Functionalized Carbon Spheres Research Articles

Crosslinking assembly of Propenyl-Calix[4]-Crown-6 interpenetrating functional mesoporous carbon Spheres: High selectivity and stability to Remove Cs(I) from high acid solution

The calix[4]-crown-6 ligand shows high selectivity for Cs(I) over other alkali and alkaline earth metal cations, making it a promising candidate for radiocesium separation. However, its high viscosity and poor adhesion limit its practical use and stability. In this study, an alkenyl-functionalized calix[4]-crown-6 (p-C[4]C6) was developed. Using a mesoporous structure and post-assembly techniques, a composite (p-C[4]C6/MMCs) was created via crosslinking within mesoporous matrix channels. The p-C[4]C6/MMCs exhibited high stability and practicality. The p-C[4]C6/MMCs demonstrated high selectivity, good reusability, and significant adsorption capacity (47.76 mg/g) for Cs(I) in 3.0 M HNO3. Kinetic, isotherm, and thermodynamic studies suggest a spontaneous chemical adsorption mechanism. This research provides insights into the design of calix[4]-crown-6 based materials and offers a viable approach for Cs(I) separation from high-level liquid waste (HLW).

High-performance electrochemical immunosensor based on bimetallic gold/silver functionalized carbon spheres for CYFRA 21-1 detection and information protection.

Bimetallic nanomaterial-based systems have been widely utilized across various fields due to their remarkable expandability and flexibility, including nanomedicine, diagnostics, and molecular information technology. Here, we constructed an electrochemical immunosensor using bimetallic gold/silver functionalized carbon spheres (AuAg@CSs) and mesoporous silica nanoparticles (MSNs) for the sensitive determination of cytokeratin 19 fragment antigen 21-1 (CYFRA 21-1) and ensuring information protection for textual data. The AuAg@CSs demonstrated exceptional catalytic activity towards hydrogen peroxide, generating a significant current signal. The introduction of CYFRA 21-1 facilitated the binding of MSNs, thereby forming a sandwich-type electrochemical immunosensor that resulted in a notable decrease in current. Notably, the detection limit for CYFRA 21-1 was determined to be 31 fg mL-1, accompanied by high selectivity. Furthermore, extensive textual information can be encrypted and concealed within the current responses of the electrochemical nanosensing system. By establishing a threshold, these current signals can be represented as a series of binary strings, which can subsequently be segmented into shorter strings. Through information coding methods, these shorter binary strings can be assembled and decrypted, ultimately merging into meaningful textual content. This study promotes the synthesis and multifunctional application of bimetallic nanomaterials, providing innovative solutions to enhance the sensing sensitivity of electrochemical immunosensors and paving the way for advancements in molecular digitization.

Functionalized Carbon Spheres for Energy-Efficient CO2 Capture: Synthesis, Application, and Reaction Mechanism

Functionalized Carbon Spheres for Energy-Efficient CO₂ Capture: Synthesis, Application, and Reaction Mechanism

Waste-biomass tar functionalized carbon spheres with N/P Co-doping and hierarchical pores as sustainable low-cost energy storage materials

Biomass tar has exhibited promising potential for fabricating carbon-based functional materials. In this study, carbon materials with hierarchical pores, N/P co-doping, and oxygen-rich functional groups were prepared from glucose and biomass tar via a hydrothermal treatment combined with H3PO4 activation strategy and their electrochemical performances were evaluated. The results showed that the coating of tar inhibited agglomeration of carbon sphere derived from glucose and regulated its surface properties, resulting in hierarchical porous structure and surface functional groups. During thermal treatment, the resultant carbon materials were appropriately self-heteroatom doped by N and P from tar and H3PO4, respectively. Due to the unique structure, the specific capacitance of as-prepared carbon electrode was 199 F g−1. The symmetric TGC-600 capacitor showed excellent electrochemical properties with specific capacitance of 175 F g−1 and energy density of 6.1 Wh kg−1. Furthermore, TGC-600 capacitor showed superior cyclic stability, the capacitance retention was around 92% after 5000 runs. This study offered a green and low-cost utilization approach for biomass tar to prepare supercapacitor with excellent electrochemical performance.

