Pore-forming Effect Research Articles

Unlocking the potential of zwitterionic vapor-induced phase separation membranes synthesized from maleic anhydride in polyvinylidene fluoride-based systems for antifouling applications

This work presents an approach to form zwitterionic porous poly(vinylidene fluoride) (PVDF) membranes fabricated by vapor-induced phase separation (VIPS). The reaction between maleic anhydride groups, incorporated initially in the casting solution by blending styrene maleic anhydride (SMA), with 3-((3-aminopropyl)dimethylammonio)propane-1-sulfonate led to the desired zwitterionic moieties. XPS and FTIR analyses confirm the functionalization of the membrane. SEM analyses revealed that it did not have any major impact on the membrane morphology deemed to be close to bicontinuous. While the mean pore size of the virgin membrane was 0.57 μm, it increased to 0.85 μm suggesting the pore-forming effect of SMA during the phase-inversion process. Hydration was significantly enhanced, attributed to the zwitterionic groups on the one hand, but also to the formation of carboxylic acid and amide groups following the ring-opening reaction. It led to significant resistance to bacterial attachment as tested with 4 strains of bacteria including Escherichia coli, Stenotrophomonas maltophilia, Staphylococcus aureus and Streptococcus mutans (>99 % reduction for each). Applied in cyclic water/bacterial solution filtration tests, the modified membrane showed clear improvement in overall performances. Hence, for the virgin membrane, the initial water permeability, flux recovery ratio after the first cycle and flux recovery ratio after the second cycle were found to be 3000 L m−2 h−1.bar−1, 12 % and 53 %, respectively. For the optimized zwitterionic membrane, they were measured to be 7000 L m−2 h−1.bar−1, 26 % and 100 %, respectively. The efficacy of styrene maleic anhydride as a precursor for achieving stable and efficient zwitterionization of PVDF microfiltration membranes is evidenced, rendering it valuable for the filtration of microorganism-containing wastewater. Moreover, its potential application extends to the biomedical realm.

Efficient drug supply in stem cell cytosol via pore-forming saponin nanoparticles promotes in vivo osteogenesis and bone regeneration

Directional differentiation of stem cells is a key step in stem cell therapy. In this study, we developed saponin-based nanoparticles (Ad-SNPs) containing dexamethasone (Dex) and alpha-lipoic acid (ALA) to promote osteogenic differentiation of human mesenchymal stem cells (hMSCs) and bone regeneration. The Ad-SNPs can achieve rapid cellular uptake through a pore-forming effect without cytotoxic cationic charges. They also provide extended retention in cell cytosol due to their uptake route. These properties are advantageous in efficiently supplying drugs to the hMSCs. The combination of Dex and ALA facilitated mitochondrial fusion and prevented reactive oxygen species–induced DNA damage. It also helped to preserve mitochondrial dynamics, and the efficient supply of it provided by the Ad-SNPs induced differentiation of hMSCs into osteoblasts. The Ad-SNPs showed outstanding performance in osteoblast differentiation, maturation, and mineralization in 3D culture compared with NPs without saponin and with free drugs. When Ad-SNP-treated hMSCs were tested in a rat femoral bone defect model, they showed the fastest regeneration of bones and complete repair in the shortest period among all groups. To the best of our knowledge, this study is the first application of pore-forming saponin-based NPs with rapid cellular uptake and extended retention to stem cell therapy, and we demonstrated their promising potential in bone regeneration and efficient delivery of Dex and ALA.

Activated carbon with high mesopore ratio derived from waste Zanthoxylum bungeanum branches by KNO3-assisted H3PO4 staged activation for toluene adsorption.

