Journal of Porous Materials最新文献

Given the growing demand for nanoscale carbon materials, which possess adsorbent properties and are environmentally friendly, the present work introduces pectin as a new carbon source for synthesizing carbons mesostructured from Korea–3 (CMK-3) with a methodology designed according to the pectin characteristics. The paper presents a comparison between three samples according to their carbon source: (1) sucrose (CMK-3 SAC), (2) Sigma Aldrich analytical grade pectin (CMK-3 PEC-SA), and finally, (3) pectin extracted as agricultural residue from Golden Delicious apple (CMK-3 PEC-RA). The samples were characterized structural, morphological, and texturally by Fourier transform infrared (FTIR) and RAMAN spectroscopies, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ physisorption. Pectin structural characterizations allowed the establishment of optimal synthesis conditions. The results showed that CMK-3 synthesized using CMK-3 PEC-RA obtained superior values of specific surface area (1,534 m²/g), pore volume (1.3 m³/g) and mesopores diameters (4.5 nm) with arrangements of homogeneous nanopipes diameters of around 6.5 nm visualized with a fast Fourier transform (FFT) mask than the sample CMK-3-SAC. This fact indicates that using apple waste and its biopolymer pectin may be viable in developing CMK-3 mesoporous carbons with highly specific surface areas for fine chemical processes, considering the previous characterization and homogenization of apple waste.

Air pollution is a growing concern for the environment and public health, with particulate matter (PM) being a major contributor to adverse impacts. Filtration is a commonly used and efficient method for removing PM. However, creating a filter with good filtration efficiency using natural fibers is challenging. This research focuses on developing a porous filter based on cellulose fibers, enhanced with cationic starch (CST) and polyvinyl alcohol (PVA), and utilizing freeze drying. The findings reveal that the filter containing combination of CST and PVA significantly enhances the tensile index to 0.65. Notably, the optimized filters exhibit a high porosity of 96%. BET (Brunauer–Emmett–Teller) surface area and pore size of cellulose filters with CST and PVA were analyzed using the BET equation and Barrett–Joyner–Halenda (BJH) method, it shows BET surface area of 23.12 m²/g and nano-sized pores, which indicate their potential for effective PM capture while maintaining adequate airflow. The SEM images further illustrate the uniform pore structure, which contributes to the filter’s overall performance. The filter demonstrated PM filtration the highest removal rates of 90.27% for PM_2.5 and 99.58% for PM₁₀. The findings suggest that modifying air filters with CST and PVA additives can significantly enhance their effectiveness in capturing particulate matter while maintaining optimal airflow.

In the present work, we have developed a facile, environmentally friendly, and efficient method for one-pot synthesis of 1,4-dihydropyridine derivatives using CuCeO₂ NPs as a catalyst and ethanol as a solvent from dimedone, ammonium acetate, and various aldehydes. The porous and spherical CuCeO₂ NPs were synthesized using a simple co-precipitation method with an average crystallite size of 7.1 nm. CuCeO₂ NPs as an efficient catalyst were successfully used for the synthesis of pharmaceutically significant 1,4-dihydropyridine derivatives. Notable benefits of this approach include excellent yields, mild reaction conditions, rapid reaction time, simple workup, affordability, and reusability of catalyst.

A tremendous insight into photocatalytic technology is upon the creation of Metal-Organic Framework (MOF) derived catalysts and their application in various photocatalytic reactions. In the present study, five novel samples, each with their unique capabilities: pure CuO, MOF@CuO, pure CeO₂, MOF@CeO₂, and MOF@Ce–Cu oxides have been synthesized through a hydro/solvothermal process. The structural/textural properties, surface morphological changes, and surface oxidation states have been examined using XRD, BET surface area analysis, SEM/EDS imaging, XPS analysis, and H₂-TPR analysis. XRD reveals that the samples have been found to possess an abundance of structural defects - a result of the novel synthesis protocol. Interestingly, the samples also formed mesmerizing dendrite/spongy-like morphologies with crystal sizes measured at approximately 10 nm. However, the true set of these samples apart has a higher concentration of lower oxidation state cations (Cu⁺/Ce³⁺) strategically to balance the charge neutrality. These remarkable catalysts exhibited unique characteristic features due to their elevated levels of surface oxygen species (:left({O}_{2}^{x-}>60%right)) and remarkably lower band gap energies. Among the as-synthesized samples, MOF@Ce–Cu and MOF@CuO obtained the band gap energy as 2.82 eV and 1.19 eV respectively.

