Renewable resources (e.g., agricultural byproducts) are widely used in the production of commercial activated carbon, but the activation procedures still have serious drawbacks. Here we develop a green, activation-free, top-down method to prepare high-surface-area carbon materials from agricultural wastes through mechanochemistry. The facile mechanochemical process can smash the monolithic agricultural wastes into tiny microparticles with abundant surfaces and bulk defects, which leads to the generation of well-developed hierarchical porous structures after direct carbonization. The as-obtained carbon materials simultaneously present high surface areas (1771 m2 g–1) and large pore volumes (1.88 cm3 g–1), and thus demonstrate excellent electrochemical performances as the interlayer for lithium–sulfur batteries and much superior creatinine adsorption capabilities to the medicinal charcoal tablets. These results provide a new direction for fabricating high-surface-area porous materials without any toxic reagents or complicated activation procedures, and can spur promising electrochemical and medical applications.Keywords: Green chemistry; High-surface-area carbon material; Mechanochemistry;

A class of novel N-doped porous carbon nanospheres (PCNSs) with ultrahigh surface areas (e.g., Langmuir surface area = 3219 m2 g−1) and large templated mesopore diameters (up to 18.6 nm) was synthesized based upon a simple yet efficient copolymerization-induced self-assembly process of aniline/pyrrole co-monomers and block copolymer templates. The PCNSs exhibited enhanced adsorption properties towards creatinine and superior lithium-sulfur battery performances.

Herein, we report a general and template-free protocol to construct novel yolk–shell metal@carbon nanospheres based on confined interfacial copolymerization, which greatly simplifies the synthetic route, yields uniform nanospheres with controllable diameters, and results in highly porous carbon shells. The yolk–shell Au@carbon shows improved adsorption capacity and high catalytic ability due to the synergistic effect of Au and the porous carbon shell.

3D aligned electrospun fibers hold a promising potential in a wide range of biomedical areas, including biosensors, controlled drug release, tissue engineering, etc. Thus, a cost-effective and easy way to scale-up fabrication for 3D aligned nanofibers is highly desired. Herein, a novel yet facile preparation process of 3D aligned nanofibers (3D AFs) by an improved electrospinning technique is reported. The obtained 3D AFs show enhanced controllability on morphology and fiber density, and thus facilitate adhesion and growth of human mesenchymal stem cells within their 3D nanofiber microarchitectures, leading to an excellent in vitro biocompatibility. Moreover, the 3D AFs with aligned morphology can enhance the neuron activities and induce directional cell growth along the direction of nanofiber orientation, thereby providing an excellent cue for the anchorage and migration dependent neurons. Combined with controllable morphology and structure, it is anticipated that this finding can lead to great applications of electrospun fibers in nerve tissue engineering, diagnostics, and other biomedical fields.

Design and fabrication of the micro/nanostructures of the network units is a critical issue for porous nanonetwork structured materials. Significant progress has been attained in construction of the network units with zero-dimensional spherical shapes. However, owing to the limitations of synthetic methods, construction of porous building blocks in one dimension featuring high aspect ratios for porous nanonetwork structured polymer (PNSP) remains largely unexplored. Here we present the successful design and preparation of PNSP with a novel type of one-dimensional network unit, i.e., microporous heterogeneous nanowire. Well-defined core-shell polymer nanoobjects prepared from a gelable block copolymer, poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene are employed as building blocks, and facilely transformed into PNSP via hypercrosslinking of polystyrene shell. The as-prepared PNSP exhibits unique three-dimensional hierarchical nanonetwork morphologies with large surface area. These findings could provide a new avenue for fabrication of unique well-defined PNSP, and thus generate valuable breakthroughs in many applications.

Functional nanonetwork-structured polymers and carbons with silver nanoparticle yolks (∼20 nm) were successfully fabricated via hypercrosslinking chemistry. Benefiting from the hierarchical porous nanonetwork structure and high surface areas (up to 566 m2 g−1), the as-prepared nanocomposites demonstrated superior long-term antibacterial performances (e.g., 6 days).

Advances in the performances of many modern materials fundamentally depend upon the exploitation of new micro/nanostructures. Therefore, ingenious design of hierarchical structures through the mimicking of natural systems is of increasing importance. Currently, there is an urgent need for creation of multidimensional carbonaceous structures by integrating a customized hierarchical pore architecture and hybrid carbon framework. Here we report the pioneering fabrication of novel super-hierarchical carbons with a unique carbonaceous hybrid nanotube-interconnected porous network structure by utilizing well-defined carbon nanotube@polystyrene bottlebrushes as building blocks. Hypercrosslinking of such heterogeneous core–shell structured building blocks not only allows for constructing amorphous microporous carbon shells on the surface of graphitic carbon nanotube cores, but also leads to formation of covalently interconnected nanoscale networks. Benefiting from such a well-orchestrated structure, these super-hierarchical carbons exhibit good electrochemical performances. Our findings may open up a new avenue for fabrication of unique and unusual functional carbon materials which possess well-orchestrated structural hierarchy and thus generate valuable breakthroughs in many applications including energy, adsorption, separation, catalysis and medicine.

Both high surface areas and well-orchestrated nanomorphologies are important for porous organic polymers (POPs). However, the two key characteristics are generally difficult to be satisfied simultaneously, because the common pore-making procedures usually produce ill-defined nanomorphologies or give rise to damage of precustomized nanomorphologies. Herein, a facile yet versatile stepwise crosslinking strategy for fabrication of POPs with an unusual nanomorphology-persistent characteristic during pore-making is reported. Polystyrene nanofibers and poly(styrene-co-divinylbenzene) nanosphere arrays are utilized as building blocks, and then transformed into nanofibrillar morphology-persistent and ordered array morphology-persistent POPs via stepwise crosslinking, respectively. The stepwise crosslinking strategy includes pre-crosslinking and hypercrosslinking; the pre-crosslinking in a carefully selected poor solvent of polystyrene forms a lowly crosslinked structure, which guarantees the stability of nanomorphology during the subsequent pore-making via hypercrosslinking. The as-obtained POPs can be used as precursors for novel well-defined hyperporous carbon nanofibers and ordered carbon nanosphere arrays with excellent adsorption performances.