Waste Zanthoxylum bungeanum branches were used to prepare activated carbon adsorbents with high mesopore ratio by H3PO4 staged activation method with adding KNO3 additive. The prepared activated carbon adsorbents were characterized by SEM, BET, FT-IR, and XRD. The adsorption properties of the prepared activated carbon adsorbents were evaluated by the toluene adsorption/desorption in air. The quasi-first-order, quasi-second-order, and Bangham models were used to fit the obtained toluene adsorption results. The oxidative etching of KNO3 additive improved the pore-forming ability of the H3PO4 activator to enhance the activation pore-forming effects of the selected biomass raw material. The secondary pore-forming effects of K atoms promoted the effective expansion of the pore diameter in the activated carbon preparation process to prepare activated carbon adsorbents with high mesopore proportion. The specific surface area and mesopore proportion of the activated carbon adsorbents prepared by adding KNO3 additive exceeded 1100 m2/g and 71.00%, respectively, and the toluene adsorption capacity exceeded 370.00 mg/g. The rich mesopore structures can effectively reduce the toluene mass transfer resistance, which can promote the corresponding activated carbon adsorbent to be regenerated by low-temperature (40 °C) thermal desorption. The toluene adsorption on the prepared activated carbon adsorbents includes surface adsorption and diffusion in pore structures, and the toluene adsorption mechanism is more consistent with the Bangham kinetic model.

Study on mechanics and high temperature tribological properties of porous bearing cage material

To meet the self-lubricating performance requirements of aerospace bearing cages, poly-ether-ether-ketone (PEEK)-based self-lubricating bearing cage materials were prepared based on the Fused Deposition Molding (FDM) process. The mechanical and tribological properties under high temperature condition (200°C) of the porous self-lubricating materials were researched. The results of microstructure analysis of porous sample showed that under laboratory conditions, NaCl can exhibit excellent pore-forming effect and could be effectively removed. The mechanical test results showed that the mechanical properties of the samples showed a significant decrease with the increase in porosity, and were affected by the synergistic effect of pore creation. However, the mechanical properties of heat-treated samples can meet the performance requirements of the bearing cage. The results of the tribological performance tests under high temperature conditions showed that the wear process of the dense samples was more smoother. Further comparing with the tribological properties at room temperature, it was found that the wear resistance of PEEK samples decreased under high temperature conditions. The normalized results of the mechanical and tribological properties data show that the samples with 50 wt% of porogenic agent can express the most balanced and excellent overall performance.

Selective depolymerization of PET to monomers from its waste blends and composites at ambient temperature

Recycling of polyethylene terephthalate (PET), one of the largest varieties of synthetic polymers and the primary textile feedstock, presents a significant challenge when waste PET blends or composites are involved. Despite numerous efforts to address waste PET, it is difficult to achieve energy-efficient and selective depolymerization of PET through physical sorting systems or existing chemical means. Herein, we report a dichloromethane (DCM) and ethanol (EtOH) solvent system to selectively depolymerize PET into monomers while fully recover other mixture components. The complete depolymerization of PET and recovery of more than 99% of terephthalic acid (TPA) monomer can be achieved at room temperature within 30 min. After the reaction, TPA can be separated by simple filtration due to its insolubility in the solution. The filtrate can be reused for the recovery of PET. Molecular dynamics simulation shows that the high activity and selectivity is attributed to activating effect of DCM to PET ester groups, as well as pore-forming effect to promote PET interfacial mass transfer. Environmental energy impact and carbon emissions were evaluated and the results demonstrate the environmental friendliness of this method. This approach enables direct and efficient recycling of PET monomers from waste blends and composites, providing a viable solution to plastic and textile pollution.

Pyroptosis and airway homeostasis regulation.

Pyroptosis is a form of cell death associated with inflammation. In the maintenance of airway homeostasis, pyroptosis goes through activation and assembly of Inflammasome. The pyroptosis pathway is mediated by caspase which activates the pore-forming effect of substrate gasdermin family members. It eventually leads to lysis and release of the cell contents and then induces an inflammatory response. In this process, it participates in airway homeostasis regulation by affecting airway immunity, airway epithelial structure and airway microbiota. Therefore, we discussed the correlation between airway immunity, airway epithelial structure, airway microbiota and the mechanism of pyroptosis to describe the role of pyroptosis in airway homeostasis regulation which is of great significance for understanding the occurrence and treatment of airway inflammatory diseases.

