixation is of paramount importance. In this study, we introduce a hierarchical porous nitrogen-doped carbon sponge (NPCS) with an exceptionally high BET surface area of 3182.2 m2 g-1, achieved through a facile template-assisted polymerization method. The incorporation of inorganic salts, free radical polymerization, and deuteric freeze-drying techniques facilitates the formation of hierarchical pores within the NPCS. After sulfur fixation, the resulting S/NPCS electrode demonstrates remarkable electrochemical performance in LSBs. Specifically, it achieves an 80% sulfur utilization rate, maintains a high reversible specific capacity of 400 mA h g-1 even after 600 cycles at a demanding current density of 5.0 A g-1, and exhibits superior rate capability. It is believed that this work will inspire the rational design of cost-effective carbon-based electrodes for high-performance LSBs.

Degradation of Sulfamethoxazole by Activation of Persulfate Based on Nitrogen-Doped Mesoporous Carbon

Degradation of Sulfamethoxazole by Activation of Persulfate Based on Nitrogen-Doped Mesoporous Carbon

Synergistic vacancy engineering of Co/MnO@NC catalyst for superior oxygen reduction reaction in liquid/solid zinc-air batteries

The pursuit of efficient and economically viable catalysts for liquid/solid-state zinc-air batteries (ZABs) is of paramount importance yet presents formidable challenge. Herein, we synthesized a vacancy-rich cobalt/manganese oxide catalyst (Co/MnO@NC) stabilized on a nitrogen-doped mesoporous carbon (NC) nanosphere matrix by leveraging hydrothermal and high-temperature pyrolysis strategy. The optimized Co/MnO@NC demonstrates fast reaction kinetics and large limiting current densities comparable to commercial Pt/C in alkaline electrolyte for oxygen reduction reaction (ORR). Moreover, the Co/MnO@NC serves as an incredible cathode material for both liquid and flexible solid-state ZABs, delivering impressive peak power densities of 217.7 and 63.3 mW cm−2 and robust long-term stability (459 h), outperforming the state-of-the-art Pt/C and majority of the currently reported catalysts. Research indicates that the superior performance of the Co/MnO@NC catalyst primarily stems from the synergy between the heightened electrical conductivity of metallic Co and the regulatory capacity of MnO on adsorbed oxygen intermediates. In addition, the abundance of vacancies regulates the electronic configuration, and superhydrophilicity facilitates efficient electrolyte diffusion, thereby effectively ensuring optimal contact between the active site and reactants. Besides, the coexisting NC layer avoids the shedding of active sites, resulting in high stability. This work provides a viable approach for designing and advancing high-performance liquid/solid-state ZABs, highlighting the great potential of energy storage technology.

Effects of the chemical states of N sites and mesoporosity of N-doped carbon supports on single-atom Ru catalysts during CO2-to-formate conversion

This study explores the fabrication and characterization of mesoporous nitrogen-doped carbon replicas (MNCs) as Ru catalyst supports for CO2 hydrogenation to formate. MNC supports with a cubic Ia3d-like structure were successfully synthesized from a KIT-6 template. The mesoporosity, N content, and N states in the MNCs differed according to the precursor type, which substantially influenced the stability of single-atom Ru catalysts during CO2 conversion. In hydrogenation tests, the Ru/MNC prepared using acrylonitrile precursor (Ru/MNC-A) demonstrated the best stability, whereas the Ru/MNCs prepared using pyrrole and melamine exhibited low activity owing to Ru agglomeration and limited reactant diffusion, respectively. The excellent stability of Ru/MNC-A resulted from Ru migration and rearrangement, as evidenced by near edge X-ray absorption fine structure analyses. Ru/MNC-A and Ru/MNC-A-400 achieved an outstanding turnover number of 69,000 in CO2 hydrogenation over 72 h. Remarkably, the Ru/MNC-A catalyst demonstrated exceptional stability, attaining a TON of 315,840 over 360 h.

Organic precursors for tailored synthesis of sulfur- and nitrogen-doped mesoporous carbons: a molecular design approach.

Insights into tailoring heteroatom-doped mesoporous carbon are provided for enhanced electrocatalytic properties. This study focuses on the design and synthesis of sulfur-doped mesoporous carbon using a sulfur-containing monomer with a chemical structure similar to dopamine. The resulting material achieves remarkable catalytic activity for the oxygen reduction reaction.

