Interconnected Macroporous Network Research Articles

ZSM-5 monolithic microreactors with hierarchical porosity: Maximizing selective production of para-xylene

ZSM-5 monoliths with Si/Al ∼40 were achieved by steam assisted conversion of micro-/macroporous silica-alumina monoliths synthesized by an optimized combination of spinodal decomposition and sol-gel process. ZSM-5 monoliths exhibit a homogeneous and interconnected network of macropores of ∼30 μm diameter, with a macropore volume of ∼1 mL g−1 and a micropore volume of 0.16 mL g−1, as waited for pure ZSM-5. The skeleton of ZSM-5 monoliths featured a 3D aggregation of spherical particles of 6 μm in diameter. The latter were composed by a stacking of thin plate-like shaped crystallites. The catalytic properties of the ZSM-5 monoliths were assessed through their use as catalytic microreactor in the continuous flow alkylation of toluene with methanol. An outstanding for para-xylene selectivity of 81 % was achieved possibly ascribable due to the maximization of pore openings of sinusoidal channels as a result of the plate-like morphology of the ZSM-5 crystallites.

Constructing spherical-beads-on-string structure of electrospun membrane to achieve high vapor flux in membrane distillation

Hydrophobic membranes with a reentrant-like structure have shown high hydrophobicity and high anti-wetting properties in membrane distillation (MD). Here, PVDF spherical-beads-on-string (SBS) fibers were electrospun on nonwoven fabric and used in the MD process. Such a reentrant-like structure was featured with fine fibers, a low ratio of bead length to bead diameter, and high bead frequency. It was revealed that the SBS-structured membranes exhibited an exceptional capability for vapor flux, due to the formation of a network of more interconnected macropores than that of fibers and fusiform-beads-on-string structures, ensuring unimpeded vapor diffusion. In the desalination of formulated seawater (3.5 wt.% NaCl solution), a vapor flux of 61 ± 3 kg m−2 h−1 with a salt rejection of >99.98 % was achieved at a feed temperature of 60 °C. Furthermore, this SBS structured membrane showed satisfactory seawater desalination performance with a stable flux of 40 kg m−2 h−1 over a 27 h MD process. These findings suggest a viable approach for fabricating SBS-structured membranes that significantly enhance vapor flux in MD for desalination applications. Besides, the hydrophobic membranes with SBS structure can be prepared by single-step electrospinning, and it is facile to scale-up manufacture. This strategy holds promise for advancing the development of high-performance MD membranes tailored for efficient seawater desalination processes.

Synthesis of oxygen vacancy-engineered Fe2O3 nanospheres on three-dimensional reduced graphene oxide for ultra-energy density performance of asymmetric supercapacitors

The synthesis of oxygen vacancy (VO) -engineered Fe2O3 (Fe2O3-x) nanospheres on three-dimensional reduced graphene oxide (3D rGO/Fe2O3-x) is proposed via a gentle and high-efficiency hydrothermal approach under reducing conditions for a high-performance asymmetric supercapacitors. The smooth and rounded 3D rGO/Fe2O3-x hydrogel appears to be intact, which possesses extremely light weight and excellent strength. The micromorphology of 3D rGO/Fe2O3-x presents a 3D interconnected macroporous network structure, and the Fe2O3-x nanospheres are distributed on the surface of 3D rGO. The specific capacity of the 3D rGO/Fe2O3-x is up to 273.2 mAh/g. An asymmetric supercapacitor 3D rGO/Fe2O3-x||3D rGO exhibits an ultrahigh energy density of 114 Wh/kg at a power density of 140 W/kg. Over 20000 cycles, the capacitance retention fading and the coulombic efficiency are 6.18% and ∼100%, respectively. Outstanding supercapacitor performances of the 3D rGO/Fe2O3-x||3D rGO are attributed to the formation of the VOs in Fe2O3 crystal structure and the distribution of Fe2O3-x nanospheres on the 3D rGO. The 3D rGO/Fe2O3-x displays great potential for utilization as high-performance supercapacitors.

Evaluation of reproducible cryogel preparation based on automated image analysis using deep learning.

