Abundant Mesoporous Structure Research Articles

Silica-Modified Ordered Mesoporous Carbon for Optimized Impedance-Matching Characteristic Enabling Lightweight and Effective Microwave Absorbers.

Ordered mesoporous carbon (OMC) is considered to be a prospective carbon-based material for microwave absorption because of its abundant well-ordered mesoporous structures, high specific surface area, numerous active sites, and facile preparation process. However, its development has been seriously hindered by its poor impedance-matching characteristic. Herein, silica-modified OMC composites with a designable impedance-matching transition layer are successfully fabricated via a self-assembly method and succeeding calcination treatment. In addition, the silica in OMC@SiO2 composites can maintain the mesoporous structure, which facilitates the scattering and reflection of microwaves in the tunnel structure. The as-prepared sample OMC-5@SiO2 exhibits a minimum reflection loss (RL) value of -40.7 dB at 10.8 GHz with 2 mm and an effective absorption bandwidth (RL ≤ -10 dB) of 4.8 GHz with a thinner absorber thickness of 1.5 mm. We believe that the as-prepared OMC@SiO2 composites can be prospective candidates as high-efficiency and lightweight microwave absorbers.

Chitosan modified Ti-PILC supported PdOx catalysts for coupling reactions of aryl halides with terminal alkynes

Biopolymer of chitosan (CS) and titanium pillared clays (Ti-PILCs) have been combined in a hybrid as advanced supports for immobilization of PdOx=0,1 species to prepare novel PdOx=0,1@Ti-PILC/CS nano-composite catalysts. The Ti-PILC materials showed high specific surface areas and abundant meso-porous structure with many irregular pore channels caused by collapses of layered structure of clay during Ti pillaring process. Both CS chains and sub-nano sized PdOx particles were successfully incorporated into the pore channels of Ti-PILC, resulting in a decrease in both the specific surface areas and uniform distribution of pore size. Besides conventional methods characterizations, the strong interactions between PdOx species and Ti-PILC/CS support were further evidenced with positron annihilation lifetime spectroscopy studies. The resultant PdOx@Ti-PILC/CS catalyst was highly active for the coupling reactions of aryl halides with phenyl acetylenes. It was recyclable and gave excellent yield up to 13 runs with low leaching of Pd species.

MnO2/rGO/CNTs Framework as a Sulfur Host for High-Performance Li-S Batteries.

Lithium-sulfur batteries are very promising next-generation energy storage batteries due to their high theoretical specific capacity. However, the shuttle effect of lithium-sulfur batteries is one of the important bottlenecks that limits its rapid development. Herein, physical and chemical dual adsorption of lithium polysulfides are achieved by designing a novel framework structure consisting of MnO2, reduced graphene oxide (rGO), and carbon nanotubes (CNTs). The framework-structure composite of MnO2/rGO/CNTs is prepared by a simple hydrothermal method. The framework exhibits a uniform and abundant mesoporous structure (concentrating in ~12 nm). MnO2 is an α phase structure and the α-MnO2 also has a significant effect on the adsorption of lithium polysulfides. The rGO and CNTs provide a good physical adsorption interaction and good electronic conductivity for the dissolved polysulfides. As a result, the MnO2/rGO/CNTs/S cathode delivered a high initial capacity of 1201 mAh g−1 at 0.2 C. The average capacities were 916 mAh g−1, 736 mAh g−1, and 547 mAh g−1 at the current densities of 0.5 C, 1 C, and 2 C, respectively. In addition, when tested at 0.5 C, the MnO2/rGO/CNTs/S exhibited a high initial capacity of 1010 mAh g−1 and achieved 780 mAh g−1 after 200 cycles, with a low capacity decay rate of 0.11% per cycle. This framework-structure composite provides a simple way to improve the electrochemical performance of Li-S batteries.

