Carbon Spheres Research Articles

Spiny Co3O4@Hollow Carbon Spheres─Polyacrylonitrile/Carbon Black Fiber-Based Bifunctional Air Electrodes.

In the realm of zinc-air batteries, high bifunctional catalytic efficacy is intimately tied to the evaluation of catalysts. Consequently, the pursuit of proficient bifunctional catalysts that can efficiently catalyze both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a paramount objective in this research area. In this study, the spiny cobalt tetroxide (Co3O4) encapsulated hollow carbon spheres (HCSs) are constructed by anchoring Co3O4 onto HCS via hydrothermal or annealing treatment. The strategic interface design of the HCS encourages an abundance of sites while simultaneously facilitating the proliferation of spiny Co3O4, offering an expansive surface area and abundant active sites. The surface active Co3+ ions and the induction of surface oxygen vacancies in spiny Co3O4 encapsulated HCS endow it with outstanding bifunctional catalytic activity and stability. After spray-coating and subsequent annealing of the spiny Co3O4 encapsulated HCS catalyst on the flexible carbon-based polyacrylonitrile (PAN) nanofiber support, the spiny Co3O4 encapsulated HCS-PAN/carbon black (C) 800 air electrode is successfully integrated. Moreover, the optimized spiny Co3O4 encapsulated HCS-PAN/C 800 air electrode displays a decreased potential difference (ΔE) of 0.77 V for catalyzing the ORR and OER performance. This work introduces a promising candidate approach for exploring innovative bifunctional oxygen electrocatalysts, targeting enhanced efficiency in portable energy storage applications.

Surface curvature-driven adsorption-reduction mechanism over hollow N-doped carbon enhances recovery of precious metal ions from wastewater.

The recovery of precious metal ions (PMI) from wastewater has great significances from both economic and environmental perspectives. However, current recovery methods face limitations, including low efficiency and selectivity, as well as challenges in practical applications. In this study, hollow N-doped carbon spheres (HNC) are proved to be promising for improving anionic AuCl4- and PdCl42- recovery via the curvature effect, outperforming non-curved carbon (commercial active carbon and carbon nanosheet) due to their unique curvature effect. The maximum recovery capacities of HNC for AuCl4- and PdCl42- reach as high as 304.90 mg·g -1 and 84.31 mg·g -1 (calculated as metallic elements), far exceeding those of activated carbon (175.9 mg·g -1 for Au and 46.87 mg·g -1 for Pd) and carbon nanosheet (33.92 mg·g -1 for Au and 4.33 mg·g -1 for Pd). The recovery processes of HNC could reach equilibrium within 1 h, exhibiting a rapid recovery kinetic process. The superior recovery performance of HNC can be attributed to the adsorption-reduction mechanism. The convex surface of HNC concentrates a lot of electrons due to the curvature effect, facilitating the electron transfer from HNC to PMI. The key reduction process is thus induced on the electron-rich outer surface of the sphere. Remarkably, the increased curvatures significantly boost the PMI recovery, further confirming the importance of curvature effect. In addition, HNC materials exhibit superior anti-interference ability against co-existing ions and potential practicability. Therefore, innovative adsorption-reduction mechanism and curvature effect are proposed, which offer a new prospect in developing cost-effective recovery technology of precious metals and environmental remediation.

Sodium Ion Diffusion Behavior in Multiple Open/Closed Pore Ratios of Novel β-Cyclodextrin-Derived Hard Carbon Anode Materials.

Plateau-dominated hard carbon with a high rate of performance is challenging to obtain, and the in-depth mechanism of pore structure on the diffusion of sodium ions remains unclear. In this study, a facile liquid-phase molecular reconstruction strategy is proposed to regulate the orientation of the β-cyclodextrin molecules and prepare spherical hard carbon with continuous and ordered pore channels. Through detailed characterization, this approach is confirmed to optimize the accumulation of Na+ in the dispersion region, thus improving the plateau kinetics and enhancing the utilization of closed pores. The as-obtained β-cyclodextrin-derived spherical hard carbon has a much greater specific surface area (129 m2 g-1) than the pristine sample (2.91 m2 g-1) but a similar initial Coulombic efficiency. Additionally, the plateau region still exists when the current density is at 30 C (7.5 A g-1), contributing to a high capacity of 179 mAh g-1. This study provides a meaningful promotion to kinetics of hard carbon at the low-voltage region.

Supercarbon assembly inspired two-dimensional hourglass fermion.

