Hollow Mesoporous Carbon Nanospheres Research Articles

Ultrafine Ru nanoparticles anchored on N-doped mesoporous hollow carbon spheres as a highly efficient bifunctional catalyst for Li–CO2 batteries

Rechargeable Li–CO2 battery is a facilitative and promising device for the conversion of CO2 to electrochemical energy. However, it remains a challenge to enhance the sluggish decomposition kinetics of lithium carbonate as the discharge product. Herein, the Ru nanoparticles anchored on N-doped mesoporous hollow carbon nanospheres (Ru-AHCNs) are designed as cathode to enhance the electrochemical performance of Li–CO2 battery. The Ru-AHCNs cathode displays a high discharge specific capacity of 11194.4 mA h g−1 at the current density of 100 mA g−1. In addition, the Ru-AHCNs cathode can stably run over 50 cycles and maintain a small overpotential (<1.38 V) with a limited capacity of 1000 mA h g−1 at 100 mA g−1. The excellent stability and catalytic activity of the cathode are ascribed to the following factors: (i) Uniform deposition of Ru nanoparticles in hollow carbon nanospheres can enhance the decomposition of Li2CO3 and provide considerable exposure to active sites. (ii) N-doped mesoporous hollow carbon nanospheres can provide abundant electron transport channels and promote the nucleation of discharge products. These results evidently prove the reversible formation and decomposition of the discharge products, indicating that Ru-AHCNs cathode possesses excellent bifunctional catalytic activity.

Revealing interfacial charge redistribution of homologous Ru-RuS2 heterostructure toward robust hydrogen oxidation reaction

Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reaction (HOR). Herein, we employ a partial desulfurization strategy to construct a homologous Ru-RuS2 heterostructure anchored on hollow mesoporous carbon nanospheres (Ru-RuS2@C). The disparate work functions of the heterostructure contribute to the spontaneous formation of a unique built-in electric field, accelerating charge transfer and boosting conductivity of electrocatalyst. Consequently, Ru-RuS2@C exhibits robust HOR electrocatalytic activity, achieving an exchange current density and mass activity as high as 3.56 mA cm−2 and 2.13 mA μgRu-1, respectively, exceeding those of state-of-the-art Pt/C and most contemporary Ru-based HOR electrocatalysts. Surprisingly, Ru-RuS2@C can tolerate 1000 ppm of CO that lacks in Pt/C. Comprehensive analysis reveals that the directional electron transfer across Ru-RuS2 heterointerface induces local charge redistribution in interfacial region, which optimizes and balances the adsorption energies of H and OH species, as well as lowers the energy barrier for water formation, thereby promoting the HOR performance.

Achieving long-life and efficient sodium storage through encapsulating Fe3Se4 nanoparticles within hollow mesoporous carbon nanospheres

The application of Fe3Se4 in sodium-ion batteries is limited due to its poor cycling performance and inferior rate capability. Herein, we employ a multi-step process, involving solution adsorption, molten adsorption, calcination and gaseous selenization, to encapsulate Fe3Se4 nanoparticles within monodispersed hollow mesoporous carbon nanospheres (Fe3Se4@HMCN). The space-confined effect of HMCNs refines Fe3Se4 nanoparticles, compelling Fe3Se4 to adhere to the internal wall of HMCNs. In half-cells, Fe3Se4@HMCN exhibits remarkable rate capability at current densities of 0.1–10 A g−1, and exceptional cycling performance (525 mAh g−1 at 1.0 A g−1 after 400 cycles, 282 mAh g−1 at 5.0 A g−1 after 1800 cycles, 204 mAh g−1 after 2000 cycles at 10.0 A g−1), surpassing both pure HMCNs and bare Fe3Se4. The composite structure significantly improves Na storage performance of Fe3Se4, while Fe3Se4 also contributes the majority of the capacity of the composite. Kinetic studies further unveil rapid Na+ transport, low reaction impedance and a predominant pseudocapacitive effect. In Fe3Se4@HMCN//Na3V2(PO4)3 full cell, Fe3Se4@HMCN sustains a discharge capacity of 175 mAh g−1 after 1200 cycles at 5.0 A g−1. The superior electrochemical performance is attributed to the nanoencapsulation structure based on HMCNs, which synergistically enhances electron conduction, ion transport and structural stability of Fe3Se4.