In-situ synthesis of Cu/Cu2+1O/carbon spheres for the electrochemical sensing of glucose in serum

Based on the serious influence of the diabetes and the high need on the efficient monitoring of blood glucose, the development of the simple method for the sensitive and accurate analysis of glucose is extremely desirable and attractive for the life quality of diabetic patients. Herein, a facial method was reported for the synthesis of Cu/Cu 2+1 O nanoparticles modified carbon spheres (Cu/Cu 2+1 O/CSs) via in-situ reduction of the adsorbed Cu 2+ ions onto the surface of carbon spheres. The dependence of the different adsorption amount of Cu 2+ ions and the calcination temperature on the morphology and composition of Cu/Cu 2+1 O/CSs was investigated and characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), XRD, and Fourier transformed infrared spectroscopy (FTIR). The as-prepared Cu/Cu 2+1 O/CSs was further developed for the analysis of glucose, where the functionalized carbon spheres and the well distributed Cu/Cu 2+1 O nanoparticles with the multivalence copper presented the efficient electrochemical catalytic ability towards glucose, leading to the improved electrochemical behavior. It exhibited a wide concentration range from 0.30 μM to 24.50 mM with the high sensitivity and low detection limit (66 nM). Besides, the Cu/Cu 2+1 O/CSs showed the favorable anti-interference and stability. Moreover, the sensor was successfully applied for the sensing of glucose in human serum samples. This work developed a facial and efficient approach for the functionalization of carbon spheres, and could serve as a reliable platform for the electrochemical analysis and medical diagnostics.

Eu(III) complex coated carbon sphere core-shell material for fluorescence detection, catalytic reduction and real-time monitoring of nitrophenol compounds

In this work, we rationally designed an integrated system that fixed the Eu-L complexes on the surface of functionalized carbon spheres through electrostatic adsorption as a new type of catalyst. The catalyst CS@Eu-L can realize fluorescence sensing, in-situ removing and real-time monitoring of nitrophenols compounds (NPCs). CS@Eu-L can detect 4-NP in aqueous solution with high sensitivity (Ksv = 4.1 × 104 M−1). At the same time, CS@Eu-L can also act as a catalyst to reduce 4-NP to 4-AP with an apparent reaction rate of 5.92 × 10-3 s−1. Furthermore, the mechanism for the selective sensing of NPCs was also explored and explained by energy competition between NPCs and Eu(III). Moreover, CS@Eu-L has good fluorescence sensing and catalytic cycle stability. It is worth mentioning that the multiple functions of CS@Eu-L are aimed at the same target compound. CS@Eu-L is expected to provide a possible means for sustainable green catalysts in wastewater detection and treatment.

Improved tribological behavior of lubricating oil dispersed with hybrid nanoparticles of functionalized carbon spheres and graphene nano platelets

A novel synthesis method of Functionalized Carbon Spheres (FCS) coated with Graphene nanoplatelets (GNP) using a simple sonication technique is reported. The FCS/GNP hybrid nanoparticles were found to be effectively improving the tribological characteristics of lubricating oils. For the synthesis of FCS, Carbon Spheres (CS) synthesized via non-catalytic chemical vapor deposition was functionalized using nitric acid. The hybrid nanoparticles were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Raman spectroscopy. The tribological behavior of CASTROL-20 W 40 engine oil dispersed with different concentrations of FCS and GNP using ultrasonication was investigated using a four-ball tester. The tribological behavior of FCS and GNP were investigated separately to compare the tribological performance of the FCS/GNP hybrid nanoparticles. The neat oil dispersed with 0.275 wt% of FCS/GNP hybrid nanoparticles in 10:1 ratio shows excellent dispersion and stability for 30 days without the addition of any surfactant. The results indicate that the addition of these hybrid nanoparticles causes a remarkable reduction (~18%) in the Coefficient of Friction (COF) of the neat oil. The optical image of wear scar on the ball immersed in neat oil shows a significant reduction in the Wear Scar Diameter from 425.6 µm to 390.0 µm with the addition of hybrid nanoparticles. The Raman mapping of the wear scar on chromium steel ball reveals that the FCS/GNP hybrid nanoparticles remain unseparated after the tribology test.

Tailoring Polymer Colloids Derived Porous Carbon Spheres Based on Specific Chemical Reactions.