Lithium-sulfur batteries hold great potential as next-generation energy storage devices; however, their practical use is limited by the low conductivity of elemental sulfur and the significant “shuttle effect” that occurs in sulfur-based electrodes. This study proposes a co-doping strategy involving cobalt and nitrogen to enhance the interaction between lithium sulfide and the host material. Cobalt-nitrogen co-doped hollow porous carbon nanopolyhedra (H-CoNC) were prepared as efficient sulfur host materials. The Zeolite imidazole skeleton (Zn/Co-ZIF), derived from a metal-organic framework (MOF), exhibits enhanced chemical adsorption capabilities of cobalt nanoparticles on polysulfides, thereby improving the effective utilization of active sulfur. Simultaneously, the MOF framework undergoes carbonization at elevated temperatures, resulting in a hollow porous carbon material that imparts high conductivity to the skeleton and provides abundant pathways for Li + diffusion. Due to its distinctive structure, H-CoNC@S mitigates the shuttle effect and improves the polysulfide reaction kinetics as a cathode. Leveraging these advantages, the H-CoNC@S cathode retains a specific capacity of 692 mAh g⁻¹ after 150 cycles at a current density of 100 mA g⁻¹, exhibiting a high capacity retention rate of 92.2%. Furthermore, it delivers a reversible discharge capacity of 512 mAh g⁻¹ at a high rate of 500 mA g⁻¹, illustrating its potential for practical applications in lithium-sulfur batteries.

For the first time, isomorphic substitution solid solutions of MFI-type zeolites (ZSM-5) H_x[Al³⁺_x Ti⁴⁺ _ySi⁴⁺_12−x-yO₂₄] (MFI-(Si,Al,Ti) were synthesized by hydrothermal method under the same conditions. A detailed characterization of the sample composition, the phase with the zeolite structure, the particle surface, as well as the crystal structure, the local structure of titanium and the microstructure was carried out using EDX, FTIR, DSC, XPS, EXAFS/XANES, S/TEM, BET, and BJH methods. It was established the difference between the initial compositions of solid solutions (Al ≤ 1.52 mol.% and Ti ≤ 4.28 mol.%) and the real one (Al ≤ 0.5 mol.% and Ti ≤ 1.0 mol.%) caused by the presence of anatase impurity phase or amorphous oxygen aluminum containing phase, uncontrolled potassium impurities in MFI-(Si,Al,Ti) samples and different amounts of molecules residues outside the framework (outside the square brackets) in the zeolite crystal structure with the formation of intercalated phases H_x[Al³⁺_xTi⁴⁺_ySi⁴⁺_12−x-yO₂₄] × wA (A = H₂O and TPAOH). The established correlations between the individual characteristics of MFI-(Si,Al,Ti) with low Al and Ti content in the zeolite phase and their catalytic activity made it possible to find optimal MFI-(Si,Al,Ti) compositions for use as catalysts: maximum selectivity ​​(97.1 and 97.9%) in the reaction of allyl chloride epoxidation to epichlorohydrin were achieved for samples with the highest Ti content in the zeolite phases and Ti³⁺ ions on MFI-(Si,Al,Ti) surface; in N₂O decomposition reaction, maximum conversion value (52% at 650 °C) was obtained on MFI-(Si,Al,Ti) with an X-ray amorphous phase, maximum specific surface area, minimum content of Ti ions and a large Al content in the zeolite phase.