Kinetically promoted hydrogen generation by Ru nanoparticles decorated CoB2O4 on mesoporous carbon spheres with rich oxygen vacancies for NaBH4 hydrolysis

Developing heterostructured catalysts with highly active and reusable is an urgent task to achieve green hydrogen production via NaBH4. Herein, we proposed a novel NaCl template method, which involves solid-state physical grinding of metal salts, reducing agents and prepared carbon spheres with the participation of sodium chloride to synthesize Ru-particles decorated CoB2O4 supported on hollow mesoporous carbon nanospheres (Ru/CoB2O4@C) catalysts for efficient and durable H2 generation through alkaline hydrolysis of NaBH4. The optimized catalyst with a Ru content of 3.0 wt% exhibits a high hydrogen generation rate of 8139 mL min−1gcat-1 and a low activation energy of 33.2 kJ mol−1 for NaBH4 hydrolysis, which is one of the most efficient catalysts reported recently. The extraordinary performance is mainly attributed to the synergistic effect between Ru and CoB2O4 species and abundant oxygen vacancies, which facilitate charge redistribution and provide more active sites, thereby enhancing the catalytic activity. Density functional theory calculations support the proposed Michaelis-Menten mechanism, where BH4− and H2O are adsorbed on electron-rich Ru and electron-deficient CoB2O4 surfaces, respectively, and the reaction energy barrier for the rupture of the B-H bond as the rate-determining step is only 1.37 eV, synergistically promoting the hydrolysis of NaBH4. Our study provides an innovative method for designing efficient and stable catalysts for green hydrogen generation.

Fluffy ultrathin WO3 nanoneedle clusters in-situ grown in mesoporous hollow carbon nanospheres as advanced anode for lithium-ion batteries

Fluffy ultrathin WO3 nanoneedle clusters are in-situ grown in mesoporous hollow carbon nanospheres (MHCSs) via unique material impregnation and confined molten reaction in MHCS nanoreactors. Through transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Raman spectra and X-ray photoelectron spectroscopy analyses, it can be found that WO3 nanoneedles with 5–10 nm in thickness and ∼140 nm in length are encapsulated within each MHCS with 150–250 nm in diameter and 30–40 nm in shell thick. Thermal gravimetric analysis reveals the WO3 content of 83.5 wt%. Lithium storage performance was evaluated by galvanostatic charge/discharge cycling, cyclic voltammogram and electrochemical impedance spectroscopy. The composite exhibits remarkable rate performance (average discharge capacity of 1352 mAh g−1 at 0.1 A g−1 and 105 mAh g−1 at 10 A g−1) and excellent cycling performance (1094 mAh g−1 at 0.2 A g−1 after 50 cycles, 760 mAh g−1 at 1 A g−1 after 500 cycles, 351 mAh g−1 at 5 A g−1 after 2000 cycles). The composite also presents outstanding kinetics properties, such as high Li+ diffusion coefficient, strong capacitive effect, and low electrochemical impedance. The superior electrochemical performance is attributed to unique “ship-in-a-bottle” structure. MHCSs facilitate electron transfer and ion diffusion, buffer volume change of WO3 and maintain the integrity of WO3. Furthermore, fluffy ultrathin nanoneedle cluster structure endows WO3 with high electrochemical activity.

Confined synthesis of ternary FeCoMn single-atom nanozyme in N-doped hollow mesoporous carbon nanospheres for synergistic chemotherapy and chemodynamic cancer therapy

Recently, nanozymes show increasing biological applications and promising possibilities for therapeutic intervention, while their mediated therapeutic outcomes are severely compromised due to their insufficient catalytic activity and specificity. Herein, ternary FeCoMn single atoms were incorporated into N-doped hollow mesoporous carbon nanospheres by in situ confinement pyrolysis at 800 °C as high-efficiency nanozyme. The confinement strategy endows the as-prepared nanozyme with the enhanced catalase- and oxidase-like activities. Specifically, the FeCoMn TSAs/N-HCSs nanozyme can decompose intracellular H2O2 to generate O2 and subsequently convert O2 to cytotoxic superoxide radicals (O2∙–), which can initiate cascade enzymatic reactions in tumor microenvironment (TME) for chemodynamic therapy (CDT). Moreover, the cancer therapy was largely enhanced by loading with doxorubicin (DOX). Impressively, the FeCoMn TSAs/N-HCSs nanozyme-mediated CDT and the DOX-induced chemotherapy endow the DOX@FeCoMn TSAs/N-HCSs with effective tumor inhibition, showing the superior therapeutic efficacy.

NiCo2 O4 /Hollow Mesoporous Carbon Nanosphere Hybrids Enabling Super-Hydrophobicity, Thermal Insulation, and Highly Efficient Microwave Absorption.

