Journal of Porous Materials最新文献

A series of binder-free MCM-22 zeolite catalysts were synthesized within 60 h using a vapor-phase transport (VPT) method, employing MCM-22 precursors prepared via hydrothermal crystallization as seeds. The synthesized zeolites were systematically investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier-transform infrared spectra (FT-IR), ²⁷Al magic angle spinning nuclear magnetic resonance (MAS NMR), N₂ adsorption–desorption, temperature-programmed desorption of ammonia (NH₃-TPD), and X-ray fluorescence (XRF) techniques. The results demonstrated that the addition of precursor seeds (PS) with crystallization time of 36, 48, 60, and 72 h significantly modified the crystal morphologies and improved pore structures and acidic properties of the final products compared to which was synthesized with conventional calcined seed. Specifically, the binder-free MCM-22, PS of which was crystallized for 48 h, exhibited the largest specific surface area, pore volume, and the highest acid site density, leading to superior activity and selectivity in the alkylation of benzene with benzyl alcohol. Furthermore, XRD, FT-IR, SEM, and thermogravimetric analysis (TGA) of PS provided insights into the possible mechanism for the highly efficient synthesis of binder-free MCM-22 zeolites. This work provided a novel and efficient approach for the synthesis of binder-free MCM-22 zeolites, showing potential applications in catalyst industry.

To enhance the thermal stability of SiO₂ aerogels at high temperature, this study proposes a method involving the incorporation of MgAl₂O₄ nanoparticles into SiO₂ aerogels to improve their high-temperature stability. By comparing the performance of MgAl₂O₄-SiO₂ aerogel with pure SiO₂ aerogels after heat treatment at high temperatures, it is demonstrated that the MgAl₂O₄ nanoparticles significantly enhances the thermal stability of SiO₂ aerogels at elevated temperatures while almost no effect on thermal conductivity, about 0.0312 and 0.0322 W/(m·K). The MgAl₂O₄-SiO₂ aerogels exhibit superior thermal stability and insulation performance compared to pure SiO₂ aerogels at temperatures exceeding 800 ℃. Notably, even after heat treatment at 1100℃, a condition that causes pure SiO₂ aerogels to nearly lose their porous structure, the MgAl₂O₄-SiO₂ aerogels retain a specific surface area of 81.95 m²/g and thermal conductivity of 0.0584 W/(m·K).

A zirconium imidazole propyl sulfonate (Zr-HIMPs) catalyst was synthesized for the catalytic transfer hydrogenation of furfuryl alcohol (FA) to ethyl levulinate (EL). Under optimized conditions (120 °C, 2 h, 0.2 mmol of Zr-HIMPs catalyst), the reaction achieved 95.03% conversion of furfuryl alcohol (FA) and 92.02% yield of ethyl levulinate (EL), with no significant improvement observed upon further increasing the catalyst loading. The catalyst demonstrated excellent reusability over four cycles with minimal activity loss. Characterization techniques confirmed its structural stability and high density of acid-base pairs, which synergistically enhanced catalytic performance. A plausible reaction pathway was proposed to elucidate the mechanism.

The interfacial chemical bonding strategy has been proposed by utilizing the expanded graphite (EG) as substrate to overcome the inherent low conductivity of covalent organic frameworks (COFs) in supercapacitor in this work. A redox-active COF material grows in situ on the EG surface through a solvent-free synthesis method, successfully constructing a novel layered porous EG@COF composite. Analysis results of BET, XPS and resistivity of materials demonstrate that the EG@COF not only preserves the intrinsic high specific surface area of COFs, but also effectively reduces interfacial contact resistance via amidation reaction, significantly enhancing charge transfer efficiency. Electrochemical studies reveal that the optimized EG@COF-3 electrode has a high specific capacitance of 501 F g^− 1 at 1 A g^− 1, with 92.3% capacity retention after 10,000 cycles, demonstrating a good cycling stability. Furthermore, the assembled EG@COF//AC asymmetric supercapacitor achieves an energy density of 16.4 Wh kg^− 1 at a power density of 806.0 W kg^− 1. This work provides an effective solution to improve the conductivity of COF materials.

The usual synthesis of face-centered cubic FDU- 12 mesoporous silica reported in the literature does not mention the role of some experimental conditions that govern its structural and textural properties. In particular, the order of introducing the silica source into the reaction medium, the closing of the recipient setup, the concentration of the swelling agent, as well as the more researched influence of heat treatment on the material characteristics. In this study, the results indicated that the homogenization of F127 and TMB is essential before the introduction of TEOS into the reaction chamber to obtain a more ordered porous structure. This, together with maintaining the nominal concentrations of all chemical compounds by properly isolating the reaction chamber from the outside atmosphere, was crucial. The evaluation of TMB concentration revealed that the increase of TMB resulted in increased surface area, pore volume, and size, leading to entrance pores of different sizes, related to different amounts of TMB inside the F127 micelles. The best structural/textural results were achieved by a hydrothermal treatment (HT) of 100 °C, while higher HT increased pores sizes, but it raised disorder. Finally, the papain incorporation in the silica matrix preserved its catalytic properties and induced better catalytic activity, with around 42% higher efficiency than the isolated enzyme. The evaluation of papain delivery showed rapid release within one hour, followed by a slow, continuous release over time, finishing in 1 h.