Porous carbon spheres derived from polymer colloids with regular geometry, monodispersed morphology, well-controlled contents and structures play important roles in many areas of application, such as energy storage/conversion, gas adsorption/separation, catalysis, and chemo-photothermal therapy. Suitable polymerization reaction and synthetic strategy are both critical for the obtainment of stable polymer colloids as carbon precursors. Basic polymerization reactions are the cornerstones of synthetic strategies, which directly provides the direct molecular-based design of functionalized polymer/carbon spheres. Thus, this progress report mainly focuses on the summary of suitable polymerization reactions for colloidal polymer derived porous carbon spheres. Recent advances in the synthetic strategies and applications are also discussed, including their corresponding polymerization reactions. Finally, the perspectives for the development of polymer derived porous carbon spheres are provided based on the controlled synthesis of polymer colloids and optimization over the carbonization process to achieve highly functionalized carbon spheres for practical applications.

Hydrangea-like N/O codoped porous carbons for high-energy supercapacitors

Carbons with specific morphologies, compositions and structures have aroused scientific and technological interest due to their intriguing and overwhelming properties for multi-purpose applications. Herein, a novel route to convert Knoevenagel copolymer into hydrangea-like, N/O codoped, and high-surface-area porous carbon (HPC) spheres with excellent supercapacitive performances is presented. By crosslinking p-phenylenediacetonitrile with two aromatic aldehyde co-monomers, as-prepared material exhibits a unique architecture of intertwined nanosheets uniformly self-assembled on the surfaces of microporous spheres. Featuring a large adsorbing platform (1963 m2 g−1), multi-scale pore structure and diverse N/O functional groups, HPC electrode carbonized-activated at the optimal temperature of 700 °C yields a prominent capacitance of 330 F g−1 at 1 A g−1, along with a satisfactory rate capability of 221 F g−1 at 20 A g−1 in KOH electrolyte. More importantly, taking advantage of a refined interphase between the high-concentration water-in-salt Li-TFSI layer and the ion-accessible hydrangea surface, HPC-based supercapacitor gives a higher energy delivery of 32.9 Wh kg−1 at 575 W kg−1 than the common devices using KOH (10.93 Wh kg−1 at 100 W kg−1) and Na2SO4 (24.9 Wh kg−1 at 180 W kg−1), with high-voltage aqueous durability of 90.5% retention over 10,000 cycles at 2.3 V. This inspiring work enriches the methodology for fabricating functionalized carbon spheres that are expected to boom diverse applications.

In Situ Pore Self-Formed Strategy for the Preparation of Sulfur-Doped Hierarchical Porous Carbon Spheres for Supercapacitors

Hierarchical porous carbon spheres (HPCSs) have been widely used in energy storage and conversion due to their open framework, high specific surface area and chemical stability. Here, we report a novel and facile method to synthesize porous phenolic resin spheres through an in situ pore self-formed strategy. The phenolic resin spheres can directly transform into sulfur-doped HPCSs by carbonization and activation. The hierarchical porous structure maximizes the specific surface area and facilitates ion diffusion and transport. Combine with the hierarchical porous structure, high specific surface area and suitable S doping content, the HPCSs-based symmetric supercapacitor presents high energy density of 12 Wh kg−1 and outstanding power output capability of 28 kW kg−1. This methodology provides a new way for the preparation of HPCSs and other functional porous carbon spheres with adjustable pore structure and surface properties.

Phosphonate functionalized carbon spheres as Brønsted acid catalysts for the valorization of bio-renewable α-pinene oxide to trans-carveol

Herein, we report a simple route for the synthesis of phosphonate functionalized Brønsted solid acid carbon spheres as heterogeneous catalyst for the valorization of bio-derived α-pinene oxide. The Brønsted acidity was generated via two steps; hydrothermal carbonization of sugar to produce carbon microspheres followed by PCl3 treatment to form phosphonate functionalized carbon. The presence of phosphonate was confirmed by CP-MAS 31P and 13C NMR. In addition, the presence of the P-C, O-P-C and HO-P[double bond, length as m-dash]O bonds of the phosphonate group was confirmed by FT-IR, 31P NMR, and XPS. SEM-EDAX analysis revealed the presence of a phosphorus content of ∼1.71 wt% on the surface of the catalyst while elemental mapping showed a uniform dispersion of phosphorus over the carbon spheres. The as-synthesized Brønsted solid acid catalyst was used for the isomerization of α-pinene oxide which gave 100% conversion with 67% trans-carveol selectivity in highly polar basic solvent in 1 h reaction time. Also, the catalyst showed good recyclable activity even after five cycles.