The combination of 2D magnetic nanosheets and mesoporous carbon with unique interfaces shows considerable prospects for microwave absorption (MA). However, traditional assembly procedures make it impossible to accurately manage the assembly of magnetic nanosheets in carbon matrices. Herein, a reverse strategy for preparing complex magnetic nanosheet cores inside carbon-based yolk-shell structures is developed. This innovative approach focuses on controlling the initial crystallite formation sites in a hydrothermal reaction as well as the inflow and in situ growth behavior of 2D NiCo-layered double hydroxide precursors based on the capillary force induced by hollow mesoporous carbon nanospheres. Accordingly, the as-prepared YS-CNC-2 absorber exhibits remarkable MA performances, with an optimal reflection loss as low as -60.30dB at 2.5mm and an effective absorption bandwidth of 5.20GHz at 2.0mm. The loss of electromagnetic waves (EMW) depends on natural resonance loss, dipole polarization relaxation, and multiple scattering behavior. Ontopof that, the functionalized super-hydrophobic MA coating is produced in spraying and curing processes utilizing YS-CNC-2 nanoparticles and fumed silica additives in the polydimethylsiloxane matrix. The excellent thermal insulation, self-cleaning capability, and durability in diverse solutions of the coating promise potential applications for military equipment in moist situations.

Cooperative regulation of hard template and emulsion self-assembly to the synthesis of N/O co-doped mesoporous hollow carbon nanospheres for supercapacitors

Hollow carbon nanospheres have attracted more and more attention as supercapacitor materials due to their excellent electrical conductivity, high theoretical surface area, high accumulation and rapid ion transfer and diffusion. In this work, we employed the Stöber method to create silica as a template, and then applied self-assembly and dopamine polymerization on the surface of the template to form SiO2@TMB-F127-PDA micelles. Then the nitrogen-doped mesoporous hollow carbon nanospheres (N-MHCNs) were prepared by carbonization and etching on the formed carbon precursors. The effect of dopamine amount on the structure and properties of N-MHCNs was systematically studied. Microstructural characterization results reveal that the morphology of N-MHCNs can be changed from sheet to sphere, and the particle size of N-MHCNs can be 33.8–225.7 nm, the specific surface area is distributed in the range of 175.9–430.1 m2 g−1. Due to the N,O heteroatomic co-doping and Porous spherical structure (with a small particle size of 33 nm, and a large specific surface area of 430.1 m2 g−1), typical sample N-MHCNS-2 shows excellent electrochemical performance in supercapacitors. And it has the highest specific capacitance (241 F g−1) at 0.5 A g−1 current density, excellent rate performance (capacity retention rate of 79 % when current density increases from 0.5 to 10 A g−1) and good cycling ability (capacity retention rate of 90.4 % after 3000 cycles), indicating that it shows great potential in energy storage. This approach provides new opportunities for the controllable synthesis of hollow mesoporous nanospheres and it can be extended to other systems such as hollow metals, metal oxide nanomaterials and carbon-based hybrids.

Boosting lithium storage performance of Co-Sn double hydroxide nanocubes in-situ grown in mesoporous hollow carbon nanospheres

Herein, facile in-situ synthesis of double hydroxide CoSn(OH)6 nanocubes within mesoporous hollow carbon nanospheres (MHCSs) has been successfully developed through solution impregnation and solid-phase molten reaction, using MHCSs as nanoreactors. Several CoSn(OH)6 nanocubes with side length of 50∼80 nm are encapsulated in every MHCS with a diameter of 300–400 nm. When CoSn(OH)6@MHCS is evaluated as an anode material for lithium-ion batteries, it achieves exceptional rate capability (1684 and 626 mAh g−1 at 0.1 and 10 A g−1) and excellent cycle performance (1512 mAh g−1 at 0.2 A g−1 after 140 cycles, 1023 mAh g−1 at 1 A g−1 after 400 cycles, 512 mAh g−1 at 5 A g−1 after 500 cycles). The outstanding electrochemical performance is mainly attributed to the unique “ship-in-a-bottle” encapsulation structure. The mesoporous carbon shells of MHCSs facilitate electrolyte penetration and electron transfer. The large inner cavity of MHCSs promotes full contact between CoSn(OH)6 with electrolyte, and accommodates free expansion/contraction of CoSn(OH)6. The semi-enclosed carbon shell prevents the detachment and aggregation of the inner CoSn(OH)6. These structure merits can remarkably enhance reaction kinetics and structure stability of CoSn(OH)6. The stable and high-capacity output of the full cell demonstrates the great potential of CoSn(OH)6@MHCS in practical applications.

