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Graphitic carbon nanocages (CNCs) have garnered attention as viable candidates for potassium storage, primarily due to their notable crystallinity, large surface area, and rich porosity. Yet, the development of a rapid, scalable, and economically feasible synthesis approach for CNCs persists as a formidable challenge. This study presents a rapid (millisecond‐scale) and scalable (gram‐scale) method for fabricating mesoporous CNCs characterized by high purity and orderly graphitic structures, utilizing the flash Joule heating technique. Employed for potassium storage, the CNC electrode developed herein exhibits exceptional performance metrics, including initial capacity, rate capability, and cycling stability, surpassing numerous carbonaceous materials previously documented. Impressively, it delivers a high initial capacity of 312.3 mAh g−1 at 0.1 A g−1, maintains 175.1 mAh g−1 at a high rate of 2.0 A g−1, and retains 219.6 mAh g−1 over 1000 cycles at 1.0 A g−1. Molecular dynamics simulations and in situ characterizations are employed to elucidate this robust behavior. This work underscores the significant advantages of the flash Joule heating technique in synthesizing carbonaceous materials for potassium storage applications. [ABSTRACT FROM AUTHOR]

A new and highly sensitive voltammetric technique was described in this study for the concurrent detection of endocrine disruptors bisphenol A (BPA) and bisphenol AF (BPAF) based on carbon nanocages (CNCs) and copper oxide nanochains (CuONCs). The CNCs was prepared by the solvothermal method and characterized using various techniques. Utilizing the nanocomposite of CNCs and CuONCs, the voltammetric sensor demonstrated outstanding performance in detecting BPA and BPAF simultaneously with distinct oxidation peaks and increased current peaks. The voltammetric signals have linear relationships with the two bisphenols ranging from 0.500 μM to 100 μM with a detection limit of 0.16 µM for BPA and 0.14 µM for BPAF. The newly designed sensor showed reliable consistency, long-term durability and anti-interference ability, and performed well in analyzing real water samples, indicating great potential for environmental monitoring.

Zn-ion hybrid supercapacitors (ZHCs) combining merits of battery-type and capacitive electrodes are considered to be a prospective candidate in energy storage systems. Tailor-made carbon cathodes with high zincophilicity and abundant physi/chemisorption sites are critical but it remains a great challenge to achieve both features by a sustainable means. Herein, a hydrogen-bonding interaction-guided self-assembly strategy is presented to prepare iodine-doped carbon nanocages without templates for boosting zinc-ion storage by nucleophilicity. The biomass ellagic acid contains extensional hydroxy and acyloxy groups with electron-donating ability, which interact with melamine and ammonium iodide to form organic supermolecules. The organic supermolecules further self-assemble into a nanocage-like structure with cavities under hydrothermal processes via hydrogen-bonding and π-π stacking. The carbon nanocages as ZHCs cathodes enable the high approachability of zincophilic sites and low ion migration resistance resulting from the interconnected conductive network and nanoscale architecture. The experimental analyses and theoretical simulations reveal the pivotal role of iodine dopants. The I5−/I3− doping anions in carbon cathodes have a nucleophilicity to preferentially adsorb the Zn2+ cation by the formation of C+-I5−-Zn2+ and C+-I3−-Zn2+. Of these, the C+-I3− shows stronger bonding with Zn2+ than C+-I5−. As a result, the iodine-doped carbon nanocages produced via this template-free strategy deliver a high capacity of 134.2 mAh/g at 1 A/g and a maximum energy and power density of 114.1 Wh/kg and 42.5 kW/kg. [ABSTRACT FROM AUTHOR]

[Display omitted] Single-atom transition metal-based nitrogen-doped carbon (M−N x −C) is regarded as high-efficiency and cost-effectiveness alternatives to replace noble metal catalysts for oxygen reduction reaction (ORR) in renewable energy storage and conversion devices. In this work, rich FeCo dual-single atoms were efficiently entrapped into N -doped carbon nanocages (FeCo DSAs-NCCs) by simple pyrolysis of the bimetallic precursors doped zeolitic imidazolate framework-8 (ZIF-8), as affirmed by a series of characterizations. The graphitization degree of the N -doping carbon substrate was regulated by modulating the pyrolysis temperature and the types of the metal salts. The typical catalyst substantially improved the alkaline ORR performance, with the onset potential (E onset) of 0.99 V (vs. RHE) and half-wave potential (E 1/2) of 0.88 V (vs. RHE). Ultimately, the catalyst-assembled Zn-air battery possessed a higher open-circuit voltage of 1.501 V, larger power density of 123.7 mW cm−2, and outstanding durability for 150 h. This study provides a guide on developing ORR catalysts for electrochemical energy conversion and storage technology. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have appealed tremendous interests in electrocatalytic oxygen evolution reaction (OER) due to its high intrinsic activity. Nevertheless, the poor electrochemical stability in harsh condition has seriously impeded their widespread application. Herein, we develop a facile strategy for realizing the substantial improvement in OER activity and stability by simultaneously engineering multicomponent phosphide heterostructure and introducing functionalized carbon nanocages. Profiting from the synergy of triple-phased heterostructure and the highly open hollow architecture, the MOF-derived Fe 2 P/Ni 2 P/NiCoP heterostructure functionalized carbon nanocages (FeNiCoP@CNC) presents a favorable catalytic performance towards OER in 1 M KOH and alkaline seawater solutions with the low overpotentials of 237 and 245 mV at 10 mA cm−2, respectively, and no significant degradation is observed over long-term stability testing of 40 h. Detailed mechanism studies demonstrate that the triple-phased phosphide interface can facilitate the electron transfer and provide more catalytic active sites, while the functionalized carbon nanocages also boost the mass transfer and protect the FeNiCoP nanoparticles from aggregation. [Display omitted] • A MOF-mediated method has been proposed for the synthesis of heterostructure. • MOF-derived Fe 2 P/Ni 2 P/NiCoP functionalized carbon nanocage is prepared. • Fe 2 P/Ni 2 P/NiCoP heterojunction provide abundant catalytically active sites. • Carbon nanocages enable efficient electron transfer and mass transport. [ABSTRACT FROM AUTHOR]

Zn-ion hybrid supercapacitors (ZHCs) combining merits of battery-type and capacitive electrodes are considered to be a prospective candidate in energy storage systems. Tailor-made carbon cathodes with high zincophilicity and abundant physi/chemisorption sites are critical but it remains a great challenge to achieve both features by a sustainable means. Herein, a hydrogen-bonding interaction-guided self-assembly strategy is presented to prepare iodine-doped carbon nanocages without templates for boosting zinc-ion storage by nucleophilicity. The biomass ellagic acid contains extensional hydroxy and acyloxy groups with electron-donating ability, which interact with melamine and ammonium iodide to form organic supermolecules. The organic supermolecules further self-assemble into a nanocage-like structure with cavities under hydrothermal processes via hydrogen-bonding and π-π stacking. The carbon nanocages as ZHCs cathodes enable the high approachability of zincophilic sites and low ion migration resistance resulting from the interconnected conductive network and nanoscale architecture. The experimental analyses and theoretical simulations reveal the pivotal role of iodine dopants. The I5−/I3− doping anions in carbon cathodes have a nucleophilicity to preferentially adsorb the Zn2+ cation by the formation of C+-I5−-Zn2+ and C+-I3−-Zn2+. Of these, the C+-I3− shows stronger bonding with Zn2+ than C+-I5−. As a result, the iodine-doped carbon nanocages produced via this template-free strategy deliver a high capacity of 134.2 mAh/g at 1 A/g and a maximum energy and power density of 114.1 Wh/kg and 42.5 kW/kg.

