Hollow Mesoporous Carbon Spheres Research Articles

Nitrogen-doped 3D hollow carbon spheres for efficient selective oxidation of C–H bonds under mild conditions

Nitrogen-doped hollow mesoporous carbon spheres present excellent conversion and selectivity in the selective oxidation of ethylbenzene at 50 °C.

Effect of different shell structure on lithium storage properties of MoS2 anode

Hollow mesoporous carbon sphere shell (HMCSS) structure of MoS 2 @C and mesosphere petal-like shell (MPLS) structure of TiO 2 @MoS 2 are synthesized by a facile strategy. HMCSS structure can effectively addressed the volume expansion and poor electrical conductivity of MoS 2 , which show that HMCSS structure of MoS 2 @C has higher discharge capacity, better rate capability and cycling performance than MPLS structure of TiO 2 @MoS 2 and pure MoS 2 . • HMCSS structure of MoS 2 @C and MPLS structure of TiO 2 @MoS 2 are synthesized by a facile strategy. • MoS 2 @C exhibit high capacity, remark cycling stability and rate capability compared with TiO 2 @MoS 2 and pure MoS 2 . • The volume expansion and poor electrical conductivity of MoS 2 can be effectively addressed simultaneously. MoS 2 , with a high theoretical specific capacity (670 mAh/g), is a good alternative to traditional graphite as anode for lithium ion batteries (LIBs). Poor conductivity and serious volume expansion during charging and discharging process, however, result in poor cycle performance and rate performance of MoS 2 anode for LIBs. Here, the TiO 2 coated in mesosphere-petal-like shell (MPLS) structure of MoS 2 (TiO 2 @MoS 2 ) and MoS 2 encapsulated in hollow mesoporous carbon spheres shell (HMCSS) structure (MoS 2 @C) are obtained, and effect of different shell structure on lithium storage properties of MoS 2 are investigated. The results show that MoS 2 @C exhibits higher discharge capacity, better rate capability and cycling performance than TiO 2 @MoS 2 and pure MoS 2 . The significantly enhanced charge and discharge performance of MoS 2 @C can be attributed to the improvement of electric conductivity and the inhibition of volume expansion result from the introduction of HMCSS structure. Also, TiO 2 @MoS 2 demonstrates remarkable lithium storage performance in comparison with pure MoS 2 , which is ascribe to MPLS structure of MoS 2 assembled from corresponding 2D nanosheets that facilitates the penetration of electrolyte and provides more sites to accommodate Li + , and which is also attribute to TiO 2 as effective mechanical support and thus alleviate volume expansion and aggregation of MoS 2 during charging and discharging process. It is believed that the different shell structure used in MoS 2 provides a novel approach to enhance the lithium storage performance of metal sulfide.

Graphene oxide wrapped hollow mesoporous carbon spheres as a dynamically bipolar host for lithium–sulfur batteries

An all-carbon based composite composed of hollow mesoporous carbon covered with graphene oxide sheets has been designed as a novel dynamically bipolar cathode host for lithium–sulfur batteries with impressive electrochemical performances.

Improved hydrogen evolution performance by engineering bimetallic AuPd loaded on amino and nitrogen functionalized mesoporous hollow carbon spheres.

A highly efficient heterogeneous catalyst was synthesized by delicate engineering of NH2-functionalized and N-doped hollow mesoporous carbon spheres (NH2–N-HMCS), which was used for supporting AuPd alloy nanoparticles with ultrafine size and good dispersion (denoted as AuPd/NH2–N-HMCS). Without using any additives, the prepared AuPd/NH2–N-HMCS catalytic formic acid dehydrogenation possesses superior catalytic activity with an initial turnover frequency value of 7747 mol H2 per mol catalyst per h at 298 K. The excellent performance of AuPd/NH2–N-HMCS derives from the unique hollow mesoporous structure, the small particle sizes and high dispersion of AuPd nanoparticles and the modified Pd electronic structure in the AuPd/NH2–N-HMCS composite, as well as the synergistic effect of the modified support.

Atomically Fe doped hollow mesoporous carbon spheres for peroxymonosulfate mediated advanced oxidation processes with a dual activation pathway

The introduction of atomically dispersed Fe atoms can modulate the PMS activation pathway; that is, the radical-mediated process of PMS activation accelerated by graphitic N is attenuated, in turn boosting electron-transfer-mediated nonradical processes.

