Journal of Porous Materials最新文献

Activated carbon fibers (ACFs) are a good support for metal catalysts due to their high specific surface area and abundant micropores. In this study, a simple catalyst preparation method was proposed to in-situ load different metal elements on coal pitch-based activated carbon fibers by impregnation and calcination technique using coal pitch-based activated carbon fibers as raw material. Different catalysts showed excellent catalytic activities for the reduction of p-nitrophenol. The results showed that the metal active elements were successfully loaded onto the activated carbon fibers. In addition, the catalyst containing Ni, Co, and Cu metal ions(ACF–3) showed excellent catalytic activity, and the conversion rate reached 95.33% at 1 min. The catalyst was recovered and reused and still showed catalytic performance after five cycles. This indicates that coal pitch-based activated carbon fibers could serve as an efficient support material for a wide range of catalytic applications.

The novel 1D/2D CuO/g-C₃N₄ binary heterojunctions with some nitrogen defects were successfully designed and constructed using a simple secondary calcination and wet precipitation method for the first time in the paper. The prepared specific samples were characterized by SEM, TEM-EDX, XRD, UV-vis DRS, XPS, N₂ adsorption-desorption isotherms, TRPL, PL emission spectra, EIS and EPR techniques. The 1D CuO nanowires (CNWs) can uniformly dispersed on the 2D g-C₃N₄ nanosheets resulting in the formation of some nitrogen defects. The lowest band gap energy of 1.75 eV and average lifetime τ_ave of 4.69 ns for the formed 1D/2D 20% CNWs/g-C₃N₄ photocatalyst can be obtained. It can efficiently compel the Cr(VI) reduction rate of 99.92% for the 90 min under simulated visible light by the synergistic effect of formed nitrogen defects and generated electrons (e⁻) and superoxide radicals (•O₂⁻) by a S-scheme mechanism according to the free radical trapping experiments and EPR results, which is 2.79 and 3.44 times higher than that of the 2D g-C₃N₄ nanosheets and 1D CuO nanowires. The 1D/2D 20% CNWs/g-C₃N₄ photocatalyst also showed high catalytic stability with a slight drop of 4.79% in the four repeated use without any change in the structure and morphology based on the XRD and SEM results. The method in this paper can provide a valuable reference and potential promising photocatalysts for the treatment of industrial Cr(VI) containing wastewater.

In this manuscript, we report the development of a multi applicable metal-free nanostructured catalyst, silica-MCM-41@Silyl-ⁿPr-DABCO-H as a Lewis acid character, which serves as an efficient and reusable catalyst for the synthesis of 5-substituted NH-tetrazoles via a one-pot [2 + 3] cycloaddition reaction between (aromatic)aliphatic nitriles and/or aryl cyanate and sodium azide. MCM-41 mesoporous silica functionalized with DABCO was synthesized by a multistep method. The structure of this multi applicable catalyst have been characterized by FT-IR, SEM, TEM, EDS, XRD, and TGA-DTA techniques and confirm the integrity of the structure and composition of the catalyst. It has shown catalytic activity in the production of NH-tetrazoles with good to excellent yields and could be recovered through seven reaction cycles. The reaction mechanisms were interpreted with the aid of quantum DFT studies, and the modified catalyst showed better catalytic efficiency than classical homogeneous catalysts such as NH₄⁺. The results obtained in this study proved silica-MCM-41@Silyl-ⁿPr-DABCO-H as an eco-friendly, metal-free alternative for organic syntheses in pharmaceutical applications where interest in NH-tetrazole derivatives is high due to their wide biological activities. The present study brings into light not only the practical applicability of this catalyst but also throws light on its mechanistic pathways with the aid of advanced computational techniques.

Both seed solution and Cetyltrimethylammonium bromide(CTAB) serve as common template agents in the synthesis of hierarchical ZSM-5 zeolites. However, their specific roles in the synthesis process have not been clearly understood. In this study, hierarchical ZSM-5 zeolites were successfully synthesized using a 1.5% mass fraction (relative to the silicon source) seed solution in combination with varying amounts of CTAB. The physical and chemical properties of the hierarchical ZSM-5 zeolites were characterized using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), low-temperature N₂ adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), ammonia temperature-programmed desorption (NH₃-TPD), pyridine-IR, and 2,4,6-collidine-IR. The investigation revealed that the CTAB content significantly influenced the synthesis of hierarchical ZSM-5 zeolites, with CTAB contributing to framework filling, charge balancing, and acting as a mesoporous template during the synthesis process, while the seed solution primarily served as a structure-directing agent. Moreover, utilizing the conversion of C8 aromatic hydrocarbons as a probe reaction, it was demonstrated that ZSM-5 zeolites synthesized with the co-assistance of seeds and CTAB exhibited enhanced conversion for ethylbenzene and m-xylene compared to samples synthesized exclusively with a seed solution.