Proper regulation of metal-nitrogen carbon (M-N-C) materials derived from zeolitic imidazolate frameworks (ZIFs) is essential to enhance the oxygen reduction reaction (ORR) performance. However, most of the reports focus on the component regulation, and the structure regulation of ZIFs-derived M-N-C materials by a simple preparation method has been barely reported. Herein, using a one-step electrospinning method with subsequent pyrolysis, we have prepared a bead-like cobalt-nitrogen co-doped carbon nanocage/carbon nanofiber (Co-N-C/CNF) composite electrocatalyst with the porous carbon nanocages arranged one by one in the highly conductive carbon nanofibers. Profiting from the fully exposed active sites and improved conductivity, the Co-N-C/CNF catalyst exhibits an excellent ORR performance even surpassing the commercial Pt/C catalyst. Density functional theory (DFT) results demonstrate that the CoNP-N1-C2 active sites on Co-N-C/CNF make the core contribution to the improvement of ORR properties. Moreover, the zinc-air battery (ZAB) based on the Co-N-C/CNF catalyst also shows outstanding discharge performance. This study provides a new strategy for the preparation and structural design for ZIFs-derived M-N-C materials as efficient ORR catalysts. [ABSTRACT FROM AUTHOR]

A new and highly sensitive voltammetric technique was described in this study for the concurrent detection of endocrine disruptors bisphenol A (BPA) and bisphenol AF (BPAF) based on carbon nanocages (CNCs) and copper oxide nanochains (CuONCs). The CNCs was prepared by the solvothermal method and characterized using various techniques. Utilizing the nanocomposite of CNCs and CuONCs, the voltammetric sensor demonstrated outstanding performance in detecting BPA and BPAF simultaneously with distinct oxidation peaks and increased current peaks. The voltammetric signals have linear relationships with the two bisphenols ranging from 0.500 μM to 100 μM with a detection limit of 0.16 µM for BPA and 0.14 µM for BPAF. The newly designed sensor showed reliable consistency, long-term durability and anti-interference ability, and performed well in analyzing real water samples, indicating great potential for environmental monitoring. [Display omitted] • Preparation of the nanocomposite of carbon nanocages (CNCs) and CuO nanochains (CuONCs) for the first time. • Voltammetric sensor for the simultaneous determination of bisphenol A and bisphenol AF. • Simple, sensitive and selective detection of bisphenol A and bisphenol AF. [ABSTRACT FROM AUTHOR]

Light-weight and exceptional microwave absorption are two vital characteristics for microwave absorbers in practical applications, but still face challenges. Herein, we employ a sacrificial template strategy to fabricate heteroatoms-doped carbon nanocages (CNs) via chemical vapor deposition, in which heteroatoms are simultaneously doped into the carbon frameworks by bubbling flowing source liquid. Compared with CNs, doped heteroatoms, accompanied with the inevitably defective arrangements in the lattice, not only decrease the electrical conductivity and balance the impedance characteristics, but also introduce structural-chemical defects and trigger dominant dipolar/defect polarization. As a result, both the minimum reflection loss (RL,min) and effective absorption bandwidth (EAB) greatly increase at an ultralow filler loading of 5 wt.% owing to internal hollow void and high specific surface area. The RL,min values reach −53.6, −43.2, and −50.1 dB for N-CNs, S-CNs, and N,S-CNs with the corresponding EAB of 4.9, 2.5, and 3.1 GHz, respectively. Furthermore, this work provides an effective strategy for the construction of heteroatoms-doped hollow carbon frameworks in large-scale production and the obtained doped carbon nanocages can be used as light-weight and high-performance microwave absorbers. [ABSTRACT FROM AUTHOR]

Designing efficient catalysts for operating CO2 electroreduction in membrane electrode assembly (MEA) faces significant obstacles. Herein, we propose an asymmetrically coordinated Ni SAC featuring axial Br coordination at NiN4Br sites anchoring onto hollow Br/N co-doped carbon nanocages, achieved through a NaBr-assisted confined-pyrolysis strategy. The Ni-NBr-C exhibits a high CO Faradaic efficiency (FECO> 97%) over the current density range of 50 to 350 mA cm-2 in the MEA device. Furthermore, Ni-NBr-C shows a stable cell voltage of 2.66 ± 0.2 V while delivering a large current density of 350 mA cm-2 over an 85-hour long-term operation, demonstrating its potential for industrial-scale applications. Advanced characterization techniques and theoretical calculations reveal that the coordination and doping of Br enhance the intrinsic activity but also highlighted that the unique pore structure improves mass transfer efficiency., (© 2024 Wiley‐VCH GmbH.)

Compositing dielectric and magnetic components have been proven effective in optimizing electromagnetic (EM) wave absorption, in which the dielectric loss capacity can be reinforced by the polarization effects of hetero‐substitutions. Here, the dielectric polarization through the energy transformation between the relatively complex permeability and permittivity in nitrogen‐doped carbon nanocages (NCNs) with sub‐nanometer Fe clusters is further boosted. As a transition state between single Fe atoms and Fe3O4 nanoparticles hetero‐substitutions, these subnanometer Fe clusters confined in NCNs can be achieved by carbonizing FePc@ZIF‐8 composites at 900 °C. Benefitting from their unique structures, an enhanced dielectric loss tangent of 1.57 is obtained at 10 GHz, which is 3.0 and 1.6 times higher than those of single Fe atoms and Fe3O4 nanoparticles hetero‐substitutions, respectively. Furthermore, the minimum reflection loss can reach −64.75 dB at 7.1 GHz (2.7 mm) and the effective absorption bandwidth is 6.2 GHz (11.8–18 GHz, covering the full P‐band) at 1.7 mm. The present study provides intrinsic insight into the dielectric polarization behaviors in subnanometer hetero‐substitutions, inspiring the design of high‐performance EM absorption materials. [ABSTRACT FROM AUTHOR]

Carbon nanocages (CNCs), with unique merits of morphology and structure, have attracted increasing attention for energy storage and conversion. However, the synthesis of CNCs reported so far suffers from relatively harsh conditions and expensive raw materials. Herein, porous CNCs are intelligently designed using low‐cost glucose as the carbon precursor via a facile K‐functionalized carbon quantum dots (K‐CQDs)‐induced assembly route under hydrothermal process. The resulting CNCs have a unique cage‐like structure, large surface area, and rich carboxyl groups. With these elegant structural merits, the as‐made CNCs anode shows a high reversible capacity of 270 mAh g−1 at 100 mA g−1 after 200 cycles and a long‐term cycling stability of 206 mAh g−1 at 2000 mA g−1 after 4000 cycles. An intercalation reaction mechanism with the K+ intercalation compound is further identified through an in‐situ Raman technique. Density functional theory simulations reveal that abundant carboxyl groups inherited from K‐CQDs can significantly promote the potassium storage capacities of the CNCs electrode. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of hydrogen peroxide (H2O2) through 2e– oxygen reduction reaction is an effective approach to replace anthraquinone process. However, most reported electrocatalysts work effectively in alkaline medium in which H2O2 will easily decompose into water. It is still of great challenge to develop cost‐effective electrocatalysts with high activity and selectivity for electrocatalytic H2O2 production in acidic media. Herein, it is first theoretically demonstrated that the adsorption energy of OOH* intermediate on carbon can be optimized by embedding Co nanoparticles (Co NPs) and tuning oxygen‐containing functional groups, ensuring high activity and selectivity. Guided by density functional theory calculations, highly porous open carbon nanocages with embedded Co NPs are designed and synthesized by template‐engaged method. The pyrolysis temperature can effectively modulate the electronic and pore structure of carbon nanocages. Impressively, the optimized carbon nanocages synthesized at 700 °C (P‐Co@C‐700) with highest percentage of –C–O–C group and defects, largest specific surface area (1351 m2 g–1), and mesoporous structure exhibit high selectivity up to 94% toward H2O2 production in 0.1 m HClO4. Furthermore, the P‐Co@C‐700 nanocages display promising application for efficient electro‐Fenton degradation of model organic pollutant. [ABSTRACT FROM AUTHOR]