Inner Wrinkled Mesoporous Hollow Carbon Spheres with Nanopillars Connected to Double Shells for Excellent Potassium Storage

Inner Wrinkled Mesoporous Hollow Carbon Spheres with Nanopillars Connected to Double Shells for Excellent Potassium Storage

Inner Wrinkled Mesoporous Hollow Carbon Spheres with Nanopillars Connected to Double Shells for Excellent Potassium Storage

Inner Wrinkled Mesoporous Hollow Carbon Spheres with Nanopillars Connected to Double Shells for Excellent Potassium Storage

Nitrogen and Sulfur Co-Doped Mesoporous Hollow Carbon Spheres for High Rate Sodium Ion Storage

Nitrogen and Sulfur Co-Doped Mesoporous Hollow Carbon Spheres for High Rate Sodium Ion Storage

A General Synthesis of Mesoporous Hollow Carbon Spheres with Extraordinary Sodium Storage Kinetics by Engineering Solvation Structure

Porous and hollow carbon materials have great superiority and prospects in electrochemical energy applications, especially for surface charge storage due to the high active surface. Herein, a general strategy is developed to synthesize mesoporous hollow carbon spheres (MHCS) with controllable texture and compositions by the synergistic effect of dopamine polymerization and metal catalysis (Cu, Bi, Zn). Mesoporous MHCS-Cu and MHCS-Bi are regular spheres, while mesoporous MHCS-Zn possesses an inward concave texture, and simultaneously has a very high surface area of 1675.5 m2 g-1 and lower oxygen content through the catalytic deoxygenation effect. MHCS-Zn displays an exceptional sodium storage kinetics and excellent long cycling life with 171.9 mAh g-1 after 2500 cycles at 5 A g-1 in compatible ether-based electrolytes. Such electrolyte enables enhanced solvated Na+ transport kinetics with appropriate electrostatic interactions at the surface of carbon anode as revealed by molecular dynamics simulations and molecular surface electrostatic potential calculations. Such an anode also displays basically constant capacity working at 0°C, and still delivers 140 mAh g-1 at 3 A g-1 under -20°C. Moreover, MHCS-Zn anode is coupled with Na3 V2 (PO4 )3 cathode to construct a hybrid capacitor, which exhibits a high energy density of 145Wh Kg-1 at a very high power of 8009 W kg-1 .

Covalent Pinning of Highly Dispersed Ultrathin Metallic-Phase Molybdenum Disulfide Nanosheets on the Inner Surface of Mesoporous Carbon Spheres for Durable and Rapid Sodium Storage.

Two-dimensional (2D) transition-metal dichalcogenide materials show potential for use in alkali metal ion batteries owing to their remarkable physical and chemical properties. Nevertheless, the electrochemical energy storage performance is still impaired by the tendency of aggregation, volume, and morphological change during the conversion reaction and poor intrinsic conductivity. Until now, ultrathin molybdenum disulfide nanosheets with a metallic-phase structure on the inner surface of mesoporous hollow carbon spheres (M-MoS2@HCS) have rarely been investigated as an anode for sodium-ion batteries. In this work, a novel M-MoS2@HCS anode was designed and synthesized by employing a template-assisted solvothermal reaction. Structural and chemical analyses indicate that the M-MoS2 nanosheets with a larger interlayer spacing compared to their semiconductor counterpart grow on the inner surface of HCS via covalent interactions. When used as the anode materials for Na+ storage, the M-MoS2@HCS anode presents durable and rapid sodium storage properties. The developed electrode shows a reversible capacity of 291.2 mAh g-1 at a high current density of 5 A g-1. After 100 cycles at 0.1 A g-1, the reversible capacity is 401.3 mAh g-1 with a capacity retention rate of 79%. After 2500 cycles at 1.0 A g-1, the electrode still delivers a reversible capacity of 320.1 mAh g-1 with a capacity retention rate of 75%. The excellent sodium storage capability of the MoS2@HCS electrode is explained by the special structural design, which reveals great potential to accelerate the practical applications of transition-metal dichalcogenide electrodes for sodium storage.

