Facile synthesis of ultrahigh-surface-area hollow carbon nanospheres for enhanced adsorption and energy storage

Surfactant-Free Assembly of Mesoporous Carbon Hollow Spheres with Large Tunable Pore Sizes

Mesoporous carbon hollow spheres (MCHS) have wide applications, including catalysis, absorption, and energy storage/conversion. Herein, we report a one-pot, surfactant-free synthesis of MCHS using three molecules: resorcinol, formaldehyde, and tetrapropyl orthosilicate. The co-condensation process between the in situ generated silica primary particles and the polymer oligomers is regulated, leading to monodispersed MCHS with adjustable pore sizes from micropores to 13.9 nm. The resultant MCHS shows excellent performance for electrochemical double-layer capacitors with high capacitance (310 F g(-1) at 1 A g(-1)), excellent rate capability (157 F g(-1) at 50 A g(-1)), and outstanding cycling stability (98.6% capacity retention after 10 000 cycles at 10 A g(-1)). Our one-pot synthesis strategy is versatile and can be extended to fabricate metal oxide@mesoporous carbon yolk-shell structures in the absence of surfactant, paving the way toward designed synthesis of nanostructured mesoporous carbon composites for various applications.

3D Polyaniline Architecture by Concurrent Inorganic and Organic Acid Doping for Superior and Robust High Rate Supercapacitor Performance

A good high rate supercapacitor performance requires a fine control of morphological (surface area and pore size distribution) and electrical properties of the electrode materials. Polyaniline (PANI) is an interesting material in supercapacitor context because it stores energy Faradaically. However in conventional inorganic (e.g. HCl) acid doping, the conductivity is high but the morphological features are undesirable. On the other hand, in weak organic acid (e.g. phytic acid) doping, interesting and desirable 3D connected morphological features are attained but the conductivity is poorer. Here the synergy of the positive quality factors of these two acid doping approaches is realized by concurrent and optimized strong-inorganic (HCl) and weak-organic (phytic) acid doping, resulting in a molecular composite material that renders impressive and robust supercapacitor performance. Thus, a nearly constant high specific capacitance of 350 F g(-1) is realized for the optimised case of binary doping over the entire range of 1 A g(-1) to 40 A g(-1) with stability of 500 cycles at 40 A g(-1). Frequency dependant conductivity measurements show that the optimized co-doped case is more metallic than separately doped materials. This transport property emanates from the unique 3D single molecular character of such system.

Molecular Lifting, Twisting, and Curling during Metal-Assisted Polycyclic Hydrocarbon Dehydrogenation

The atomistic understanding of the dissociation mechanisms for large molecules adsorbed on surfaces is still a challenge in heterogeneous catalysis. This is especially true for polycyclic aromatic hydrocarbons, which represent an important class of organic compounds used to produce novel graphene-based architectures. Here, we show that coronene molecules adsorbed on Ir(111) undergo major conformational changes during dissociation. They first tilt upward with respect to the surface, still keeping their planar configuration, and subsequently experience a rotation, which changes the molecular axis orientation. Upon lifting, the internal C-C strain is initially relieved; as the dehydrogenation proceeds, the molecules experience a progressive increase in the average interatomic distance and gradually settle to form dome-shaped nanographene flakes. Our results provide important insight into the complex mechanism of molecular breakup, which could have implications in the synthesis of new carbon-based nanostructured materials.

Nitrogen- and oxygen-containing micro–mesoporous carbon microspheres derived from m-aminophenol formaldehyde resin for supercapacitors with high rate performance

Nitrogen- and oxygen-containing micro–mesoporous carbon microspheres derived from m-aminophenol formaldehyde resin were prepared by the hydrothermal synthesis/carbonization/activation route for high-rate performance supercapacitor application.

Construction of 3D nanostructure hierarchical porous graphitic carbons by charge-induced self-assembly and nanocrystal-assisted catalytic graphitization for supercapacitors

A smart and sustainable strategy based on charge-induced self-assembly and nanocrystal-assisted catalytic graphitization is explored for the efficient construction of 3D nanostructure hierarchical porous graphitic carbons from the pectin biopolymer.