Functional nanonetwork-structured polymers with inbuilt poly(acrylic acid) linings were successfully synthesized by combining surface-initiated atom transfer radical polymerization (SI-ATRP) and hypercrosslinking chemistry, and demonstrated superior adsorption performances toward basic dyes and heavy metal ions.

A novel powdery polymer aerogel (PPA) with a hierarchical pore structure was prepared via hypercrosslinking of monodisperse poly(styrene-co-divinylbenzene) nanoparticles. Subsequently, the PPA was carbonized to obtain a powdery carbon aerogel (PCA) with a well-inherited pore structure and a much higher surface area (2354 m2 g−1). The PPA-coated and PCA-coated fibers were easily fabricated benefiting from the powdery morphologies of PPA and PCA, and demonstrated high extraction efficiencies towards hydrophobic analytes owing to their functional groups, unique three-dimensional (3D) porous nanonetworks and high surface areas.

The fabrication of advanced hierarchical porous polymers with a unique 3D nanonetwork structure composed of functional core–microporous shell nanoparticles was reported based on the development of a simple and efficient hypercrosslinking-induced self-assembly strategy.

Porous nanostructured carbon materials exhibit unique structural features such as high surface area and excellent physicochemical stability and have been of significantly scientific and technological interest because of their vital importance in many energy related applications. Synthetic polymers represent a major class of precursors for developing cutting-edge porous carbons, among which conjugated polymers have emerged as an attractive family of carbon precursors. Distinct from those typical polymer precursors, the robust conjugated structure ensures sufficient framework carbonizability and nanoarchitecture-conserving stability during carbonization process, which is crucial to the successful transformation of designed polymer architectures to finally desired carbon nanostructures. Moreover, heteroatom doping (e.g., N, S, B, and metals) or codoping can be naturally integrated into carbon framework directly by using the heteroatom-containing monomers. Especially, using the newly emerged structurally defined carbon-rich conjugated porous networks as precursors, precise control of compositions and structures of carbon materials becomes possible even at the molecular level. In this review, we will highlight recent strategies to the preparation of porous carbon materials with well-defined porous nanostructures using conjugated polymers as versatile precursors. Beginning with a brief introduction to these precursors, including linear-type conjugated polymers and conjugated porous networks, the synthetic techniques for the fabrication of porous nanostructured carbons by direct templating, self-assembly, template-free, chemical activation, and microwave irritation approaches, will be reviewed. Meanwhile, the sophisticated nanomorphologies, precisely controlled porous structures, and custom-designed functionalities of these conjugated-structure-derived carbons, together made them amenable to diverse task-specific applications, such as electrocatalysis, Li-ion batteries, supercapacitors, and adsorption. Finally, a perspective of the research directions in this field will be presented.

Due to unique high-surface-area ordered mesoporous channels interconnected with 3D network-like mesopores and π–π interactions between carbon frameworks and analytes, the as-prepared ordered mesoporous carbon-coated fiber exhibited a large adsorption amount, fast mass transport and high sensitivity.

In recent years, graphene films have been used in a series of wide applications in the biomedical area, because of several advantageous characteristics. Currently, these films are derived from graphene oxide (GO) via chemical or physical reduction methods, which results in a significant decrease in surface hydrophilicity, although the electrical property could be greatly improved, because of the reduction process. Hence, the comprehensive performance of the graphene films showed practical limitations in the biomedical field, because of incompatibility of highly hydrophobic surfaces to support cell adhesion and growth. In this work, we present a novel fabrication of bacterial cellulose nanofibers/reduced graphene oxide (BC-RGO) film, using a bacterial reduction method. Thus-prepared BC-RGO films maintained excellent hydrophilicity, while electrical properties were improved by bacterial reduction of GO films in culture. Human marrow mesenchymal stem cells (hMSCs) cultured on these surfaces showed improved cellular response with higher cell proliferation on the BC-RGO film, compared to free-standing reduced graphene oxide film without the nanoscale fibrous structure. Furthermore, the cellular adhesion and proliferation were even comparable to that on the tissue culture plate, indicating that the bacterial cellulose nanofibers play a critically contructive role in supporting cellular activities. The novel fabrication method greatly enhanced the biochemical activity of the cells on the surface, which could aid in realizing several potential applications of graphene film in biomedical area, such as tissue engineering, bacterial devices, etc.Keywords: bacterial reduction; cellulose nanofibers; graphene; hMSCs; tissue engineering

Graphene nanofibers have shown a promising potential across a wide spectrum of areas, including biology, energy, and the environment. However, fabrication of graphene nanofibers remains a challenging issue due to the broad size distribution and extremely poor solubility of graphene. Herein, we report a facile yet efficient approach for fabricating a novel class of polymer core-reduced graphene oxide shell nanofiber mat (RGO–CSNFM) by direct heat-driven self-assembly of graphene oxide sheets onto the surface of electrospun polymeric nanofibers without any requirement of surface treatment. Thus-prepared RGO–CSNFM demonstrated excellent mechanical, electrical, and biocompatible properties. RGO–CSNFM also promoted a higher cell anchorage and proliferation of human bone marrow mesenchymal stem cells (hMSCs) compared to the free-standing RGO film without the nanoscale fibrous structure. Further, cell viability of hMSCs was comparable to that on the tissue culture plates (TCPs) with a distinctive healthy morphology, indicating that the nanoscale fibrous architecture plays a critically constructive role in supporting cellular activities. In addition, the RGO–CSNFM exhibited excellent electrical conductivity, making them an ideal candidate for conductive cell culture, biosensing, and tissue engineering applications. These findings could provide a new benchmark for preparing well-defined graphene-based nanomaterial configurations and interfaces for biomedical applications.Keywords: electrospinning; graphene; hMSCs; nanofibers; tissue engineering

The pioneered construction of novel monodisperse hollow and yolk–shell structured periodic mesoporous polymer nanoparticles was reported by the development of an efficient reactive interface-guided co-assembly approach.

The interconnected ordered pore channels facilitate faster permeation of Li+ ions during the charge–discharge process than the isolated ordered pore channels, resulting in significantly enhanced capacities, better rate capabilities and more remarkable cycling stability.