Unique hollow-concave CoMoSx boxes with abundant mesoporous structure for high-performance hybrid supercapacitors

Unique hollow-concave CoMoSx boxes with abundant mesoporous structure are designed and constructed via a low-temperature calcination treatment followed by a hydrothermal process. Morphological observations show that the highly uniform and monodisperse hollow-concave CoMoSx boxes have an average size of approximately 410 nm. It is found that the hollow-concave structure of CoMoSx boxes can provide a large surface area and more active sites for the electrochemical reactions at the electrode/electrolyte interface, while reduce the volume of the inert inner cavities as well, achieving a maximum capacity of CoMoSx (784 C g−1 at a current density of 1 A g−1). Moreover, the distinctive hollow-concave structure can offer a buffer to accommodate the volume expansion/contraction of CoMoSx, thus leading to an excellent cycling stability. The CoMoSx//AC asymmetric supercapacitor device is assembled and delivers a maximum energy density of 36.9 Wh kg−1 at a power density of 0.8 kW kg−1.

The Synthesis of Mesoporous TS-1 and Its Performance for Oxidation of Diphenyl Sulfide and Dibenzyl Sulfide

TS-1 zeolite has outstanding performance in the catalytic reactions with hydrogen peroxide as catalytic promoter. However, the narrow pore size (< 1.0 nm) of traditional TS-1 makes it difficult for bulky organic compounds to contact with the active sites in the pores, which seriously limits application of TS-1. Recently, the introduction of mesoporous structure into microporous TS-1 becomes a hot research topic. Meanwhile, the huge synthesis cost of TS-1 is another main reason hindering its industrial application. In this paper, mesoporous TS-1 was successfully synthesized using sodium silicate as silicon source and titanium trichloride as titanium source under the template conditions of tetrapropylammonium hydroxide (TPAOH) and cationic polymer. The mesoporous TS-1 was characterized by X-ray diffraction (XRD), N2 adsorption, scanning electric microscopy (SEM), transmitting electric microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis Spectrum spectra (UV-Vis). Results show that the synthesized TS-1 zeolites have good crystallinity and tetra-coordinated framework Ti atoms, and there are abundant mesoporous structures in the zeolite crystals. The results of oxidation experiments show that conversion of diphenyl sulfide and dibenzyl sulfide with mesoporous TS-1 are 97.3 % and 85.3 % respectively, while that conversion with microporous TS-1 are 75.7 % and 63.5 respectively.

Sea urchin-like Co3O4@Pd Nanoneedles with 3D open-structured matrix as efficient catalytic cathode for Li-O2 batteries

In this study, both morphology-related factors and catalytic activity factors were taken into account simultaneously and sea urchin-like Co3O4 nanoneedles grown on nickel foam were synthesized via a facile hydrothermal strategy (grass-like Co3O4 were also prepared for comparison). Most noteworthy is that 3D open-structured sea urchin-like Co3O4 exposing more Co3+ sites with large specific surface area and abundant mesoporous structure exhibited superior electrocatalytic performance as compared to 1D structured grass-like Co3O4 and former reported 3D structured electrodes (i.e., urchin shaped, flower shaped). Pd decorated sea urchin-like Co3O4 was also prepared through a simple impregnationmethod. When served as binder/carbon-free catalytic cathode for Li-O2 batteries, the problems about limited capacity, large overpotential and poor cycle life were effectively improved. The catalytic electrode displayed a low overpotential of 1.12 V, high specific capacity (8819.2 mA h g−1) at a current density of 200 mA g−1 and long cycle life with the capacity limited at 500, 1500, 2500, even 3500 mA h g−1, overmatching most of the transition-metal-oxides based catalytic electrodes, which are intrinsically dependent on the characteristic design in both morphology and catalytic active sites of the electrodes.