Rational manipulation of hollow structure with uniform heterojunctions is evolving as an effective approach to meet the lightweight and high‐performance microwave absorption for metal‐organic frameworks (MOFs) derived absorbers. Herein, a new and controlled synergistic protecting‐etching strategy is proposed to construct shelled ZIF‐67 rhombic dodecahedral cages using tannic acid under theoretical guidance, then hollow Co@N‐doped carbon nanocages with uniform heterojunctions and hierarchical micro‐meso‐macropores are obtained via a pyrolysis process, which addresses the shortcomings of using sacrificing templates or corrosive agents. The outer Co@N‐doped carbon shell, composed of highly dispersive core‐shell heterojunctions, possesses micro‐mesopores while the inner hollow macroporous cavity endows the absorbers with lightweight characteristics. Accordingly, the maximum reflection loss is −60.6 dB at 2.4 mm and the absorption bandwidth reaches 5.1 GHz at 1.9 mm with 10 wt% filler loading, exhibiting superior specific reflection loss compared with the vast majority of previous MOFs derived absorbers. Furthermore, this synergistic protecting‐etching strategy provides inspiration for precisely creating a hollow void inside other MOFs crystals and broadens the desirable candidates for lightweight and high‐efficient microwave absorbers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical N-doped carbon nanocages exhibit robust structure for confining LiBH 4. • 50LBH@NC-NbF 5 initiates dehydrogenation at 140.6 °C. • 50LBH@NC-NbF 5 can retain 93% reversible H 2 capacity after 20 cycles. • In-situ formed NbB 2 species is considered the final active and stable nanocatalyst. • N heteroatoms can anchor Nb cations and weaken B-H bonds proved by DFT calculations. A synergetic approach of nanoconfinement coupling with in-situ formed nanocatalysts was developed to fabricate a novel and robust nano-LiBH 4 system. The nanoconfining scaffold exhibits an unparalleled 3D hierarchical architecture featuring micro-, meso-, and macro-pores assembled by 2D interconnected nanosheets that consist of 0D hollow nitrogen-doped carbon nanocages. This structure possesses an accumulated pore width of 7.79 nm, extremely high pore volumes of 3.16 cm3/g, and a theoretical loading capacity of 67.9 wt% for LiBH 4. The in-situ formed NbB 2 species transformed from initial NbF 5 nanoparticles is confirmed as the final active nanocatalyst. It is worth mentioning that the defective N heteroatoms within the scaffold can serve the role of coordinating with Nb cations and weaken the B-H bonds as supported by the DFT calculations. With an optimized loading of 50 wt% LiBH 4 , the initial dehydrogenation temperatures can be reduced to 140.6 °C, and the system can rapidly release 7.55 wt% H 2 at 320 °C within 39 min. Furthermore, the nanoconfined system exhibits excellent low-temperature reversibility, retaining 93 % of its capacity after 20 cycles at 300 °C. This study provides innovative perspectives on the design of novel scaffold structures doped with defective heteroatoms for the nanoconfinement and synergetic catalysis of de/rehydrogenation for metal borohydrides. [ABSTRACT FROM AUTHOR]

Nitrogen/oxygen co-doped carbon nanocages (NOCN) have been deemed as promising materials in renewable energy-storage applications. Herein, we report a facile one-pot hydrothermal approach for formation of three-dimensional (3D) flower-like MoS 2 nanoflakes/NOCN composite (MoS 2 @NOCN) with excellent storage properties as anode for supercapacitor. As a result, ultrathin MoS 2 nanosheets were vertically grown onto the surface of NOCN, which can prevent sheet aggregation and provide a rapid pathway for electron transfer. The as-prepared MoS 2 @NOCN composites were characterized by electrochemical measurements to demonstrate the supercapacitor performance. The results indicate that MoS 2 @NOCN-3 exhibited a high specific capacitance (240.8 F g−1 at 0.5 A g−1) and excellent rate performance (approximately 46.4 % from 1 A g−1 to 10 A g−1). The as-obtained composites demonstrated their potential applications in supercapacitor electrode materials. The three-dimensional (3D) flower-like MoS 2 nanoflakes/NOCN composite (MoS 2 @NOCN) was synthesized via a one-pot hydrothermal method. The ultrathin MoS 2 nanosheets anchored on the surfaces of NOCN can fully and directly make contact with electrolyte, leading to a reduced internal resistance and a high C s. [Display omitted] • A novel 3D flower-like MoS 2 /NOCN were fabricated through hydrothermal method. • MoS 2 /NOCN-3 exhibited relatively good electrochemical properties in supercapacitor. • Synergistic effects between the NOCN and MoS 2 improve the electrochemical performance. [ABSTRACT FROM AUTHOR]

The carbon‐based nanomaterials have attracted intensive interests as promising metal‐free electrocatalysts to reduce or even eliminate the use of precious‐metal catalysts on oxygen reduction reactions (ORR). In this regard, we developed 3D hollow carbon nanocages confining high‐loading sulfur fabricated by chemical vapor deposition (CVD) method employing self‐sacrificial templates (basic magnesium carbonate). Under different fabrication temperatures, the as‐designed samples obtained different morphologies, compositions and structural properties. With the largest specific surface area (1306 m2 g−1), highest heteroatom doping content (6.04 at.% of S) and well‐balanced pore distribution, the electrocatalysts synthesized under 800 °C could catalyze the ORR process through the ideally efficient four‐electron transfer pathway. The remarkable catalytic selectivity and stability of the optimal material in alkaline electrolyte resulted from the synergistic effects of structural and chemical characteristics. Moreover, primary Zn‐air batteries built with the sulfur loaded carbon nanocage air electrodes revealed high open‐circuit voltage (1.42 V) and good stability in comparison with the counterpart using commercial Pt/C catalyst. These findings provide a new avenue for designing the metal‐free electrocatalysts for various renewable energy storage and conversion technologies. [ABSTRACT FROM AUTHOR]

The development of highly active, inexpensive, and stable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts to replace noble metal Pt and RuO 2 catalysts remains a considerable challenge for highly demanded reversible fuel cells and metal-air batteries. Herein, a novel nitrogen doped carbon nanocage (N–CNC-900) is fabricated via facile carbonization of bimetal-organic framework (BMOF). The newly obtained N–CNC-900 catalyst is featured by multiple carbon layers with a wide lattice spacing of 0.434 nm and the aperture of approximate 10 nm, ultrahigh specific surface area and abundant N doping amount as well. As results, the optimized N–CNC-900 exhibits a low overpotential of 1.52 V toward OER at a current density of 10 mA/cm2, and also show a large half-wave potential of 0.90 V for ORR, respectively. High activity and stability toward the bifunctional oxygen electrocatalysis are also demonstrated on the N–CNC-900. When explored as air cathode for rechargeable Zn-air battery, a high open-circuit voltage (1.54 V) and long-term stability (after cycling 200 h) can be realized, outperforming the commercial Pt/C + RuO 2 association. This outstanding performance can be attributed to improved reaction kinetics of both ORR and OER, which originates from the enlarged lattice spacing in the few-layer conductive carbon nanocage structure and the existing metal-nitrogen-carbon (M-N x -C). These results forebode the optimized N–CNC-900 presenting a promising application in metal-air batteries, as well the lattice modulation of carbon materials providing a novel approach for designing advanced electrocatalysts. The newly obtained N–CNC-900 catalyst is featured with multiple carbon layers with a wide lattice spacing of 0.434 nm and the aperture of approximate 10 nm, ultrahigh specific surface area and abundant N doping amount. N–CNC-900 possesses abundant catalytic active sites and high catalytic activity. The rechargeable Zn-air battery based N–CNC-900 exhibited outstanding performance: high open-circuit voltage, long-term stability and large power density. Image 1 • Novel carbon nanocages with N doped multiple carbon layers were prepared. • The lattice spacing was enlarged to 0.434 nm with rich active sites. • The optimized N–CNC-900 exhibited excellent bifunctional electrocatalysis. • The fabricated Zn-air battery presented outstanding performance. [ABSTRACT FROM AUTHOR]

The rational design of bifunctional oxygen electrocatalysts with unique morphology and luxuriant porous structure is significant but challenging for accelerating the reaction kinetics of rechargeable Zn-air batteries (ZABs). Herein, zinc-mediated Fe, N-codoped carbon nanocages (Zn-FeNCNs) are synthesized by pyrolyzing the polymerized iron-doped polydopamine on the surface of the ZIF-8 crystal polyhedron. The formation of the chelate between polydopamine and Fe serves as the covering layer to prevent the porous carbon nanocages from collapsing and boosts enough exposure and utilization of metal-based active species during carbonization. Furthermore, both the theoretical calculation and experimental results show that the strong interaction between polyhedron and polydopamine facilitates the evolution of high-activity zinc-modulated FeNx sites and electron transportation and then stimulates the excellent bifunctional catalytic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). As expected, the Zn-air battery with Zn-FeNCNs as an air cathode displays a superior power density (256 mW cm -2 ) and a high specific capacity (813.3 mA h gZn -1 ), as well as long-term stability over 1000 h. Besides, when this catalyst is applied to the solid-state battery, the device exhibited outstanding mechanical stability and a high round-trip efficiency under different bending angles., (© 2023 Wiley‐VCH GmbH.)

