Carbon Nanospheres Research Articles

Tailored “Staggered Reaction” toward N/S Codoped Hollow Porous Carbon Nanospheres for Supercapacitors

Tailored “Staggered Reaction” toward N/S Codoped Hollow Porous Carbon Nanospheres for Supercapacitors

Regulation of the diatomic-site electronic structure with alloy nanoparticles in hollow carbon nanospheres for efficient oxygen reduction and evolution reactions

Regulation of the diatomic-site electronic structure with alloy nanoparticles in hollow carbon nanospheres for efficient oxygen reduction and evolution reactions

Efficient removal of copper ions through photothermal enhanced flow-electrode capacitive deionization.

Removing Cu2+ from wastewater through capacitive deionization at low temperatures is a great challenge. Herein, a new strategy for enhancing the performance was developed using photothermal carbon nanospheres as the electrodes. Upon irradiating with sunlight, the Cu2+ removal rate and Cu2+/Na+ selectivity were increased by 74% and 43%, respectively.

Heterogeneous interface engineering to enhance oxygen electrocatalytic activity for rechargeable zinc–air batteries

Co/CoO heterojunctions embedded in N-doped hollow carbon nanospheres coupled with multiple active sites promote the electron transfer of oxygen-related intermediates and modulate surface engineering promoting ORR/OER activity.

The Effect of Molten Salt Composition on Carbon Structure: Preparation of High Value-Added Nano-Carbon Materials by Electrolysis of Carbon Dioxide.

The electrochemical conversion of CO2 into high value-added carbon materials by molten salt electrolysis offers a promising solution for reducing carbon dioxide emissions. This study focuses on investigating the influence of molten salt composition on the structure of CO2 direct electroreduction carbon products in chloride molten salt systems. Using CaO as a CO2 absorber, the adsorption principle of CO2 in LiCl-CaCl2, LiCl-CaCl2-NaCl and LiCl-CaCl2-KCl molten salts was discussed, and the reasons for the different morphologies and structures of carbon products were analyzed, and it was found that the electrolytic efficiency of the whole process exceeded 85%. Furthermore, cathode products are analyzed through Scanning Electron Microscope (SEM), X-Ray Diffractometer (XRD), Thermal Gravimetric Analyzer (TGA), Raman Spectra and Fourier Transform Infrared (FTIR) techniques with a focus on the content and morphology of carbon elements. It was observed that the carbon content in the carbon powder produced by molten salt electrochemical method exceeded 99%, with most carbon products obtained from electrolysis in the Li-Ca chloride molten salt system being in the form of carbon nanotubes. In contrast, the Li-Ca-K chloride system yielded carbon nanospheres, while a mixture was found in the Li-Ca-Na chloride system. Therefore, experimental results demonstrate that altering the composition of the system allows for obtaining the desired product size and morphology. This research presents a pathway to convert atmospheric CO2 into high value-added carbon products.

Covalent organic framework derived single-atom copper nanozymes for the detection of amyloid-β peptide and study ofamyloidogenesis.

Sensitive and accurate detection of theamyloid-β (Aβ) monomer is of fundamental significance for early diagnosis of Alzheimer's disease (AD). Herein, inspired by the specific Cu-Aβ monomer coordination, a cutting-edge colorimetric assay based on single-atom Cu anchored N-doped carbon nanospheres (Cu-NCNSs) was developed for Aβ monomer detection and anamyloidogenesis study. By directly pyrolyzing Cu2+-incorporated covalent organic frameworks (COFs), the resulting Cu-NCNSs with ahighloadingof Cu (8.04 wt %) exhibited outstanding peroxidase-like activity. The strong binding affinity of Aβ monomer to Cu-NCNSs effectively inhibited their catalytic activity, providing the basis for the colorimetric assay. The Cu-NCNSs-based sensor showed a detection limit of 1.182nM for Aβ monomer, surpassing traditional techniques in terms of efficiency, accuracy and simplicity. Moreover, the system was successfully utilized for Aβ monomer detection in rat cerebrospinal fluid (CSF). Notably, the distinct inhibitory effects of monomeric and aggregated Aβ species on the catalytic activity of Cu-NCNSs were allowed for monitoring of the dynamic aggregation process of Aβ. Compared to thioflavin T (ThT), the most widely used amyloid dye, the detection system exhibited greater sensitivity towards toxic Aβ oligomers, which was crucial for early AD diagnosis and treatment. Our work not only sheds light on the rational design of highly active single-atom nanozymes from COFs but also expands the potential applications of nanozymes in early disease diagnosis.