Development of facile synthetic procedures for the fabrication of well-defined hollow carbon nanospheres with a highly porous shell structure is still a very important but really challenging issue. Herein, we report a facile hypercrosslinking strategy to prepare hollow microporous carbon nanospheres with a BET surface area as high as 1166 m2 g−1. SiO2@polystyrene core–shell nanospheres were first prepared, and then were treated through a hypercrosslinking reaction to provide the polystyrene shell with well-developed microporosity. Moreover, the as-constructed hypercrosslinked shell structure ensures a good framework carbonizability and nanostructure inheritability during the high-temperature carbonization process. The porous structure and morphology of the resulting hollow microporous carbon nanospheres can be easily tailored by varying the hypercrosslinking and carbonization conditions. Due to the rational integration of a highly microporous shell structure and a well-defined hollow spherical morphology in the nanometer range, the hollow microporous carbon nanospheres prepared here show good electrochemical performances as active electrodes of lithium ion batteries and supercapacitors.

Multifunctionalization of microporous polymers is highly desirable but remains a significant challenge, considering that the current microporous polymers are generally hydrophobic and nonresponsive to different environmental stimuli and difficult to be carbonized without damage of their well-defined nanomorphology. Herein, we demonstrate a facile and versatile method to fabricate water-dispersible, pH/temperature responsive and readily carbonizable hairy microporous polymeric nanospheres based on combination of the hyper-cross-linking chemistry with the surface-initiated atom transfer radical polymerization (SI-ATRP). The hyper-cross-linking creates a highly microporous core, whereas the SI-ATRP provides diverse functionalities by surface grafting of hairy functional blocks. The as-prepared materials present multifunctional properties, including sensitive response to pH/temperature, high adsorption capacity toward adsorbates from aqueous solution, and valuable transformation into well-defined microporous carbon nanospheres because of hybrid of carbonizable core and thermo-decomposable protection shell. We hope this strategy could promote the development of both functional microporous polymers and advanced hairy nanoparticles for multipurpose applications.

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.

Novel MnO multi-core@nitrogen-doped carbon shell nanoparticles (MCNCmSPs) were developed through a facile polydopamine adhesive-assisted compositing procedure. Owing to their advanced multi-core@shell nanostructure, the as-prepared MCNCmSPs exhibited remarkable electrochemical performance as lithium-ion battery anode.

Formation of a uniform interface between the carbon precursor and the selected template is critical for preparing high-quality nanoporous carbons. It can be accomplished by various templating procedures but still remains a challenge, especially for microporous carbons. A new strategy to fabricate well-defined microporous carbon nanosphere (MCNS) materials via molecular-scale interfacial engineering using an organic/inorganic hybrid molecule as the building block was designed. A commercially available octaphenyl polyhedral oligomeric silsesquioxane was selected as such a building block and transformed into the MCNS products via cross-linking of organic components, followed by carbonization, and subsequent removal of monodispersed silica domains, surrounded by molecular-scale carbon/silica interfaces. The obtained MCNS materials exhibit very large surface area (e.g., 2264 m2/g) and fast and selective sorption, and thus demonstrate excellent adsorption and supercapacitance properties. These findings could provide a new benchmark for preparing well-defined nanoporous carbons for various applications.

A class of carbon/silica composite with a porous bicontinuous nanostructure is prepared via a simple sol–gel method and then used as anode material for lithium-ion batteries. The reversible specific capacity of the as-prepared composite stays over 560 mAh g−1 after 30 cycles, much higher than that of many other carbon materials including commercial graphite and carbon/silica composites. The good electrochemical performance can be ascribed to the following three factors: (i) continuous silica gel framework stores most of lithium ions; (ii) continuous carbon framework not only restrains the volume change during repeated insertion and extraction of lithium ions, but also represents an excellent conductive skeleton throughout the composite; (iii) nanopores among the carbon/silica bicontinuous framework are helpful to the mass transport and can further buffer the volume change of silica.

Hollow polymer nanospheres (HPNSs) have received an increased level of attention, not only for their fundamental scientific interest, but also for technological applications. Despite a great deal of research effort, most of the current HPNSs are suffering from a poor polydispersity as well as a particle size larger than 500 nm. Here, we report the synthesis of highly monodisperse hollow microporous polystyrene nanospheres (MHMPNSs) with diameters as low as 120 nm based on a facile hypercrosslinking strategy. We utilize the rapid formation of an almost unreactive crosslinked polystyrene outer skin during the initial hypercrosslinking process, to minimize the undesired inter-sphere crosslinking. Due to the intra-sphere hypercrosslinking, the resulting MHMPNSs possess a well-developed microporous shell structure. The MHMPNSs are able to be used as potential absorbents toward organic vapors, because of their unique hollow core and microporous shell characteristics.

A simple and effective way to introduce micropores into skeleton of carbon aerogel (CA) without damaging its unique 3D mesoporous nanonetwork has been successfully developed by NH3-assisted semicarbonization. During the NH3-assisted semicarbonization process, nitrogen functional groups with high thermo-decomposable ability like pyrrolic/pyridine and pyridinic can be introduced into the semicarbonized aerogel framework by substituting oxygen functional groups with low thermo-decomposable ability like C═O quinone-type groups and then escape from the resultant CA framework during the subsequent carbonization, thus forming abundant micropores inside carbon framework under the circumstance of keeping wonderful stability of mesoporous nanonetwork structure. Compared with the traditional CA without NH3 assistance during semicarbonization, the as-prepared novel CA represents a much higher surface area (1100 vs 620 m2 g–1) and a compatible mesopore structure. Meanwhile, such a NH3 treatment confers many useful nitrogen functional groups on the nanonetwork framework. The novel CA is then used as electrode material of supercapacitors and shows a much higher capacitance and comparable high capacitance retention as compared with the traditional CA.

Controlling carbon frameworks of nanocarbons from microporous to nonporous without imposing any additional treatment on a given type of precursor currently remains a great challenge. Here, a facile approach for tailoring different pore characteristics of carbon frameworks for nanocarbons from polypyrrole (PPy) precursors has been achieved based on the significant effect of reaction medium on the conjugation degree of PPy chains. Nanocarbon from PPy synthesized in NaOH solution (CPPy-NaOH) has numerous micropores with a BET surface area up to 482 m2 g−1, which is 10-fold higher than that of nanocarbon with an almost nonporous carbon framework from PPy polymerized in HCl solution (CPPy-HCl). This could be attributed to a distinct difference in the conjugation degree of the PPy chains. A much lower conjugation degree for the PPy precursor of CPPy-NaOH facilitates formation of micropores during carbonization. CPPy-NaOH exhibits much higher specific capacitance than CPPy-HCl. Furthermore, CPPy-NaOH gives much larger surface efficiency and higher capacitance retention ratios as compared to a commercial activated carbon for supercapacitors.