By using a tight-binding model, first-principles calculations, and abinitio molecular dynamics simulations, we theoretically demonstrate that the C76-Td-assembled two-dimensional (2D) honeycomb lattice is stable at room temperature and is resistant to mechanical deformation. We disclose that each C76-Td mimics a single carbon atom (geometrically and electronically); hence, it plays the role of one supercarbon. This inspires that the 2D material exhibits an exotic hourglass-like fermion at the Fermi level. Furthermore, we suggest that biaxial strains could modify the hourglass shape, including the electronic Fermi velocity, and induce magnetization. Hexagonal boron nitride can be employed as a protective layer without affecting the electronic structure of this material. This hourglass fermion has the potential to serve as a promising material for high-speed electronic devices and to bridge the gap between zero-dimensional spherical carbon clusters and two-dimensional graphene.

Permanent Nanobubbles in Water: Liquefied Hollow Carbon Spheres Break the Limiting Diffusion Current of Oxygen Reduction Reaction.

Porous liquids have traditionally been designed with sterically hindered solvents. Alternatively, recent efforts rely on dispersing microporous frameworks in simpler solvents like water. Here we report a unique strategy to construct macroporous water by selectively incorporating hydrophilicity on the surfaces of hydrophobic hollow carbon spheres (HCS). Specifically, we show that the stable dispersion surface ionized HCS in water while retaining the inherent porosity. The electrocatalytic conversion of small gas molecules in aqueous electrolytes is limited by the concentration and diffusion rates of gas molecules in water. In this case, macroporous water exhibited 6 times gas uptake compared to nonporous (pure) water. By leveraging the high gas capacity and enhanced diffusion kinetics, the limiting diffusion current of oxygen reduction reaction (ORR) in macroporous water is 2 times that in nonporous water, offering promising prospects for sustainable energy conversion technologies.

Highly selective catalytic hydrogenation of furfural and acetophenone on S-doped mesoporous carbon Sphere-Supported Pd nanocluster catalyst

The efficient catalytic conversion of the biomass platform molecule furfural into biofuels or other high-value-added chemicals is currently a research hotspot. However, the hydrogenation of furfural possesses challenges due to the occurrence of multiple side reactions that generate various by-products. Herein, S-doped mesoporous carbon spheres (CS-S) with an ordered and accessible structure were precisely designed and synthesized. Subsequently, ∼1.8 nm Pd nanoclusters were immobilized within the radial mesoporous structure of CS-S to obtain a Pd/CS-S catalyst. This catalyst was used for the hydrogenation of furfural and acetophenone into tetrahydrofurfuryl alcohol (THFA) and 1-phenylethanol, respectively, and 99 % conversion and more than 90 % selectivity were achieved. Mechanistic study revealed that the electron-deficient Pd nanoclusters anchored on CS-S exhibit higher adsorption energies for reactant molecules, thus facilitating the pre-adsorption and activation of substrate molecules. Moreover, the Gibbs free energy for each step of the hydrogenation process is lower on the electron-deficient Pd metal surface, leading to excellent catalytic hydrogenation performance. In addition, the Pd/CS-S catalyst also exhibited remarkable recyclability and stability over multiple reaction cycles. This work facilitates the construction of stable metal nanocluster-based catalysts for enabling highly selective catalytic hydrogenation.

Core–shell structured carbon@tin sulfide@hard carbon spheres as high-performance anode for low voltage sodium-ion battery

Core–shell structured carbon@tin sulfide@hard carbon spheres as high-performance anode for low voltage sodium-ion battery

A litchi-like carbon sphere decorating with HfO2/Co heterostructures to significantly improve the electrochemical performance of lithium-sulfur battery

A litchi-like carbon sphere decorating with HfO2/Co heterostructures to significantly improve the electrochemical performance of lithium-sulfur battery

Constructing CoS2/FeS2 heterostructures on hollow carbon spheres with promoted reaction kinetics for high-rate and stable sodium storage

Constructing CoS2/FeS2 heterostructures on hollow carbon spheres with promoted reaction kinetics for high-rate and stable sodium storage

Magnetopyrite Fe1-xS modified with N/S-doped carbon as a synergistic electrocatalyst for lithium-sulfur batteries.