Development of Electrode-Supported Proton Conducting Solid Oxide Cells and their Evaluation as Electrochemical Hydrogen Pumps

Protonic ceramic solid oxide cells (P-SOCs) have gained widespread attention due to their potential for operation in the temperature range of 300–500 °C, which is not only beneficial in terms of material stability but also offers unique possibilities from a thermodynamic point of view to realize a series of reactions. For instance, they are ideal for the production of synthetic fuels by hydrogenation of carbon dioxide and nitrogen, upgradation of hydrocarbons, or dehydrogenation reactions. However, the development of P-SOC is quite challenging because it requires a multifront optimization in terms of material synthesis and fabrication procedures. Herein, we report in detail a method to overcome various fabrication challenges for the development of efficient and robust electrode-supported P-SOCs (Ni-BCZY/BCZY/Ni-BCZY) based on a BaCe0.2Zr0.7Y0.1O3−δ (BCZY271) electrolyte. We examined the effect of pore formers on the porosity of the Ni-BCZY support electrode, various electrolyte deposition techniques (spray, spin, and vacuum-assisted), and thermal treatments for developing robust and flat half-cells. Half-cells containing a thin (10–12 μm) pinhole-free electrolyte layer were completed by a screen-printed Ni-BCZY electrode and evaluated as an electrochemical hydrogen pump to access the functionality. The P-SOCs are found to show a current density ranging from 150 to 525 mA cm–2 at 1 V over an operating temperature range of 350–450 °C. The faradaic efficiency of the P-SOCs as well as their stability were also evaluated.

Recycling of sewage sludge in clay-free thermal insulation brick: assessment of microstructure, performance, and environment impact.

Recycling municipal sewage sludge in fired bricks not only contributes to environmental protection, but is also an alternative to natural clay resource. The complex compositions of sludge have a great influence on the brick property. This work presents a systematical investigation on fired bricks made only with sludge and shale. The physicochemical properties of the raw mixtures, macroscopic performance, microstructure, and its evolution were quantitatively determined. The coordination between shale and sludge enables the blend of raw materials to achieve the desired gradation and plasticity. Although a reduction in compressive strength was observed, the open porosity was increased to 31.6% and thermal conductivity was reduced to 0.51W·(m·K)-1, indicating the benefit to the performance of lightweight thermal insulation bricks. The fitting results confirm the pore-forming effect induced by the organic matter in the sludge. The obtained bricks possess good performance, especially in thermal insulation properties, and environmental and economic benefits.

Research on performance optimization of Loess-based ceramic membrane supports with Bauxite-dolomite-talc as additives

Inorganic ceramic membranes have attracted much attention due to their advantages of long life, acid and alkali corrosion resistance, and easy cleaning, but they have not been widely used due to the high cost. In order to obtain a ceramic membrane with low cost and good performance, in this paper, loess-based ceramic membrane support was prepared by using loess as raw material, bauxite as aluminum source, dolomite as pore-forming agent and talc as plasticizer. Response surface optimization was used to determine the optimal addition parameters of ingredients. In addition, the factors affecting the performance of the supports were analyzed in terms of material composition, microscopic morphology, and porosity. The results show that the addition of talc conduced to avoid the negative impact of the pore-forming effect of dolomite on the mechanical strength of the support, and the optimum proportioning parameters are 48.85 wt% of bauxite, 9.93 wt% of dolomite and 8 wt% of talc. Under this condition, the bending strength was 42.24 MPa, the pure water flux was 8323.73 l·m−2·h−1·MPa−1, and the average pore throat radius was 5.15 μm. The performance of the best sample reaches the application performance of porous ceramic supports, which provides a theoretical basis for the wide application of low-cost ceramic membrane supports.