Recent Advances in the Adsorption of Different Pollutants from Wastewater Using Carbon-Based and Metal-Oxide Nanoparticles

In recent years, nanomaterials have gained special attention for removing contaminants from wastewater. Nanoparticles (NPs), such as carbon-based materials and metal oxides, exhibit exceptional adsorption capacity and antimicrobial properties for wastewater treatment. Their unique properties, including reactivity, high surface area, and tunable surface functionalities, make them highly effective adsorbents. They can remove contaminants such as organics, inorganics, pharmaceuticals, medicine, and dyes by adsorption mechanisms. In this review, the effectiveness of different types of carbon-based NPs, including carbon nanotubes (CNTs), graphene-based nanoparticles (GNPs), carbon quantum dots (CQDs), carbon nanofibers (CNFs), and carbon nanospheres (CNSs), and metal oxides, including copper oxide (CuO), zinc oxide (ZnO), iron oxide (Fe2O3), titanium oxide (TiO2), and silver oxide (Ag2O), in the removal of different contaminants from wastewater has been comprehensively evaluated. In addition, their synthesis methods, such as physical, chemical, and biological, have been described. Based on the findings, CNPs can remove 75 to 90% of pollutants within two hours, while MONPs can remove 60% to 99% of dye in 150 min, except iron oxide NPs. For future studies, the integration of NPs into existing treatment systems and the development of novel nanomaterials are recommended. Hence, the potential of NPs is promising, but challenges related to their environmental impact and their toxicity must be considered.

Photonic Band Gap Engineering by Varying the Inverse Opal Wall Thickness.

We demonstrate the band gap programming of inverse opals by fabrication of different wall thickness by atomic layer deposition (ALD). The opal templates were synthesized using polystyrene and carbon nanospheres by the vertical deposition method. The structure and properties of the TiO2 inverse opal samples were investigated using Scanning Electron Microscope (SEM) and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction (XRD) and Finite Difference Time Domain (FDTD) simulations. The photonic properties can be well detected by UV-Vis reflectance spectroscopy, while diffuse reflectance spectroscopy appears to be less sensitive. The samples showed visible light photocatalytic properties using Raman microscopy and UV-Visible spectrophotometry, and a newly developed digital photography-based detection method to track dye degradation. In our work, we stretch the boundaries of a working inverse opal to make it commercially more available while avoiding fully filling and using cheaper, but lower-quality, carbon nanosphere sacrificial templates.

Molecular‐level Modulation of N, S‐Co‐Doped Mesoporous Carbon Nanospheres for Selective Aqueous Catalytic Oxidation of Ethylbenzene

AbstractSelective oxidation of aromatic alkanes into high value‐added products through benzylic C−H bond activation is one of the main reactions in chemical industry. On account of the constantly increasing demand for mass production, efficient, eco‐friendly and sustainable catalysts are urgently needed. Herein, we describe a facile and versatile emulsion‐assisted interface self‐assembly strategy towards molecular‐level fabrication of co‐doped mesoporous carbon nanospheres with controllable active N and S species. The method enables a high degree of control over nanoparticle sizes, mesoporous nanostructures, contents of heteroatoms and the chemical composition. The optimized catalyst exhibits high catalytic performance of 97 % ethylbenzene conversion and 98 % selectivity to acetophenone. Density functional theory simulations reveal that N, S‐co‐doping leads to the redistribution of charge and spin densities, introducing more active carbon atoms and realizing aerobic oxidation of ethylbenzene efficiently. This work presents a general strategy for molecular‐level design of carbon‐based catalysts, and also provides new insight into the influence of heteroatom‐doping on catalytic properties.