Synthesis and application of acrylate copolymer as high ink-absorption and fast drying coating agent for polyester fabric

A series of acrylate-based coating agents with high ink-absorption and fast drying properties (MBAH) were achieved by emulsion copolymerization with methyl methacrylate (MMA), butyl acrylate (BA), allyl polyethylene glycol (APEG) and hydroxyethyl methacrylate (HEMA). The effect of hydrophilic APEG dose on MBAH performances was discussed and analyzed emphatically. Then the chemical structure and particle morphology of MBAH emulsion were characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM), respectively. The results of Brurauer-Emmerr-Teller (BET) test revealed the existence of abundant micropores and mesoporous structures in MBAH film. Afterwards, MBAH as a finishing agent was coated on polyester fabric. The ink-absorption performances of MBAH on polyester fabrics were comprehensively characterized by ink-drying time, K/S value and ink-absorption rate, which indicated that when the APEG dose was 7 wt% of the total monomers, MBAH exhibited excellent ink-absorption property. The ink-drying times and K/S values of three color inks (Red, Blue and Black) on MBAH coated fabrics were 6 s, 7 s, 9 s, and 8.5, 10.9, 19.8, respectively and the ink-absorption rate of Black ink on MBAH coated polyester fabric was 53.2% at 24 h, suggesting that MBAH was far better than the traditional ink-absorption agent.

Manganese-based multi-oxide derived from spent ternary lithium-ions batteries as high-efficient catalyst for VOCs oxidation

Valuable metals such as manganese, cobalt, nickel and copper are recycled from spent ternary lithium-ions batteries (LiBs) and are considered as the active metal precursor to prepare based-manganese multi oxide for VOCs oxidation. The results of characterization analysis indicate that the catalyst from spent LiBs shows larger specific surface area of 26.80 m2/g as well as abundant mesoporous structures on the surface, higher molar ratio of Mn4+/Mn3+ (0.70) and Olatt/Oads (1.68), better low-temperature reductivity and stronger intensity of weak acid sites in comparison with those of pure manganese oxides. The evaluation experiments show that the catalyst from waste exhibits more excellent catalytic performance of toluene combustion in comparison with pure manganese oxides. Furthermore, the presence of considerable amount of lithium and aluminum ions can severely weaken the catalytic activity while the co-existence of nickel, cobalt and copper ions contribute a lot to facilitate the catalytic behavior. In-situ DRIFT study implies that the introduction of lithium, aluminum, nickel, copper and cobalt into pure manganese oxides can facilitate toluene conversion to various extents, following the consecutive steps via benzyl species, benzoyl oxide species, benzaldehyde species, benzoate species and the primary intermediates are benzoate species.

Nitrogen and oxygen co-doped ordered dual-mesoporous carbon for supercapacitors

Multi-element doped mesoporous carbon materials are considered as one of the most promising electrode materials for supercapacitors due to their large specific surface area, abundant mesoporous structure, heteroatom doping and good conductivity. Herein, the N, O co-doped ordered mesoporous carbon (N/O-OMC) were successfully prepared by the solid-solid grinding method using KIT-6 as template, Fe(NO3)3 as catalyst, and polyvinylpyrrolidone (PVP) as source of C, N, and O. The effect of PVP amount on the structural parameters of the sample was also discussed. The resulting N/O-OMC replicated the morphology of KIT-6 and showed suitable N and O doping, a large specific surface area and an ordered dual-mesoporous structure. As the electrode materials, N/O-OMC exhibit excellent specific capacitance of 229 F g−1 at 1 A g−1, excellent rate performance (79.5%) and cycle stability (92.3% after 5000 cycles). This multi-element doped mesoporous carbon material was proved a good candidate for high-performance electrode materials.