Efficient removal of Cd(II) by phosphate-modified biochars derived from apple tree branches: Processes, mechanisms, and application

Phosphate (P)-modified biochar is a good material for cadmium (Cd) immobilization, and the pore-forming effect of potassium ions (K+) can favor the P loading on biochar. However, few studies have been done specifically on Cd(II) removal by composites of potassium phosphates with biochar, and the removal potential and mechanisms are not clear. Herein, apple tree branches, a major agricultural waste suitable for the development of porous materials, were pyrolyzed individually or together with KH2PO4, K2HPO4·3H2O, or K3PO4·3H2O to obtain biochars to remove Cd(II), denoted as pristine BC, BC-1, BC-2, and BC-3, respectively. The results showed that the orthophosphates containing more K+ enlarged the specific surface area, total pore volume and phosphorus loading of biochar. Co-pyrolysis of apple tree branches and P promoted the thermochemical transformation of P species. Only weak signal of orthophosphate was observed in the pristine BC, while the presence of orthophosphate, pyrophosphate and metaphosphate were detected in BC-1, and BC-2 and BC-3 showed the presence of orthophosphate and pyrophosphate. The maximum Cd(II) adsorption capacities of pristine BC, BC-1, BC-2 and BC-3 were 10.4, 88.5, 95.8, and 116 mg·g−1, respectively. Orthophosphate modification enhanced the Cd(II) adsorption capacity due to the formation of Cd-P-precipitates, namely Cd5(PO4)3Cl, Cd5(PO4)3OH, Cd3(PO4)2, Cd2P2O7, and Cd(PO3)2. Furthermore, higher cation exchange efficiencies between Cd(II) and K+ in P-modified biochars also contributed to their high Cd(II) adsorption capacity. Cd(II) removal by BC-3 from artificially polluted water bodies showed more than 99.98% removal rates. Application of BC-3 also reduced the diethylene triamine pentaacetic acid-extracted Cd(II) in soil by 69.1%. The co-pyrolysis of apple tree branches and potassium phosphates shows great prospect in Cd(II) wastewater/soil treatment and provide a promising solution for agricultural waste utilization and carbon sequestration.

Highly porous building ceramics based on «clay-ash microspheres» and «zeolite-ash microspheres» mixtures

The possibility of obtaining highly porous heat-insulating ceramic materials based on compositions of mineral binding components (clay and zeolite rock) with ash-containing waste from the combustion of solid fuel (ash microspheres) is considered.It has been established that the pore-forming effect of ash microspheres in mixtures with low-melting clay is due to both the porous macrostructure of the ash component (the presence of hollow spherical particles) and the nature of physicochemical processes in the “clay – ash microspheres” and “zeolite – ash microspheres” systems (the synthesis of anorthite and mullite proceeding with an increase in molar volume).The creation of highly porous ceramic structures from mixtures of ash microspheres with zeolite rock, in addition to the structural features of microspheres, is also due to the structural (channel) porosity of zeolite minerals. The established pore-forming effect of zeolite rock and ash microspheres made it possible to develop a method for preparing a semi-dry masses from these compositions and to propose a technological scheme for obtaining a highly porous ceramic brick.The use of zeolite rock as a binder in a mixture with ash microspheres in content up 60–95 wt%, modified with zeolite-lignosulfonate slip, makes it possible to obtain a highly efficient constraction and thermal insulation ceramic brick with a compressive strength of 18–30 MPa, volume weight 930–1100 kg/m3 and thermal conductivity 0.22–0.31 W/m·K at a firing temperature of 950–1000 °C.

Zwitterionic Polysulfone Copolymer/Polysulfone Blended Ultrafiltration Membranes with Excellent Thermostability and Antifouling Properties.