Molecular-level Modulation of N, S-Co-Doped Mesoporous Carbon Nanospheres for Selective Aqueous Catalytic Oxidation of Ethylbenzene.

Selective oxidation of aromatic alkanes into high value-added products through benzylic C-H bond activation is one of the main reactions in chemical industry. On account of the constantly increasing demand for mass production, efficient, eco-friendly and sustainable catalysts are urgently needed. Herein, we describe a facile and versatile emulsion-assisted interface self-assembly strategy towards molecular-level fabrication of co-doped mesoporous carbon nanospheres with controllable active N and S species. The method enables a high degree of control over nanoparticle sizes, mesoporous nanostructures, contents of heteroatoms and the chemical composition. The optimized catalyst exhibits high catalytic performance of 97 % ethylbenzene conversion and 98 % selectivity to acetophenone. Density functional theory simulations reveal that N, S-co-doping leads to the redistribution of charge and spin densities, introducing more active carbon atoms and realizing aerobic oxidation of ethylbenzene efficiently. This work presents a general strategy for molecular-level design of carbon-based catalysts, and also provides new insight into the influence of heteroatom-doping on catalytic properties.

Morphology-controlled mesoporous core–shell carbon nanospheres decorated with Cu nanoparticles as highly efficient and reusable catalyst

Environmental pollution caused by industrial waste has recently become a serious issue. Therefore, effective pollutant removal using nanotechnology is required, in which catalysts based on precious metals, such as Pt, Ag, Au, and Pd, are widely utilized. However, the manufacturing costs of precious metal catalysts are high. In this study, copper, a promising metal for catalysis, is evaluated as an alternative to precious metal catalysts because of its low cost, high efficiency, and abundant natural reserves. However, nanoparticle agglomeration is problematic when evaluating the catalytic performance of isolated metal nanoparticles. To solve this problem and maintain a high catalytic activity of Cu, in this study, Cu was loaded on a mesoporous carbon support derived from a carbon precursor with a core–shell structure. The core–shell-structured carbon precursor was obtained by coating resorcinol-formaldehyde polymer spheres as the core with a 50 nm thick polydopamine shell with 10 nm mesopores through π–π stacking interactions. A copper precursor was used to form Cu(OH)2 on the surface of the support, and then the nanocomposite was synthesized at 500 °C for 2 h. The synthesized copper-carbon nanocomposite exhibits high catalytic activity owing to its high specific surface area, porosity, and accessible internal space. It exhibits excellent catalytic activity and stability, along with excellent reusability, in the reduction of 4-nitrophenol to 4-aminophenol using NaBH4. Moreover, excellent catalytic activity, exceeding 99 %, was achieved in the reduction of another organic dye, methylene blue.

Synthesis of multi-element (F,N,S) doped carbon nanospheres derived from polystyrene as lubricant additives for tribological performance improvement

Synthesis of multi-element (F,N,S) doped carbon nanospheres derived from polystyrene as lubricant additives for tribological performance improvement

Tailoring Porous N-Doped Carbon Nanospheres for 3D Bottom-Up Electrode Design: A Versatile Synthesis Toolbox for Particle Size Independent Pore Size Control.

The rational design of carbon-based electrode materials plays an important role in improving the electrochemical properties of both, energy storage and energy conversion electrodes and devices. For most applications, well-defined and easily processable porous carbon-based electrode materials with controlled particle morphology (ideally spherical), particle size, and intraparticle pore size are desired. Here, a hard-templating synthesis toolbox is reported for highly-monodisperse meso- and macroporous N-doped carbon nanospheres (MPNCs) as a versatile material platform for the 3D bottom-up design of porous electrodes. With this approach, it is possible to change the MPNC pore size without affecting the particle size. By changing the template size, the pore size is adjusted between 15 and 99nm while maintaining a particle size ≈300nm. MPNCs are further used in electrochemical double-layer capacitors (EDLCs) as model application to demonstrate pore size effects on the performance independently from particle size effects, resulting in increasing specific capacitances for decreasing pores sizes, which correlates well with the surface area of the MPNCs and mass transport phenomena in the electrode. In conclusion, the toolbox allows to control intraparticulate porosities while keeping interparticulate properties constant, essential parameters to enable a true bottom-up 3D electrode design.