Co-Existence of Iron Oxide Nanoparticles and Manganese Oxide Nanorods as Decoration of Hollow Carbon Spheres for Boosting Electrochemical Performance of Li-Ion Battery.

Here, we report that mesoporous hollow carbon spheres (HCS) can be simultaneously functionalized: (i) endohedrally by iron oxide nanoparticle and (ii) egzohedrally by manganese oxide nanorods (FexOy/MnO2/HCS). Detailed analysis reveals a high degree of graphitization of HCS structures. The mesoporous nature of carbon is further confirmed by N2 sorption/desorption and transmission electron microscopy (TEM) studies. The fabricated molecular heterostructure was tested as the anode material of a lithium-ion battery (LIB). For both metal oxides under study, their mixture stored in HCS yielded a significant increase in electrochemical performance. Its electrochemical response was compared to the HCS decorated with a single component of the respective metal oxide applied as a LIB electrode. The discharge capacity of FexOy/MnO2/HCS is 1091 mAhg−1 at 5 Ag–1, and the corresponding coulombic efficiency (CE) is as high as 98%. Therefore, the addition of MnO2 in the form of nanorods allows for boosting the nanocomposite electrochemical performance with respect to the spherical nanoparticles due to better reversible capacity and cycling performance. Thus, the structure has great potential application in the LIB field.

Template-free construction of hollow mesoporous carbon spheres from a covalent triazine framework for enhanced oxygen electroreduction

The construction of hollow mesoporous carbon nanospheres (HMCS) avoiding the use of traditional soft/hard templates is highly desired for nanoscience yet challenging. Herein, we report a simple and straightforward template-free strategy for preparing nitrogen, sulfur dual-doped HMCSs (N/S-HMCSs) as oxygen reduction reaction (ORR) electrocatalysts. The unique hollow spherical and mesoporous structure was in-situ formed via a thermally initiated hollowing pathway from an elaborately engineered covalent triazine framework. Regulation of pyrolysis temperatures contributed to precisely tailoring of the shell thickness of HMCSs. The resulting N/S-HMCS900 (pyrolyzed at 900 °C) possessed high N and S contents, large specific surface areas, rich and uniform mesopores distribution. Consequently, as a metal-free ORR electrocatalyst, N/S-HMCS900 exhibits a high half-wave potential, excellent methanol tolerance and great long-term durability. Additionally, density functional theory calculations demonstrate that N, S-dual dopant can create extra active sites with higher catalytic activity than the isolated N-dopant. This strategy provides new insights into the construction of hollow and mesoporous multi-heteroatom-doped carbon materials with tunable nanoarchitecture for various electrochemical applications.

Sandwich-type electrochemical aptasensor based on hollow mesoporous carbon spheres loaded with porous dendritic Pd@Pt nanoparticles as signal amplifier for ultrasensitive detection of cardiac troponin I

Signal amplification is crucial to improve the sensitivity for the electrochemical detection of cardiac troponin I (cTnI), one of the ideal biomarkers for early acute myocardial infarction (AMI) diagnosis. Herein, we developed a novel signal amplification strategy to construct a sandwich-type electrochemical aptasensor for the detection of cTnI. Core-shell Pd@Pt dendritic bimetallic nanoparticles loaded on melamine modified hollow mesoporous carbon spheres (Pd@Pt DNs/NH2-HMCS) was prepared as labels to conjugate with thiol-modification DNA aptamers probe for signal amplification. While introducing numerous amino groups, the melamine functionalized hollow mesoporous carbon spheres (NH2-HMCS) retained the edge-plane-like defective sites for the adhesion and electrocatalytic reduction of H2O2. With the unique characteristics of NH2-HMCS, it not only enhanced the dispersity and loading capacity of core-shell Pd@Pt dendritic bimetallic nanoparticles (Pd@Pt DNs), but also improved the stability of bonding by the affinity interaction between Pd@Pt DNs and amino groups of melamine. Meanwhile, the synergistic catalysis effect between Pd@Pt DNs and NH2-HMCS significantly enhanced the electrocatalytic reduction of H2O2 and further amplified the signal. Under optimal conditions, this recommended aptasensor for cTnI detection displayed a wide dynamic range from 0.1 pg/mL to 100.0 ng/mL and a low detection limit of 15.4 fg/mL (S/N = 3). The sensor also successfully realized the analysis of cTnI-spiked human serum samples, meaning potential applications in AMI diagnosis.