Summary: In this study, we introduce the potential for a new catalyst support, namely, carbon nanocages (CNCs) for anodic direct methanol fuel cell (DMFC). The synthesis, characterization and catalytic activities of four electrocatalysts, PtRu/CNC, PtNi/CNC, PtFe/CNC and PtCo/CNC, have been investigated. These electrocatalysts are synthesized using pyrolysis, followed by a microwave‐assisted ethylene glycol reduction method. From X‐ray diffraction analysis, PtNi/CNC and PtRu/CNC showed the smallest crystallite particle size of Pt‐alloy, which corresponded to the (111) plane. The Raman spectra confirmed the presence of the carbon support material in all prepared electrocatalysts. The ratio value of the D band and G band (ID/IG) of all prepared samples was not much different within the electrocatalyst and CNC. The ID/IG values calculated for the CNC, PtNi/CNC, PtRu/CNC, PtCo/CNC and PtFe/CNC electrocatalysts were 0.90, 0.89, 0.83, 0.78 and 0.77, respectively. Therefore, the number of defects of graphitization in increasing order (ID/IG) was PtFe/CNC < PtCo/CNC < PtRu/CNC < PtNi/CNC < CNC. Brunauer‐Emmett‐Teller analysis revealed that the CNC support has a mesoporous‐type structure with a high surface area of 416 m2 g−1, which indicates that this support has a high potential to act as an excellent catalyst support. From the cyclic voltammetry curve, PtRu/CNC showed the highest catalytic activity in methanol electro‐oxidation and reached a value of 427 mA mg−1, followed by PtNi/CNC (384.11 mA mg−1), PtCo/CNC (150.53 mA mg−1) and PtFe/CNC (144.11 mA mg−1). PtFe/CNC exhibited a higher ratio value of If/Ib (3.24) compared with PtRu/CNC (2.34), PtNi/CNC (1.43) and PtCo/CNC (1.62). These values show that the combination of Pt and Fe catalysts in PtFe/CNC had better CO tolerance than PtRu/CNC, PtNi/CNC and PtCo/CNC electrocatalysts. The higher performance of PtRu/CNC was attributed to the fact that it had the smallest bimetallic‐Pt crystallite; there was a smooth distribution of bimetallic‐Pt on its CNC support, as shown by field emission scanning electron microscopy; it had the highest electrochemical surface area value (16.23 m2 g−1); and it had an overall catalytic performance enhanced by the advantages of the unique and large surface area from the CNC as support material. In passive DMFC mode, PtRu/CNC showed a maximum power density of 3.35 mW cm−2, which is 1.72 times higher than that of the PtRu/C commercial electrocatalyst. [ABSTRACT FROM AUTHOR]

Potassium–selenium (K‐Se) batteries have attracted increasing attention for their potential as stationary energy storage systems due to their high theoretical energy density and low cost. The major challenges of these batteries are the low utilization of active selenium, sluggish kinetics, and the volume change during cycling. Herein, a N and O dual‐doped porous carbon nanocage anchored with carbon nanotubes (CNTs) (denoted as NO‐nanocage/CNT) is designed as a host for Se. This material combines multiple advantages, such as abundant N/O active sites and excellent electrical conductivity, to realize highly efficient immobilization of Se and polyselenide and fast redox kinetics. The hollow carbon skeleton, with abundant micro and mesoporous structures, shortens the diffusion distances between the ions/electrons and accommodates the volume expansion of the active materials. Density functional theory calculations further confirm that the NO‐nanocage/CNT exhibits strong chemical affinity to K2Se, which is in agreement with the experimental results. The Se@NO‐nanocage/CNT cathode displays a remarkable reversible capacity (623 mAh g−1 at 0.1 A g−1) and an ultra‐long cycle life (274 mAh g−1 after 3500 cycles at 1.0 A g−1). The design presented in this paper offers a new approach for the design of multifunctional Se hosts for advanced alkali metal‐chalcogen batteries. [ABSTRACT FROM AUTHOR]

The use of adsorption capacity of porous and large-surface-area materials is an important approach to treat dye-containing effluents. In this study, the porous carbon nanocages (CNCs) were synthesized from the precursor of phenol in home-made chemical vapor deposition (CVD) setup at 600–1000°C, and were convincingly characterized. The as-prepared CNCs are amorphous, porous and hollow, and have the size of 50–100 nm in width, 100–200 nm in length and several nm in thickness, causing to the large surface area of 800 m2/g and pore volume of 1.63 cm3/g. The growth of amorphous-like CNCs was related to the thermolysis species of phenol. Interestingly, each CNC has large volume hollow coelom and small opening (a typical ink bottle pore), being in favor of adsorption but in disfavor of desorption, thus it is very fit for acting as the adsorbent of dye. As expected, the products showed excellent adsorbility of rhodamine B when compared with the most used activated carbon having straight and slit pore structures, displaying broad application prospects in removing dye from wastewater. The porous and amorphous carbon nanocages synthesized from phenol in home-made chemical vapor deposition have large volume hollow coelom and small opening, and show excellent adsorbility of rhodamine B compared with the most used activated carbon having straight and slit pore structures, displaying broad application prospects in removing dye from wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • RuO 2 quantum dots anchored on porous carbon nanocages (RQD@PCN) are synthesized. • The RQD@PCN serves as a novel cathode material for Zn-ion hybrid capacitors. • The RQD@PCN cathode presents superior electrochemical performance. • Zn2+/H+ co-participated charge storage mechanism is revealed for the RQD@PCN cathode. Zn-ion hybrid capacitors (ZICs) are a novel and promising electrochemical energy storage system, while exploring high-performance cathode materials is essential for the development of ZICs. Herein, we propose hydrous ruthenium oxide quantum dots (RuO 2 QDs) anchored on porous carbon nanocages (PCNCs) as a new cathode material for ZICs. For the RuO 2 QDs@PCNCs material, hydrous RuO 2 QDs with a small size of 2–3 nm uniformly disperse on the PCNC support, providing large electrode–electrolyte interface for electrochemical reactions and abundant active sites for ion storage. Consequently, the RuO 2 QDs@PCNCs cathode material displays desirable electrochemical performance in ZICs, including a large capacity of 224 mAh g−1 at 0.4–1.8 V, superior rate capability (showing 156 mAh g−1 capacity even at a large current of 20 A g−1) and good stability during a long-term cycling test over 20,000 cycles, significantly superior to currently-reported cathode materials for ZICs. An ultrahigh energy density of 180 Wh/kg is achieved for the RuO 2 QDs@PCNCs cathode-based ZICs. Mechanism investigations point out the capacitive behavior-dominated and Zn2+/H+ co-participated charge storage process with fast electrochemical kinetics for the RuO 2 QDs@PCNCs cathode in ZICs. This work not only provides a new choice for high-performance cathodes but also enriches the electrochemical theory of ZICs. [ABSTRACT FROM AUTHOR]