Activated Mesoporous N-Doped Carbon Nanospheres As Scaffolds for Li-S Battery Cathodes with High Capacity Retention

Currently, lithium-ion batteries rely on critical metals from third-world countries, which raises environmental and ethical concerns despite their popularity due to long device life and high capacity. Lithium-sulfur batteries (LSB) with sulfur as a cathode material, provide a compelling alternative. They offer high theoretical capacity and energy density, 3-5 times greater than lithium-ion batteries [1]. Sulfur, the fifth most abundant element on Earth, make LSBs cost-effective and environmentally friendly. However, LSBs have some critical drawbacks, such as low conductivity, volume expansion and cathode degradation, and irreversible loss of active materials due to polysulfides shuttle. To overcome these challenges, our group has developed activated nitrogen-doped mesoporous carbon nanospheres (MPNC) with high surface area [2,3] to load and encapsulate sulfur. In this work, we systematically explored the impact of the MPNC pore sizes, i.e. in meso- and micropore size range, on the performance of LSBs cathodes.The S@MPNC cathodes exhibited excellent cycling stability, retaining between 92 to 97% of the initial capacity over 200 cycles with a coulombic efficiency higher than 96 %, even at a high current density of 0.5 mAh·cm−2, among the best results reported to date. Cathode materials based on smaller pore sizes resulted in an increased initial capacity. However, larger pore sizes of MPNC can operate with higher sulfur loadings, better retaining their capacity than smaller pore S@MPNC nanocomposites due to the facilitated ion diffusion.In summary, the MPNC porous carbon structure provides enough space to host large amounts of sulfur to enhance the stability, accommodate the volume change of sulfur during cycling, and mitigate the dissolution of polysulfide intermediates.

Design of Highly Dispersed Pt Entities on Mesoporous N-Doped Carbon Nanospheres – Improving Pt Utilization for Hydrogen Evolution

Considering the global and growing technological demand for platinum, increasing its utilization is key in the context of green hydrogen production by proton exchange membrane water electrolysis. An effective strategy to increase Platinum utilization in Pt/C hydrogen evolution electrocatalysts is to increase the Pt dispersion on the conductive carbon support and to reduce the Pt nanoparticle size down to Pt clusters or even Pt single sites. In that context utilization of 3D porous N-doped carbon supports is helpful to form and stabilize highly dispersed Pt species and achieve high mass activities.In here we present two approaches for the synthesis of such electrocatalysts with high Pt dispersion for hydrogen evolution: one based on a simple wet impregnation with subsequent thermal reduction, the other based on a vapor phase CVD deposition. We use N-doped mesoporous carbon nanospheres as supports, with high surface area and surface functionality to build Pt nanoparticles, clusters, and single sites.The Pt speciation, depending on the synthesis approach, was thereby investigated a. o. by XRD, XPS, ac-STEM, XAS and electrochemical CO stripping. In all cases, when high Pt dispersion was achieved in form of Pt clusters and single sites, ultra-high mass activity was demonstrated at the RDE level [1,2].Literature:[1] Zeng, Z.; Küspert, S.; Balaghi, S. E.; Hussein, H. E. M.; Ortlieb, N.; Knäbbeler‐Buß, M.; Hügenell, P.; Pollitt, S.; Hug, N.; Melke, J.; Fischer, A. Small 2023, 2205885.[2] Küspert, S.; Campbell, I. E.; Zeng, Z.; Balaghi, S. E.; Ortlieb, N.; Thomann, R.; Knäbbeler‐Buß, M.; Allen, C. S.; Mohney, S. E.; Fischer, A. Small 2024, 2311260.