Enhancing the Electrochemical Performance of Sodium‐Ion Batteries by Building Optimized NiS2/NiSe2 Heterostructures

AbstractNiS1.23Se0.77 nanosheets closely attached to the internal surface of hollow mesoporous carbon sphere (HMCS) to form a NiS1.23Se0.77 nanosheets embedded in HMCS (NSSNs@HMCS) composite as the anode of sodium ion batteries (SIBs) is reported by a facile synthesis route. The anode exhibits a superior reversible capacity (520 mAh g−1 at 0.1 A g−1), impressive coulombic efficiency (CE) of up to 95.3%, a high rate capacity (353 mAh g−1 at 5.0 A g−1), excellent capacity retention at high current density (95.6%), and high initial coulombic efficiency (ICE) (95.1%). Firstly, the highest ICE for NiS2/NiSe2‐based anode can be ascribed to ultrathin layered structure of NiS1.23Se0.77 nanosheet and highly efficient electron transfer between the active material and HMCS. Secondly, the optimized NiS2/NiSe2 heterostructure at the nanoscale of the inside HMCS is formed after the first discharge/charge cycles, which can provide rich heterojunction interfaces/boundaries of sulfide/selenides to offer faster Na+ pathways, decrease the Na+ diffusion barriers, increase electronic conductivity, and limit the dissolution of polysulfides or polyselenides in the electrolyte. Finally, the hollow structure of the HMCS accommodates the volume expansion, prevents the pulverization and aggregation issues of composite materials, which can also promote outstanding electrochemical performance.

Ru complex and N, P-containing polymers confined within mesoporous hollow carbon spheres for hydrogenation of CO2 to formate

Ru complex and N, P-containing polymers confined within mesoporous hollow carbon spheres for hydrogenation of CO2 to formate

Self-healing effect of epoxy coating containing mesoporous polyaniline hollow spheres loaded with benzotriazole

Recently, people pay more attention to the application of mesoporous nanomaterials in organic coatings owing to their high corrosion inhibitor loading rate, which could strongly improve organic coatings anticorrosion performance. However, traditional nanomaterials were used only as the hosts for corrosion inhibitors because they do not have corrosion inhibition function, which restricted the further improvement of the anticorrosion performance of organic coatings. If the mesoporous materials have corrosion inhibition function, it will be inferred to further improve the coating performance.To address this problem, a novel mesoporous nanomaterial: mesoporous polyaniline hollow spheres (MPHS) were synthesized using mesoporous carbon hollow spheres (MCHS) as the hard template and PS100-b-PEO114 as the soft template. MPHS loaded with benzotriazole (MPHS@BTA) was introduced into epoxy coating as an anticorrosion pigment, and then the anticorrosion properties of epoxy coatings were systematically investigated.The BET surface area, total pore volume and average pore diameter of MPHS were 568 cm2 g−1, 1.3 cm3 g−1 and 8.9 nm, respectively. Due to high specific area and high pore volume, the loading rate of BTA in MPHS was up to 27 wt%. Epoxy coating blended with 2 wt% MPHS@BTA presented the best anticorrosion and self-healing properties, which was ascribed to the synergistic effect of the passivation function of PANI and the corrosion inhibition effect of BTA.

Rational construction of well-defined hollow double shell SnO2/mesoporous carbon spheres heterostructure for supercapacitors

The selection of proper electrode materials and the design of rational structure are two efficient approaches to improve the electrochemical performance of supercapacitors. Carbonaceous materials have become an important choice of electrode materials due to their good electrical conductivity and accommodation for volume expansion of metal oxides. In this contribution, hollow double-shell structured H-SnO2/MesCHS (mesoporous carbon hollow spheres) heterostructure is successfully achieved by silica template and in-situ polymerization methods. The H-SnO2/MesCHS composites demonstrate a specific surface area of 747.7 m2 g-1 and an average pore size of ca. 4.9 nm in the mesoporous carbon shell, where the outer layer of mesoporous hollow carbon layer act as a buffer to confine the volume expansion of the inner hollow tin oxide sphere. As consequence, hollow double-shell H-SnO2/MesCHS heterostructure demonstrates an excellent electrochemical performance with a high specific capacitance of 470 F g-1, exceptional cycling stability (88.4% retention of capacitance over 4000 cycles) and outstanding coulombic efficiency of 86.5% at high current density of 20 A g−1. The work provides an alternative route for the preparation of spherical hollow heterostructures materials with tunable double shell architectures, which may potentially be used as electrode materials for high-performance of energy storage.