The contamination in water is being increased with the increase in industrial processes and their elimination has become a major problem worldwide. This work is aimed to design an efficient anionic adsorbent for the elimination of cationic contaminants from water. We prepared an anionic hydrogel by simultaneous polymerization and crosslinking of 3-sulfopropyl methacrylate potassium salt and magnetized it by fabricating iron nanoparticles via in situ reduction of iron (II) ions. The formation of poly(3-sulfopropyl methacrylic acid) [p(SPMA)] and its chemical structure was supported by Fourier transform infra-red (FTIR) spectroscopy. The scanning electron microscopy (SEM) illustrated the porous surface of the p(SPMA) while X-Ray diffraction (XRD) study showed that the pristine adsorbent was having amorphous nature and magnetized one showed crystalline nature. P(SPMA) was found to be thermally stable below 350 ℃ as demonstrated by thermogravimetric analyser (TGA). Upon contacting with water, the p(SPMA) absorbed 91.26% while its iron nanoparticle containing p(SPMA) absorbed 99% water contents, exhibiting water uptake by a non-Fickian mechanism. The synthesized p(SPMA) hydrogel exhibited a maximum adsorption capacity of 1874 mgg^− 1 for methylene blue with a corresponding equilibrium time of 2 h. After magnetization, the adsorption capacity was increased to 2364 mgg^− 1 and equilibrium time was decreased to 18 min. The pH_zpc was found to be 5 and maximum adsorption occurred at pH 7. The simulation of adsorption data with adsorption isotherms and kinetics showed that adsorption was followed by Freundlich adsorption isotherm and pseudo first-order kinetics, respectively. So, this work introduces a material with the ease of synthesis and significant ability of decontamination of water via adsorption.

Converting waste cooking oil into biofuels, which are sustainable and renewable, is a viable path for the power and transportation sectors. This study investigated the performance of trimetallic oxide catalysts in catalytic cracking of waste cooking oil into renewable hydrocarbons. The activities have been compared to that of mono and bimetallic oxide catalysts. Metals were incorporated into activated carbon (AC) to prepare monometallic oxides, bimetallic oxides and trimetallic oxides, with a total metal loading of 10 wt%. The reactions were conducted in a batch reactor at 400^oC for one hour. The catalysts were characterized by N₂ physisorption, XRD, SEM-EDX, and TPD-NH₃/CO₂. This study showed that using trimetallic oxides lead to higher liquid yield and lower coke formation in the reaction, compared to both mono- and bimetallic oxide catalysts. Particularly, using NiO-Fe₃O₄-ZnO/AC gave the highest liquid yield (> 90 wt%) with merely 0.05 wt% coke formation. The liquid product predominantly comprised hydrocarbons reaching concentrations as high as 52.44%. NiO-Fe₃O₄-ZnO/AC possessed 836 m²/g BET surface area, 0.43 cm³/g pore volume and 1.92 nm pore diameter with 20,114 µmol/g strong acidity and 85 µmol/g strong basicity.

A high surface-area activated carbon was prepared from biomass of hazelnut shell (HS) using dual activators of KOH and Zn(NO₃)₂‧6H₂O. The texture properties of Hazelnut Shell-derived Activated Carbons (HSACs) can be controlled through adjusting the mass ratio of Zn(NO₃)₂‧6H₂O. According to CO₂ adsorption on HSACs, a remarkable uptake of 3.8 mmol g^-1 and the highest ideal adsorbed solution theory selectivity of 44.4 for CO₂/N₂ at 1.0 bar and 298 K were observed in HSAC-2, which possessed lowest specific surface area, highest micropore volume, highest carboxyl and carbonyl and lowest ether and hydroxyl groups. The synergistic effect of pore morphology, and surface functional groups plays a critical role in the adsorption of CO₂. Excellent CO₂ adsorption and separation effect can be achieved by utilizing the structural properties of HS itself, demonstrating HSACs are biomass adsorbent for CO₂ with great development prospects.