Tailored 3D Porous N-Doped Carbon Nanospheres for Bottom-up Electrode Design - Independent Pore and Particle Size Control for the Use in Model Electrodes

Design of porous carbon-based electrode materials and derived porous electrode structures is crucial for the performance of electrochemical energy storage and conversion devices. In that context carbon-based electrode material building blocks with well-defined properties are desired. Such properties include controlled morphology (preferably spherical), particle size, and intra-particle porosity along with controlled composition, surface chemistry, and processability. These factors influence the particle arrangement and electrode structure during processing, as well as electrolyte interaction, distribution, and mass transport phenomena within the electrode.In this work, we introduce a hard-templating method for producing highly uniform meso- and macroporous N-doped carbon nanospheres with independently tuneable pore and particle sizes, serving as a versatile material platform for the bottom-up design of 3D porous carbon electrodes. We could thereby customize the pore sizes between approximately 10 to 100 nm at a constant particle size, while particle sizes between 50 and 300 nm could be achieved for a constant pore size. Other physicochemical parameters such as chemical composition, graphitization, and surface functionalization remained constant across all samples, allowing for the exclusive investigation of pore and particle size effects independently from each other.We further used our different N-doped carbon nanospheres as building blocks for 3D porous electrodes and studied these in electrochemical double-layer capacitors with the aim to (i) showcase the versatility of our materials and (ii) examine pore and particle size effects on the performance. Indeed, electrochemical double-layer capacitors serve as an excellent model system for such investigations due to their sensitivity to carbon particle surface area, pore size, and mass transport phenomena within the 3D percolated structure of porous carbon electrodes.

Ionic-Liquid-Assisted synthesis of N, F, and P codoped FeNC/HSs on hollow carbon nanospheres for Li–S batteries

The severe shuttle effect and slow redox kinetics of polysulfides are major obstacles to the practical application of lithium sulfur batteries. In this study, we proposed a method for synthesizing hollow carbon nanospheres supported by iron single-atom catalysts using [HMIM] PF6 ionic liquid (IL) as a promoter. Metal single atoms are embedded in carbon nanospheres to mitigateshuttle effects and enhance the bidirectional redox kinetics of sulfur. The incorporation of iron sites is beneficial for the reduction reaction of polysulfides, and the addition of ionic liquids not only increases the porosity of the catalyst but also enhances the loading of iron atoms. The sulfur cathode with metal single atom pairs exhibited an ultra-high capacity retention rate of 73.8 % after 150 cycles at 0.2C. Even under a high sulfur load of 6.58 mg cm−2 and a current density of 0.2C, an ideal areal capacity of 4.64mAh cm−2can still be maintained. Impressively, the assembled button cell battery achieved a high discharge capacity of 1451mAh/g and maintained 867.9mAh/g after 150 cycles at 0.2C. This work provides new insights into designing loaded single-atom catalysts for application in lithium sulfur batteries.

Porous Nitrogen-Doped Carbon Supported Pt Nanocatalyst for Efficient Oxygen Reduction Reactions

Oxygen reduction reaction (ORR) at catalyst surface is the key kinetic limiting step in fuel cells that influence the overall cell performance in the energy conversion process. Rational design of the carbon supports with unique morphology and controllable porosity is challenging and significant for efficient and durable oxygen reduction electrocatalysis. Nitrogen-doped carbon nanospheres with uniform size and precise control over mesopores and micropores have been derived from mussel-inspired biomimetic polydopamine through a facile colloidal synthesis method and subsequent high-temperature pyrolysis. The unique surface structure of this nitrogen-doped carbon also dictated the morphologies of the deposited platinum nanoparticles, alleviating the particle dissolution, detachment, and agglomeration issue, which are main factors for catalyst degradation in working conditions. The ORR activity and durability of this electrocatalysts were studied in both rotational disk electrode (RDE) system and membrane electrode assembly (MEA), and a detailed structure-property relationship between porosity of carbon supports, Pt morphologies and fuel cell ORR performance was uncovered. This work is informative to researchers working in electrochemical materials field for developing efficient and robust electrocatalyst supports.Acknowledgement: This research was supported by the Hydrogen and Fuel Cell Technologies Office (HFTO), Office of Energy Efficiency and Renewable Energy, US Department of Energy (DOE) through the Million Mile Fuel Cell Truck (M2FCT) consortium, technology managers G. Kleen and D. Papageorgopoulos.