Cryogels represent a class of porous sponge-like materials possessing unique properties including high-fidelity reproduction of tissue structure and maximized permeability. Their architecture is mainly based on an interconnected network of macropores that provides sufficient stability while allowing the movement of substances through the material. In most cryogel applications, the pore size is very important, especially when the material is used as a 3D scaffold for tissue culture, applied as a filter, or utilized as a membrane. In this study, poly(dimethylacrylamide-co-2-hydroxyethyl methacrylate) cryogels have been prepared by two preparation methods to investigate the reproducibility of homogeneous pore structures and pore sizes. Automated image analysis algorithms were developed to rapidly evaluate cryogel pore sizes based on scanning electron microscopy (SEM) images. The quantification approach contained a unique combination of classical and deep learning-based algorithms. To validate the accuracy of the two models, we compared the results obtained from automated SEM image analysis with those from manual pore size determinations and mercury intrusion porosimetry (MIP) measurements. Effect sizes were calculated to compare the results from manual and automated pore size measurements for the cryogel reproducibility series. 81% of the values obtained revealed only trivial differences, which strongly suggests that automated image analysis can reliably substitute the manual evaluation of cryogel pore sizes. The use of an adapted reactor setup yielded cryogels with heterogeneous morphologies in the absence of recognizable pore structures. With the conventional cryogel preparation using plastic syringes, the obtained cryogels represented highly reproducible morphologies and pore sizes in the range between 17 and 22 μm. Calculated effect sizes within the cryogel replicate series revealed only trivial differences between the obtained pore sizes in 83.5% or 99.4% of the data (classical approach and deep learning-based approach, respectively).

Scaffolds for Cartilage Tissue Engineering from a Blend of Polyethersulfone and Polyurethane Polymers

In recent years, one of the main goals of cartilage tissue engineering has been to find appropriate scaffolds for hyaline cartilage regeneration, which could serve as a matrix for chondrocytes or stem cell cultures. The study presents three types of scaffolds obtained from a blend of polyethersulfone (PES) and polyurethane (PUR) by a combination of wet-phase inversion and salt-leaching methods. The nonwovens made of gelatin and sodium chloride (NaCl) were used as precursors of macropores. Thus, obtained membranes were characterized by a suitable structure. The top layers were perforated, with pores over 20 µm, which allows cells to enter the membrane. The use of a nonwoven made it possible to develop a three-dimensional network of interconnected macropores that is required for cell activity and mobility. Examination of wettability (contact angle, swelling ratio) showed a hydrophilic nature of scaffolds. The mechanical test showed that the scaffolds were suitable for knee joint applications (stress above 10 MPa). Next, the scaffolds underwent a degradation study in simulated body fluid (SBF). Weight loss after four weeks and changes in structure were assessed using scanning electron microscopy (SEM) and MeMoExplorer Software, a program that estimates the size of pores. The porosity measurements after degradation confirmed an increase in pore size, as expected. Hydrolysis was confirmed by Fourier-transform infrared spectroscopy (FT-IR) analysis, where the disappearance of ester bonds at about 1730 cm-1 wavelength is noticeable after degradation. The obtained results showed that the scaffolds meet the requirements for cartilage tissue engineering membranes and should undergo further testing on an animal model.

Recycled ZnO‐fused macroporous 3D graphene oxide aerogel composites for high‐performance asymmetric supercapacitors

AbstractIn the arena of energy storage device, asymmetric supercapacitors (ASCs) are considered a key category due to its high‐power density and energy densities. In this study, a novel macroporous microrecycled ZnO nanoparticles (mi‐ZnO NPs) recovered from spent Zn–C battery‐decorated three‐dimensional graphene aerogel (GA) composite has been synthesized via simple eco‐friendly synthetic method, which is used as a proficient anode material to fabricate ASC. The interconnected macroporous networks and ∼40‐nm microrecycled ZnO NPs incorporated GA (mi‐ZnO–GA) enhanced the surface area of anode materials, which lead to achieve a formation of high‐performance ASC. Here, we composed ASCs from a microrecycled ZnO thin film (cathode) and mi‐ZnO–GA composite (anode), which reveals fast charging/discharging characteristics, stable widen cell voltage, superior power, and energy densities (13.7 W h/kg, 13.2 kW/kg), and finally stable cyclability (76.8% retention after 5000 cycles). These outcomes open up the window for microrecycled ZnO NPs incorporated GA (mi‐ZnO–GA) as a prominent anode material for high‐performance energy storage devices.

Experimental and modeling of tetracycline degradation in water in a flow-through enzymatic monolithic reactor.