Nitrogen-doped graphitized carbon materials have been proposed as promising catalytic materials for oxygen evolution reaction in alkaline water-electrolysis hydrogen production. In this study, newly graphene-like graphitized carbon nanocages and nitrogen-doped graphitized carbon nanotubes are controllably prepared by using Tween-20 as molecular precursor, Ni as graphitization catalyst and urea as nitrogen source. The as-prepared materials are characterized by X-Ray Diffraction, scanning electron microscope, transmission electron microscopy and Raman spectroscopy X-ray photoelectron spectroscopy. The OER electrochemical performances are evaluated by linear sweep voltammetry and chronoamperometry. It is found that the nitrogen-doped graphitized carbon nanotubes have higher oxygen evolution activity, lower oxygen evolution overpotential and desirable electrochemical stability relative to graphitized carbon nanocages, demonstrating it is a promising catalytic material for OER in alkaline water-electrolysis hydrogen production. Nitrogen-doped graphitized carbon from molecular precursor is successfully fabricated as non-metal electrocatalyst for oxygen evolution reaction (OER). Unlabelled Image • Nitrogen-doped graphitized carbon nanotubes with controllable length are successfully prepared. • Tween-20 molecular precursor was used for rational design of nitrogen-doped graphitized carbon. • An efficient and low-cost carbon-powder-protection solid-phase synthesis strategy is proposed. • Synergistic effect between Ni-catalyzed graphitization and in-situ N doping with urea is proved. • The nitrogen-doped carbon nanotubes exhibit favorable excellent activity and stability for OER. [ABSTRACT FROM AUTHOR]

The smallest spherical carbon nanocage so far, [2.2.2]carbon nanocage, has been synthesized by the cationic rhodium(I)/H8‐binap complex‐catalyzed regioselective intermolecular cyclotrimerization of a cis‐1‐ethynyl‐4‐arylcyclohexadiene derivative followed by the triple Suzuki–Miyaura cross‐couplings with 1,3,5‐triborylbenzene and reductive aromatization. This cage molecule is highly strained, and its ring strain is between those of [6] and [5]cycloparaphenylenes. A significant red‐shift of an emission maximum was observed, compared with that of known [4.4.4]carbon nanocage. The sequential cyclotrimerizations of a cis‐1,4‐diethynylcyclohexadiene derivative with the same rhodium(I) catalyst followed by reductive aromatization failed to afford [1.1.1]carbon nanocage; instead, a β‐graph‐shaped cage molecule was generated. [ABSTRACT FROM AUTHOR]

Abstract Energy storage based on sodium ions is considered to be one of the most promising candidates for large-scale applications. However, designing nanostructured anodes with ultralong cycle life, superior rate capability, and high specific capacitance is still a challenge. Herein, we report that nitrogen functionalized carbon nanocages with optimized structures as anodes in sodium-ion half cells demonstrate a superior capacity of 402 mA h g−1 at 50 mA g−1, excellent rate performance with 101 mA h g−1 at 10 A g−1, and an ultra-long cycle life by retaining 81% of its initial capacity after 5000 cycles at 10 A g−1. It can be observed that carbons with high nitrogen doping level and few-layer graphene domains are proved to be effective for sodium ion storage. Benefiting from the merits of structure and electrochemical performance of nitrogen functionalized carbon nanocages, the sodium-ion capacitors by using identical carbon electrodes achieves a high energy density of 102.5 W h kg−1 and an outstanding cycle life of 100,000 cycles with 74.2% of the capacity retention. This work opens a new opportunity for designing high-performance carbon electrodes with scalable production for next-generation energy storage. Graphical abstract Image 1 Highlights • Na+ storage is boosted by tuning microstructure, porosity, and doping in carbons. • The as-built all carbon sodium-ion capacitors show high energy and long cycle life. • The facile one-step synthesis approach is promising for advanced energy storage. [ABSTRACT FROM AUTHOR]

Single-atom transition metal-based nitrogen-doped carbon (M-N x -C) is regarded as high-efficiency and cost-effectiveness alternatives to replace noble metal catalysts for oxygen reduction reaction (ORR) in renewable energy storage and conversion devices. In this work, rich FeCo dual-single atoms were efficiently entrapped into N-doped carbon nanocages (FeCo DSAs-NCCs) by simple pyrolysis of the bimetallic precursors doped zeolitic imidazolate framework-8 (ZIF-8), as affirmed by a series of characterizations. The graphitization degree of the N-doping carbon substrate was regulated by modulating the pyrolysis temperature and the types of the metal salts. The typical catalyst substantially improved the alkaline ORR performance, with the onset potential (E onset ) of 0.99 V (vs. RHE) and half-wave potential (E 1/2 ) of 0.88 V (vs. RHE). Ultimately, the catalyst-assembled Zn-air battery possessed a higher open-circuit voltage of 1.501 V, larger power density of 123.7 mW cm -2 , and outstanding durability for 150 h. This study provides a guide on developing ORR catalysts for electrochemical energy conversion and storage technology., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Abstract: As an emerging electrochemical energy storage device, potassium‐ion batteries (PIBs) have drawn growing interest due to the resource‐abundance and low cost of potassium. Graphite‐based materials, as the most common anodes for commercial Li‐ion batteries, have a very low capacity when used an anode for Na‐ion batteries, but they show reasonable capacities as anodes for PIBs. The practical application of graphitic materials in PIBs suffers from poor cyclability, however, due to the large interlayer expansion/shrinkage caused by the intercalation/deintercalation of potassium ions. Here, a highly graphitic carbon nanocage (CNC) is reported as a PIBs anode, which exhibits excellent cyclability and superior depotassiation capacity of 175 mAh g−1 at 35 C. The potassium storage mechanism in CNC is revealed by cyclic voltammetry as due to redox reactions (intercalation/deintercalation) and double‐layer capacitance (surface adsorption/desorption). The present results give new insights into structural design for graphitic anode materials in PIBs and understanding the double‐layer capacitance effect in alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

Multi-yolk-shell SnCo@N-doped carbon nanocages with controllable carbon shell thickness are well fabricated by a novel approach. The multi-yolk-shell SnCo@N-doped carbon nanocages form an enough void volume to compensate the volume expansion of SnCo nanoparticles during Li + insertion. To optimize the electrochemical properties, SnCo@N-doped carbon nanocages with controllable carbon shell thickness can be tailored by coating polydopamine (PDA) with various thicknesses on CoSn(OH) 6 hollow nanocubes in the second step of the synthesis process. Multi-yolk-shell SnCo@N-doped carbon nanocages with the optimized shell thickness exhibit a high initial discharge capacity (1025 mAhg −1 ) and remarkable cyclic stability (611 mAhg −1 after 100 cycles) as Li-ion batteries anode. This work may open a wonderful way for the rational design of alloy@carbon composites with tailorable structures for next-generation anode nanomaterials in Li-ion battery. [ABSTRACT FROM AUTHOR]

The exploration of various porous nanocarbon materials with an extraordinary electrochemical capacitive performance in ionic liquid (IL) electrolytes is urgently needed for development of the next-generation energy storage devices. Significant improvements in energy density have been achieved, however, supercapacitors with IL electrolytes usually suffer from issues related to low power density and large IR drop. Herein, we report an unprecedented carbon nanomesh that is made up of interconnected densely-packed carbon nanocages with ultrathin partially graphitic shells. The large specific surface area and well-developed mesopores combined with its unique structural features, make it a very competitive material for high-performance supercapacitor in IL electrolyte. Notably, this unique nanosheets morphology with lots of in-plane nanopores on their surface can provide fast cross-plane ion diffusion pathways, and meanwhile, the carbon nanocages with partially graphitic shells ensure the rapid electron transfer. The supercapacitor assembled with the optimized sample can deliver a high specific capacitance (up to 194 F/g at 1 A/g), superior rate capability (68% capacitance retention at 70 A/g), low IR drop (0.685 V at 70 A/g). Moreover, benefiting from the wide working voltage and high-rate capability, the energy densities can maintain at 56.1 Wh/kg even at an ultrahigh power density of 61.250 kW/kg. Strikingly, the as-assembled supercapacitor can successfully power a light-emitting diodes (LED, 2.2 V) module with 53 red LED lights demonstrating its great potential for practical applications in energy storage devices. [ABSTRACT FROM AUTHOR]