Porous prussian blue analogs derived nickel-iron bimetallic phosphide nanocubes on conductive hollow mesoporous carbon nanospheres for stable and flexible high-performance supercapacitor electrode

Nickel-iron bimetallic phosphide (Ni-Fe-P) is the ideal battery-type materials for supercapacitor in virtue of high theoretical specific capacitance. Nevertheless, its actual adhibition is astricted on account of inferior rate capability and cyclic stability. Herein, we constructed hierarchical core–shell nanocomposites with hollow mesoporous carbon nanospheres (HMCS) packaged via prussian blue analogs derived Ni-Fe-P nanocubes (Ni-Fe-P@HMCS), as a positive electrode for hybrid supercapacitor (HSC). Profiting from the cooperative effects of Ni-Fe-P nanocubes with small size and good dispersibility, and HMCS with continuously conductive network, the Ni-Fe-P@HMCS composite electrode with abundantly porous architectures presents an ultrahigh gravimetric specific capacity for 739.8 C g−1 under 1 A g−1. Specially, the Ni-Fe-P@HMCS electrode presents outstanding rate capability of 78.4% (1 A g−1 to 20 A g−1) and cyclic constancy for 105% after 5000 cycles. Density functional theory implies that the composite electrode possesses higher electrical conductivity than bare Ni-Fe-P electrode by reason of the incremental charge density, and the electrons transferring from NiFe3P4 to HMCS layers. Additionally, the assembled Ni-Fe-P@HMCS//HMCS HSC facility delivers the high energy density for 64.1 Wh kg−1, remarkable flexibility and mechanical stability. Thus, this work proffers a viable and efficacious measure to construct ultra-stability electrode for high-performance portable electronic facilities.

Corrosion inhibition performance of developed epoxy coatings containing carbon nanocapsules loaded with diethylenetriamine

In recent years, hollow structured nanomaterials owe high attention to research, especially when applied to organic coatings due to their high surface area, loading capacity, and flexible shape and structure. Towards this direction, mesoporous hollow carbon nanospheres (MPHS) have been synthesized using the self-assembly method with an average diameter of 280 nm using silica particles as a hard template. The etching of the silica cores was carried out using alkaline etching with NaOH which effectively removed the cores as confirmed by the EDX and FTIR. The MPHS has BET surface area, pore volume, and pore radius of 830.8 m2/g, 1.1 cc/g, and 3.4 nm respectively which support the loading of diethylenetriamine (DETA). The DETA acts as a corrosion inhibitor, surface modifier, and hardener loaded into MPHS with a high loading rate (44 %) to develop MPHS@ DETA. 3 wt% of the MPHS@ DETA was blended with an epoxy coating (MPHS@ DETA-EP) as an anti-corrosion pigment and then the properties of the developed epoxy coatings were systematically characterized. The developed MPHS@ DETA-EP shows excellent anti-corrosion behavior after continuous exposure to corrosive media for 40 days making the coating suitable for several industrial applications.

A strategy to improve tribological performances of solvent-based phenol−formaldehyde resin by using oil-containing nanocapsules

Enhancing the tribological properties of immersed resin is a common and effective method to prolong the service life of aero self-lubricating spherical plain bearing. Herein, using hollow mesoporous carbon nanospheres (HMCNs) as containers, the oil-containing carbon nanocapsules (Oil@C), which were obtained by the incipient wetness impregnation method, were applied as reinforced particles to improve the tribological properties of solvent-based phenol−formaldehyde (PF) resin. Specifically speaking, the Oil@C was monodispersed and uniform with the diameter of 190 nm, shell thickness of 12.5 nm and oil containing rate of 70.59 wt%. With the content of Oil@C reach to 5 wt%, the coefficient of friction (COF) of PF composite decreased about 81.9% (from 0.54 to 0.098). Moreover, the service life of the PF composite prolonged greatly, from 460 s to 5 h. According to the analyzation of morphology and transfer film of the friction pairs, it revealed that the released oil played a key role in the realization of self-lubricating property of PF composites, inhibiting the transfer of PF resin and exfoliation of coating. However, there were different degrees of decline occurred on the shear strength of the PF composites, which needs further improvement.