Membrane fouling has been one of the most important challenges in membrane separation operations. In this study, we report a facile strategy to prepare antifouling polysulfone (PSf) UF membranes by blending amphiphilic zwitterion polysulfone-co-sulfobetaine polysulfone (PSf-co-SBPSf) copolymer. The copolymer chemical structure was characterized by 1HNMR spectroscopy. The PSf/PSf-co-SBPSf blend membranes with various zwitterionic SBPSf segment contents exhibited better surface hydrophilicity and excellent antifouling ability compared to PSf and PSf/PEG membranes. The significant increase of both porosity and water permeance indicates that the PSf-co-SBPSf has a pore-forming effect. The pure water flux and flux recovery ratio of the PSf/PSf-co-SBPSf blend membranes were both remarked to improve 286.43 L/m2h and 92.26%, while bovine serum albumin (BSA) rejection remained at a high level (97.66%). More importantly, the water flux and BSA rejection see minimal variance after heat treatment, indicating excellent thermostability. Overall, the PSf/PSf-co-SBPSf blend membranes achieved a comprehensive performance of sustainable hydrophilic, high permeation flux, and remarkable antifouling ability, thus becoming a promising candidate in high-temperature separation application.

Tailoring Release Profiles of BCS Class II Drugs Using Controlled Release Amorphous Solid Dispersion Beads with Membrane-Reservoir Design: Effect of Pore Former and Coating Levels.

Poor aqueous solubility is a major limiting factor during the development of BCS Class II drug candidates in a solid oral dosage form. Conventional amorphous solid dispersion (ASD) systems focus on maximizing the rate and extent of release by employing water-soluble polymeric crystallization inhibitors; however, they often encounter rapid supersaturation and solution-mediated phase transformation (SMPT). Therefore, in this work, a controlled release membrane was introduced onto ASD beads to mitigate the SMPT problem. A membrane-reservoir controlled release amorphous solid dispersion (CRASD) bead system was designed, and the effects of the coating thickness and pore former content on drug release profiles were investigated. CRASD beads were manufactured by spray-coating polyvinyl acetate with polyvinylpyrollidone (PVP) as a pore former onto sugar bead substrates layered with the ASD reservoir of celecoxib and PVP. Raising the pore former content and/or lowering the coating level imparted higher release rates and supersaturation levels. The extent of release, measured by the area under the curve, was greatest when an optimal balance between the release rate and peak concentration could be established, corresponding to a high pore former/high coating level combination. Attributed to a thicker membrane structure with a higher pore former, rapid initial release could be achieved, yet controlled gradually for several hours, avoiding the critical threshold where the onset of SMPT predominates. The greater membrane capacity to transiently immobilize drug molecules (i.e., preserve amorphicity) and gradually release drug over a prolonged duration may be key to balancing supersaturation on both sides of the membrane; hence coating variables should be tactfully selected to exploit this benefit.

Three-dimensional hierarchical porous carbon derived from resorcinol formaldehyde-zinc tatrate/poly(styrene-maleic anhydride) for high performance supercapacitor electrode

Herein, we propose a three-dimensional hierarchical porous carbon (THPC) derived from interpenetrating polymer networks (IPNs) of resorcinol formaldehyde-zinc tartrate and poly(styrene-maleic anhydride) (RF-Zn/PSMA), which was prepared via a gel swelling method. The three-dimensional hierarchical and interconnected pore structure involving micro-, meso- and macropores benefits from the synergistic pore-forming effect of PSMA pyrolysis and zinc tartrate decomposition during carbonization process. A high specific surface area of 742 m2 g−1 together with a cheese-like morphology was found for obtained THPC, exhibiting a high specific capacitance of 235 F g−1 at 1 A g−1 in 6 M KOH. THPC assembled symmetrical supercapacitor using 6 M KOH and 1 M Na2SO4 as electrolytes deliver energy outputs of 6.47 and 15.3 Wh kg−1 at 100 and 180 W kg−1, respectively. More attractively, the assembled supercapacitor based on the THPC achieves a high energy outputs of 50.45 Wh kg−1 at 350 W kg−1 in EMIMBF4 under wide potential window of 3.5 V, indicating its practical application prospect. Our findings open up new playgrounds for the design and electrochemical application of hierarchical porous carbon using IPNs as precursor.