Exploration of carbon nanoarchitectures with lower cost and excellent rate capability is of great importance, however, still remains a significant challenge. In the present work, a facile procedure for the fabrication of porous carbon nanocages (PCNCs) with a superior rate capability for supercapacitors has been developed. This approach is based on directly carbonization of sodium polyacrylate and subsequently chemical etching through a simple immersing-filtration-activation process. The extraordinary structures and morphologies of PCNCs has lots of structural advantages for supercapacitor applications. The supercapacitor assembled with the optimized sample can deliver a large specific capacitance (161 F/g at 1 A/g), superior rate capability (capacitance retention as high as 77.6% at 30 A/g), tiny IR drop (0.407 V at 30 A/g). Furthermore, in view of the wide working voltage (2.7 V) and excellent rate capability, the energy densities can retain at 30.2 Wh/kg at a large power density of 20.3625 kW/kg. Remarkably, the as-assembled supercapacitor can light 11 red light-emitting diodes (LED, 1.5 V) in parallel highlighting its enormous potential for practical applications. [ABSTRACT FROM AUTHOR]

Developing an efficient cathode is essential to obtain high rate capability and rechargeable lithium oxygen (Li-O2 ) batteries. Herein, ruthenium (Ru)-functionalized hierarchical carbon nanocages (hCNCs) are synthesized and employed as a cathode catalyst for Li-O2 batteries. The as-prepared cathode exhibits high discharge capacity, low charge potential (8135 mAhg-1 with 3.85V charge potential at a current density of 0.08 mAcm-2 ), outstanding rate capability (3416 mAhg-1 at a current density of 0.48 mAcm-2 ) and good stability up to 78 cycles at a limited capacity of 500 mAhg-1 . Such excellent battery performance is ascribed to the synergistic effect of the interconnected hierarchically porous structure of hCNCs, which can facilitate effective electrolyte immersion and efficient Li-O2 mass transport, and the high catalytic activity of Ru nanoparticles. [ABSTRACT FROM AUTHOR]

In this paper, Co-based metal organic frameworks were prepared through a facile method. After successive carbonization and oxidation treatment, the Co 3 O 4 /Co/carbon nanocages (COCCNCs) with hollow dodecahedral shape were obtained. Co 3 O 4 /Co/carbon nanocages with a high surface area (183.9 m 2 g −1 ) and uniform pore distribution were employed as an anode material for LIBs and exhibited a high reversible specific capacity (850 mA hg −1 at 100 mA g −1 ), improved Coulombic efficiency, superior rate capability (485 mA hg −1 at a high current density of 5000 mA g −1 ) and excellent cycling stability (505 mA hg −1 can be remained after 600 cycles at 2000 mA g −1 ). Such a superior lithium storage performance is largely ascribed to the unique architecture composed of well-dispersed Co 3 O 4 (ca. 9 nm) and Co (ca. 5 nm) nanocrystals embedded in hollow carbon nanocages with graphitic structure. This architecture not only avoids particle aggregation and nanostructure cracking upon cycling, but also provides continuous and flexile conductive carbon frameworks to facilitate the fast ions and electrons transportation. [ABSTRACT FROM AUTHOR]

The conversion of non-condensable pyrolysis gases from plastic feedstock into carbon nanomaterials through catalytic chemical vapor deposition was investigated. Three samples, namely low density polyethylene (LDPE), polypropylene (PP) and a mixture of four plastics (MP), containing LDPE (40%), PP (40%), polystyrene (PS) (10%) and polyethylene terephthalate (PET) (10%), were used as raw materials in the pyrolysis process. The plastics were initially pyrolyzed at 600 °C producing condensable oils and non-condensable gases. The non-condensable gases were further heated in the second reactor either at 500 or 800 °C. Heating at 800 °C caused decomposition of the gases to intermediate products (methane, ethylene and condensable oils), which were converted over a nickel-based catalyst into multi-walled carbon nanotubes with similar yields and properties regardless of the plastic feedstock. Heating at 500 °C had no effect on the composition of non-condensable pyrolysis gases. However, the carbon materials produced over the catalyst had different yields and structures implying the influence of plastic feedstock on the properties of materials was more pronounced at lower synthesis temperature. At 500 °C, the MP non-condensable pyrolysis gases were converted into a mixture of carbon nanocages and multi-walled carbon nanotubes with higher graphitization degree compared to carbon materials from PP and LDPE, which were mainly multi-walled carbon nanotubes. Furthermore, the carbon yield was the highest using PP followed by LDPE and MP samples (32%, 21% and 3%, respectively). The lower carbon yield using LDPE compared to PP was attributed to the lower concentration of unsaturated hydrocarbons in the pyrolysis gas, while the low yield using MP was caused by the presence of PET in the plastic mixture, decreasing the reactivity of hydrocarbon gases over the catalyst. [ABSTRACT FROM AUTHOR]

The commercialization of dye-sensitized solar cells (DSSCs) has been severely hindered by high cost and scarcity of Pt as counter electrode (CE). Up to date, the design of low-cost Pt-free CE materials with an ideal combination of high electrical conductivity, excellent catalytic activity and satisfactory long-term electrochemical stability still poses challenges to researchers. In this work, we have developed novel CoNi alloy@carbon nanotubes embedded carbon nanocages (CoNi@CNTs-C) as the CE of DSSCs for the first time, by applying Co/Ni bimetallic metal organic framework (MOF) as the template. The power conversion efficiency (PCE) of DSSCs can be maximized by simply optimizing the ratio of Ni 2+/ Co 2+ precursor ratio during the synthesis. As a result, the DSSC based on CoNi@CNTs-C-200 CE with a Co/Ni atomic ratio of 9:1 exhibits a remarkable PCE of 9.04%, showing a ∼15% enhancement compared to that of Pt CE (7.88%). Notably, the CoNi@CNTs-C-200 CE also demonstrates excellent long-term electrochemical stability over 300 cyclic voltammetry cycles, which is much superior to that of conventional Pt CE. Thus, the CoNi@CNTs-C demonstrates a great potential as a low-cost, stable and efficient CE material for next-generation DSSCs. [ABSTRACT FROM AUTHOR]

In this work, we first obtained carbon nanocages (CNCs) with nanoporous structure and high specific surface area via a template synthesis method, and then prepared a LiBH 4 @CNCs hydrogen storage composite by combining melting LiBH 4 into the CNCs. Temperature programmed desorption (TPD) analyses show that the composite starts to release hydrogen at 200 °C, with the maximal desorption peak occurs at about 320 °C, which is 180 °C lower than that of the pure LiBH 4 . Also, the final hydrogen desorption capacity reaches 7.5 wt.%. We also see enhanced reversible properties of the composite, of which 78% initial hydrogen is absorbed after five de/rehydrogenation cycles at 400 °C. The further studies show that the LiBH 4 can react with the oxygen-containing group of CNCs to form LiBO 2 during the infiltration process. The LiBO 2 dispersed on the scaffold of CNCs further reacts with LiBH 4 to release more hydrogen, and the reaction product Li 3 BO 3 as an efficient catalyst can significantly improve the reversible hydrogen storage properties of the LiBH 4 . The synergetic effect of nanoconfinement of CNCs and catalysis of Li 3 BO 3 is proved to be largely beneficial for the decomposition process and reversible hydrogen absorption of LiBH 4 . [ABSTRACT FROM AUTHOR]