Rational design of effective cathode host materials is an effective way to solve the problems of serious shuttle and slow conversion of polysulfides in lithium-sulfur batteries (LSBs). However, the redox reaction of sulfur differs from conventional "Rocking chair" type batteries and involves a cumbersome phase transition process, so a single-component catalyst cannot consistently and steadily enhance the reaction rate throughout the redox process. In this work, a hybrid composed of magnetopyrite Fe1-xS catalyst-modified with N/S-doped porous carbon spheres (Fe1-xS@NSC) is proposed as a novel sulfur host to synergistically promote the adsorption and redox catalysis conversion of polysulfides. In this hybrid, the NSC skeleton provides excellent electrical conductivity and abundant adsorption sites for the physical immobilization of polysulfides; the magnetopyrite Fe1-xS nanoparticles promote the fast conversion reaction from Li2S2 to Li2S, affording strong adsorption and catalytic conversion. The optimal LSB with Fe1-xS@NSC manifests a high initial capacity of 971mAhg-1 at 0.2 C (1 C=1675mAhg-1) and a retention rate of up to 75% after 100 cycles. This work can provide a new approach for rationalizing the novel transition metal sulfide/porous carbon-based composite hosts with efficient lithium polysulfides (LiPSs) adsorption and catalytic conversion in high-performance lithium-sulfur batteries.

Metal organic framework derived hollow heterostructured NiS2/ZnS/C hybrid spheres for enhanced sodium-ion storage properties

In this paper, we report the fabrication of metal organic framework (MOF)-derived heterostructured NiS2/ZnS nanoparticles embedded in hollow carbon spheres (denoted as NiS2/ZnS/C) using Ni-MOF as template precursor through a combined method of solvothermal, ion adsorption and subsequent sulfurization. The hollow spherical morphology and in-situ carbon layer confinement of active materials offer rich channels and paths for rapid ion/electron transport, alleviate the volume changes and agglomeration effect during cycling. Moreover, the built-in electric field created at the heterointerfaces of NiS2/ZnS can promote the Na+ transport kinetics. Benefitting from these advantages, the optimal NiS2/ZnS/C electrode shows a high reversible capacity (568 mAh/g at 1.0 A/g), superior rate property (401 mAh/g at 5.0 A/g) and outstanding long-term cycling stability (79 % retention over 3000 cycles at 5.0 A/g). This design concept is expected to be utilized for constructing other anode materials with heterostructures for SIBs.

Catalytic transfer hydrogenolysis of lignin derived aromatic ethers over MOF derived porous carbon spheres anchored by Ni species

The efficient hydrogenolysis of CO ether bonds in lignin is the key for producing bio-oil and high-value chemicals. In this work, we synthesized a series of Ni-MOF-derived porous carbon spheres anchored Ni catalysts (Ni/C-x-T) with different metal/ligand molar ratios and calcination temperatures through solvothermal and carbothermal reduction method, and evaluated their catalytic transfer hydrogenolysis (CTH) performance for lignin model compounds using isopropanol as H-donor. The Ni/C-2-400 catalyst exhibited the excellent CTH performance, affording almost 100 % conversion of 2-phenoxy-1-phenylethanol even at a low reaction temperature of 120 °C. It was worth noting that the further hydrogenation of hydrogenolysis products phenol and ethylbenzene could be controlled by adjusting the reaction conditions, achieving phenol and ethylbenzene as main products at 120 °C, cyclohexanol and ethylbenzene at 140 °C, and cyclohexanol and ethylcyclohexane at 200 °C for 4 h. Based on the characterization results, the high catalytic activity of Ni/C-2-400 was attributed to the good dispersion and small particle size of metal Ni particles. Mechanistic studies showed that the cleavage of CO ether bonds was the main reaction pathway, and high temperature helped accelerate hydrogenolysis and subsequent hydrogenation. Moreover, the Ni/C-2-400 catalyst had good stability and applicability to other model compounds. This work could provide some help for the upgrading of lignin and its derivative.

Recent advances in producing hollow carbon spheres for use in sodium−sulfur and potassium−sulfur batteries

Recent advances in producing hollow carbon spheres for use in sodium−sulfur and potassium−sulfur batteries

Design and synthesis of iron-nickel oxide/nickel oxide at carbon sphere for effective electrochemical detection of hazardous pesticide fenitrothion

Design and synthesis of iron-nickel oxide/nickel oxide at carbon sphere for effective electrochemical detection of hazardous pesticide fenitrothion

Role of curvature in modulating electronic structure of active sites on hollow carbon spheres for efficient decontamination in catalytic ozonation process

Role of curvature in modulating electronic structure of active sites on hollow carbon spheres for efficient decontamination in catalytic ozonation process