Cobalt/nitrogen co-doped porous carbon nanosheets as highly efficient catalysts for the oxygen reduction reaction in both basic and acidic media

Cobalt/nitrogen co-doped porous carbon nanosheets as highly-efficient catalysts for ORR in both basic and acidic electrolytes have been prepared by using cobalt porphyrin based conjugated microporous polymer nanosheet as a precursor.

Fabrication and electrochemical performance of novel hollow microporous carbon nanospheres

A new class of hollow microporous carbon nanospheres with good electrochemical performances was fabricated through a facile hypercrosslinking strategy.

Mango stone-derived activated carbon with high sulfur loading as a cathode material for lithium–sulfur batteries

A mango stone-derived activated carbon/sulfur composite cathode with a high sulfur loading of 71 wt% for long cycle-life Li–S batteries.

Facile synthesis of bowl-shaped nitrogen-doped carbon hollow particles templated by block copolymer “kippah vesicles” for high performance supercapacitors

This paper reports a simple self-assembly strategy towards bowl-shaped carbon-containing hollow particles for high volumetric capacitance supercapacitors, as well as an unprecedented potential application for block copolymer vesicles in energy storage.

Single-step flame synthesis of carbon nanoparticles with tunable structure and chemical reactivity

Single-step flame synthesis technique providing the opportunity for in situ manipulation of the structure and chemical reactivity of carbon nanoparticles.

A Metal-Free Supercapacitor Electrode Material with a Record High Volumetric Capacitance over 800 F cm(-3)

A metal-free supercapacitor electrode material is prepared by the hybridization of graphene and polyaniline in a very compact way without sacrificing their gravimetric capacitance. It exhibits a record high volumetric capacitance over 800 F cm(-3).

Multi-dimensional construction of a novel active yolk@conductive shell nanofiber web as a self-standing anode for high-performance lithium-ion batteries

A novel active yolk@conductive shell nanofiber web with a unique synergistic advantage of various hierarchical nanodimensional objects including the 0D monodisperse SiO2 yolks, the 1D continuous carbon shell and the 3D interconnected non-woven fabric web has been developed by an innovative multi-dimensional construction method, and thus demonstrates excellent electrochemical properties as a self-standing LIB anode.

Compressed porous graphene particles for use as supercapacitor electrodes with excellent volumetric performance

This work presents a new class of porous graphene particles with a three-dimensional microscale network and an ultrahigh specific surface area (2590 m(2) g(-1)), which is obtained by the KOH activation of a compact graphene hydrogel. As supercapacitor electrodes, such porous graphene particles show high compressibility and little capacitance loss when subjected to a compressive force up to 40 MPa, yielding an excellent volumetric performance with an ionic liquid electrolyte. Such carbon materials show great promise for applications needing high volumetric energy.

Nitrogen-doped dual mesoporous carbon for the selective oxidation of ethylbenzene

A nanocasting method to fabricate nitrogen-doped dual mesoporous carbon is proposed by the carbonization of nitrile functional ionic liquid (FIL) grafted SBA-15 for the first time. These carbon materials have high nitrogen content (12.8%), large specific surface areas (763 m(2) g(-1)) and uniform rod morphologies, which are derived from FILs grafted on the surface of SBA-15. Furthermore, by adjusting the impregnation amount of ionic liquids on SBA-15, pore structures of these carbon materials can be adjusted from single to dual mesopores. The developed dual mesoporous carbon materials exhibit good catalytic performance in the selective oxidation of ethylbenzene, ascribed to the promoting effects of nitrogen-doping, high surface area and dual mesostructure. It may be concluded that the dual mesostructure has an advantage over a single mesostructure to obtain a fast mass transport rate, resulting in higher acetophenone yield.

Hollow Ag/carbon microporous spheres with high catalytic activity based on a bio-inspiration polydopamine reaction platform

Based on polydopamine reaction platform, hollow Ag/carbon microporous spheres with high catalytic activity were prepared through a template-assisted method, which is promising to replace other noble metal catalysts in metal catalytic reactions.