Polyethylene glycol (PEG) is used to induce the self-assembly of phenol/formaldehyde (PF) resol and triblock copolymer Pluronic P123 by improving the interaction between the PF resol and P123, leading to the formation of a two-dimensional (2D) hexagonal ordered mesostructure. Ordered mesoporous polymers (OMPs) prepared by such a PEG-induced self-assembly method exhibit typical 2D hexagonal nanostructures with narrow pore size distribution. PEG may additionally act as a micropore-forming agent because of its thermal decomposition in this new synthetic approach, leading to the introduction of micropores into the polymeric framework. The resultant OMPs with rigid network frameworks can be directly transformed after a carbonization process into ordered mesoporous carbons. Furthermore, it is demonstrated that the as-obtained ordered mesoporous materials could have great potential applications as absorbents for organic vapors and electrodes in supercapacitors.

A facile route to fabricate nitrogen-doped ordered nanoporous carbons (NONCs) was developed based on in situ polydopamine coating onto the pore surface of ordered nanoporous silica. The NONC exhibits very attractive capacitive properties, including unusually large capacitances up to 538 F g−1, highly efficient electrochemically active surface area and good cycling stability.

A new class of advanced porous network structured carbon materials exhibits very attractive capacitive properties when utilized as electrodes for organic electrolyte supercapacitors, including large capacitances up to 210 F g−1, unusually high energy densities of 21.4–41.8 W h kg−1 at power densities of 67.5–10800 W kg−1, and excellent cycling stability.

A facile approach to fabricate novel highly microporous carbons has been developed by direct carbonization of lowly cross-linked polystyrene. The as-prepared highly microporous carbons demonstrate unusually high micropore rate (97%), high surface area (1108 m2 g−1) and uniform pore size distribution, and thus exhibit excellent size-selective adsorption and electrochemical properties.

A very important yet really challenging issue to address is how to greatly increase the energy density of supercapacitors to approach or even exceed those of batteries without sacrificing the power density. Herein we report the fabrication of a new class of ultrahigh surface area hierarchical porous carbon (UHSA-HPC) based on the pore formation and widening of polystyrene-derived HPC by KOH activation, and highlight its superior ability for energy storage in supercapacitors with ionic liquid (IL) as electrolyte. The UHSA-HPC with a surface area of more than 3000 m2 g−1 shows an extremely high energy density, i.e., 118 W h kg−1 at a power density of 100 W kg−1. This is ascribed to its unique hierarchical nanonetwork structure with a large number of small-sized nanopores for IL storage and an ideal meso-/macroporous network for IL transfer.

A novel type of nanoporous carbon with a 3D nanonetwork-interconnected 2D ordered mesoporous structure is successfully fabricated based on the self-assembly of triblock copolymer F127 and phenol–formaldehyde resol among the nanonetwork from tetraethyl orthosilicate. The as-constructed nanoporous carbons have two unique nanostructure advantages: (1) different from common solid framework for nanonetwork-structured carbons, their carbon framework is made of 2D ordered hexagonal mesopores; (2) unlike isolated mesopores for conventional ordered mesoporous carbons, their neighboring ordered mesopores are interconnected by 3D network-like mesopores. Such a well-defined carbon nanostructure is favorable for fast mass transport, mainly because it can make full use of both the 2D ordered mesoporous structure and the 3D interconnected nanonetwork. The as-prepared nanoporous carbons exhibit great potential as adsorbents toward organic vapor and as electrodes for supercapacitors.

The ordered 2D reverse hexagonal pore morphology facilitates rapid ion diffusion more than the disordered wormhole-like pore morphology, thus leading to superior electrochemical properties such as rate capabilities.

As an important method for preparing ordered mesoporous polymeric and carbonaceous materials, the organic template directed self-assembly is facing challenges because of the weak noncovalent interactions between the organic templates and the building blocks. Herein we develop a novel reactive template-induced self-assembly procedure for fabrication of ordered mesoporous polymer and carbon materials. In our approach, the aldehyde end-group of reactive F127 template can react with the resol building block to in-situ form a stable covalent bond during the self-assembly process. This is essential for an enhanced interaction between the resol and the template, thus leading to the formation of an ordered body-centered cubic mesostructure. We also show that the ordered mesoporous carbon product exhibits superior capacitive performance, presenting an attractive potential candidate for high performance supercapacitor electrodes.Keywords: covalent interaction; ordered body-centered cubic mesostructure; porous polymer and carbon; reactive template-induced self-assembly; supercapacitor

The design and control of polymeric nanoscale network structures at the molecular level remains a challenging issue. Here we construct a novel type of polymeric nanoscale networks with a unique microporous nanofiber unit employing the intra/interbrush carbonyl cross-linking of polystyrene side chains for well-defined cylindrical polystyrene molecular bottlebrushes. The size of the side chains plays a vital role in the tuning of nanostructure of networks at the molecular level. We also show that the as-prepared polymeric nanoscale networks exhibit high specific adsorption capacity per unit surface area because of the synergistic effect of their unique hierarchical porous structures. Our strategy represents a new avenue for the network unit topology and provides a new application for molecular bottlebrushes in nanotechnology.Keywords: adsorption; atom transfer radical polymerization (ATRP); cross-linking; nanopore; nanoscale network; polystyrene molecular bottlebrush

A nanopores array in ordered mesoporous materials matters significantly to the reactant molecules arriving at the active catalytic sites in the interior of the nanostructure. However, how this effect works in the case of electrocatalysis needs investigating. We present that the nanopores array of carbon supports plays a significant role in determining Pt's accessibility and electroactivity. The ordered mesoporous carbons with interconnected pore channels (CMK-3) provide Pt nanoparticles with more than one order of magnitude superior Pt utilization efficiency and alcohol electrooxidation activity to those with isolated pore channels by carbon wall (FDU-15). This becomes more prominent in the case of the electrooxidation of isopropanol with a bigger molecular size and lower polarization. These findings indicate the significant role of nanoarchitectures in Pt's accessibility and electroactivity. It is possible to extend this concept to the other fine chemistry typical of surface activity and facile mass transport of molecules.

