Carbon Spheres Research Articles

High efficiency azo dye removal via a combination of adsorption and photocatalytic processes using heterojunction Titanium dioxide nanoparticles on hierarchical porous carbon

Amidst the rapid development of the textile industry, wastewater problems also arise. High-performance materials for reactive black 5 (RB5) dye treatment by adsorption and photocatalysis were evolved using Titanium dioxide (TiO2) nanoparticles on carbon media. Herein, the synthesis of spherical carbon via the water–in–oil emulsion method alongside a sol–gel process and the production of TiO2 nanoparticles using the precipitation procedure of Titanium isopropoxide and carbonization at 700–900 °C for 2 h are a novel approach in this work. The characterization of these materials indicates that different temperatures result in distinct properties, for instance, raised pores on the surface of the media and changes in the crystal structure of TiO2. The results show that the as-synthesized material carbonized at 900 °C had distinguished dye adsorption, up to 430 ppm in 1 h, due to their high surface area and pore volume. On the contrary, the calcined 700 °C condition had the prominent photocatalytic efficiency on account of the heterojunction band gap between anatase and rutile crystal structure. A mixed phase minimizes the charge recombination, subsequently increasing the photocatalytic capability.

C@Ag core-shell structure as lubricating additives towards high efficient lubrication

Efficient cooperative lubrication can be achieved via the introduction of core-shell structure lubricant additives with hard core and soft shell, for obtaining the expected anti-wear performance from the structural changes in the friction process. In this study, C@Ag microspheres with a core-shell structure were prepared by the redox method with carbon spheres as the core and Ag nanoparticles as the shell. Their tribological behaviors as base oil (G1830) additive with different concentrations were investigated in detail. Compared with base oil, the addition of C@Ag particles at 0.5 wt% can reduce the coefficient of friction (COF) and wear volume (Wv) up to 15.5% and 88%, respectively. More importantly, C@Ag particles provide superior lubrication performance to single additive (like carbon sphere (CS) and Ag nanoparticle). C@Ag core-shell particles contribute to the formation of tribo-film by melt bonding of flexible Ag and carbon sphere (CS) toward excellent self-repair performance and high-efficiency lubrication. Hence, core-shell structural nanoparticles with hard-core and soft-shell hold bright future for high-performance lubrication application.

Controllable synthesis and magnetization of Fe3O4 microspheres wrapped with amorphous carbon

A straightforward solvothermal methodology was employed to synthesize [Formula: see text] microspheres and [Formula: see text]@C hybrids, where amorphous carbon encapsulated [Formula: see text] microspheres. This encapsulation was achieved by meticulously controlling the reaction duration and glucose concentrations within the hydrothermal process. Analysis via X-ray diffraction and Raman spectroscopy confirmed that all specimens retained a homogeneous [Formula: see text] phase. Following encapsulation, the [Formula: see text] particles were uniformly distributed across the amorphous carbon spheres, with fine particle sizes in the hybrids measuring less than 20 nm. Magnetic characterization revealed that parameters such as saturation magnetization, remanent magnetization, and coercivity of the [Formula: see text] microspheres could be significantly adjusted by varying the hydrothermal reaction time. Notably, the hybrids exhibited a 5- to 10-fold increase in both coercivity and remanent magnetization when compared to the pristine [Formula: see text] microspheres. Nonetheless, the saturation magnetization of the hybrids reached up to 90% of that observed in bulk [Formula: see text]. These magnetic properties are predominantly influenced by the size effect associated with the nanostructured [Formula: see text].

CuFeS2/Carbon Sphere Nanocomposites for Improved Capacitive Performance

CuFeS2 has many advantages, like high electrical conductivity, multiple redox centers, natural abundance and nontoxic. However, the low capacitance limits their application. In this work, we use carbon spheres (CS) prepared from starch to modify CuFeS2. The prepared CuFeS2/CS shows special structures with the CS as the core and CuFeS2 as the shell. These CuFeS2/CS nanocomposites show improved capacitive performance. CuFeS2/CS has a specific capacitance of 349.4[Formula: see text]F[Formula: see text]g[Formula: see text] at 0.5[Formula: see text]A[Formula: see text]g[Formula: see text], four times that of pristine CuFeS2 (88.8[Formula: see text]F[Formula: see text]g[Formula: see text], which might be attributed to the increased electrolyte diffusion capacity. The cyclic stability is also slightly improved, from 86.4% of the pristine CuFeS2 to 90.5% of the CuFeS2/CS nanocomposites due to the rigid structure of both crystal CuFeS2 and firm CS. These CuFeS2/CS nanocomposites are expected to be used in high-performance supercapacitor applications.