Hypercrosslinked mesoporous poly(ionic liquid)s with high density of ion pairs: Efficient adsorbents for Cr(VI) removal via ion-exchange

Ion-exchange is one of the most efficient methods for removal of water pollutants, like hexavalent chromium (Cr(VI)). Herein, we report the preparation and application of a family of hypercrosslinked imidazolium-based poly(ionic liquid)s (PILs) with different crosslinker lengths, ion contents, and textural properties. We discover the hypercrosslinking porous structure and the anion content (corresponding to the theoretical adsorption capacity) of PILs play decisive roles in their capture capacities towards Cr(VI). Among them, PVIm-6-SCD prepared by free-radical polymerization of monomer with higher anion content and subsequent supercritical CO2 drying (SCD) displays excellent textural properties such as abundant mesoporous structure, high surface area and large pore volume. It facilitates the exposure of high density of exchangeable Br− in PVIm-6-SCD, thereby speed up the mass transfer during ion-exchange for Cr(VI). It shows a high utilization of the adsorption sites (84.5%) and a very high Cr(VI) adsorption capacity (236.8 mg·g−1, 25 °C), which is much higher than those of the literature reported adsorbents. Remarkably, PVIm-6-SCD exhibits good selectivity for Cr(VI) in the presence of competing anions including chloride (Cl−), nitrate (NO3−), dihydrogen phosphate (H2PO4−), and sulphate (SO42−). Moreover, it is effective for Cr(VI) removal under a broad range of pH (2–12). Besides, it has good reusability, showing potential industrial application prospects. This work highlights the PILs with high density of ion pairs for application in wastewater treatment.

Scalable mesoporous silicon microparticles composed of interconnected nanoplates for superior lithium storage

Constructing micro-nano hierarchical porous structure is an effective strategy to solve key issues arising from the large volume change of silicon-based materials during cycling. Herein, we successfully obtain the mesoporous silicon microparticles composed of nanoplates driven from waste glass by the magnesiothermic reduction reaction. The two-dimensional nanoplates and abundant mesoporous structure in the microparticles not only effectively mitigate the mechanical strains caused by volume changes but also promote lithium ion diffusion. The silicon microparticles display outstanding lithium storage performance including extremely high first Coulombic efficiency (85.1%), remarkable reversible specific and volumetric capacities (1793 mAh g−1 and 747 mAh cm−3 after 120 cycles at 200 mA g−1, 1000 mAh g−1 after 360 cycles at 500 mA g−1) and impressive rate performance (1183.7 mA h g−1 at 1 A g−1). Simultaneously, the corresponding electrode exhibits significantly less impedance build-up and smaller electrode thickness increase than that of commercial silicon nanoparticles. Furthermore, the scalable and cost-effective method makes it an attractive candidate for next generation lithium ion batteries anode materials.

High electrical conductivity of 3D mesporous carbon nanocage as an efficient polysulfide buffer layer for high sulfur utilization in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries display a high theoretical energy density compared with commercial lithium-ion batteries (LIBs). However, there are several major challenges including the poor conductivity and large volumetric expansion of sulfur, and the shuttle effect and uncontrollable deposition of lithium polysulfides, which lead to the low sulfur utilization and poor cycle life in practical applications. The fabrication of state-of-the-art separator based on high electrical conductivity of 3D porous carbon is believed to restrain the shuttle effect of lithium polysulfides and control the deposition of lithium sulfide. Herein, we report a kind of 3D mesporous carbon nanocage (PCN) with a high electrical conductivity as an efficient polysulfide buffer layer on PP separator in Li-S batteries for high sulfur utilization. The extraordinary electrical conductivity of the 3D PCN can promote the transformation reaction of Li2S/sulfur-to-lithium polysulfides between PCN separators and sulfur cathode. During charge/discharge, PCN serves as a buffer layer to redistribute the shuttling back of LiPSs owing to its abundant mesoporous structure. Thereby, Li-S batteries using PCN separator shows an extraordinary initial discharge capacity of 1044 mAh g−1 which still remains 652 mAh g−1 after 200 cycles at 1C. This is a significantly boost for sulfur utilization compared with that in Li-S batteries using PP separator. In addition, the advanced Li-S batteries with PCN separators reveal a superior areal capacity (2.5 mAh cm−2) at a high sulfur loading amount of 7.34 mg cm−2, showing the potential in practical application.