A green method for the preparation of nitrogen-doped mesoporous carbon and its application in adsorptive desulfurization

Nitrogen-doped porous carbons (NMCs) were prepared using a green method.

A dual-template synergistic assembly strategy towards the synthesis of extra-small nitrogen-doped mesoporous carbon nanospheres with large pores.

Functional mesoporous carbon nanomaterials with large pores and small particle sizes have broad accessibility, but remain challenging to achieve. This study proposed a dual-template synergistic assembly strategy to facilely synthesize extra-small nitrogen-doped mesoporous carbon nanospheres with large pores in a low-cost manner. Directed by the synergistic effect of the combination of surfactants, sodium oleate (anionic surfactant) and triblock copolymer-P123 (nonionic surfactant) were selected as templates to construct nanomicelles (nanoemulsions), which were co-assembled with melamine-based oligomers to form composite nanomicelles, thus obtaining nitrogen-doped mesoporous polymer nanospheres (NMePS) and then nitrogen-doped mesoporous carbon nanospheres (NMeCS). Based on Schiff base chemistry, the melamine-based oligomers with self-assembly capability were synthesized as precursors, which is different from the conventional synthetic route of melamine-formaldehyde resin. The key parameters involved in the route were investigated comprehensively and correlated with the characterization results. Furthermore, the 50 nm-scale particle size and the large mesoporous size of 5.5 nm of NMeCS can facilitate effective mass transport, coupled with their high nitrogen content (15.7 wt%), contributing to their excellent performance in lithium-ion batteries.

Rational design of p-ZnS@CN with 3D interconnected hierarchical pore structure through pyrolysis of an organic hybrid zinc thiocyanide for electrochemical lithium storage

3D interconnected porous carbon-coupled metal-sulfide composites have been demonstrated as promising lithium storage materials owing to their large surface areas as well as the acceleration effect to electrochemical kinetics. However, constructing these materials with ordered hierarchical pore structure is still a challenge. To address this issue, we found that the crystals of an organic hybrid zinc thiocyanide [Zn(NCS)2(phen)2] (phen = 1,10-phenanthroline) could become a fluid at 400 °C, and during the melting process, the phen ligand was simulatneously carbonized to form nitrogen-doped carbon materials, while the Zn(NCS)2 species were converted into ZnS quantum dots. This property could allow us to employ a hard template strategy for preparation of a porous p-ZnS@CN composite featuring 3D interconnected hierarchical structure, namely employing SiO2 nanospheres as sacrificial template and [Zn(NCS)2(phen)2] as precursor and thermal treatment this mixture at 400 °C. The as-obtained p-ZnS@CN (p = porous structure, CN = nitrogen-doped carbon) composite possesses ordered macro- and mesoporous nitrogen-doped carbon structures, where the ZnS quantum dots are embedded in. Due to their structural features, p-ZnS@CN showed a superior lithium storage performance in comparison with ZnS nanoparticles. The well-defined 3D interconnected hierarchical pore structure not only enhances the efficiency of lithium-ion diffusion, but also offers ample void space to buffer the volume expansion during lithiation. Given the diversity of crystalline organic hybrid metal thiocyanates, this work opens a new avenue of preparing 3D interconnected porous carbons-coupled metal-sulfide composites.

Metal-organic framework-derived cation regulation of metal sulfides for enhanced oxygen evolution activity

Heteroatom doping serves as an important strategy to improve the oxygen evolution reaction (OER) activity of transition-metal compounds, while the investigation of intrinsic active sites and mechanisms remains insufficient. In this work, a facile cation regulation strategy is reported to boost the OER activity of metal sulfides via pyrolysis of the Ni-Co bimetallic metal-organic framework. The obtained Ni-substituted CoS nanoparticles on nitrogen-doped mesoporous carbon (Ni-CoS/NC) catalyst achieves a current density of 10 mA cm−2 at a small overpotential of 270 mV with a Tafel slope of 37 mV dec−1 in 1.0 mol L−1 KOH. Through a combination of spectroscopy study and theoretical computations, the activity origin is revealed at the atomic level. The CoxNi1–xOOH serves as the real active site for the OER generated by the Ni-CoS/NC reconstruction under oxidation potential during OER. The Ni substitution results in a strong electronic interaction between the two metals, thus generating more negatively charged Co atoms and more positively charged Ni atoms in the electrocatalyst. The metal sites with regulated electronic structure exhibit enhanced surface adsorption of OOH* and reduce the OER overpotential. Meanwhile, the conductive porous carbon scaffold facilitates electron transfer, mass diffusion, and the accessibility of active sites. This work not only provides a feasible cation regulation strategy for the design of high-performance electrocatalysts for low-cost energy storage and conversion systems, but also yields fresh insight into the activity enhancement mechanisms and intrinsic active sites.