MOF derived M/Sn/N (M= Mg, Mn) based carbon nanospheres as highly efficient multicomponent electrocatalysts towards hydrogen evolution and photovoltaics

Constructing multicomponent electrocatalysts towards efficient energy conversion is widely adopted strategy, in this regard, high performance metal/nonmetal codoped carbon electrode materials have attained great consideration. Still, the electroacatalytic susceptibility, abundant intrinsic active sites, and stable electrochemical performance in different electrolytes are considered as underline challenges, which can be addressed by rational structural modifications to build a hybrid electroactive material. In this work, unique Sn based multicomponent carbon nanospheres are firstly developed as highly efficient bi-functional electrocatalysts in solar cells and hydrogen evolution. The designed electrocatalysts feature the combined effect of dispersed bimetal active sites and sufficient nitrogen components within spherical carbon framework, which readily enhanced the charge transfer rate via multiple channels, boosting the triiodide reduction reaction (IRR) and hydrogen evolution reaction (HER). As a result, solar cell with Mn/Sn-NC based counter electrodes (CEs) exhibited an excellent power conversion efficiency (PCE) of 8.39 %, outperforming Pt (7.67 %). Moreover, superior HER kinetics are also demonstrated by Mn/Sn-NC with a small overpotential of 127.8 mV at 10 mA cm−2 and tafel slope of 77 mV dec−1. The rational design of the carbon nanospheres with MnSn2 bimetal nanoparticles and N doping promotes a high electrochemically active surface area, low charge-transfer resistance, excellent electrochemical stability, and superior electrocatalytic activity, providing a promising route to construct highly efficient materials towards multiple energy conversion applications.

Atomically dispersed Co/Mn immobilized on O, N dual doped hollow carbon spheres as sulfur host for lithium sulfur batteries

The regulation of the chemical coordination environment in the electrocatalyst can effectively suppress the shuttle effect of sulfur species in lithium-sulfur batteries. However, the mechanism of the atomically dispersed dual metal atom with the coordination of various heteroatoms used as the sulfur cathode catalyst and trapper remains unknown. This study introduces, for the first time, atomically dispersed Co and Mn in-situ immobilized on O, N dual-doped hollow carbon spheres (SACoMn/C-(N, O)) as sulfur host. Experiments combined with density functional theory calculations reveal that the synergy between Co-(N, O) and Mn-(N, O) sites enhances the nucleation/deposition and decomposition capabilities of Li2S. This enhancement is attributed to the anchoring-coupling-conversion behavior of sulfur species on the SACoMn/C-(N, O) surface, which effectively restrains the shuttle effect and facilitates the conversion kinetics. Moreover, the cooperation of dual metal atoms with O, N non-metal atoms embedded in the carbon network structure accelerates electric transport and ion diffusion kinetics. The cathode demonstrates a high initial specific capacity of 890 mAh·g−1 at 1 C and show exceptional long-term cycling durability, with a low capacity degradation of 0.037 % per cycle after 1700 cycles. This research may offer novel insights into the design of dual metal atom-decorated, functionalized carbon materials to improve the conversion reaction in sulfur cathodes.

Chemical activation and magnetization of carbonaceous materials fabricated from waste plastics and their evaluation for methylene blue adsorption.