Preparation of micron-sized carbon nanowalls-grown spherical carbon particles by thermal chemical vapor deposition with a tungsten mesh heater and alcohol

Preparation of micron-sized carbon nanowalls-grown spherical carbon particles by thermal chemical vapor deposition with a tungsten mesh heater and alcohol

One-step preparation of waste epoxy resin-derived nanosized carbon aerogel and its high supercapacitor performance

Energy storage devices serve critical roles in both harvesting energy from new energy sources and supplying energy to consumers, and the performance of supercapacitors is heavily reliant on the performance of activated material, which is determined by the qualities achieved during the specified preparation process. Herein, due to the merit of isotropy of 0D carbon nanoparticles in structure and current transfer, spherical carbon aerogels (CA) with the size of ϕ ~ 100 nm are carbonized within 3 min in air in an open tube furnace, in which those waste epoxy resin blocks are chosen and reused as the carbon source. After the activation, the surface of activated CA (ACA) becomes rough, and its specific surface area reaches 1222.40 m2·g−1. The above ACA owns high electrochemical supercapacitor performance: Referring to the ACA-based electrode, a specific capacitance of 298.8 F·g−1 at 1 A·g−1 (vs. 2.0 F·g−1 for CA) and 92.81 % retention after 20,000 cycles of repeated charge/discharge. As for its symmetric supercapacitor (SSC), it has good CV behavior even at 1000 mV·s−1, accompanied by an energy density of 20.92 W h·kg−1 at the power density of 300 W·kg−1, and 12.34 W h·kg−1 even at 12000 W·kg−1.

MoS2@porous biochar derived from rape pollen as anode material for lithium‐ion batteries

AbstractPreparation of porous carbon from natural biomass offers attractive features to facilitate the specific capacity and promote the rate capability of lithium‐ion battery (LIB). Herein, the hollow mesh porous rape pollen carbon (RPC) microsphere derived from treated RP (TRP) was utilized as a skeleton to load MoS2 nanoparticles. The MoS2@porous biochar‐derived RP (MoS2@RPC) anode materials were obtained by the hydrothermal–pyrolysis route. Attributing to the synergistic effect of spherical, hollow, and mesh porous carbon skeletons, larger specific surface areas, evenly distributed MoS2 nanoparticles, and an appropriate amount of TRP, the MoS2@RPC‐1.0 (TRP amount of 1.0 g) anode material reveals exceptional rate capability and cycling stability. A high specific capacity of ∼800 mAh g−1 at 100 mA g−1 is observed after 100 cycles, and that of ∼600 mAh g−1 at 500 mA g−1 is also obtained after 500 cycles. In conclusion, the MoS2@porous biochar composite is expected to become one of the most promising anode materials for LIBs.

PtRu Intra‐Cluster Electron Modulation Accelerates Multi‐Scenario Hydrogen Evolution Reaction

AbstractThe development of advanced nanomaterial manufacturing technology and the in‐depth analysis of the structure‐activity relationship are conducive to the sustainable development of platinum‐based catalysts in terms of low cost and high performance. The in situ conversion of Pt4+ and Ru3+ is creatively achieved into highly dispersed, small‐sized heterojunction clusters in the confined space by reductant preset framework materials, and these clusters benefited from the hollow carbon spheres gap supramolecular self‐assembly strategy to achieve high exposure. The intra‐cluster Ru→Pt electron transfer and induced electronic structure modulation enhance the adsorption and activation of H2O molecules at the interface, accelerating the desorption coupling of [H] at the Pt or Ru site. As a catalyst, PtRu/BNHCSs have achieved significant hydrogen production from electrolyzed water in multiple scenarios, exceeding the performance of the commercial Pt/C catalyst. These scenarios include high‐current water splitting to hydrogen in both pH‐neutral and simulated seawater, direct seawater hydrogen production, and anion‐exchange membrane integrated continuous and efficient electrolytic hydrogen production. In situ Fourier transform infrared and in situ Raman interface monitoring techniques reveal the interfacial adsorption behavior of H2O, providing important experimental and theoretical insights for understanding and revealing the synergistic effect and the interfacial reaction behavior of intra‐cluster atoms of PtRu heterojunction.

Co/Co7Fe3 heterostructures with controllable alloying degree on carbon spheres as bifunctional electrocatalyst for rechargeable zinc-air batteries

Co/Co7Fe3 heterostructures with controllable alloying degree on carbon spheres as bifunctional electrocatalyst for rechargeable zinc-air batteries