Impact on Anode Performance of Lithium-Ion Batteries by Deep Cryogenic Treated SnSb/C Nanofiber Derived From Inorganic Precursors

Abstract The major obstacle prohibiting the practical application of Sn-based anodes is drastic volume variation during cycling processes. Here, polyacrylonitrile (PAN) was acted as a carbon source, and stannic chloride pentahydrate (SnCl4·5H2O) and antimony chloride (SbCl3) were used as SnSb precursors. SnSb/C nanofibers were prepared via simple electrospinning, deep cryogenic treatment, and carbonization, and it is applied in anode materials for lithium-ion batteries (LIBs) to achieve excellent cycle performance (115.5% capacity retention for 100 cycles). The improvement of electrochemical performance is mainly attributed to the synergistic effect of deep cryogenic treated special SnSb/C nanofibers precursor. In the deep cryogenic treatment process, the crystalline water in the precursor has a pore-forming effect, and the porous nanofiber structure leads to the phenomenon of capacity increase. The above results indicate that comprehensive consideration of deep cryogenic treatment and nanofiber precursors is a new idea to enhance the electrochemical performance of LIBs anode materials.

Polyaniline–poly(styrene sulfonate) hydrogel derived hierarchically porous N, S-codoped carbon for high-performance supercapacitors

On account of the limited energy density of carbon-based supercapacitors, the heteroatom-doped carbons with hierarchically porous structure are extensively developed. Unfortunately, the facile synthesis remains a huge challenge. Herein, a hierarchically porous N, S-codoped carbon is prepared by carbonizing the conducting polymer hydrogel of polyaniline–poly(styrene sulfonate) (PANI–PSS), in which the PANI and PSS act as nitrogen and sulfur sources, respectively. Owing to inherent porous structure of hydrogel, and the pore-forming effects of Na+ ions and the inorganic byproducts, the resultant carbons exhibit ideal hierarchically porous structure with high specific surface area. The electrochemical performance is investigated by using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge, and the results show that the product prepared at 750 °C (NSC-750) exhibits the highest specific capacitance (376 F g−1 at 0.5 A g−1), and the smallest inner impedance, originating from its highest specific surface area (755 m2 g−1) and moderate doping of heteroatoms. The feasibility of product is demonstrated by the NSC-750 symmetric supercapacitor, which delivered high energy density of 11.7 Wh kg−1 with a power density of 250 W kg−1. The hydrogel-derived hierarchically porous N, S-codoped carbon with superior electrochemical performance highlights a facile and feasible pathway to synthesize high-performance carbons for supercapacitors.

Green and stable piezoresistive pressure sensor based on lignin-silver hybrid nanoparticles/polyvinyl alcohol hydrogel

Hydrogel-based piezoresistive sensors have high practical value in many revolutionary applications, such as intelligent and electronic devices. However, with existing hydrogels, it is very difficult to achieve a combination of good mechanical properties, stable conductivity, and simple/green fabrication method. In this study, hybrid organic-inorganic nanoparticles (lignin-silver hybrid nanoparticles, Lig-Ag NPs) were synthesized by using alkaline lignin as the organic component and silver nanoparticle (Ag NPs) as the inorganic component. Interaction between the lignin and Ag NPs leads to the composite of hybrid nanoparticles that not only decreased the release of Ag NPs but also generated dynamically stable semi-quinone radicals in lignin. After compositing with polyvinyl alcohol (PVA) matrix, Lig-Ag NPs provided strong sacrificial hydrogen bonds and facilitated the delivery of electronic. Benefiting from these structural features and the pore-forming effect of ammonia (from Lig-Ag NPs solution), the PVA/Lig-Ag NPs hydrogel exhibits outstanding compressibility, pressure sensitivity, and stability of signal response. This study provides a green and simple design strategy for piezoresistive pressure sensors based on nanocomposite hydrogel.