In this study, novel adsorbents were synthesized via the activation and magnetization of carbon spheres, graphene, and carbon nanotubes fabricated from plastics to improve their surface area and porosity and facilitate their separation from aqueous solutions. Fourier transform infrared spectroscopy "FTIR", X-ray diffraction "XRD", energy-dispersive X-ray spectroscopy "EDX", transmission electron microscope "TEM", and X-ray photoelectron spectroscopy "XPS" affirmed the successful activation and magnetization of the fabricated materials. Further, surface area analysis showed that the activation and magnetization enhanced the surface area. The weight loss ratio decreased from nearly 60% in the case of activated graphene to around 25% after magnetization, and the same trend was observed in the other materials confirming that magnetization improved the thermal stability of the fabricated materials. The prepared carbonaceous materials showed superparamagnetic properties according to the magnetic saturation values obtained from vibrating sample magnetometry analysis, where the magnetic saturation values were 33.77, 38.75, and 27.18 emu/g in the presence of magnetic activated carbon spheres, graphene, and carbon nanotubes, respectively. The adsorption efficiencies of methylene blue (MB) were 76.9%, 96.3%, and 74.8% in the presence of magnetic activated carbon spheres, graphene, and carbon nanotubes, respectively. This study proposes efficient adsorbents with low cost and high adsorption efficiency that can be applied on an industrial scale to remove emerging pollutants.

A comprehensive study of carbon nanoparticle shape and orientation effects on composite elastic properties using FEA

In this study, three critical parameters that influence the effective composite properties of Carbon nanoparticles were tested and modeled using finite elements through Digimat Finite Element Analysis (FEA) software, employing representative volume elements (RVE). The primary parameters under consideration are the fiber shape, fiber orientation, and fiber volume fraction. Four of the many different shapes of Carbon nanoparticles, namely Tubes, Disk, Sphere, and Cylinder, were investigated, coupled with four distinct orientations for tubes: horizontal, aligned at 45°, random, and vertical each varying in the carbon fiber volume fraction. The material of choice was pure epoxy resin because of the nature of the bonding between its two phases and its wide range of usage. Forces were applied along the X-axis, coupled with shear in the XY plane. This study revealed that the orientation of CNTs primarily influences the Elastic Young’s modulus, whereas the size of the CNTs has the main effect on the shear modulus, followed by orientation. The horizontal CNTs demonstrated superior Young’s modulus, but the random orientation had a more pronounced impact on the shear modulus variation. Regarding the analysis of the nanoparticles shapes, the disk shape with fixed orientation revealed the highest elastic modulus, after which the cylinder shape and the sphere recorded the minimum elastic modulus among the three studied shapes.

Fischer-Tropsch synthesis: Platinum promoted Co@HCS catalysts

Hollow carbon sphere (HCS) nanoreactors were used as a catalyst support for Co, with Pt as a promoter. The hollow morphology of the HCSs nanoreactor was exploited to study the influence of the Pt promoter nanoparticle location relative to that of the Co3O4 (Co 10 wt%) nanoparticles (dCo = 3.5 – 12.5). Furthermore, the effect of Pt on the reduction behaviour and activity of the Co FTS catalyst was evaluated. The synthesis and use of Pt nanoparticles supported on/in Co@HCS FT catalysts to give CoPt@HCS and Pt/(Co@HCS) catalysts are reported. Electron microscopy, ex situ PXRD, BET, and TPR studies revealed that the prepared catalysts were successfully synthesized with well dispersed Co nanoparticles. It was observed that the proximity between the Co and Pt influenced the Co hcp/fcc ratios. A secondary hydrogen spillover effect was invoked to account for the reduction of Co3O4 on 1Pt/(10Co@HCS) at 335 °C. The complete reduction of Co3O4 to Co metal on 10Co1Pt@HCS at 350 °C was attributed to a primary hydrogen spillover effect. Following catalyst activation at 350 °C, the primary spillover process resulted in a catalyst exhibiting higher Fischer–Tropsch activity (approximately 2×) compared to both the unpromoted catalyst and catalysts where Pt and Co were separated by the HCS. This enhanced activity was partially attributed to the Co phases formed on the carbon support during reduction and the degree of catalyst reduction, which depended on the type of hydrogen spillover process. A comparison of the reduction ability of Os, Ru and Pt on the reduction of Co supported on/in HCSs and the impact of the promoter on Co hcp/fcc ratios is reported.