In this work, the laccase from Trametes versicolor was immobilized in highly porous silica monoliths (0.6-cm diameter, 0.5-cm length). These monoliths feature a unique homogeneous network of interconnected macropores (20 μm) with mesopores (20 nm) in the skeleton and a high specific surface area (330 m2/g). The enzymatic monoliths were applied to degrade tetracycline (TC) in model aqueous solutions (20 ppm). For this purpose, a tubular flow-through reactor (FTR) configuration with recycling was built. The TC degradation was improved with oxygen saturation, presence of degradation products, and recirculation rate. The TC depletion reaches 50% in the FTR and 90% in a stirred tank reactor (CSTR) using crushed monoliths. These results indicate the importance of maintaining a high co-substrate concentration near active sites. A model coupling mass transfers with a Michaelis-Menten kinetics was applied to simulate the TC degradation in real wastewaters at actual TC concentration (2.8 10-4 ppm). Simulation results show that industrial scale FTR reactor should be suitable to degrade 90% of TC in 5 h at a flow rate of 1 mL/min in a single passage flow configuration. Nevertheless, the process could certainly be further optimized in terms of laccase activity, oxygen supply near active sites, and contact time.

Integrating Nanosensors into Macroporous Hydrogels for Implantation.

Macroporous hydrogels are an attractive platform for implantable sensors because the network of interconnected macropores facilitates tissue integration. Embedded sensing elements, in our case, plasmonic gold nanoparticles, can transduce the presence, absence, and concentration of biochemical markers to the outside. We present here how to integrate such nanosensors into a macroporous hydrogel while preserving the nanosensor functionality in order to produce implantable sensors. We demonstrate that out of four different polymers, the poly(2-hydroxyethyl methacrylate-poly(ethylene glycole)diacrylate copolymer (pHEMA-PEGDA) results in a working sensor. Our approach of incorporating nanosized sensor elements into a hydrogel matrix generally identifies suitable polymers for implantable sensor systems.

Cryogel-Integrated Biochip for Liver Tissue Engineering

Microfluidic systems and polymer hydrogels have been widely developed for tissue engineering. Yet, only a few tools combining both approaches, especially for in vitro liver models, are being explored. In this study, an alginate-based cryogel-integrated biochip was engineered for dynamic hepatoma cell line culture in three dimensions (3D). The alginate cryogel was covalently cross-linked in the biochip at subzero temperatures (T < 0 °C) to create a scaffold with high mechanical stability and an interconnected macroporous network. By varying the alginate concentration and the cross-linker ratio, Young's modulus of the cryogel can be fine-tuned between 1.5 and 29 kPa, corresponding to the range of stiffness of the different physiological states of the liver. We demonstrated that HepG2/C3A cells can be cultured and maintained as viable under dynamic conditions in this device up to 6 days. Albumin synthesis and glucose consumption increased over the cell culture days. Moreover, a 3D cell structure was observed across the entire height of the biochip, which was preserved following alginate lyase treatment to remove the cryogel-based scaffold. In summary, these results represent a proof of concept of an interesting cell culture technology that should be further investigated to engineer healthy and cirrhotic liver models.

Injectable, macroporous scaffolds for delivery of therapeutic genes to the injured spinal cord.

Biomaterials are being developed as therapeutics for spinal cord injury (SCI) that can stabilize and bridge acute lesions and mediate the delivery of transgenes, providing a localized and sustained reservoir of regenerative factors. For clinical use, direct injection of biomaterial scaffolds is preferred to enable conformation to unique lesions and minimize tissue damage. While an interconnected network of cell-sized macropores is necessary for rapid host cell infiltration into—and thus integration of host tissue with—implanted scaffolds, injectable biomaterials have generally suffered from a lack of control over the macrostructure. As genetic vectors have short lifetimes in vivo, rapid host cell infiltration into scaffolds is a prerequisite for efficient biomaterial-mediated delivery of transgenes. We present scaffolds that can be injected and assembled in situ from hyaluronic acid (HA)-based, spherical microparticles to form scaffolds with a network of macropores (∼10 μm). The results demonstrate that addition of regularly sized macropores to traditional hydrogel scaffolds, which have nanopores (∼10 nm), significantly increases the expression of locally delivered transgene to the spinal cord after a thoracic injury. Maximal cell and axon infiltration into scaffolds was observed in scaffolds with more regularly sized macropores. The delivery of lentiviral vectors encoding the brain-derived neurotrophic factor (BDNF), but not neurotrophin-3, from these scaffolds further increased total numbers and myelination of infiltrating axons. Modest improvements to the hindlimb function were observed with BDNF delivery. The results demonstrate the utility of macroporous and injectable HA scaffolds as a platform for localized gene therapies after SCI.