In this paper, we report the electrochemical capacitive properties of polystyrene-based hierarchical porous carbon (PS-HPC) for supercapacitors. Compared to many porous carbons such as a commercially available activated carbon and an ordered mesoporous carbon, PS-HPC has a unique three-dimensionally (3D) interconnected micro-, meso- and macroporous network and thus exhibits faster ion transport behavior and a larger utilization of surface area in electric double layer capacitors. The 3D interconnected meso- and macroporous network originates respectively from the compact and loose aggregation of crosslinked polystyrene-based carbon nanoparticles, and is able to facilitate rapid ion transfer/diffusion rates. Furthermore, PS-HPC's micropores exist from the 3D interconnected network inside these crosslinked polystyrene-based carbon nanoparticles, thus giving an exceptional electrochemically accessible surface area for charge accumulation. As a result, the capacitance retention ratio and capacitance per surface area of PS-HPC at a high sweep rate of 200 mV s−1 are as high as 84% and 28.7 μF cm−2, respectively. These encouraging results demonstrate the promising application of PS-HPC for high performance supercapacitors.

A unique hierarchical architecture is successfully constructed in a wormhole-like mesopore structure via a multiple nanocasting route. This novel type of hierarchical porous carbon (HPC) consists of three-dimensional ordered macropores (ca. 150 nm) with interconnecting pore windows, and the walls of these macropores are rich in wormhole-like mesopores (ca. 2.7 nm) and large spherical mesopores (ca. 10 nm), as well as a significant microporosity, presenting a macro-meso-microporous structure with a three-dimensional interconnectivity. Such a hierarchically porous structure may provide fine diffusion pathways for reaction species, which is demonstrated by the experimental result of an enhanced performance in a supercapacitor. For example, with the introduction of a hierarchical porous structure for fast transport and effective access of ions, the as-prepared HPC exhibits a specific capacitance as high as 247 F g−1, whereas traditional wormhole-like mesoporous carbon has only a specific capacitance of 176 F g−1.

Pt2Sn1 nanoparticles supported on wormholelike mesoporous carbons (WMCs) with three different pore diameters, namely WMC-F7, WMC-F30, and WMC-F0 have been synthesized by adopting a modified pulse microwave-assisted polyol method. The pore diameters (Dp) of WMC-F7, WMC-F30, and WMC-F0 are 8.5 nm, 4.4 nm, and 3.1 nm respectively, while the particle size of Pt2Sn1 (DPt) on each support is identical (∼3 nm). Based on the experimental results, it has been found that the pore diameter plays an important role in the electrochemical activity of Pt2Sn1 catalysts towards ethanol electrooxidation reaction (EOR). Pt2Sn1/WMC-F7 catalyst exhibits the highest electrochemical surface area (ESA) and activity towards EOR. Moreover, Pt2Sn1/WMC-F7 gives the comparable activity to the Pt2Sn1 supported on the commercial XC-72 carbon. However, in the cases of WMC-F30 (DPt < Dp < 2 DPt) and WMC-F0 (Dp = DPt) as the supports, the corresponding catalysts obtain much lower ESA and EOR activity with respect to WMC-F7 (Dp > 2 DPt). This could be attributed to the easy accessibility of Pt2Sn1 nanoparticles in the case of WMC-F7 with Dp > 2 DPt for the easy fuel transportation, and consequently the EOR activity has been greatly improved.

A simple and effective template-free method to fabricate hierarchical porous carbon (HPC) has been successfully developed by adopting linear polystyrene resin as raw material, anhydrous aluminium chloride as Friedel–Crafts catalyst, and carbon tetrachloride as crosslinker and solvent. Experimental results show that the as-constructed carbonyl (–CO–) crosslinking bridges between polystyrene chains provide simultaneously to its hierarchical porous polystyrene precursor, both a high crosslinking density and a proper amount of oxygen atoms, and thus achieve good framework carbonizability and nanostructure inheritability during carbonization. The as-prepared HPC's hierarchical porous structure exhibits interesting uniqueness: micropores (<2 nm) are from the network inside crosslinking polystyrene-based carbon nanoparticles of 10–30 nm in size, and mesopores (2–50 nm) and macropores (50–400 nm) result from the compact and loose aggregation of these network nanoparticles, respectively; and these micro-, meso- and macropores are three-dimensionally interconnected to each other. Its Brunauer–Emmett–Teller surface area and total pore volume are 679 m2g−1 and 0.66 cm3g−1, respectively.

A novel type of hierarchical porous carbon has been successfully prepared by constructing intra- and inter-sphere –CO– crosslinking bridges of monodisperse styrene–divinylbenzene copolymer nanospheres. The –C6H4– crosslinking bridges ensure good stability of the nanospheres during swelling and crosslinking, and the –CO– crosslinking bridges play an important role in achieving good nanostructure inheritability during carbonization.

A one-step nanocasting method to prepare a bimodal mesoporous carbon from a highly hydrophobic carbon precursor, i.e., petroleum pitch, has been successfully developed by adopting tetrahydrofuran and hydrofluoric acid as solvent and catalyst, respectively, for the gelation reaction of tetraethyl orthosilicate and water. Experimental results show that the introduction of proper amounts of petroleum pitch does not hamper this gelation reaction, thus forming a uniform silica/carbon composite. It was found that the as-prepared nanoporous carbon has a three-dimensional 3.4 nm-sized wormholelike mesoporous network with well-distributed 17.1 nm-sized particlelike mesopores. Such a bimodal mesoporous carbon has a high Brunauer–Emmett–Teller surface area (782 m2 g−1) and a very large total pore volume (3.0 cm3 g−1).