Surface crystallized supramolecular to achieve highly dispersed ultrafine nano-palladium in-situ deposition to promote thermal/electrocatalytic reduction

To promote the greening and economization of industrial production, the development of advanced catalyst manufacturing technology with high activity and low cost is an indispensable part. In this study, nitrogen-doped hollow carbon spheres (NHCSs) were used as anchors to construct a supramolecular coating formed by the self-assembly of boron clusters and β-cyclodextrin by surface crystallization strategy, with the help of the weak reducing agent characteristics of boron clusters, highly dispersed ultra-small nano-palladium particles were in-situ embedded on the surface of NHCSs. The deoxygenation hydrogenation of nitroaromatics and the reduction of nitrate to ammonia were used as the representatives of thermal catalytic reduction and electrocatalytic reduction respectively. The excellent properties of the constructed Pd/NHCSs were proved by the probe reaction. In the catalytic hydrogenation of nitroaromatics to aminoaromatics, the reaction kinetic rate and activation energy are at the leading level. At the same time, the constructed Pd/NHCSs can also electrocatalytically reduce nitrate to high value-added ammonia with high activity and selectivity, and the behavior of Pd/NHCSs high selectivity driving nitrate conversion was revealed by density functional theory and in situ attenuated total reflection Fourier transform infrared (ATRFTIR) technique. These results all reflect the feasibility and superiority of in-situ anchoring ultra-small nano-metals as catalysts by surface crystallization to build a supramolecular cladding with reducing properties, which is an effective way to construct high-activity and low-cost advanced catalysts.

Soft template-induced self-assembly strategy for sustainable production of porous carbon spheres as anode towards advanced sodium-ion batteries

Doped porous carbon is a prominent sodium anode material with high specific surface area (SSA) and abundant pore structure. Compared with the traditional “hard template” technique for the synthesis of porous carbon, the “soft template” method offers a more efficient synthesis process and simplified template removal. In response to the urgent need for eco-friendly synthesis methods for functional doping, our research introduces an innovative method using biomass-derived tannic acid as a precursor. We have successfully synthesized N/S double-doped porous spherical carbon materials (DF-N/S) through a self-assembly process driven by hydrogen bonding and solvent evaporation. As an anode material for sodium-ion batteries (SIBs), DF-N/S demonstrates superior electrochemical performance, achieving a specific capacity of 327.04 mAh g−1 at a current density of 0.05 Ag-1 in ether-based electrolytes. The remarkable sodium storage efficiency of DF-N/S has been thoroughly examined through kinetic analyses and ex-situ characterization methods. This study aims to provide a sustainable and widely adaptable method for the soft template production of doped carbon, while also shedding light on the intricacies of energy storage mechanisms in both ether/ester-based electrolytes.

Silver-Assisted Chemical Etching for the Fabrication of Porous Silicon N-Doped Nanohollow Carbon Spheres Composite Anodes to Enhance Electrochemical Performance.

Silicon (Si) shows great potential as an anode material for lithium-ion batteries. However, it experiences significant expansion in volume as it undergoes the charging and discharging cycles, presenting challenges for practical implementation. Nanostructured Si has emerged as a viable solution to address these challenges. However, it requires a complex preparation process and high costs. In order to explore the above problems, this study devised an innovative approach to create Si/C composite anodes: micron-porous silicon (p-Si) was synthesized at low cost at a lower silver ion concentration, and then porous silicon-coated carbon (p-Si@C) composites were prepared by compositing nanohollow carbon spheres with porous silicon, which had good electrochemical properties. The initial coulombic efficiency of the composite was 76.51%. After undergoing 250 cycles at a current density of 0.2 A·g-1, the composites exhibited a capacity of 1008.84 mAh·g-1. Even when subjected to a current density of 1 A·g-1, the composites sustained a discharge capacity of 485.93 mAh·g-1 even after completing 1000 cycles. The employment of micron-structured p-Si improves cycling stability, which is primarily due to the porous space it provides. This porous structure helps alleviate the mechanical stress caused by volume expansion and prevents Si particles from detaching from the electrodes. The increased surface area facilitates a longer pathway for lithium-ion transport, thereby encouraging a more even distribution of lithium ions and mitigating the localized expansion of Si particles during cycling. Additionally, when Si particles expand, the hollow carbon nanospheres are capable of absorbing the resulting stress, thus preventing the electrode from cracking. The as-prepared p-Si utilizing metal-assisted chemical etching holds promising prospects as an anode material for lithium-ion batteries.