Novel microrecycled ZnO nanoparticles decorated macroporous 3D graphene hybrid aerogel for efficient detection of NO2 at room temperature

A novel macroporous microrecycled ZnO nanoparticles (NPs) recovered from spent Zn-C battery decorated three-dimensional (3D) graphene aerogel hybrid materials has been synthesized via simple eco-friendly synthetic method. The 3D graphene aerogel demonstrate interconnected macroporous networks and the microrecycled ZnO NPs displayed a size of ∼ 40 nm are attached uniformly on the surface of graphene flakes. When being used as NO2 sensors for detecting low concentration of NO2 gas molecules, this macroporous 3D hybrid structure achieved a higher response value along fast response-recovery time characteristics with superior selectivity and repeatability behaviour at room temperature (RT, 20 °C). The elevated NO2 sensing properties for this 3D structure is mainly associated with improved conductivity and porous structure of graphene as well as the interaction between p-type graphene and n-type zinc oxide. Along with the representation of elevated NO2 sensing performance, mechanism behind this sensing phenomenon also discussed in this study. These results and the low-cost, light-weight and eco-friendly fabrication features indicate that the proposed microrecycled ZnO NPs decorated 3D graphene aerogel hybrid sensor is a promising building block for the advancement of high-performance NO2 sensors for real field applications.

Biodegradable Iron-Based Foams for Potential Bone Replacement Material

Iron and iron-phosphorus open-cell foams were tested for their potential use as synthetic bone graft substitutes. The samples were manufactured using a replica method based on a powder metallurgical approach. Iron foams alloyed with 0.5 wt. % of phosphorus were prepared with the aim of enhancing the mechanical properties and manipulating the corrosion rate. The manufactured foams were tested for their microstructure, porosity, corrosion behaviour and mechanical properties. SEM analyses of the foams’ microstructures confirmed the presence of an open, three-dimensional interconnected macroporous network similar to that of the human bone. The corrosion behaviour was studied by a static immersion test and potentiodynamic polarisation in Hank’s solution. The results showed that the presence of phosphorus slightly decreased the corrosion rate as compared to pure iron foams. The mechanical properties studied by a compression test confirmed a positive effect of phosphorus on the mechanical properties of the manufactured foams.

Remarkable performance of microstructured ceria foams for thermochemical splitting of H2O and CO2 in a novel high–temperature solar reactor

Thermochemical splitting of H2O and CO2 applying redox materials constitutes a sustainable option for synthetic fuel production and CO2 valorization. It consists of two-step process based on the creation of oxygen vacancies in non-stoichiometric oxides during solar-driven thermal reduction, followed by the material re-oxidation with H2O and/or CO2 to generate syngas (H2/CO), the building block for a wide variety of synthetic hydrocarbon fuels. In this work, a monolithic solar reactor was designed and tested integrating reticulated porous ceria (open-cell foams) heated by concentrated solar energy. The influence of various operating parameters on the thermochemical reactor performance was investigated. Increasing the temperature or decreasing the pressure in the reduction step was found to enhance the maximum reduction extent reached by the redox material (CeO2-δ), thereby improving the fuel production capacity. In addition, a decrease of the oxidation temperature led to higher fuel production rate, despite an increase of the temperature swing between the reduction and oxidation steps. Increasing the oxidant concentration also sharply enhanced the oxidation rate. Peak CO production rate approaching 10 mL/min/g was achieved with ceria foams (exhibiting micron-sized grains forming an interconnected macroporous network within the struts) during their reoxidation upon free cooling with pure CO2 stream (after reduction at 1400 °C), thus strongly outperforming (by a factor of about x8) the previous maximum values reported to date. This result was attributed to the fine and stable granular microstructure of the reticulated ceria foams. The solar reactor reliability and robustness during high-temperature two-step redox cycling were demonstrated with an average cycle production of 5.1 mL/g of H2 and CO, and peak solar-to-fuel efficiencies above 8%. The highly reactive reticulated foams with 10 and 20 ppi (pore per inch) were cycled for about 69 h (51 cycles) of continuous on-sun operation without any decrease in performance, thus evidencing their noteworthy thermochemical and microstructural stability.