Pt Single Atoms Supported on N-Doped Mesoporous Hollow Carbon Spheres with Enhanced Electrocatalytic H2 -Evolution Activity.

The electronic metal-support interaction (EMSI) plays a crucial role in catalysis as it can induce electron transfer between metal and support, modulate the electronic state of the supported metal, and optimize the reduction of intermediate species. In this work, the tailoring of electronic structure of Pt single atoms supported on N-doped mesoporous hollow carbon spheres (Pt1 /NMHCS) via strong EMSI engineering is reported. The Pt1 /NMHCS composite is much more active and stable than the nanoparticle (PtNP ) counterpart and commercial 20wt% Pt/C for catalyzing the electrocatalytic hydrogen evolution reaction (HER), exhibiting a low overpotential of 40mV at a current density of 10mA cm-2 , a high mass activity of 2.07 A mg-1 Pt at 50mV overpotential, a large turnover frequency of 20.18 s-1 at 300mV overpotential, and outstanding durability in acidic electrolyte. Detailed spectroscopic characterizations and theoretical simulations reveal that the strong EMSI effect in a unique N1 -Pt1 -C2 coordination structure significantly tailors the electronic structure of Pt 5d states, resulting in promoted reduction of adsorbed proton, facilitated H-H coupling, and thus Pt-like HER activity. This work provides a constructive route for precisely designing single-Pt-atom-based robust electrocatalysts with high HER activity and durability.

Synthesis and Characterization of Novel Hybrid Flocculants Based on Potato Starch Copolymers with Hollow Carbon Spheres.

Novel carbon nanofiller-based starch-g-polyacrylamide hybrid flocculation materials (St-PAM-CS) were in situ prepared using potato starch (St), acrylamide (AM), and hollow mesoporous carbon spheres (CSs; diameters of 300–400 nm). Structures of different St-PAM-CS systems were characterized by Fourier transform infrared (FTIR) spectroscopy, X-Ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), laser scanning microscopy (LSM), and particle size analysis. The flocculation tests were evaluated by removing high turbidity kaolin suspension—initial absorbance 1.84. The effect of the St to AM molar ratio, doses, and content of CSs in hybrids on flocculation efficiency were examined. Satisfactory flocculation efficiency was obtained for all hybrids with 1 wt.% of the CS component. The highest reduction of the kaolin suspension absorbance (to 0.06) was observed for a 3 mL dose of the starch hybrid with the highest AM content. Additionally, St-PAM-CS showed a reduction in the sludge volume in time. The hybrids reached better flocculation efficiency in relation to the reference systems without CSs. The proposed flocculation mechanism (considering bridging, patching, and formation of hydrogen bonds) has been confirmed by the recorded results.

Enhancement of catalytic esterification by tuning molecular diffusion in sulfonated carbon

In this study, enhanced catalytic esterification of hollow sulfonated mesoporous carbon spheres (HMCS-S) by modulating the molecular diffusion ability was investigated. A modified one-pot method was used for the synthesis of HMCS-S with different pore sizes. The catalytic activity of HMCS-S was tested by esterification of fatty acids (FAs) and methanol. The fatty acids with varying chain lengths (i.e. valeric acid (C5), caprylic acid (C8), lauric acid (C12)) were used to reflect the enhancement effect of molecular diffusion ability. The results showed that the catalytic activity of HMCS-S was enhanced by increasing pore size, especially for long-chain FAs (C12). Equivalently, the TOF value of HMCS-S among sulfonated carbon with different morphologies is higher, which is attributed to ideal molecular diffusion ability depending on the texture and surface properties of HMCS-S.