Pt nanoparticles are successfully deposited on wormholelike mesoporous carbons (WMCs) using a pulse microwave-assisted polyol method. WMCs with two different pore diameters are used. The particle size of Pt on both supports is identical, about 3 nm. It has been found that Pt utilization efficiency is very low when the pore diameter of WMCs (Dp) is equal to the diameter of Pt nanoparticles (DPt). However, in the case that Dp is more than twice DPt, the electrochemical surface area and Pt utilization efficiency are dramatically enhanced, and in turn, hydrogen electrooxidation activity is greatly improved.

In the present paper, we demonstrate the importance of the role of a mass transport pathway (MTP) in wormholelike mesoporous carbon (WMC) through studying the ion diffusion behaviors within two different wormholelike mesopore networks with and without MTP. Our results reveal that the introduction of MTP is very helpful in improving ion diffusion properties. The as-prepared WMC with a MTP of ca. 9.7 nm exhibits notably better electric double layer performance as compared to the conventional WMC without a MTP. For example, even at the quick sweep rate of 50 mV s−1, the surface specific capacitance of the former is 21.6 μF cm−2, which is almost 4 times as high as that of the latter (5.5 μF cm−2).

Polyaniline (PANI) with carbon aerogel (CA) as conducting filler has been synthesized by an in situ chemical oxidative polymerization method. Scanning electron microscopy, infrared spectra, cyclic voltammetry and X-ray diffraction indicate that the three-dimensional carbon nano-network of CA is entirely buried inside the PANI matrix and its introduction basically does not change the structure of PANI. The electrochemical performances of the as-prepared PANI materials with CA filler are evaluated by means of galvanostatic charge–discharge test, cyclic voltammetry and electrochemical impedance spectroscopy. It is found that the electrochemical performances of PANI are notably improved due to the introduction of CA filler. For example, when operating at a large current density of 50 mA cm−2, CA-modified PANI with the optimal CA/aniline ratio of 1.0 wt% exhibits a specific capacitance as high as 226 F g−1, whereas neat PANI has only 89 F g−1. The CA modification mechanism of PANI has been discussed in detail.

Ordered mesoporous carbon/carbon aerogel (OMC/CA) composites have been obtained by a simple ultrasonic mixing technique. It is found that there exists a synergistic effect between OMC’s channel-like mesopores and CA’s network-like mesopores during electrochemical charge–discharge process; and the maximum synergistic coefficient arrives at 0.37 when CA content is 30 wt.%. As a result, the as-prepared OMC/CA composites can make full use of the two-dimensional order of mesoporous structure of OMC and the three-dimensional connectivity of mesoporous structure of CA, and thus, exhibit much better electrochemical properties as compared to OMC and CA alone.

A kind of polyacrylonitrile-based carbon with a 3-D continuous mesopore structure was prepared by using silica gel as a template. Both the mesopore structure and the nitrogen content could be easily tailored by controlling the carbonization temperature. With decreasing the carbonization temperature, the porosity gradually decreased, while the nitrogen content increased. The sample carbonized at 800 °C and showed the highest specific capacitance of 210 F g−1 at the current density of 0.1 A g−1, which could still stay over 90% when the current density increased by 10 times. The good electrochemical properties could be ascribed to the following three factors: (1) the great pseudocapacitance of nitrogen functionalities, which is 28% of the total capacitance, (2) the 3-D continuous pore structure with a high mesoporosity of 92.5%, and (3) the enhanced wettability resulting from the nitrogen on the carbon skeleton.

Platinum catalysts supported on carbon aerogel (Pt/CA) with different pore structures were synthesized by an ethylene glycol liquid-phase reduction method. The Pt/CA catalysts were characterized by X-ray diffraction, transmission electron microscopy, and cyclic voltammetry. The effect of the pore structures of CAs on the electrochemical performance of Pt/CA for a direct methanol fuel cell was also analyzed. Experimental results indicate that the Pt/CA catalysts synthesized have achieved an extremely uniform Pt dispersion. The size of the Pt nanoparticles is 2.3 nm. The electrochemical active area and mass activity of the Pt/CA catalyst prepared on a CA with R/C (resorcinol/cetyltrimethylammonium bromide molar ratio) = 125 reach 87.4 m2 g−1 and 395.3 A g−1, respectively, which are significantly higher than those of commercial Pt/C catalysts.

A novel ordered mesoporous carbon with an interconnected channel structure (OMC-IC) has been successfully fabricated by adding proper hydrophilic SiO2 nanoparticles to the solution of triblock copolymer F127 and phenol-formaldehyde resol. Experimental results show that the presence of SiO2 nanoparticles does not hamper the self-assembly of F127 and resol to form an ordered two-dimensional hexagonal mesostructure. The neighboring channels of the OMC-IC are interconnected after removing SiO2 nanoparticles with a diameter larger than the thickness of the carbon wall. Such an interconnectivity of channels is beneficial in improving ion diffusion properties. The as-prepared OMC-IC exhibits much lower impedance to ion transport within both the channels and the micropores in the carbon wall, and thus has better electric double layer performance as compared to the conventional OMC with an unconnected channel structure.

The porous structure of pitch-based carbon aerogels (P-CAs) can be modified by KOH activation. It is found that decreasing the carbonization temperature of precursor CAs and increasing the mass ratio of KOH to CAs help to the formation of 0.7 nm-sized micropores and 2.7 nm-sized mesopores, respectively. The origin and the pore size of micropores play an important role in controlling electrochemical properties. The carbonization-forming micropores have stronger energy storage efficiency than activation-forming micropores, and only those with diameter below 1 nm (Microp < 1 nm) are the crucial place to storage energy. Due to the substantive increase of the number of the Microp < 1 nm, the highest specific capacitance of the as-prepared activated samples can reach 187.2 F g−1 at 5 mA cm−2, 1.8 times as large as that of their precursor CAs. Furthermore, this capacitance is still up to 173.3 F g−1 when increasing the current density to 50 mA cm−2, indicating that the activated samples have a high-rate charge–discharge performance.