KOH-activated hollow carbon spheres with surface functionalization for high-capacity and long-cycle-life lithium-selenium batteries

Lithium-selenium (Li-Se) batteries are considered promising alternatives to lithium-ion batteries due to their higher volumetric capacity and energy density. However, they still face limitations in efficiently utilizing the active selenium. Here, we develop surface-functionalized mesoporous hollow carbon nanospheres as the selenium host. By using KOH activation, the surface of the carbon nanospheres is functionalized with hydroxyl groups, which greatly improve the utilization of selenium and facilitate the conversion of lithium selenides, leading to much higher capacities compared to ZnCl2 activation and untreated carbon nanospheres. Theory and experimental evidence suggest that surface hydroxyl groups can enhance the reduction conversion of polyselenides to selenides and facilitate the oxidation reaction of selenides to elemental selenium. In-situ and ex-situ characterization techniques provided additional confirmation of the hydroxyl groups electrochemical durability in catalyzing selenium conversion. The meticulously engineered Se cathode demonstrates a high specific capacity of 594 mA h g−1 at 0.5C, excellent rate capability of 464 mA h g−1 at 2C, and a stable cycling performance of 500 cycles at 2C with a capacity retention of 84.8 %, corresponding to an ultra-low-capacity decay rate of 0.0144 % per cycle, surpassing many reported lithium-selenium battery technologies.

Radial channel boosting stress release in hollow carbon spheres for high-rate sodium ions storage

Carbon spheres are appealing anode materials for advanced sodium ions batteries. However, several major hurdles to address are the stress-accumulation associated with the drastic volume change, the sluggish sodium ions diffusion kinetics, and poor electrochemically active sites inside. Herein, the von Mises stress distribution uncovers the critical role of the radial channel on the strain relaxation behavior based on the finite element method. Based on the finite element simulation, the radial porous hollow carbon spheres are proposed and synthesized by a universal strategy with a hard-template approach and dynamic graphitization. RPHCSs dominate opened micro-mesoporous features through the shell. With fast sodium ion diffusivity kinetics and much more accessible electrochemical active sites in shell, RPHCSs electrodes deliver a high specific capacity of 103.0 mAh g−1 even at 4000 mA g−1 with a high capacity contribution ratio > 0.1 V (81.1 %), suggesting its great superiority in the application of high-rate sodium ions storage. Such architecture provides a promising structural platform for the fabrication of high-performance carbon spheres material for other electrochemical energy storage systems.

Hydrophobic-treated yolk-shell SnS2@CSs Z-scheme confinement reactor for solar-electro-driven hydrogen peroxide production in neutral media

The diffusion and adsorption properties of the O2/H2O corpuscles at active sites play a crucial role in the fast photo-electrocatalytic reaction of hydrogen peroxide (H2O2) production. Herein, SnS2 nanosheets with abundant interfacial boundaries and large specific areas are encapsulated into hollow mesoporous carbon spheres (CSs) with flexibility, producing a yolk-shell SnS2@CSs Z-scheme photocatalyst. The nanoconfined microenvironment of SnS2@CSs could enrich O2/H2O in catalyst cavities, which allows sufficient internal O2 transfer, improving the surface chemistry of catalytic O2 to O2− conversion and increasing reaction kinetics. By shaping the mixture of SnS2@CSs and polytetrafluoroethylene (PTFE) on carbon felt (CF) using the vacuum filtration method, the natural air-breathing gas diffusion photoelectrode (AGPE) was prepared, and it can achieve an accumulated concentration of H2O2 about 12 mM after a 10 h stability test from pure water at natural pH without using electrolyte and sacrificial agents. The H2O2 product is upgraded through one downstream route of conversion of H2O2 to sodium perborate. The improved H2O2 production performance could be ascribed to the combination of the confinement effect of SnS2@CSs and the rich triple phase interfaces with the continuous hydrophobic layer and hydrophilic layer to synergistically modulate the photoelectron catalytic microenvironment, which enhanced the transfer of O2 mass and offered a stronger affinity to oxygen bubbles. The strategy of combining the confined material with the air-breathing gas diffusion electrode equips a wide practical range of applications for the synthesis of high-yield hydrogen peroxide.