Designing a hierarchical nanosheet ZSM-35 zeolite to realize more efficient ethanol synthesis from dimethyl ether and syngas

Abstract In this work, a dual-catalyst bed reactor packed with the combination of hierarchical nanosheet HZSM-35 (Hi-NZ35) zeolite and CuZnAl catalyst was proposed to realize more efficient ethanol synthesis from dimethyl ether (DME) and syngas (CO+H2). The nanosheet ZSM-35 (NZ35) zeolite was prepared via a direct hydrothermal synthesis route and the CuZnAl catalyst was prepared by co-precipitation method. Moreover, a series of Hi-NZ35x zeolites were obtained from NZ35 zeolite by further treatment with varied NaOH aqueous solution using hydrothermal process (“x” means the NaOH solution concentration of 0.2-0.6 M). The catalysts properties, such as crystallinity, porosity, acidity, morphology and composition, were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, NH3 temperature-programmed desorption (NH3-TPD), H2 temperature-programmed reduction (H2-TPR), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). It was found that Hi-NZ350.4 zeolite was more effective to obtain hierarchical porosity with mesopore volume up to 0.131 cm3 g−1. For single DME carbonylation reaction, the NZ35 zeolite exhibited superior catalytic activity (32.2%) and stability compared with conventional ZSM-35 (CZ35) zeolite. Furthermore, improved catalytic activity (42.0%) was observed on Hi-NZ350.4 zeolite owing to its abundant mesoporous structure. This result revealed that the hierarchical porosity of zeolite could effectively promote the catalytic performance of zeolite for DME carbonylation reaction. For the ethanol synthesis using the optimized catalysts combination of Hi-NZ350.4 zeolite and CuZnAl catalyst, the DME conversion was about 47.2% with higher ethanol productivity of 840.2 mmol kg−1 h−1.

Preparation and photocatalytic activity of Ag-modified GO-TiO2 mesocrystals under visible light irradiation

Nanosized metallic Ag particles modified graphene oxide-TiO2 mesocrystals (Ag/GO-TMCs) were successfully synthesized by photoreduction deposition method. The morphology, crystallization, structural features and chemical compositions of the as-prepared Ag/GO-TMCs catalysts were investigated using HRTEM, XRD, Raman spectra, XPS, UV–vis DRS, PLS, and N2 adsorption-desorption measurements. Ag nanoparticles were found to be evenly distributed on the surface of TiO2 mesocrystals (TMCs) and graphene oxide (GO). The Ag/GO-TMCs catalysts featured high crystallinity, abundant mesoporous structure, large surface area, and improved visible-light response. Photocatalytic applications of the catalysts for degradation of Rhodamine B (RhB) and dinitro butyl phenol (DNBP) under visible light irradiation were investigated. The results showed that the highly enhanced photocatalytic activity was obtained with Ag/GO-TMCs catalysts. The Ag/GO-TMCs photocatalyst with AgNO3/GO-TMCs mass ratio of 0.075:1 exhibited the highest photocatalytic degradation of RhB and DNBP under 3 h of visible light irradiation. The superior photocatalytic activity of Ag/GO-TMCs may be attributed to the higher visible-light absorbance ability and surface plasmon resonance (SPR) effect of Ag nanoparticles and GO. The Ag-GO/TMCs materials could be deemed as promising photocatalysts for organic contaminants removal under visible light irradiation, in assessing their high photocatalytic efficiency and good repeatability.

Bimetal-Organic Framework-Derived Porous Rodlike Cobalt/Nickel Nitride for All-pH Value Electrochemical Hydrogen Evolution.

