Journal of Porous Materials最新文献

In general, hierarchical zeolite synthesis will produce waste, which will cause many problems for environmental pollution. The waste that comes from the synthesis of zeolites, such as the use of hazardous chemicals from the use of many solvents, additional templates, silica sources used, and other precursors that are not environmentally friendly. One solution to the problem is to use bio-based templates. The advantage of using this bio-based template is that it is environmentally friendly, reduces dependence on hazardous chemicals, and supports sustainability for bio-based templates such as carbohydrates, chitin, and others. The use of the previously mentioned templates in zeolite synthesis can produce hierarchical pores, high crystallinity, and catalytic properties that are not inferior to conventional zeolites obtained, and more cost-effective. The efforts are expected to fulfill the principles of green chemistry, which prioritizes the environment to provide better prospects for the synthesis of hierarchical zeolites in the future.

Rodlike ZSM-5 zeolite microspheres (R-Z5) were synthesized via a seed induced hydrothermal method with S-1 seeds in the presence of β-cyclodextrin (CD). The synthesized ZSM-5 zeolites were characterized with XRD, SEM, N₂ adsorption and desorption, NH₃-TPD, the catalytic performance of R-Z5 catalysts was studied for the methanol to propylene (MTP) reaction. The effects of the ratio of CD/SiO₂ on the morphologies and textural properties of the products were discussed in detail. A possible formation process of R-Z5 was proposed. The results showed that CD played a key role in the preparation of R-Z5, which could be ascribed to the amphipathy of CD for the formation of rodlike ZSM-5 crystals. Compared with the conventional seed induced method, R-Z5 zeolites possessed the larger BET surface area and mesopore volumes and the more moderate acidic sites. Moreover, the synthesized R-Z5 catalysts exhibited excellent conversion activity (64 h) and propylene selectivity (41.35%) in the primary catalytic performance of MTP reaction.

Magnetised attapulgite (ATP-Fe₃O₄) adsorbent was synthesised using a sonochemistry approach for the solid phase extraction of As³⁺ from stimulated and unrefined crude oil samples. The average size of the Fe₃O₄ nanoparticles estimated from the Transmission Electron Microscopy (TEM) image was 10 nm. The TEM analysis also showed that Fe₃O₄ nanoparticles agglomerated in the ATP’s tube and on its surface. The X-ray diffraction analysis (XRD) indicates that the crystallinity of the ATP reduced after the magnetisation process. The saturation magnetisation of the ATP-Fe₃O₄ was determined to be only 2.8 emu g^-1. Under the optimum conditions (pH = 7, adsorbent dosage = 0.6 g, contact time = 90 min and sample volume = 50 mL), the As³⁺ removal was more than 98% for both types of oil. The limits of detection (LOD) and relative standard deviations (RSD%) were 2.88 ng mL^-1 and 0.3423%, respectively. The adsorption process follows the pseudo-first-order kinetic model (R² = 0.9696) and adheres to the Langmuir isotherm model (R² = 0.9925). The reusability study showed that ATP-Fe₃O₄ is highly stable and can be reused five times with almost 100% removal efficiency. This research outcome aligns with the United Nations Sustainable Goal 7, Affordable and Clean Energy.

CO₂ is the most prevalent greenhouse gas that traps heat and raises the global temperature. To stabilize or reduce concentrations of this greenhouse gas, it is mandatory to decompose CO₂. So we have synthesized AlPO₄ and ZnO₄-AlPO₄ catalysts using tetrapropylammonium hydroxide (TPAOH) as a template. The synthesized catalysts are systematically characterized by physicochemical methods. XRD analysis proved that AlPO₄ has a tetrahedral framework. But the ZnO₄-AlPO₄ has two separate frameworks, such as a novel ZnO₄ and AlPO₄, in which the ZnO₄ framework is sandwiched between the AlPO₄ frameworks. As of now, such kind of sandwich framework has not yet been reported. Textural evaluation shows that there is a formation of two types of pores, namely cylindrical (AlPO₄) and slit-shaped pore (ZnO₄-AlPO₄). The conversion of cylindrical pores into slit pores in ZnO₄-AlPO₄ may be due to the formation of a ZnO₄ sandwiched framework in AlPO₄. It is confirmed by the BET analysis. The acidity and thermal stability of the materials are confirmed by the TPD and TGA analyses. The acidity of AlPO₄ (0.44 mmol/g) may be due to the deposition of Al³⁺ in the pores and surface of the material. The HR-TEM analysis proved the morphology of the synthesized materials. The synthesized materials are applied for CO₂ decomposition. The maximum conversion is reached above 95% and oxygen selectivity is above 55% in both catalysts.