One-Pot Synthesis of Ultra-Small Pt Nanoparticles-Loaded Nitrogen-Doped Mesoporous Carbon Nanotube for Efficient Catalytic Reaction.

In this study, Pt nanoparticles-loaded nitrogen-doped mesoporous carbon nanotube (Pt/NMCT) was successfully synthesized through a polydopamine-mediated "one-pot" co-deposition strategy. The Pt source was introduced during the co-deposition of polydopamine and silica on the surface of SiO2 nanowire (SiO2 NW), and Pt atoms were fixed in the skeleton by the chelation of polydopamine. Thus, in the subsequent calcination process in nitrogen atmosphere, the growth and agglomeration of Pt nanoparticles were effectively restricted, achieving the in situ loading of uniformly dispersed, ultra-small (~2 nm) Pt nanoparticles. The method is mild, convenient, and does not require additional surfactants, reducing agents, or stabilizers. At the same time, the use of the dual silica templates (SiO2 NW and the co-deposited silica nanoclusters) brought about a hierarchical pore structure with a high specific surface area (620 m2 g-1) and a large pore volume (1.46 cm3 g-1). The loading process of Pt was studied by analyzing the electron microscope and X-ray photoelectron spectroscopy of the intermediate products. The catalytic performance of Pt/NMCT was investigated in the reduction of 4-nitrophenol. The Pt/NMCT with a hierarchical pore structure had an apparent reaction rate constant of 0.184 min-1, significantly higher than that of the sample, without the removal of the silica templates to generate the hierarchical porosity (0.017 min-1). This work provides an outstanding contribution to the design of supported noble metal catalysts and also highlights the importance of the hierarchical pore structure for catalytic activity.

Nitrogen-doped hollow mesoporous carbon spheres for efficient oxygen reduction

Extensive investigations have been devoted to nitrogen-doped carbon materials as catalysts for the oxygen reduction reaction (ORR) in various conversion technologies. In this study, we introduce nitrogen-doped carbon materials with hollow spherical structures. These materials demonstrate significant potential in ORR activity within alkaline media, showing a half-wave potential of 0.87 V versus the reversible hydrogen electrode (RHE). Nitrogen-doped hollow carbon spheres (N-CHS) exhibit unique characteristics such as a thin carbon shell layer, hollow structure, large surface area, and distinct pore features. These features collectively create an optimal environment for facilitating the diffusion of reactants, thereby enhancing the exposure of active sites and improving catalytic performance. Building upon the promising qualities of N-CHS as a catalyst support, we employ heme chloride (1 wt%) as the source of iron for Fe doping. Through the carbonization process, Fe-N active sites are effectively formed, displaying a half-wave potential of 0.9 V versus RHE. Notably, when implemented as a cathode catalyst in zinc-air batteries, this catalyst exhibits an impressive power density of 162.6 mW cm−2.

2D N-doped layered mesoporous carbon sheets for high-performance electrochemical hydrogen storage

The rapid growth in energy demands and environmental concerns have drawn great attention to the development of new functional materials for sustainable energy technologies. As an emerging material, mesoporous carbon-based materials exhibit unique properties and have been considered promising candidates for electrochemical hydrogen storage applications. However, pure mesoporous carbon as electrode material may suffer from sluggish electrolyte transportation kinetic and poor hydrophilicity. Two-dimensional layered structure with high exposure area and nitrogen doping, which provides the improved accessibility of ions as well as the hydrophilicity of carbon materials, can cope with these two challenges. Here, the nitrogen-doped layered mesoporous carbon sheets, prepared by the double-hard-template route, were characterized using various technologies and investigated the electrochemically stored hydrogen energy properties. The results exhibit that hydrogen storage can be achieved around 104 mAh g−1 at 100 mA g−1, and the capacity retention was 85.4% at 2 A g−1. Moreover, it also displays superior cycling stability with a retention of 98% upon 300 cycles. According to the obtained results, the layered mesoporous carbon sheets demonstrated suitable capacity as a potential and promising active material for hydrogen-proton-related devices.