The influence of carbon spheres and graphene synthesized by thermal method as platinum-tin electrocatalyst supports to enhance the ethanol oxidation

The influence of carbon spheres and graphene synthesized by thermal method as platinum-tin electrocatalyst supports to enhance the ethanol oxidation

D-band center engineering of single Cu atom and atomic Ni clusters for enhancing electrochemical CO2 reduction to CO

The rational design of catalysts with atomic dispersion and a deep understanding of the catalytic mechanism is crucial for achieving high performance in CO2 reduction reaction (CO2RR). Herein, we present an atomically dispersed electrocatalyst with single Cu atom and atomic Ni clusters supported on N-doped mesoporous hollow carbon sphere (CuSANiAC/NMHCS) for highly efficient CO2RR. CuSANiAC/NMHCS demonstrates a remarkable CO Faradaic efficiency (FECO) exceeding 90% across a potential range of −0.6 to −1.2 V vs. reversible hydrogen electrode (RHE) and achieves its peak FECO of 98% at −0.9 V vs. RHE. Theoretical studies reveal that the electron redistribution and modulated electronic structure—notably the positive shift in d-band center of Ni 3d orbital—resulting from the combination of single Cu atom and atomic Ni clusters markedly enhance the CO2 adsorption, facilitate the formation of *COOH intermediate, and thus promote the CO production activity. This study offers fresh perspectives on fabricating atomically dispersed catalysts with superior CO2RR performance.

Realizing low-level electrical leakage conductance of PVC based dielectric composites containing amorphous carbon spheres

Realizing low-level electrical leakage conductance of PVC based dielectric composites containing amorphous carbon spheres

Adjustable nanoarchitectonics of N-doping Yolk-Shell carbon spheres via “Pyrolysis-Capture” method for High-Performance supercapacitor

The energy storage capacity of porous carbon materials is closely tied to their surface structure and chemical properties. However, developing an innovative and straightforward approach to synthesize yolk-shell carbon spheres (YCs) remains a great challenge till date. Herein, we prepared a series of porous nitrogen-doped yolk-shell carbon spheres (NYCs) via a “pyrolysis-capture” method. This method involves coating the resorcinol–formaldehyde (RF) resin sphere with a layer of compact silica shell induced by 2-methylimidazole (ME) catalysis to produce a confined nano-space. Based on the confined effect of compact silica shell, volatile gases emitted from the RF resin and ME during pyrolysis can not only diffuse into the pores of the RF resin but can also be captured to form an outer carbon shell. This results in the tunable structures of NYCs materials. As the pyrolysis temperature rises, the shell thickness of NYCs reduces, the pore size expands, the roughness increases, and the N/O content of surface elements is enhanced. Notably, as an electrode material used forsupercapacitors,the optimized NYCs-800 exhibits excellent performance with a capacitance of 301.2F g−1 at the current density of 1 A/g and outstanding cycling life stability of 96.1% after 10,000 cycles. These results signify that controlling the surface structure and chemical properties of NYCs materials is an effective approach for constructing advanced energy storage materials.

Development of a vibration-damping, sound-insulating, and heat-insulating porous sphere foam system and its application in green buildings

With the development of green buildings, people pay more attention to the quality of the indoor sound environment. The air sound insulation performance of floors and exterior walls plays a key role in today's green buildings. The thermal performance of the enclosure structure's floor and exterior wall heat transfer resistance is an important factor in reducing building carbon emissions in green buildings. The aim of this paper is to study the efficiency of the acoustic and thermal insulation of a foaming system with porous carbon balls and the combination of different structural ways of construction boards and external walls. The acoustic and thermal parameters of different sound insulation and thermal insulation systems designed with porous carbon sphere foam and inserted into the floors and exterior walls are compared to highlight the optimal structure. The theoretical and experimental tests showed that to improve the sound insulation performance of the floor, a sound insulation system needs to be placed on the surface of the floor in contact with the impact object and inlaid in the vertical gap in contact with the floor and the wall. Furthermore, it has been determined that the surface of the foam particle acoustic ball with micropores has good sound absorption performance. Finally, the high-quality building thermal insulation material with low thermal conductivity in any combination with the floor slabs and the external wall structure improves the thermal insulation performance.