Large scale synthesis of nitrogen-doped nanoporous carbon spheres based on miniemulsion polymerization for efficient dye removal

Functional nanoporous carbon spheres (NPCS) are important for applications ranging from adsorption, catalysis, separation to energy storage and biomedicine. We demonstrated a facile method to synthesize uniform NPCS, involving the formation of polyacrylonitrile@poly (γ-methacryloxypropyl trimethoxysilane) (PAN@PMPS) composite particles via seeded miniemulsion polymerization of PAN nanoparticles (NPs), carbonization, and subsequent removal of the outer PMPS shell. The influences of the addition of water phase inhibitor sodium nitrite and crosslinking agent divinylbenzene on the morphologies of PAN@PMPS composite particles were investigated. The adsorption performance of NPCS towards methylene blue (MB) was investigated. The results showed that uniform PAN@PMPS composite particles were obtained with average diameters of ~ 149 nm when using NaNO2 as water phase inhibitor. PMPS layer prevented PAN core aggregation/fusion during the carbonization process, resulting in the formation of individual NPCS. Uniform NPCS exhibiting diameters of ~ 122 nm, with the accessible surface area (~ 202 m2/g), and high nitrogen content (13.75 wt%) was obtained. NPCS exhibited excellent adsorption capacity towards MB with the maximum value of 117.89 mg/g at 298 K from aqueous solution. This miniemulsion polymerization-based strategy provides a new, facile approach to prepare high-performance porous carbon spheres in industrialization promise.

Individual Nanoporous Carbon Spheres with High Nitrogen Content from Polyacrylonitrile Nanoparticles with Sacrificial Protective Layers

Functional nanoporous carbon spheres (NPC-S) are important for applications ranging from adsorption, catalysis, separation to energy storage, and biomedicine. The development of effective NPC-S materials has been hindered by the fusion of particles during the pyrolytic process that results in agglomerated materials with reduced activity. Herein, we present a process that enables the scalable synthesis of dispersed NPC-S materials by coating sacrificial protective layers around polyacrylonitrile nanoparticles (PAN NPs) to prevent interparticle cross-linking during carbonization. In a first step, PAN NPs are synthesized using miniemulsion polymerization, followed by grafting of 3-(triethoxysilyl)propyl methacrylate (TESPMA) to form well-defined core-shell structured PAN@PTESPMA nanospheres. The cross-linked PTESPMA brush layer suppresses cross-linking reactions during carbonization. Uniform NPC-S exhibiting diameters of ∼100 nm, with relatively high accessible surface area (∼424 m2/g), and high nitrogen content (14.8 wt %) was obtained. When compared to a regular nanoporous carbon monolith (NPC-M), the nitrogen-doped NPC-S demonstrated better performance for CO2 capture with a higher CO2/N2 selectivity, an increased efficiency in catalytic oxygen reduction reactions, as well as improved electrochemical capacitive behavior. This miniemulsion polymerization-based strategy for the preparation of functional PAN NPs provides a new, facile approach to prepare high-performance porous carbon spheres for diverse applications.

Approachable Way to Synthesize 3D Silica Hollow Nanospheres with Mesoporous Shells via Simple Template‐Assisted Technique

Abstract3D porous silica hollow nanospheres (PSHNSs) with mesoporous walls have been successfully fabricated by simple template‐assisted method using tetraethoxysilan (TEOS) as a silica precursor and glucose‐derived functionalized carbon spheres (FCSs) as hard templates. Template‐precursor hybrid composite spheres were formed by direct adsorption of the silica precursor onto the surface layers of the FCSs. After etching of the template via oxidation in air, free standing 3D PSHNSs were obtained. The resulting PSHNSs were ∼ 85 nm in size as indicated by both SEM and TEM images. BET analysis has shown that nanospheres to have a large specific surface area up to 400 m2/g. The fascinating structure of 3D PSHNSs may provide more accessibility and good contacts with reactants that is very important in the fields of catalysts, gas adsorbent, heavy metals removal, electronics, and so on.