Interfacial Electron Distribution of Co Nanoparticles Supported on N‐Doped Mesoporous Hollow Carbon Spheres Endows Highly Efficient ORR, OER, and HER

AbstractThe tailoring of the charge transfer between support material and transition metal active phase is an effective strategy for fine tuning the electronic structure of the catalyst active site, and hence improving the activity and stability of the reaction. This works presents that Co nanoparticles supported on N‐doped mesoporous hollow carbon nanospheres (Co/NMHCS) decouple the effect of electronic structure on catalytic performance. The detailed experimental and theoretical results reveal the charge distribution at the Co/NMHCS interface due to N‐doped MHCS. With tuning the electron redistribution, the interface between Co nanoparticles and NMHCS as the active site shows the strong capability to adsorb and reduce the OOH* and proton, thus leading to the optimal ORR, OER, and HER activity in Co/NMHCS. Furthermore, Co/NMHCS‐based Zn–air battery exhibits high power density of 185 mW cm−2, and high gravimetric energy density of 753 mAh gZn−1. Density functional theory (DFT) reveals the electrons accumulate directly on the NMHCS support, which originates from an interplay between Co nanoparticles and the NMHCS support. This work provides constructive guidance for precisely regulating the interface electronic structures to achieve excellent electrocatalytic performance.

Confined Assembly of Hydrated Vanadium Oxide into Hollow Mesoporous Carbon Nanospheres for Fast and Stable K+ Storage Capability.

The rational structural design of the electrode materials is significant to enhance the electrochemical performance for potassium ion storage, benefiting from the shortened ion diffusion distance, increased conductivity, and pseudo-capacitance promotion. Herein, hydrated vanadium oxide (HVO) nanosheets with enriched oxygen defects are well confined into hollow mesoporous carbon spheres (HMCS), producing Od -VOH@C nanospheres through one-step hydrothermal reaction. Attributed to the restricted growth in the HMCS, the HVO nanosheets are loosely packed, generating abundant interfacial boundaries and large specific areas. As a result, Od -VOH@C nanospheres show increased reaction kinetics and well buffer the volume effects for the K+ storage. Od -VOH@C delivers stable capacities of 138 mAh g-1 at 2.0 A g-1 over 10000 cycles in half-cells attributed to the high pseudo-capacitance contribution. The K+ storage mechanism of insertion and conversion reaction is confirmed by ex situ X-ray diffraction, Raman, and X-ray photoelectron spectroscopy analyses. Moreover, the symmetric potassium-ion capacitors of Od -VOH@C//Od -VOH@C deliver a high energy density of 139.6Wh kg-1 at the power density of 948.3W kg-1 .

Enhancing the electronic and ionic transport of flow-electrode capacitive deionization by hollow mesoporous carbon nanospheres

Flow-electrode capacitive deionization (FCDI) is a promising desalination technology by virtue of its infinite electrosorption capacity and possible continuous operation. However, FCDI still suffers from the limited electronic and ionic transport of its flow-electrode. Herein, we first employed hollow mesoporous carbon nanospheres (HMCNs) as flow-electrode to improve FCDI desalination performance. To understand the dependence of FCDI performance on the structural properties of flow-electrodes, two other samples, activated carbon (AC) and solid mesoporous carbon nanospheres (SMCNs), were selected for comparison. The results showed that HMCNs flow-electrode exhibited excellent rheological behaviors with good dispersibility and increased viscosity. EIS analysis proved that HMCNs flow-electrode had a decreased electrical resistance and enhanced ion diffusion. As expected, HMCNs exhibited improved desalination performance compared with AC and SMCNs. In particular, at 1.2 V with 10 % mass loading, the average salt removal rate, charge efficiency, and energy consumption reached 0.040 mg/cm2∙min, 92.9 %, and 0.035 kWh/mol, respectively. The excellent desalination performance should be attributed to the structural advantage of HMCNs in electronic and ionic transport. Overall, this study provides insights into the dependence of FCDI performance on the structural properties of flow-electrodes, thereby progressing the FCDI technology in relation to electronic/ionic transport.

Modification of silica particles with poly(phenylboronic acid) brushes for fabricating hollow mesoporous carbon nanospheres

AbstractPorous carbon nanospheres have attracted extensive attention due to their excellent advantages in specific surface area, pore distribution, and electronic conductivity. Herein, boron‐doped hollow carbon nanospheres with mesoporous walls have been successfully synthesized via a combination of hard/soft templating and boronic acid/sugar ligation. Surface‐initiated Cu(0) mediated reversible deactivation radical polymerization was used to initiate the polymerization of 2‐hydroxyethyl acrylate and poly(ethylene glycol) methyl ether acrylate from the surface of silica. 4‐carboxy‐3‐fluorophenylboronic acid was introduced as a boron precursor by N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide hydrochloride coupling and fructose was introduced as a carbon precursor by boronic esters. After carbonization and template etching, boron‐doped porous carbon spheres could be obtained. We believe such in‐situ heteroatom‐doped method has great potential in preparing hollow mesoporous carbon nanospheres with excellent properties.