Cryogel-Integrated Biochip for Liver Tissue Engineering

Microfluidic systems and polymer hydrogels have been widely developed for tissue engineering. Yet only a few tools combining both approaches, especially for in vitro liver models, are being explored. In this study, an alginate-based cryogel-integrated biochip was engineered for dynamic hepatocyte cell culture in three dimensions (3D). The alginate cryogel was covalently cross-linked in the biochip at subzero temperatures (T < 0 °C) to create a scaffold with high mechanical stability and an interconnected macroporous network. By varying the alginate concentration and the cross-linker ratio, the Young’s modulus of the cryogel can be fine-tuned between 1.5 and 29 kPa, corresponding to the range of stiffness of the different physiological states of the liver. We demonstrated that HepG2/C3A cells can be cultured and maintained viable under dynamic conditions in this device up to 7 days. Albumin synthesis and glucose consumption increased over the cell culture days. Moreover, a 3D cell structure was observed across the entire height of the biochip, which was preserved following alginate lyase treatment to remove the cryogel-based scaffold. In summary, these results suggest a promising cell culture technology with great potential for pharmaceutical industries to engineer healthy and cirrhotic liver models for middle-throughput predictive toxicology and drug screening.

Poly(3-hydroxybutyrate-co-3-hydroxyexanoate) scaffolds with tunable macro- and microstructural features by additive manufacturing

Polymer microstructural engineering by additive manufacturing (AM) represents a powerful tool to functionalize tissue engineering scaffolds. This article reports on the processing of polymer/solvent/non-solvent ternary mixtures through their extrusion in a non-solvent bath as an innovative phase inversion-based AM approach to engineer poly(3-hydroxybutyrate-co-3-hydroxyexanoate) (PHBHHx) scaffolds porosity. The processing of PHBHHx mixtures with different chloroform/ethanol ratio into scaffolds characterized by a dual-scale porosity is described by highlighting how an interconnected network of macropores can be endowed with a tunable microporosity, formed a result of the phase inversion process governing polymer solidification. In particular, the study demonstrates that varying the non-solvent percentage in the ternary mixture represents an effective means to tailor the macropores size along scaffold vertical cross-section and the local micropores concentration in the polymer matrix. These structural changes are demonstrated to significantly affect scaffold overall porosity and tensile modulus, as well as its ability to support in vitro the proliferation of preosteoblast cells. The developed manufacturing strategy combines an advanced material engineering method effective on dual-scale size levels, with a modern approach to the sustainable processing of naturally-derived polyesters that minimizes the employment of halogenated solvents.

Cellulose-based biomaterials integrated with copper-cystine hybrid structures as catalysts for nitric oxide generation.

Bionanocomposite materials were developed from the assembly of polymer-coated copper-cystine high-aspect ratio structures (CuHARS) and cellulose fibers. The coating of the metal-organic materials with polyallylamine hydrochloride (PAH) allows their covalent linkage to TEMPO-oxidized cellulose by means of EDC/NHS. The resulting materials can be processed as films or macroporous foams by solvent casting and lyophilization, respectively. The films show good mechanical behavior with Young's moduli around 1.5 GPa as well as resistance in water, while the obtained foams show an open network of interconnected macropores with average diameters around 130 μm, depending on the concentration of the initial suspension, and compression modulus values around 450 kPa, similar to other reported freeze-dried nanocellulose-based aerogels. Based on these characteristics, the cellulose/PAH-CuHARS composites are promising for potential biomedical applications as implants or wound dressing materials. They have proved to be effective in the decomposition of low molecular weight S-nitrosothiols (RSNOs), similar to those existing in blood, releasing nitric oxide (NO). This effect is attributed to the presence of copper in the crystalline structure of the CuHARS building unit, which can be gradually released in the presence of redox species like ascorbic acid, typically found in blood. The resulting biomaterials can offer the interesting properties associated with NO, like antimicrobial activity as preliminary tests showed here with Escherichia coli and Staphylococcus epidermidis. In the presence of physiological concentration of RSNOs the amount of generated NO (around 360 nM) is not enough to show bactericidal effect on the studied bacteria, but it could provide other properties inherent to NO even at low concentration in the nM range like anti-inflammatory and anti-thrombotic effects. The cytotoxic effect recorded of the films on rat brain endothelial cells (BMVECs) is least significant and proves them to be friendly enough for further biological studies.