Carbon aerogels and their precursory polymer aerogels are an important class of porous materials, because they have a unique three-dimensional interconnected nanonetwork structure that can minimize diffusive resistance to mass transport. However, production of conventional aerogels in a monolithic form remains problematic, because of risk of explosive polymerization, tedious supercritical/freeze drying steps, extra ball milling, and difficulty in controlling micro/nanostructures. Here we show that novel powdery carbon aerogels and their polymer aerogel precursors have been developed by utilizing shape-persistent nanoparticles as building blocks, followed by hypercrosslinking for forming a well-defined 3D interconnected nanonetwork with numerous interstitial nanopores and intraparticle micropores. The resulting aerogels are in a microscale powdery form. The preparation route is much more feasible for scaling up, due to avoidance of explosive polymerization and facile drying at ambient pressure. By simple carbonization, powdery carbon aerogels can be obtained with a high surface area of 2052 m2 g−1. Benefiting from structural advantages, the aerogels demonstrate excellent electrochemical performances in supercapacitors and lithium-sulfur batteries.Download high-res image (266KB)Download full-size image

The fabrication of advanced hierarchical porous polymers with a unique 3D nanonetwork structure composed of functional core–microporous shell nanoparticles was reported based on the development of a simple and efficient hypercrosslinking-induced self-assembly strategy.

A nanopores array in ordered mesoporous materials matters significantly to the reactant molecules arriving at the active catalytic sites in the interior of the nanostructure. However, how this effect works in the case of electrocatalysis needs investigating. We present that the nanopores array of carbon supports plays a significant role in determining Pt's accessibility and electroactivity. The ordered mesoporous carbons with interconnected pore channels (CMK-3) provide Pt nanoparticles with more than one order of magnitude superior Pt utilization efficiency and alcohol electrooxidation activity to those with isolated pore channels by carbon wall (FDU-15). This becomes more prominent in the case of the electrooxidation of isopropanol with a bigger molecular size and lower polarization. These findings indicate the significant role of nanoarchitectures in Pt's accessibility and electroactivity. It is possible to extend this concept to the other fine chemistry typical of surface activity and facile mass transport of molecules.

Advances in the performances of many modern materials fundamentally depend upon the exploitation of new micro/nanostructures. Therefore, ingenious design of hierarchical structures through the mimicking of natural systems is of increasing importance. Currently, there is an urgent need for creation of multidimensional carbonaceous structures by integrating a customized hierarchical pore architecture and hybrid carbon framework. Here we report the pioneering fabrication of novel super-hierarchical carbons with a unique carbonaceous hybrid nanotube-interconnected porous network structure by utilizing well-defined carbon nanotube@polystyrene bottlebrushes as building blocks. Hypercrosslinking of such heterogeneous core–shell structured building blocks not only allows for constructing amorphous microporous carbon shells on the surface of graphitic carbon nanotube cores, but also leads to formation of covalently interconnected nanoscale networks. Benefiting from such a well-orchestrated structure, these super-hierarchical carbons exhibit good electrochemical performances. Our findings may open up a new avenue for fabrication of unique and unusual functional carbon materials which possess well-orchestrated structural hierarchy and thus generate valuable breakthroughs in many applications including energy, adsorption, separation, catalysis and medicine.

The pioneered construction of novel monodisperse hollow and yolk–shell structured periodic mesoporous polymer nanoparticles was reported by the development of an efficient reactive interface-guided co-assembly approach.

A class of novel N-doped porous carbon nanospheres (PCNSs) with ultrahigh surface areas (e.g., Langmuir surface area = 3219 m2 g−1) and large templated mesopore diameters (up to 18.6 nm) was synthesized based upon a simple yet efficient copolymerization-induced self-assembly process of aniline/pyrrole co-monomers and block copolymer templates. The PCNSs exhibited enhanced adsorption properties towards creatinine and superior lithium-sulfur battery performances.

The ordered 2D reverse hexagonal pore morphology facilitates rapid ion diffusion more than the disordered wormhole-like pore morphology, thus leading to superior electrochemical properties such as rate capabilities.

Controlling carbon frameworks of nanocarbons from microporous to nonporous without imposing any additional treatment on a given type of precursor currently remains a great challenge. Here, a facile approach for tailoring different pore characteristics of carbon frameworks for nanocarbons from polypyrrole (PPy) precursors has been achieved based on the significant effect of reaction medium on the conjugation degree of PPy chains. Nanocarbon from PPy synthesized in NaOH solution (CPPy-NaOH) has numerous micropores with a BET surface area up to 482 m2 g−1, which is 10-fold higher than that of nanocarbon with an almost nonporous carbon framework from PPy polymerized in HCl solution (CPPy-HCl). This could be attributed to a distinct difference in the conjugation degree of the PPy chains. A much lower conjugation degree for the PPy precursor of CPPy-NaOH facilitates formation of micropores during carbonization. CPPy-NaOH exhibits much higher specific capacitance than CPPy-HCl. Furthermore, CPPy-NaOH gives much larger surface efficiency and higher capacitance retention ratios as compared to a commercial activated carbon for supercapacitors.

A novel type of nanoporous carbon with a 3D nanonetwork-interconnected 2D ordered mesoporous structure is successfully fabricated based on the self-assembly of triblock copolymer F127 and phenol–formaldehyde resol among the nanonetwork from tetraethyl orthosilicate. The as-constructed nanoporous carbons have two unique nanostructure advantages: (1) different from common solid framework for nanonetwork-structured carbons, their carbon framework is made of 2D ordered hexagonal mesopores; (2) unlike isolated mesopores for conventional ordered mesoporous carbons, their neighboring ordered mesopores are interconnected by 3D network-like mesopores. Such a well-defined carbon nanostructure is favorable for fast mass transport, mainly because it can make full use of both the 2D ordered mesoporous structure and the 3D interconnected nanonetwork. The as-prepared nanoporous carbons exhibit great potential as adsorbents toward organic vapor and as electrodes for supercapacitors.

In this paper, we report the electrochemical capacitive properties of polystyrene-based hierarchical porous carbon (PS-HPC) for supercapacitors. Compared to many porous carbons such as a commercially available activated carbon and an ordered mesoporous carbon, PS-HPC has a unique three-dimensionally (3D) interconnected micro-, meso- and macroporous network and thus exhibits faster ion transport behavior and a larger utilization of surface area in electric double layer capacitors. The 3D interconnected meso- and macroporous network originates respectively from the compact and loose aggregation of crosslinked polystyrene-based carbon nanoparticles, and is able to facilitate rapid ion transfer/diffusion rates. Furthermore, PS-HPC's micropores exist from the 3D interconnected network inside these crosslinked polystyrene-based carbon nanoparticles, thus giving an exceptional electrochemically accessible surface area for charge accumulation. As a result, the capacitance retention ratio and capacitance per surface area of PS-HPC at a high sweep rate of 200 mV s−1 are as high as 84% and 28.7 μF cm−2, respectively. These encouraging results demonstrate the promising application of PS-HPC for high performance supercapacitors.