Bridging hollow carbon nanostructures to hierarchically pomegranate-like microspheres for efficient oil adsorption and catalysis applications

Hierarchical carbon superstructures that built from primary nanoscale objects and featured with a micro- or macroscopic architecture are highly desired, as credited by the synergistically integrated specialties. Here, we present a simple “microconfined-assembly-locking” approach to achieve pomegranate-like mesoporous carbon microspheres (PMCMs), in which the Pickering droplet-confined colloidal particle assembly and surfactant-directed interfacial locking are coupled. The formed PMCMs possess a unique micro-nano-hierarchical structure that consisting numerous mesoporous hollow carbon nanospheres within a permeable crust. Benefitting from this hierarchical arrangement, such a peculiar architecture not only preserves high surface area, large pore volume and good accessibility of the nano-building blocks, but also upgrades in mechanical strength and easy handling ability. In addition, this strategy allows the interior microstructures to be manipulated through combinatorial varying the assembled colloidal particles and interfacial chemical locking processes. Notably, the PMCMs show superior sorption capacity and cyclability for organics or oils from water in a fixed-bed system, which could also be applied to enhance the catalytic performance in hydrogenation of aromatic compounds after loading with Ru nanoparticles. This synthetic method provides a powerful bridge between nanoscale objects and microscale patterning, and paves a way to access other novel superstructures for expanding their potential applications.

Hollow mesoporous carbon nanospheres from self-generating dual template synergetic assembly for enhanced curcumin release

Hollow mesoporous carbon nanospheres from self-generating dual template synergetic assembly for enhanced curcumin release

Synergistic effect and nanostructure engineering of three-dimensionally hollow mesoporous spherical Cu3P/TiO2 in aqueous/flexible Zn–air batteries

Designing materials with electron/mass transfer effectively improves catalytic activity by synergistic effects between different species. Herein, we report a high-temperature pyrolysis strategy to induce charge transfer of Cu3P loaded TiO2 3D hollow mesoporous carbon nanospheres (Cu3P/TiO2@NC). Density functional theory (DFT) calculations disclose that synergistic between Cu3P and TiO2 can optimize the adsorption of oxygen intermediates and endow fast reaction kinetics. Cu3P/TiO2@NC with hollow mesoporous structure can establish a favorable three-phase interface and shorten the electronic/mass transport path to accelerate reaction kinetics. Consequently, Cu3P/TiO2@NC indicated robust electrocatalytic activity in alkaline medium compared to single-component catalysts and benchmark Pt/C. Cu3P/TiO2@NC exhibits a greater power density of 182.9 mW cm−2 and excellent cyclability over 220 h than Pt/C + RuO2 in Zn-air battery. The flexible properties endow Cu3P/TiO2@NC with promising application prospects in wearable electronic devices. This work may provide an avenue to construct hollow-porous-structured catalysts with synergistic effects for renewable energy devices.

Molecular self-assembly derived hollow mesoporous carbon nanospheres with different pore and wall structure as ultra-stable anode for sodium-ion batteries

Two kinds of hollow mesoporous carbon nanospheres (HMCNs) are synthesized by molecular self-assembly in solution, carbonization and followed etching technique with different silicon precursors “tetraethyl orthosilicate (TEOS, labeled as E) and tetrapropyl orthosilicate (TPOS, labeled as P)”. The growth and Na+ storage mechanisms of HMCNs are proposed via systematically structural characterization and electrochemical analysis. Both two kinds of HMCNs deliver satisfactory Na+ storage performance when used as anode materials for sodium-ion batteries (SIBs), in which HMCNs-E exhibits higher specific capacity (386.5 mAh g−1 at 100 mA g−1 for initially reversible discharge and 207.7 mAh g−1 after 100 cycles) and better rate capability (152.5 mAh g−1 even under 1 A g−1 after 1000 cycles). This could be attributed to the smaller pore size and thinner shell of HMCNs-E compared to HMCNs-P, which not only allows the sufficient approach of Na+ center to electrode surface, but provides shorter diffusion length and makes full use of the active sites within mesoporous shell of HMCNs-E, resulting in its better electrochemical performance.