Three dimensional (3D) nanostructured assembly of MoS2-WS2/Graphene as high performance electrocatalysts

A promising electrocatalyst material composed of 2D layered MoS2-WS2 heterostructure hierarchically assembled into a 3D highly interconnected macroporous network of graphene was facilely fabricated. This in-situ synthesis method involves hydrothermal reaction followed by moderate thermal annealing which guarantees the uniform distribution of the MoS2-WS2 heterojunctions within graphene matrix. The presence of 3D conductive and porous graphene network and the combined merits of MoS2 and WS2 endow the resulting 3D MoS2-WS2/graphene nanohybrids with unique conductivity pathways and channels for electrons and with outstanding electrocatalytic performance towards enhanced hydrogen evolution reaction (HER). This 3D nanohybrid delivered the small overpotential of 110 mV, and the small Tafel slope of 41 mV per dec, demonstrating high HER activity. Furthermore, the resulting nanohybrids exhibit excellent stability as very trivial drop in the current density was noticed even after 2000 cycles. The superior electrocatalytic performance of 3D MoS2-WS2/graphene over other non-precious metal electrocatalysts is accredited to the robust synergism of 2D MoS2-WS2 with 3D graphene that offer ample active sites and improved conductivity for HER. The proposed approach can be further extended to modify other layered transition metal dichalcogenides with hierarchical 3D porous structure as a competent electrocatalysts for HER.

Microarchitecture of poly(lactic acid) membranes with an interconnected network of macropores and micropores influences cell behavior

Tissue engineering scaffolds require a three-dimensional architecture with controlled pore size and structure to host tissue formation. Here we used the non-solvent induced phase separation (NIPS) process to prepare porous asymmetric membranes made of poly(lactic acid) (PLA) using dimethylformamide (DMF) as solvent and water as non-solvent. The addition of a polymer additive to the PLA solution has made it possible to increase and control the size of open macropores at the membrane bottom surface and to generate a dual pore architecture consisting of an interconnected network of macropores and micropores. Based on the study of the compatibility of PLA with the polymer additive we propose that the dual pore architecture is generated through a two phase separations process. Membrane surface could be functionalized with hyaluronan (HA) and, whatever the cell type considered, HA-functionalization enhanced cell proliferation. Interestingly, a strong effect of macropore size and surface functionalization by HA on cell colonization and cell proliferation within membranes and membrane morphology on cell organization was demonstrated. Cancer cell lines were able to adopt an in vivo tumor-like behavior, endothelial cells reconstituted a vascular-like structure and mesenchymal stem cells adopted a specific organization which can open perspectives for their use and conservation. These results show that our membranes with controllable dual pore architecture offer great potentialities in tissue and tumor engineering.

Curved Fragmented Graphenic Hierarchical Architectures for Extraordinary Charging Capacities.

An approach to assemble hierarchically ordered 3D arrangements of curved graphenic nanofragments for energy storage devices is described. Assembling them into well-defined interconnected macroporous networks, followed by removal of the template, results in spherical macroporous, mesoporous, and microporous carbon microball (3MCM) architectures with controllable features spanning nanometer to micrometer length scales. These structures are ideal porous electrodes and can serve as lithium-ion battery (LIB) anodes as well as capacitive deionization (CDI) devices. The LIBs exhibit high reversible capacity (up to 1335 mAh g-1 ), with great rate capability (248 mAh g-1 at 20 C) and a long cycle life (60 cycles). For CDI, the curved graphenic networks have superior electrosorption capacity (i.e., 5.17 mg g-1 in 0.5 × 10-3 m NaCl) over conventional carbon materials. The performance of these materials is attributed to the hierarchical structure of the graphenic electrode, which enables faster ion diffusion and low transport resistance.

Hierarchically porous nitrogen-doped carbon as cathode for lithium–sulfur batteries

Abstract Porous nitrogen-doped carbon is an especially promising material energy storage due to its excellent conductivity, stable physicochemical properties, easy processability, controllable porosity and low price. Herein, we reported a novel well-designed hierarchically porous nitrogen-doped carbon (HPNC) via a combination of salt template (ZnCl2) and hard template (SiO2) as sulfur host for lithium–sulfur batteries. The low-melting ZnCl2 is boiled off and leaves behind micropores and small size mesopores during pyrolysis process, while the silica spheres are removed by acid leaching to generate interconnected 3D network of macropores. The HPNC-S electrode exhibits an initial specific capacity of 1355 mAh g–1 at 0.1 C (1 C = 1675 mAh g–1), a high-rate capability of 623 mAh g–1 at 2 C, and a small decay of 0.13% per cycle over 300 cycles at 0.2 C. This excellent rate capability and remarkable long-term cyclability of the HPNC-S electrode are attributed to its hierarchical porous structures for confining the soluble lithium polysulfide as well as the nitrogen doping for high absorbability of lithium polysulfide.