Great progress has been made in the methanol to aromatics (MTA) reaction over ZSM-5 zeolite, the location of Al atoms in ZSM-5 framework is very important for understanding the relationship among structure and activity of catalytic reaction system. In this paper, a series of ZSM-5 zeolites with different acid distribution and Al sites were prepared by changing the tetrapropyl ammonium hydroxide (TPAOH) content in the synthetic gel. When the ratio of TPA⁺/Si increased to 0.4,the results showed that the quantity of Al sites at the channel intersections reach a maximum.This leads to variations in acidity and distribution, and lead to the selectivity of BTX increased from 17.74 to 22.52%, simultaneously. When the ratio of TPA⁺/Si continues to increase to 0.5, the catalytic performance decreases and the BTX selectivity decreases to 13.62%. Therefore, the Al location and synergistic hydrogenation of Brønsted and Lewis acids the performance of ZSM-5 zeolite catalyst, and the zeolite with a higher proportion of Al in the intersection channels shows higher BTX selectivity in the methanol to aromatics reaction. This study elucidates the relationship between the distribution of MTA reaction products and Al sites, establishing the synthesis-structure-performance relationship of zeolite, and providing the experimental basis for rational design of catalysts.

Diatomaceous earth is widely used due to its porous structure, cost-effectiveness, abundant supply, and eco-friendly properties. While current applications require high-temperature treatment, geopolymerization can produce diatomite-based geopolymers at low temperatures, encouraging net zero emissions and sustainable growth. In this study, the method of fabricating geopolymer materials from diatomite with high SiO₂ content with active alkaline solution from 10M NaOH mixed with sodium silicate hydrothermally treated at 180 °C for 10 h is presented. The synthesized diatomite-based geopolymers show the volumetric density spanning from 0.54 to 0.60 g cm⁻³ and the thermal conductivity of 0.141 W/mK. Structural properties were studied by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) methods that showed the formation of geopolymer material. The use of hydrothermal conditions in the production of diatomite-based geopolymer presents a promising method for fabricating porous, lightweight materials. Furthermore, diatomite-based geopolymers show potential as lightweight and thermal insulation materials for building applications.

Conversion of greenhouse gas carbon dioxide to valuable products is important to reach carbon balance and sustainability, of which catalytic cycloaddition of CO₂ to cyclic carbonates has attracted much attention. Here, a biomass-derived zwitterionic polymer has been synthesized and characterized. The prepared polymer with porous structure was employed for the catalytic cycloaddition of atmospheric CO₂ and epoxides in excellent yields with a broad substrate scope under solvent-, co-catalyst, and metal-free conditions. The synthesized polymer with good thermostability could be readily recovered and recycled four times at least. Moreover, this catalytic system provided satisfactory performance with up to 96% yield of cyclic carbonate even in the gram-level scale-up reaction under the optimal standard conditions. The catalytic mechanism has also been preliminarily discussed.

Silica foam serves as a versatile substrate for the development of heterogeneous catalysts with customizable shapes. In this study, silica foam was successfully modified with NaY zeolite (Foam/Zeo) and heteropoly acid (Foam/Zeo/HPA) to create innovative composite materials. Comprehensive characterization using FT-IR, XRD, SEM, TGA, NH₃-TPD, and BET analyses confirmed the uniform dispersion of zeolite and heteropoly acid within the silica foam matrix, preserving its structural integrity. The resulting composites exhibited a well-balanced micro-mesoporous structure with enhanced acidic sites. The catalytic performance of Foam/Zeo and Foam/Zeo/HPA was evaluated in the esterification of acetic acid with five different alcohols and the transesterification of sunflower oil, animal fats, and waste oils. Foam/Zeo/HPA achieved a remarkable esterification efficiency of 89.97%, while Foam/Zeo demonstrated superior efficiency in transesterification, reaching 96.13%. Notably, both composites retained over 90% of their catalytic activity after five reaction cycles, demonstrating excellent reusability and durability. These characteristics, combined with their balanced acidity and structural stability, underscore the potential of Foam/Zeo and Foam/Zeo/HPA as highly effective and sustainable catalysts for industrial organic reactions, including biofuel production and fine chemical synthesis.