Developing advanced hydrogen evolution reaction (HER) electrocatalysts is of great significance. Herein, we report porous rodlike cobalt-nickel bimetal nitrides (Co xNi yN) as high-efficiency HER electrocatalysts in a wide pH range through nitridation from a bimetal-organic framework (MOF-74) precursor. Thanks to collaborative superiorities of high surface areas, abundant mesoporous structure, perfect metal element dispersion, and electron modulation effect, the as-prepared Co xNi yN possess a superior catalytic ability toward HER at all pH values. In particular, the optimal Co2Ni1N requires overpotentials of 102.6 and 92.0 mV to afford a current density of 10 mA cm-2 in alkaline and acidic solution, respectively. In addition, it also presents favorable activity in neutral media and excellent stability under different pH conditions. The present study not only offers a strategy for the design and synthesis of porous bimetal nitrides derived from binuclear MOF but also brings up new avenues for the development of cost-effective and competent all-pH HER catalysts for renewable energy systems.

Improved electrocatalytic activity of δ-MnO2@MWCNTs by inducing the oriented growth of oxygen reduction products in Li-O2 batteries

The carbon supported composite catalysts for Li-O2 batteries with optimized structure seem attractive in terms of their advantages of electronic conductivity and light weight. In this work, a facial solvothermal method was employed to prepare the composite with 34 wt% δ-MnO2 wrapped on the surface of MWCNTs in form of monomolecular layer by the chemical binding (δ-MnO2@MWCNTs). The experimental results indicate that δ-MnO2@MWCNTs retains the high specific surface area and abundant mesoporous structure of MWCNTs. Moreover, the dominated (002) facet and abundant oxygen vacancies of the δ-MnO2 layer accelerate the adsorption of O2 and elongate the O-O bond, which promote the oxygen reduction reaction activity. In particular, the oriented growth of discharge products (Li2O2) forming flake- and flower-like depositions with an increase of DOD ensures the stable reaction zone in the cathode with sufficient charge transfer and oxygen diffusion channel. Therefore, the Li-O2 batteries with δ-MnO2@MWCNTs as cathode catalysts demonstrate the high discharge capacity of 28517 mA h g−1 with the voltage platform of 2.82 V in the initial discharge (100 mA g−1) and the excellent rate performance with 75% capacity retention at current density of 1000 mA g−1. Meanwhile, the δ-MnO2 @MWCNTs catalysts are of benefit to the excellent electrochemical reversibility with 190 cycles (100 mA g−1) and 20 cycles (1000 mA g−1) under a limited discharge depth of 1000 and even 4000 mA h g−1, respectively.

NiCo2S4 nanocores in-situ encapsulated in graphene sheets as anode materials for lithium-ion batteries

Bimetallic sulfides were extensively studied as an advanced electrode material for lithium-ion batteries because of their high conductivity and superior capacity compared to metal oxides. We herein have successfully fabricated ultrafine NiCo2S4 nanocores in-situ encapsulated in graphene sheets (NiCo2S4@GS) with three-dimensional porous network structures through a cation adsorption process and subsequent hydrothermal-annealing reaction. In the NiCo2S4@graphene sheets nanohybrids, graphene sheets with abundant mesoporous network structure can be served as a conductive matrix and also be a protective buffer layer to suppress the volume expansion of NiCo2S4 nanoparticles. The NiCo2S4@GS-1 electrodes deliver a high reversible capacity of 813 mAh g−1 upon 200 cycles at 0.2 A g−1, ultralong cycling life of 535 mAh g−1 upon 1000 cycles at 2 A g−1, and excellent rate capability. Additionally, the advanced button-type full batteries were assembled via coupling NiCo2S4@GS-1 anodes with commercial LiFePO4 cathodes showing superior cycle stability and practicability. This work points out an innovative and scalable strategy for preparing composite electrode materials for lithium-ion batteries.