A novel type of hierarchical porous carbon has been successfully prepared by constructing intra- and inter-sphere –CO– crosslinking bridges of monodisperse styrene–divinylbenzene copolymer nanospheres. The –C6H4– crosslinking bridges ensure good stability of the nanospheres during swelling and crosslinking, and the –CO– crosslinking bridges play an important role in achieving good nanostructure inheritability during carbonization.

A new class of advanced porous network structured carbon materials exhibits very attractive capacitive properties when utilized as electrodes for organic electrolyte supercapacitors, including large capacitances up to 210 F g−1, unusually high energy densities of 21.4–41.8 W h kg−1 at power densities of 67.5–10800 W kg−1, and excellent cycling stability.

Polyaniline (PANI) with carbon aerogel (CA) as conducting filler has been synthesized by an in situ chemical oxidative polymerization method. Scanning electron microscopy, infrared spectra, cyclic voltammetry and X-ray diffraction indicate that the three-dimensional carbon nano-network of CA is entirely buried inside the PANI matrix and its introduction basically does not change the structure of PANI. The electrochemical performances of the as-prepared PANI materials with CA filler are evaluated by means of galvanostatic charge–discharge test, cyclic voltammetry and electrochemical impedance spectroscopy. It is found that the electrochemical performances of PANI are notably improved due to the introduction of CA filler. For example, when operating at a large current density of 50 mA cm−2, CA-modified PANI with the optimal CA/aniline ratio of 1.0 wt% exhibits a specific capacitance as high as 226 F g−1, whereas neat PANI has only 89 F g−1. The CA modification mechanism of PANI has been discussed in detail.

In the present paper, we demonstrate the importance of the role of a mass transport pathway (MTP) in wormholelike mesoporous carbon (WMC) through studying the ion diffusion behaviors within two different wormholelike mesopore networks with and without MTP. Our results reveal that the introduction of MTP is very helpful in improving ion diffusion properties. The as-prepared WMC with a MTP of ca. 9.7 nm exhibits notably better electric double layer performance as compared to the conventional WMC without a MTP. For example, even at the quick sweep rate of 50 mV s−1, the surface specific capacitance of the former is 21.6 μF cm−2, which is almost 4 times as high as that of the latter (5.5 μF cm−2).

Due to unique high-surface-area ordered mesoporous channels interconnected with 3D network-like mesopores and π–π interactions between carbon frameworks and analytes, the as-prepared ordered mesoporous carbon-coated fiber exhibited a large adsorption amount, fast mass transport and high sensitivity.

The interconnected ordered pore channels facilitate faster permeation of Li+ ions during the charge–discharge process than the isolated ordered pore channels, resulting in significantly enhanced capacities, better rate capabilities and more remarkable cycling stability.

A simple and effective template-free method to fabricate hierarchical porous carbon (HPC) has been successfully developed by adopting linear polystyrene resin as raw material, anhydrous aluminium chloride as Friedel–Crafts catalyst, and carbon tetrachloride as crosslinker and solvent. Experimental results show that the as-constructed carbonyl (–CO–) crosslinking bridges between polystyrene chains provide simultaneously to its hierarchical porous polystyrene precursor, both a high crosslinking density and a proper amount of oxygen atoms, and thus achieve good framework carbonizability and nanostructure inheritability during carbonization. The as-prepared HPC's hierarchical porous structure exhibits interesting uniqueness: micropores (<2 nm) are from the network inside crosslinking polystyrene-based carbon nanoparticles of 10–30 nm in size, and mesopores (2–50 nm) and macropores (50–400 nm) result from the compact and loose aggregation of these network nanoparticles, respectively; and these micro-, meso- and macropores are three-dimensionally interconnected to each other. Its Brunauer–Emmett–Teller surface area and total pore volume are 679 m2g−1 and 0.66 cm3g−1, respectively.

A facile route to fabricate nitrogen-doped ordered nanoporous carbons (NONCs) was developed based on in situ polydopamine coating onto the pore surface of ordered nanoporous silica. The NONC exhibits very attractive capacitive properties, including unusually large capacitances up to 538 F g−1, highly efficient electrochemically active surface area and good cycling stability.

Polyethylene glycol (PEG) is used to induce the self-assembly of phenol/formaldehyde (PF) resol and triblock copolymer Pluronic P123 by improving the interaction between the PF resol and P123, leading to the formation of a two-dimensional (2D) hexagonal ordered mesostructure. Ordered mesoporous polymers (OMPs) prepared by such a PEG-induced self-assembly method exhibit typical 2D hexagonal nanostructures with narrow pore size distribution. PEG may additionally act as a micropore-forming agent because of its thermal decomposition in this new synthetic approach, leading to the introduction of micropores into the polymeric framework. The resultant OMPs with rigid network frameworks can be directly transformed after a carbonization process into ordered mesoporous carbons. Furthermore, it is demonstrated that the as-obtained ordered mesoporous materials could have great potential applications as absorbents for organic vapors and electrodes in supercapacitors.

A unique hierarchical architecture is successfully constructed in a wormhole-like mesopore structure via a multiple nanocasting route. This novel type of hierarchical porous carbon (HPC) consists of three-dimensional ordered macropores (ca. 150 nm) with interconnecting pore windows, and the walls of these macropores are rich in wormhole-like mesopores (ca. 2.7 nm) and large spherical mesopores (ca. 10 nm), as well as a significant microporosity, presenting a macro-meso-microporous structure with a three-dimensional interconnectivity. Such a hierarchically porous structure may provide fine diffusion pathways for reaction species, which is demonstrated by the experimental result of an enhanced performance in a supercapacitor. For example, with the introduction of a hierarchical porous structure for fast transport and effective access of ions, the as-prepared HPC exhibits a specific capacitance as high as 247 F g−1, whereas traditional wormhole-like mesoporous carbon has only a specific capacitance of 176 F g−1.