Mammalian histones facilitate antimicrobial synergy by disrupting the bacterial proton gradient and chromosome organization

First proposed as antimicrobial agents, histones were later recognized for their role in condensing chromosomes. Histone antimicrobial activity has been reported in innate immune responses. However, how histones kill bacteria has remained elusive. The co-localization of histones with antimicrobial peptides (AMPs) in immune cells suggests that histones may be part of a larger antimicrobial mechanism in vivo. Here we report that histone H2A enters E. coli and S. aureus through membrane pores formed by the AMPs LL-37 and magainin-2. H2A enhances AMP-induced pores, depolarizes the bacterial membrane potential, and impairs membrane recovery. Inside the cytoplasm, H2A reorganizes bacterial chromosomal DNA and inhibits global transcription. Whereas bacteria recover from the pore-forming effects of LL-37, the concomitant effects of H2A and LL-37 are irrecoverable. Their combination constitutes a positive feedback loop that exponentially amplifies their antimicrobial activities, causing antimicrobial synergy. More generally, treatment with H2A and the pore-forming antibiotic polymyxin B completely eradicates bacterial growth.

Effect of Pore Former on Carbon Black–Polytetrafluoroethylene‐Based Monolithic Gas Diffusion Media for Proton Exchange Membrane Fuel Cells

Herein, carbon fiber gas diffusion media are replaced by carbon black (CB) and polytetrafluoroethylene (PTFE) composite diffusion media. Uniformly thick monolithic layers are synthesized by a novel die‐cast process. They are evaluated for electrical conductivity, contact resistance, hydrophobicity, porosity, and mechanical integrity. Monolithic layers possess combined properties of a microporous layer and gas diffusion layer with a mixed tri‐modal pore structure. The monolithic layers are further improved by inducing pores with pore formers. These layers are characterized for use in proton exchange membrane fuel cells. Pore formers increase the porosity and pore volume, and their effects on performance are revealed. The effect of porous structure on catalyst utilization is assessed by cyclic voltammetry. The power density of monolithic layers is on par with standard layers, whereas the pore‐induced monolithic layers achieve 27% higher power density compared with standard layers. The synthesized composite gas diffusion media are significantly insensitive to changes in humidity and represent an excellent alternative for use in fuel cells.

Lignin-based multi-channels carbon nanofibers @ SnO2 nanocomposites for high-performance supercapacitors

The lignin-based multi-channels carbon nanofibers (MCNFs) @ SnO2 nanocomposites with various microstructures are synthesized via co-electrospinning by regarding Poly (vinyl pyrrolidone) (PVP)–SnCl2·2H2O as shell materials and lignin-Poly (methyl methacrylate) (PMMA) at different mass ratios as core materials, followed by heat treatment and acid treatment. The experimental results show that when the mass ration of lignin to PMMA in the core region is 5:5, the obtained nanocomposites possess hierarchical internal channels, porous surface, and high specific surface area. This optimized nanocomposite as supercapacitor electrode shows high specific capacitance of 406 F g−1 at current density of 0.5 A g−1. In addition, the electrode exhibits unexceptionable cycling stability with only 5% capacitance decay over 10 000 cycles at 10 A g−1. Furthermore, the symmetric supercapacitor using the optimized nanocomposites as electrodes possesses remarkable power and energy densities. The superior electrochemical performance of nanocomposites is benefited from the hierarchical structures of MCNFs, faradaic pseudocapacitance of SnO2, and pore-forming effect of SnCl2·2H2O. The unique hierarchical nanocomposites show great potential in future development of lignin-based low-cost, non-toxic and eco-friendly carbon materials for high-performance energy storage devices.