A carbon nanocages-mediated fluorescent aptasensor for aflatoxin B1 detection was successfully constructed by the T7 exonuclease double recycling amplification. The aptasensor has high accuracy and sensitivity. [Display omitted] • A novel carbon nanocages was prepared as a highly efficient quenching material with three-dimensional structure. • A carbon nanocages-mediated fluorescent aptasensor was constructed based on T7 exonuclease double recycling amplification. • The proposed aptasensor was successfully applied to AFB1 detection in real samples. • Double recycling amplification strategy based on T7 exonuclease has excellent sensitivity and potential application prospects. Aflatoxin B1 (AFB1) is strongly toxic and carcinogenic to human body and has been found in many agricultural products, so rapid and sensitive detection of AFB1 is essential for food safety and human health. Herein, a fluorescent aptasensor based on T7 exonuclease (T7 EXO) double recycling amplification was established, and novel nanomaterial carbon nanocages (CNCs) were introduced as fluorescence resonance energy transfer (FRET) receptors to quench the fluorophore-labeled DNA probe (FAM-cDNA). The CNCs as three-dimensional structured nanomaterials have higher quenching efficiency than conventional quenching materials due to their larger specific surface area and strong conjugated adsorption capacity. In the presence of target AFB1, the T7 EXO drives a double recycling amplification reaction, which ultimately causes a large amount of FAM-cDNA to be digested. In this process, the FAM labeled on the cDNA will be separated from the strand with the digestion procedure, thus avoiding adsorption by CNCs and maintaining its signal. The limit of detection (LOD) is as low as 1.4 pg/mL. The successful determination of AFB1 in real samples demonstrated that this method has excellent potential application prospects. In addition, the effect of potential interfering substances in real samples was analyzed, and the aptasensor presented a good interference immunity. [ABSTRACT FROM AUTHOR]

In this work, a novel and sensitive sandwich-type electrochemical aptasensor has been developed for thrombin detection based on platinum nanoparticles (Pt NPs) decorated carbon nanocages (CNCs) as signal tags. The morphological and compositional of the Pt NPs/CNCs were examined using transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The results showed that the Pt NPs with about 3–5 nm in diameter were well dispersed on the surface of CNCs. The thiolated aptamer was firstly immobilized on the gold electrode to capture the thrombin molecules, and then aptamer functionalized Pt NPs/CNCs nanocomposites were used to fabricate a sandwich sensing platform. Then, the high-content Pt NPs on carbon nanocages acting as hydrogen peroxide-mimicking enzyme catalyzed the reduction of H 2 O 2 , resulting in significant electrochemical signal amplification. Differential pulse voltammetry is employed to detect thrombin with different concentrations. Under optimized conditions, the approach provided a good linear response range from 0.05 pM to 20 nM with a low detection limit of 10 fM. This Pt NPs/CNCs-based aptasensor shows good precision, acceptable stability and reproducibility, which provided a promising strategy for electrochemical aptamer-based detection of other biomolecules. [ABSTRACT FROM AUTHOR]

Silicon (Si) is an ideal anode materials of lithium-ion batteries (LIBs) due to its ultrahigh theoretical capacity. However, its commercialization is severely hampered because the intrinsic poor electrical conductivity and huge volume expansion during lithiation/delithiation process lead to rapid capacity decay. Designing Si/carbon composite is a feasible way for enhancing performance of Si. Here, a porous N-doped carbon nanocages@Si nanoparticles (NC@Si-20) microcapsules was prepared by encapsulating Si nanoparticles (SiNPs) into zeolitic imidazolate frameworks-90 (ZIF-90), coating covalent-organic frameworks (COFs) with well-ordered pores around ZIF-90@SiNPs, etching ZIF-90, and calcining COFs@SiNPs under N 2 in turn. The porous N-doped carbon nanocages derived from COFs formed three-dimensional protective shells around SiNPs, which not only improved the electrical conductivity of microcapsules but also provided more buffer space for volume expansions of SiNPs to slow down the attenuation of capacity. When applying for the anode of LIBs, the obtained NC@Si-20 microcapsules showed high capacity of 1015 mAh g−1 at 100 mA g−1 after 100 cycles and good cycling stability. The approximate theoretical capacity contribution of Si can be up to 2363 mAh g−1. Combining with the benefits of both carbon nanocages derived from COFs (stability and recyclability) and Si (high capacity), this work developed a promising material for LIBs. [Display omitted] • A N-doped carbon nanocages@silicon nanoparticle (NC@Si-20) microcapsule was synthesized. • The NC@Si-20 microcapsule provides large spaces for volume expansion of SiNPs and slows down capacity decay. • The porous N-doped carbon nanocage facilitates Li+ transfer to contact with SiNPs. • NC@Si-20 shows high capacity of 1015 mAh g−1 at 100 mA g−1 after 100 cycles and good cycling stability. • The Si in NC@Si-20 microcapsule shows a superior theoretical capacity contribution of 2362 mAh g−1. [ABSTRACT FROM AUTHOR]

Facile and stable nanocomposites, carbon nanocages (CNCs)-reduced graphene oxide (RGO), were developed via one-pot in situ solvothermal reaction in this study. Transmission electron microscope, scanning electron microscope, X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, atomic focus microscope, N 2 adsorption/desorption isotherms, thermogravimetric analysis and Fourier-transform infrared were performed to characterize the CNCs-RGO hybrid material. The electrochemical detections of catechol (CC) and hydroquinone (HQ) were investigated by means of cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The excellent electrocatalytic activity and reversibility have been shown on the modified electrode toward oxidation of both CC and HQ in 0.04 M acetate buffer solution (pH = 4.0). The relationship between the oxidation peak current of CC and its concentration was linear over the range from 1 to 400 μM in the presence of 100 μM HQ, and the linear relationship between the oxidation peak current of HQ and its concentration can be obtained range from 1 to 300 μM in the presence of 100 μM CC. The detection limits (S/N = 3) for CC and HQ were 0.40 and 0.87 μM, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology. To improve the electrochemical activity and durability of conventional Pt catalyst used in PEMFCs, we prepare Pt–Ir alloy catalysts supported on homemade graphitic carbon nanocages (CNCs). Results from cyclic voltammetry (CV) and linear sweep voltammetry (LSV) show that the alloy catalyst with an atomic Pt/Ir ratio of 1:1 supported on CNCs with a high degree of graphitization exhibits an excellent electrocatalytic activity. Furthermore, this alloy catalyst shows a drastic improvement in durability and stability over the unalloyed Pt catalyst supported on the same CNCs and the catalyst from a commercial source (Johnson Matthey Co.). It is found that the concurrent uses of well-graphitized CNCs as the support material and Ir as the alloying element are critical for the observed improvement. Such a Pt–Ir alloy catalyst provides a new replacement for the conventional Pt catalyst with not only a drastic improvement in durability but also a reduction in Pt usage by 50% as well. [Copyright &y& Elsevier]

Carbon nanocages (CNCs) have attracted tremendous interest in heterogeneous catalysis due to their promising properties of porous structure and improved mass transfer. Nevertheless, the controlled synthesis of CNCs remains a great challenge. Herein, we have shown the successful construction of functionalized N-doped CNCs (NCNCs) via a one-stone-two-birds strategy. The selective use of hexacarbonyl molybdenum (Mo(CO) 6 ) can not only protect the profile of the ZIF-8 precursor from collapse during thermal treatment but also be sacrificed for the functionalization of NCNCs after pyrolysis. Detailed mechanism studies reveal that Mo(CO) 6 evolves into MoO 3 on the surface of ZIF-8 and then facilitates the rapid pyrolysis of ZIF-8, leading to the formation of NCNCs decorated with small-sized MoC nanoparticles (MoC/NCNCs). The versatility of this one-stone-two-birds strategy has been validated by the generations of Cr- and W-decorated NCNCs. Moreover, MoC/NCNCs can serve as a selective and stable catalyst for furfural hydrogenation. This work provides a facile and universal strategy for fabricating and functionalizing CNCs, which attracts research interest in the fields of chemistry, material science, catalysis, and beyond.