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This review paper explores the application of activated carbons (ACs) in skin whitening cosmetics and their basic characteristics as a catalyst. Firstly, the physical and chemical properties of ACs, as well as their theoretical basis as catalysts, were introduced. Subsequently, a detailed analysis was conducted on the mechanism of ACs in promoting the reactivity of hydroquinone (HQ), including physical adsorption, chemical interactions, and the role of surface functional groups. The paper compared the performance of different types of ACs such as wood-based, coconut shell-based, coal-based, and supported ACs in catalytic reactions and compared them with other catalysts. In order to optimize the catalytic performance of ACs, strategies for changing preparation methods and conditions were explored, such as physical and chemical activation methods, microwave-assisted preparation, and adjustment of carbonization temperature and time. In addition, the paper also discusses the potential advantages of ACs in whitening cosmetics, such as improving the effectiveness of whitening ingredients and enhancing product safety, as well as the challenges faced, including stability issues and possible side effects. The future development directions include innovation and improvement of AC-materials, in-depth research on their interaction with the skin, development of composite materials, and the application of green chemistry in the preparation of ACs. Finally, the paper explores the binding mechanism of ACs with other whitening agents and its limitations in formulation and environment and summarizes the application prospects of ACs in cosmetics.

The porous structure of scaffolds is critical in facilitating cellular activities such as mass transport, cell migration, and vascularization. The pore size and porosity of the scaffold need to be adjusted according to the specific tissue to enable long-term cultivation in vitro. Therefore, selecting the method to be used in the porosity characterization is critical. In addition to analyzing pore characteristics, micro-computed tomography (Micro-CT) can assess parameters such as the degree of anisotropy, interconnectivity, and hydroxyapatite (HAp) density in bone tissue scaffolds, providing advantages over alternative methods. In this study, a bacterial cellulose-HAp scaffold was fabricated, and its porosity, pore distribution, wall thickness distribution, surface area, degree of anisotropy, and HAp density were characterized. Additionally, 3D models of the scaffold were generated using Micro-CT imaging. The findings of this study demonstrate that Micro-CT is an effective tool for measuring these critical parameters in soft, foam, or flexible scaffolds without causing structural damage. The advantages of this technique over alternative methods are also emphasized. Upon examining the Micro-CT results of the scaffolds designed for bone tissue engineering, it was found that the pore sizes predominantly ranged from 90 to 150 μm, with a maximum pore size of 320 μm. The porosity was approximately 85%, the degree of anisotropy was 1.06, and the HAp density was 125 mg/cm³. It was concluded that these parameters are suitable for bone formation, indicating that the produced scaffolds are suitable for bone tissue engineering.

Boron-doped ordered mesoporous carbons (B-OMCs) were synthesized by a one-pot self-assembly technique in a water/acetic acid solvent system, using resorcinol and formaldehyde as carbon source, boric acid as boron source and triblock copolymer (Pluronic F127) as the structure directing agent. The effects of the water/acetic acid (W/A) molar ratio, polymerization temperature (T_p), and carbonization temperature (T_c) on the resultant structural properties were examined in detail. Synthesized B-OMCs displayed bimodal pore size distributions, consisting of identically small-sized mesopores (D_p = 3.8 nm) and larger mesopores which varied in size and texture depending on the solvent composition and temperature. In general, lower W/A ratios and high polymerization temperature favored the formation of smaller-sized mesopores, leading to higher surface areas as high as 764 m²/g (W/A: 0.75, T_p: 80 °C and T_c: 900 °C). On the other hand, the average pore size increased with the W/A ratio, up to 10.5 nm (W/A: 3.25, T_p: 50 °C and T_c: 750 °C). According to TEM analysis, low polymerization temperatures led to predominantly two-dimensional hexagonal mesostructures, which shifted to three-dimensional interconnected type with the increasing temperature. Boron-doping was higher in the samples with lower W/A ratios, with 0.79% (wt) doping obtained from B-OMC-3.25-50/750. The boron doping content decreased with the polymerization temperature, down to 0.62% (wt). B-doped carbons were evaluated for their catalytic properties towards oxygen reduction reaction (ORR). Cyclic voltammetry measurements showed significant OR activities around 0.29 V which increased with the doped-boron content.