Catalytic desulfurization study in concentrated liquid waste of herbal decoctions has attracted more and more attention for meeting the stringent waste water discharge standards but remains a challenge that the catalysts are effectiveness for sulfur-containing organic compound and inorganic compound at the same time. Benzothiophene (BT) was chosen as the simulated compound for sulfur-containing organic, and Na₂S was chosen as the simulated compound for sulfur-containing inorganic. The high total sulfur removal was achieved by investigating a new kind of framework-substituted Mn-TiNTs catalyst. The desulfurization rate nearly 90% was found in complex concentrated liquid waste of herbal decoctions under the optimum condition. Additionally, the mechanism of oxidative desulfurization over Mn-doped skeleton heteroatom titanium nanotubes was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

The micro-mesoporous support was prepared by sequential desilication-dealumination of ZSM-5/Al₂O₃ pellets. The Pt–Mo catalyst doped with Sn and Zn (Pt–Mo/ZSM-5/Al₂O₃) was synthesized by wetness co-impregnation technique with aqueous solutions of metal salts to load 0.5% Pt, 2.0% Mo, 0.05% Sn and 0.5% Zn. A comprehensive analysis with XRD, TEM, N₂ physisorption, NH₃-TPD and XRF was performed to characterize the resulting samples. The Pt–Mo/ZSM-5/Al₂O₃ catalyst was investigated in isomerization of an industrial C₈ aromatic fraction with the commercial catalyst as a counterpart. The catalytic activity was evaluated in the temperature range of 360–400 °C, varying LHSV from 4 to 6 h⁻¹, at H₂ pressure of 1.0–1.5 MPa and hydrogen/feedstock volume ratio of 720 nl/l. The best results were achieved at 360℃, P = 1.0 MPa and LHSV = 4 h⁻¹ for the Pt–Mo/ZSM-5/Al₂O₃ catalyst: p-xylene/xylenes ratio = 23.9%, xylene loss = 0.4%, ethylbenzene conversion = 66.2%.

Polystyrene (PS) does not contain polar groups and atoms in its molecular structure, so it has the application prospect of preparing hydrophobic or super-hydrophobic materials. However, the common film-making method limits the application of polystyrene films in hydrophobic materials. In this paper, the ultra-high molecular weight polystyrene was prepared by emulsion polymerization at room temperature, and then the porous polystyrene fiber membrane was prepared by microfluidic nano blow spinning technology. The effects of the type of solvent and the concentration of spinning solution on the mechanical properties and hydrophobic properties of the polystyrene porous fiber film were investigated, and compared with that of general-purpose polystyrene fiber film. The results show that when dichloromethane (DCM) is used as the solvent of spinning solution, the obtained ultra-high molecular weight polystyrene fiber film has the porous structure and the best mechanical properties. The tensile strength is 0.94 MPa, which is 5.9 times that of the general-purpose polystyrene fiber film (0.16 MPa). The elongation at break is 83.1%, which is 32 times that of the general-purpose polystyrene fiber film (2.6%). At the same time, the ultra-high molecular weight polystyrene fiber film prepared under this condition also has certain hydrophobic properties (water contact Angle is 117° > 90°).

Adenanthera pavonina shells (APS), a commonly discarded biomass, were converted into activated carbon (AC) through KOH activation to introduce porosity, followed by carbonization at varying temperatures (600 °C, 700 °C, and 800 °C) under a nitrogen atmosphere. The resulting materials exhibited an amorphous carbon framework with a hierarchically porous structure, predominantly consisting of micropores and mesopores optimized for electrochemical performance. BET (Brunauer–Emmett–Teller) analysis revealed a high specific surface area of 1698 m²/g, essential for ion transport and enhanced supercapacitor performance. Among the samples, the AC prepared at 700 °C (A700) demonstrated the highest specific capacitance of 141 F/g at 1 A/g, attributed to its optimal pore structure and increased interlayer spacing, facilitating improved electrolyte ion penetration. Symmetric supercapacitor cells fabricated with this material achieved an energy density of 6.2 Wh/kg at a power density of 500 W/kg, demonstrating excellent charge storage capability. The device retained 92.99% of its initial capacitance after 5000 cycles at 1 A/g, highlighting its durability with coulombic efficiency of 98%. This study highlights the potential of APS-derived AC as a low-cost, efficient material for supercapacitors, contributing to sustainable energy storage solutions.

A rapid preparation method for high performance nitrogen-rich mesoporous carbon materials based on chitosan (CS) was explored, and its application potential in chlorogenic acid (CGA) enrichment. The mesoporous carbon (MgO-CSMC) was prepared using CS as carbon and nitrogen sources, as well as MgO nanoparticles as template, for rapid and high-capacity enrichment of CGA. Structural and morphological characterization revealed that nano-sized MgO as a template facilitated the formation of abundant mesopores, endowing MgO-CSMC with an exceptionally high specific surface area (1948 m²/g) and significant nitrogen (3.6%) and oxygen (7.3%) content. The adsorption capacity of MgO-CSMC for CGA reached up to 652 mg/g, and rapid adsorption was achieved. The adsorption mechanism showed that the adsorption of the MgO-CSMC for CGA was mainly physical adsorption, conforming to the Langmuir isothermal adsorption model and pseudo-second-order kinetic model. In addition, the adsorption thermodynamic analysis indicated that the adsorption process of the MgO-CSMC for CGA was exothermic, reversible and spontaneous. This work provides a novel route for the preparation of high-performance nitrogen-rich mesoporous carbon materials and an efficient and sustainable solution for the separation and purification of bioactive ingredients.