Synthesis of novel functional hydrothermal carbon spheres for removal of uranium from aqueous solution

A novel chelate sorbent (bis-3,4-dihydroxybenzy)p-phenylen diamine-grafted hydrothermal carbon spheres (HCS-BDBPD) had been successfully synthesized through chemical grafting method. FT-IR and SEM were used to analyze the chemical and microscopy structure of HCS-BDBPD. The batch experiments were carried out to study uranium adsorption properties of HCSs-BDBPD aimed at confirming the optimum condition for removal uranium from waste. The result showed that the sorption process was spontaneous and endothermic in nature and the maximum uranium sorption capacity of 272 mg/g was obtained under the conditions tested, the selectivity of HCSs toward uranium was improved after grafting BDBPD groups on the surface of HCSs.

Seeded Synthesis of Monodisperse Core-Shell and Hollow Carbon Spheres.

Monodisperse carbon spheres between 500 and 900 nm are hydrothermally synthesized from glucose on polystyrene seeds. Control over temperature, time, glucose concentration, and seed size yields hybrid spheres without aggregation and no additional spheres population. Pyrolysis transforms the hybrid into hollow carbon spheres preserving monodispersity. This approach provides a basis for functional carbon spheres applicable in photonics and energy storage.

RETRACTED: Experimental design and kinetic study of ultrasonic assisted transesterification of waste cooking oil over sulfonated carbon catalyst derived from cyclodextrin

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The editor reviewed and confirmed that the paper duplicated contents from the paper, “Ultrasonic-assisted biodiesel production from waste cooking oil over novel sulfonic functionalized carbon spheres derived from cyclodextrin via one-step: a way to produce biodiesel at short reaction time” published in RSC Advances 5 (2015) 55252–55261 (DOI: 10.1039/C5RA09499B). The above paper is essentially redundant without proper citation and especially almost all experimental data in two papers are duplicated even though some parts are different about the optimization of biodiesel production using conventional method with Box-Behnken design over the same catalyst for comparison and experiment on part of catalyst reusability up to 12 cycles to let researchers know more efficiency of the catalyst. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Ultrasonic-assisted biodiesel production from waste cooking oil over novel sulfonic functionalized carbon spheres derived from cyclodextrin via one-step: a way to produce biodiesel at short reaction time

A novel sulfonated carbon derived from cyclodextrin showed high catalytic activity for the ultrasonic-assisted transesterification of waste cooking oil.

Functionalized Carbon Spheres for Extraction of Nanoparticles and Catalyst Support in Water

Increased use of nanomaterials in commercial products will lead to environmental contamination in the near future. So far, limited adsorbents are available for the removal of such emerging pollutants from water. The objective of this work was to synthesize functionalized carbon nanospheres (C-spheres) for the removal of emerging nanopollutants from water and to study the mechanisms involved. C-spheres were prepared using hydrothermal carbonization of glucose. Post-modification with polyethylenimine (PEI) generated amine-coated C-spheres, followed by protonation using diluted acid solution. The surface functional groups and morphologies of the C-spheres were characterized using infrared spectroscopy and field emission scanning electron microscopy, respectively. The C-spheres were used for the extraction of citrate-capped gold and silver nanoparticles from water. The equilibrium adsorption data was interpreted using Langmuir and Freundlich isotherms, and the adsorption mechanism was investigated using kinet...

Tunable, Functional Carbon Spheres Derived from Rapid Synthesis of Resorcinol-Formaldehyde Resins

In this article, the rapid synthesis of colloidal, spherical polymer resins via enhanced copolymerization and polycondensation of resorcinol with formaldehyde is presented. The ultrasound-mediated technique assembles perfectly spherical resins in less than 5 min due to generated active species and free radicals produced in an aqueous ammonia-ethanol-water solvent. In this report, numerous controlled experiments account for and support the important role of high intensity ultrasounds in the rapid cluster formation, condensation, and gelation process of resorcinol with formaldehyde in the presence of ammonia catalyst. After a controlled heat treatment process, amorphous carbon spheres are obtained from these spherical polymer resins. The effect of temperature (up to 1100 °C) on the structural evolution of these carbon spheres is meticulously studied which is lacking in the previous literature. The resorcinol-formaldehyde resins carbonized at 600 and 900 °C demonstrate BET surface areas of 592.4 m(2)/g and 952.5 m(2)/g with specific capacitances of 17.5, and 33.5 F/g (scan rate of 5 mV/s), respectively.