Bimetallic Cofe Nanoparticles Embedded in Hierarchically Meso-Macroporous N-Doped Carbon Nanospheres As Electrocatalyst for Excellent Oxygen Reduction Reaction

Proton exchange membrane fuel cells (PEMFCs) are regarded as a highly promising technology for clean and sustainable energy conversion, but face challenges due to their reliance on costly noble metals and sluggish oxygen reduction reaction (ORR) kinetics[1]. Therefore, development of effective catalysts to serve as the alternatives of platinum group metals is required. So far, metal-nitrogen-carbon (M-N-C) materials are considered as the most promising electrocatalysts for ORR[2]. Their performance, however, are still impeded by the low density and accessibility of active metal sites. In this work, we developed a remarkable ORR electrocatalysts by assembling bimetallic CoFe nanoparticles on hierarchically meso-macroporous N-doped carbon nanospheres. This hierarchically structured meso-macroporous N-doped carbon serves as a conductive carrier and provides abundant exposed sites for the active metal species. In turn, the bimetallic CoFe nanoparticles significantly increase the total density of active catalytic sites for ORR. As a result, the optimized CoFe nanoparticles embedded in meso-macroporous N-doped carbon (CoFe@MesoMacroNC) delivered superior ORR activities in both alkali (half-wave potential = 0.943 V vs. RHE) and acid media (half-wave potential = 0.811 V vs. RHE). In addition, when the CoFe@MesoMacroNC was assembled in a Zn-air battery, it showed a higher power density of 155 mW cm-2 than commercial Pt/C (137 mW cm-2) as well as a better stability.

Amorphous MoS3 Anchored within Hollow Carbon as a Cathode Material for Magnesium-Ion Batteries.

Magnesium-ion batteries are considered the next-generation promising large-scale energy storage devices owing to the low-cost and nondendritic features of metallic Mg anode. Nevertheless, such strong electrostatic interaction between bivalent Mg2+ and crystalline cathode materials will lead to low capacity and poor diffusion kinetics, which seriously hinders the further development of magnesium-ion batteries. Herein, amorphization and anion-rich strategies are employed to prepare well-designed cathode materials with MoS3 anchored on hollow carbon nanospheres (a-MoS3/HCS). The amorphous MoS3 provides unrestricted 3D diffusion access and effectively boosts the Mg2+ diffusion kinetics, while the anion-rich feature of MoS3 offers rich active sites for Mg2+ storage and finally contributes to a high discharge capacity driven by the anionic redox mechanism. Moreover, the effective modification of hollow carbon nanospheres buffers the volumetric changes of MoS3 and improves the electron transfer efficiency. Owing to the above-mentioned multiple advantages, a-MoS3/HCS exhibits an ultrahigh discharge capacity (489.2 mAh g-1 at 50 mA g-1) and high cyclic performance (200.1 mAh g-1 at 2 A g-1 for 300 cycles), distinctly superior to those of crystalline 1T/2H-MoS2/HCS and 2H-MoS2/HCS and surpassing almost all of the molybdenum sulfide-based cathodes. Furthermore, the high-performance a-MoS3/HCS-based pouch cell with the ability to drive various mini-type devices confirms the potential application values. The excellent magnesium storage properties of a-MoS3/HCS are further verified by the related kinetics analysis, DFT theoretical calculation, and reversible electrochemical reactions. The amorphous and redox-rich tactics of a-MoS3/HCS provide an innovative pathway to explore high-efficiency cathode materials for various multivalent-ion batteries.