Nitrogen/oxygen co-doped carbon spheres with wrinkled nanocages (NOCN) were successfully synthesized using dendritic fibrous nanosilica (DFNS) as sacrificial solid template, glucose as a carbon source, and melamine as the nitrogen source. The obtained carbon nanocages (NOCN-850-3) exhibit human brain-like winkle shape, high specific surface area (813 m2 g−1), high nitrogen (16.24 at%) and oxygen contents (5.36 at%). In addition, the obtained carbon presents good specific capacitance of 311.1 F g−1 at a current density of 0.5 A g−1 in 6 M KOH and remarkable rate performance (118.1 F g−1 at a current density of 30 A g−1) and cycle stability (97.6% retention after 10,000 charge–discharge performance cycles at 10 A g−1). Meanwhile, the NOCN-850-3-based coin-type symmetric supercapacitor exhibits a maximum energy density of 12. 3 W h kg−1 at a power density of 175 W kg−1 and also a relatively low resistance in 6 M KOH aqueous electrolyte. Thus, the unique structure and nitrogen/oxygen co-doping characteristic endue the electrode material a potential application in supercapacitors. [Display omitted] • A facile strategy for the fabrication nitrogen/oxygen co-doped carbon spheres with wrinkled nanocages is proposed. • The optimal carbon (NOCN-850-3) possesses a high specific surface area, high nitrogen and oxygen contents. • NOCN-850-3 exhibits superior supercapacitive behavior to many previous carbon materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The smallest SnSb nanoparticle was synthesized. • The SnSb/3D-NPC hybrid shows the best Na-storage performances in SnSb-based materials. • The nature behind the superior properties was clarified. Sodium-ion batteries have been emerging as a potential alternative to lithium-ion batteries, especially for large-scale applications. In this work, a hybrid of ultrasmall SnSb nanoparticles (the diameter <2 nm) encapsulated in three-dimensional N-doped nanoporous carbon frameworks (SnSb/3D-NPC) was synthesized by a facile chemical reduction method. To the best of our knowledge, this is the smallest SnSb nanoparticle ever reported. As a sodium-ion battery anode, SnSb/3D-NPC delivers a high reversible capacity (693.6 mAh g−1 at 0.2 A g−1 after 100 cycles), superior rate performance (359.1 mAh g−1 at 20 A g−1) and cycling stability (266.6 mAh g−1 at 5 A g−1 after 15,000 cycles), which outperform other SnSb-based materials. These remarkable performances originate from: (i) ultrasmall SnSb nanoparticles and their uniform distribution, which increase the specific surface of electrodes and thus guarantee the full utilization of active materials, enhance pseudocapacitive contributions for Na storage, shorten Na+ diffusion distance, and reduce the strain during the sodiation/desodiation process; and (ii) the unique 3D integrated structure of SnSb/3D-NPC, which supplies a conductive network, efficient electrolyte diffusion paths and more active sites for Na+ insertion/extraction, suppresses the aggregation of SnSb nanoparticles, and buffers large volume change of SnSb through carbon nanocages during the cycling process. [ABSTRACT FROM AUTHOR]

Cardiovascular and cerebrovascular diseases induced by atherosclerosis (AS) have become the dominant cause of disability and mortality throughout the world. The typical early pathological process of AS involves the activation of inflammatory macrophages in the vulnerable plaque. In this work, we first employed chitosan-coated carbon nanocages (CS-CNCs) as nanocarriers to load Chlorin e6 (Ce6) and then linked dextran sulfate (DS) to the outermost layer by electrostatic adsorption to create a multifunctional therapeutic nanoplatform, CS-CNCs@Ce6/DS. The DS of the nanoplatform can recognize and bind to the type A scavenger receptor (SR-A), which is expressed only on the activated macrophages of the arterial plaque, so the proposed nanoplatform selectively targets these macrophages and accumulates there. Furthermore, DS can competitively inhibit cellular endocytosis of oxidized low-density lipoproteins via blocking of SR-A. The rapid photothermal conversion capability of CS-CNCs enables efficient therapeutic delivery during photothermal therapy (PTT). Interestingly, near-infrared-accelerated drug release induced by initial 808-nm laser irradiation was observed, thus enhancing the Ce6 concentration in the atherosclerotic plaque area and the efficiency of photodynamic therapy (PDT). Sequential photothermal/photodynamic ablation of the activated macrophages reduced pro-inflammatory cytokine secretion and alleviated the proliferation and migration of smooth muscle cells. These finally resulted in the stabilization and shrinkage of atherosclerotic plaques, further inhibiting the development and exacerbation of AS. Therefore, this work achieved a "1 + 1 greater than 2" effect by providing a novel approach to the treatment of atherosclerotic plaques, which is promising for the prevention of AS-related diseases.

Carbon materials, especially those with hollow structure, have gained considerable attention as the host materials for sulfur in Li–S batteries. Herein, the nanocages consisting of carbon nanotubes (CNTs) and hierarchically porous carbon (CNT-NC@GC) are synthesized using bimetallic core-shell metal-organic frameworks as precursor. CNTs are in situ introduced onto the inner/outer surface of the nanocages to form a three-dimensional conductive network throughout the entire electrode for the favorable electrolyte penetration and improved electrons/ions transfer. Abundant N-doping and Co nanoparticles decoration in the tips of CNTs or on the surface of GC shells are beneficial to immobilize soluble polysulfides. Moreover, the modified Co nanoparticles possess chemisorption and electrocatalytic activity for sulfur conversion, which can promote redox kinetics of the polysulfides and improve the cycling stability. As a result, the as-prepared CNTs-grafted nitrogen-doped carbon@graphitic carbon nanocages cathode containing 79.2 wt% of sulfur (CNT-NC@GC/S) delivers a high discharge capacity of 743 mA h g−1 after 500 cycles at a current density of 1.0C with a capacity retention of 83.6%. And the cathode with high areal sulfur loading of 4.95 mg cm−2 shows a high areal capacity of 4.01 mA h cm−2 over 100 cycles. CNTs-grafted nitrogen-doped carbon@graphitic carbon nanocages with the metallic Co embedded can suppress the shuttle effect by physical and chemical adsorption, and the integrated CNTs conductive network favors the diffusion of electron within the whole electrode and then features high utilization of sulfur. Image 1 [ABSTRACT FROM AUTHOR]

• MOFs-derived carbon nanocages have been synthesized. • Co nanoparticles are encapsulated by graphitic carbon layer. • Enhanced dielectric loss and promoted impedance matching are achieved. • The absorbers exhibit high-efficient electromagnetic wave absorption performance. Metal-organic-frameworks (MOFs)-derived carbon materials have been considered as promising candidates in electromagnetic wave absorption materials. However, precise design of MOFs-derived carbon materials with hollow structure still pose a formidable challenge. Herein, carbon nanocages have been synthesized by the direct pyrolysis of core-shell ZIF-8@ZIF-67 polyhedrons. Because of the different thermal stability of ZIF-8 core and ZIF-67 shell, the synthesized carbon nanocages are composed of N-doped carbon inner shell and Co/N-doped carbon outer shell. The micro-meso-macropores, enhanced conductive loss, strong dipolar/interfacial polarizations and core-shell Co@graphitic carbon layer favor the absorbers with high porosity, improved dielectric loss and promoted impedance matching. With a filler loading of 25 wt%, the maximum reflection loss reaches −52.5 dB at 13.1 GHz, and the effective absorption bandwidth exceeding −10 dB is 4.4 GHz (from 11.96 GHz to 15.36 GHz) with a thickness of only 2.2 mm. Furthermore, this work offers a simple and effective strategy in the fabrication of carbon nanocages with tuned chemical composition and improved impedance matching for lightweight and high-efficiency electromagnetic wave absorption materials. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP) has attracted great attention as a potential candidate for anode materials of high-energy density sodium-ion batteries (NIBs) due to its high theoretical capacity, appropriate working voltage, and natural abundance. However, the low electrical conductance and huge volumetric variation during the sodiation-desodiation process, causing poor rate performance and cyclability, have limited the practical application of RP in NIBs. Herein, we report a rational strategy to resolve these issues by encapsulating nanoscaled RP into conductive and networked carbon nanocages (denoted as RP@CNCs) using a combination of a phosphorus-amine based method and evacuation-filling process. The large interior cavities volume of CNCs and controllable solution-based method enable the ultrahigh RP loading amount (85.3 wt %) in the RP@CNC composite. Benefiting from the synergic effects of the interior cavities and conductive network, which afford high structure stability and rapid electron transport, the RP@CNC composite presents a high systematic capacity of 1363 mA h g -1 at a current density of 100 mA g -1 after 150 cycles, favorable high-rate capability, and splendid long-cycling performance with capacity retention over 80% after 1300 cycles at 5000 mA g -1 . This prototypical design promises an efficient solution to maximize RP loading as well as to boost the electrochemical performance of RP-based anodes.