Preparation of dispersed hollow carbon spheres assisted by silica/carbon shell isolation for supercapacitors

Nitrogen-doped mesoporous hollow carbon spheres are crucial in energy storage and the strategy of converting the inexpensive polymer polyacrylonitrile (PAN) into hollow carbon spheres needs to be improved. In this study, polystyrene/polyacrylonitrile (PSPAN) composite spheres were subjected to silica/carbon shell isolation to prepare nitrogen-doped hollow carbon spheres. In the carbonization process, the pyrolysis of PSPAN lead to the cavity due to the total decomposition behavior of PS. Due to the isolation of silica/carbon shells, the formation of a molten state during the pyrolysis process of PAN can be effectively prevented, thus avoiding the agglomeration of carbon spheres, and obtaining dispersed and regular hollow carbon spheres. The pore structure and specific surface area of the material were adjusted by hydrolyzing tetraethyl orthosilicate on the template surface and introducing dopamine for polymerization after different times. The hollow structure, nitrogen doping characteristics and abundant mesopores endow the NHCS with high performance in supercapacitor.

Confined synthesis of highly dispersed Ni anchored on mesoporous carbon as efficient catalyst for water splitting

Developing an efficient and low-cost bifunctional electrocatalysts with superior activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is highly required but still challenging. Herein, highly dispersed Ni species containing both Ni nanoparticles (NPs) and atomically dispersed Ni-NX on mesoporous nitrogen-doped carbon (Ni-N-C) were prepared by a facile one-pot pyrolysis strategy using dicyandiamide, citric acid and nickel acetylacetonate as raw materials. The confinement agent citric acid is quite requisite for dispersing Ni NPs and forming mesoporous graphene-like carbon substrate. Due to the uniform size of Ni NPs (3 nm) and the synergistic effect between Ni NPs and Ni-NX, and the unique mesoporous carbon structure, such Ni-N-C catalyst exhibits favorable activities for both HER and OER. The overpotentials for HER and OER are only 218 and 330 mV vs. RHE on glassy carbon to deliver a current density of 10 mA·cm−2, respectively. Moreover, this catalyst also showed good operation durability with no obvious deactivation after long-term (18 h) potentiostatic electrolysis or continuous CV tests. This work could offer a new avenue for the design of bifunctional electrocatalysts in efficient water splitting.

Synthesis of metal-free nitrogen-doped mesoporous carbon nanosheets with reference to molecular self-assembly for efficient peroxymonosulfate activation

The application of metal-free carbon materials in Sulfate radical-based advanced oxidation processes (SR-AOPs) has attracted great attention. In SR-AOPs, porosity and active sites are the keys for nitrogen-doped carbon materials to exhibit high catalytic activity. In this paper, melamine and gallic acid were selected as raw materials, preparing metal-free nitrogen-doped carbon materials by using the molecular self-assembly synthesis method. The catalysts with different structural morphology and surface chemistry were obtained by controlling the pyrolysis temperature. It proposed the formation mechanism of nitrogen-doped mesoporous carbon nanosheets (NMC). The pyrolysis temperature was critical for the regulation of surface properties as well as the structure of carbon materials. It was found that NMC-800 exhibited fluffy and porous microstructure, and various active sites on the surface of the catalyst, including graphite N, pyridine N and CO. In the NMC-800/PMS system, the SMX degradation efficiency and corresponding rate constant could achieve 90.3 % and 0.1705 min−1, respectively. Besides, the degradation pathways and intermediate products of SMX were discussed by the analysis of quenching experiments, electron spin resonance (ESR) and liquid chromatography-mass spectrometry (LC-MS).

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.