Iron-doped ordered mesoporous Co3O4 activation of peroxymonosulfate for ciprofloxacin degradation: Performance, mechanism and degradation pathway

Ordered mesoporous Co3O4 (OM-Co3O4) displayed superior performance for peroxymonosulfate (PMS) activation. While, the separation and recovery of the catalyst after catalytic oxidation needed tedious operation. In this study, the as-synthesized iron-doped OM-Co3O4 not only inherited the merits of ordered mesoporous materials such as high surface area and abundant mesoporous structure, but endowed them with ferromagnetism, facilitating their separation from the solution. Compared with spinel Co3O4, iron-doped OM-Co3O4 showed superior catalytic activity, wide application scope, excellent reusability and long-term stability, fully validated that iron-doped OM-Co3O4 can be a promising heterogeneous PMS activator for environmental application. High catalyst loading and PMS concentration were both beneficial to CIP degradation. The best CIP degradation occurred under base conditions. Chlorine and bicarbonate presented completely opposite two-side effects. The mechanism of CIP degradation was primarily attributed to SO4− and OH to a lesser extent. The rapid redox cycles of M2+/M3+ (M = Co, Fe) and O2−/O2 ensured the continuous generation of reactive oxygen species and the efficient degradation of CIP. The cleavage of piperazine ring, hydroxylation and defluorination were identified as the main oxidation pathways for CIP degradation in iron-doped OM-Co3O4 activated PMS system.

Acidic ionic liquid-functionalized mesoporous melamine-formaldehyde polymer as heterogeneous catalyst for biodiesel production

Combination of multiple excellent characteristics, such as large surface area, strong acidity, high acid density and good dispersion of active sites, in a mesoporous solid acid catalyst is desirable for achieving superior catalytic activity in production of biodiesel but challenging. Herein, an acidic ionic liquid (IL)-functionalized mesoporous melamine-formaldehyde polymer (MMFP-IL) was prepared for the first time by quaternary ammonization of mesoporous nitrogen-rich melamine-formaldehyde polymer (MMFP) with 1,3-propanesultone, followed by treatment with H3PW12O40 (HPW). The MMFP, containing abundant aminal groups and triazine rings, could be facilely synthesized from lost-cost and readily available monomers (i.e., melamine and paraformaldehyde), which provides massive sites for immobilizing more IL and HPW via chemical post-modification method. The MMFP-IL catalyst was systematically characterized, which was revealed to possess unique and outstanding properties, including abundant mesoporous structures with high specific surface area (283.0 m2/g), high acid concentration (2.2 mmol/g), strong acidity and fine distribution of acid sites. These properties endowed MMFP-IL to have excellent activity in esterification of oleic acid with methanol to produce biodiesel under mild conditions, outperforming those of various solid acids (e.g., commercial strong acidic resins and HPW). In addition, the kinetics and thermodynamics of the reaction were investigated over the MMFP-IL catalyst. More importantly, the MMFP-IL catalyst was robust, heterogeneous, and recyclable without significant deactivation after four cycles, which is attributed to the immobilization of acidic ionic liquid onto the robust MMFP via strong covalent bond.

In-situ encapsulating FeS/Fe3C nanoparticles into nitrogen-sulfur dual-doped graphene networks for high-rate and ultra-stable lithium storage

A novel FeS/Fe3C nanoparticles encapsulated in porous nitrogen-sulfur dual-doped graphene network (FeS/Fe3C@NS-G) have been successfully fabricated via a one-step in-situ pyrolysis strategy. The nitrogen and sulfur co-doped graphene networks exhibited abundant mesoporous structure and excellent electrical conductivity, facilitating fast electron transport and lithium-ion diffusion. The heterogeneous FeS/Fe3C nanoparticles are homogeneously dispersed in the three-dimensional porous graphene shell with copious internal void space which can accommodate the volume change of the nanoparticles during electrochemical reaction. The FeS/Fe3C@NS-G nanohybrids delivered excellent reversible capacity of 1003 mAh g−1 after 150 cycles at 0.1 A g−1 with a minor capacity decay rate of 1.25%. Furthermore, an ultralong cycling stability of 610 mAh g−1 after 800 cycles at 1 A g−1 with the capacity retention of 91.6% relative to the reversible capacity of the second cycle was observed. This remarkable lithium storage capacity of FeS/Fe3C@NS-G networks reveals their promising potential as anode materials for lithium-ion batteries.