Ag and Ce nanoparticles supported on silane-modified nitrogen-doped mesoporous carbon (Ag,Ce@SNC/A1SCA) obtained through green approach as heterogeneous catalyst towards the synthesis of 3,4-disubstituted isoxazol-5(4H)-one and polyhydroquinoline derivatives

In this report, an easy and facile approach for the fabrication of heterogenous, mesoporous nanostructure of graphitic carbon grafted with silane (AEAPTMS) and modified with nanoparticles of Ce and Ag, (Ag,Ce@SNC/A1SCA). The graphitization in carbon was induced by ionic liquid-assisted reaction between the glucose and ethylenediamine under mild conditions. It was characterized by thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), powder X-ray diffraction study (PXRD), ultraviolet–visible spectroscopy (UV-VIS), high-resolution transmission electron microscopy (HRTEM), field emission gun-scanning electron microscopy (FEG-SEM), elemental mapping, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), inductively coupled plasma atomic emission (ICP-AES) and fourier transform infrared spectroscopy (FT-IR). Its acts as an adaptable heterogeneous nanocatalyst in the formation of 3,4-disubstituted isoxazol-5(4H)-one and polyhydroquinoline derivatives. It displayed recyclability for five runs. The recycled catalyst was characterized by PXRD and XPS analysis. XPS analysis established the synergism between metal nanoparticles of Ag and Ce in the prepared nanomaterial.

Ni-based nanocatalyst protected by ultrathin mesoporous nitrogen-doped carbon layer with hollow structure for the efficient transfer hydrogenation of halogenated nitrobenzenes

It is of great scientific and industrial value to develop cheap and efficient supported non-noble metal-based catalysts for the selective hydrogenation of halogenated nitrobenzenes. In this work, hollow-structured Ni-based nano-catalysts coated with ultrathin nitrogen-doped carbon layers (H-Ni@NC) have been prepared. The etching of SiO2 template before calcination and decomposition of residual Ni3Si2O5(OH)4 shell into SiO2 leads to the resulting catalysts could maintain good mechanical property and stability. The H-Ni@NC catalyst prepared at 600 °C exhibits the optimal catalytic performance for the catalytic selective hydrogenation of halogenated nitrobenzenes under mild conditions (60 °C) when using hydrazine hydrate (N2H4·H2O) as the reducing agent, and could maintain its catalytic properties even after 5 consecutive runs. The contrast experiments confirm that the combination of hollow structure with N-doped carbon protective layer make the catalyst show the best catalytic effect, and the synergistic effects are further discussed in detail combined with characterization analysis. In addition, this work further reveals the mechanism of Ni-based catalysts for the transfer hydrogenation of halogenated nitrobenzenes, which may provide a reference idea for the preparation of other Ni-based catalysts.

A high affinity borate ester bond molecularly imprinted sensor based on multistage amplification of UCNPs-NH2 electrochemiluminescence with bifunctional synergistic accelerator CeO2 @N-MC for ultrasensitive detection of ribavirin

A molecularly imprinted electrochemiluminescence sensor (MIECLS) was constructed to detect ribavirin (RBV) using a bifunctional synergistic accelerator as an enhancement tool combined with boronic acid affinity molecularly imprinted polymer (MIP). Amino-functionalized upconversion nanoparticles (UCNPs-NH2) generated an electrochemiluminescence signal and promoted the production of sulfate anion radicals (SO4−•), achieving self-enhancement. Nanosized ceria (CeO2) was spatially matched with the pores of nitrogen-doped mesoporous carbon (N-MC) to form CeO2@N-MC. N-MC not only prevented CeO2 from self-aggregation but also provided electron transfer channels. The doping of CeO2 provided cyclic catalytic sites (Ce3+/Ce4+) that promoted SO4−• generation, shortening the redox reaction distance. The high-speed electron transfer center and high-efficiency cycle catalytic center enabled the bifunctional synergistic effect of CeO2@N-MC, thus greatly improving the electrochemiluminescence signal. Simultaneously, MIP formed by the combination of covalent and noncovalent actions was grafted onto the electrochemiluminescence sensing interface to construct MIECLS. The detection range and the limit of detection (LOD) were found to be 1 × 10−9–5 × 10−6 mol L−1 and 2.27 × 10−10 mol L−1, respectively. MIECLS was used for the detection of RBV in real samples with the recoveries of 86.12–95.90 %, which was consistent with the HPLC results.