It is known that the use of the Dubinin–Radushkevich method in micro-mesoporous samples does not give adequate values of micropore volumes, unlike when the samples contain only microporous. Based on that, in this work, we propose an easy method to calculate a reliable micropore volume (V_μP) of micro-mesoporous (nanopores) samples, separating the microporous region from the experimental isotherm. For this, the original isotherm is modified, estimating the thickness of the adsorbed layer (t) as a function of relative pressure and changing the external surface area (S_ext) to obtain a Type I adsorption isotherm in the microporous region; then, the DR method can be applied to the modified isotherm. This proposal, named the DR_t method, allows the calculation of a reliable V_μP of any nanoporous material using different adsorbates. Using this method, we analyzed adsorbents of distinct nature (i.e., carbons and silicas) with different adsorbates as N₂ and O₂ at 77 K, Ar at 87 K, and CO₂ at 273 K. We used this method to calculate V_μP in different samples and compare them with those obtained with the traditional DR method, highlighting that unlike the latter the DR_t method showed similar and consistent results with the different adsorbates. Therefore, the values of micropore volume calculated using the DR_t method demonstrate consistency across various adsorbates, not only for N₂ but especially for CO₂, which is suggested to analyze narrow micropore volumes.

In this paper, hydrophobic treatment by hexadecetyltrimethoxysilane (HDTMS) on the surface of Sn–Ti submicrospheres with regular morphology and uniform size prepared via a simple PVP-assisted sol-gel method was firstly reported. Their physical and chemical properties were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), N₂ adsorption-desorption isotherms, Fourier transform infrared spectroscopy (FI-IR), Uvioletvisible diffuse reflection spectroscopy (UV-vis DRS), Water contact angle (WCA), Thermogravimetric analysis (TG), Inductively coupled plasma-Atomic emission spectrometry (ICP-AES), C elemental analysis and Transmission electron microscope (TEM) techniques, and the catalytic performance in the Baeyer-Villiger (B-V) oxidation of cyclohexanone in the oxygen-benzaldehyde system was also investigated. The regular submicrospheres with anatase crystal phase can be kept well by the successful grafted hydrophobic layer. When the weight ratio of HDTMS to 12%-ST submicrospheres was 1, the maximum hydrophobic angle of 126.0º for 12%-1-C₁₆-ST catalyst can be obtained. The cyclohexanone conversion and caprolactone yield over the 12%-1-C₁₆-ST catalyst was highest, whose value was 2.32 and 3.44 times, respectively, than that of 12%-ST without hydrophobic treatment. The 12%-1-C₁₆-ST catalyst also showed good stability with only a 3.74% drop of caprolactone yield after repeated use for 5 times. This method can provide a valuable reference and potential catalyst for the industrial application in the production of caprolactone.

Carbon foam is a material with wide application, whereas it is still a challenge whether the catalytic graphitization process of carbon foam can enhance the performance of the final carbon foam material while reducing energy consumption. In this study, a comparative evaluation was performed on the catalytic effects of nickel, iron, and boron catalysts on the graphitization of carbon foam. Subsequently, the influence of different catalyst loading levels and graphitization temperatures on the thermal conductivity of graphitized carbon foam was investigated. The carbon foam materials were analyzed using X-ray Diffraction (XRD) and Raman spectroscopy, while their thermal conductivity properties were characterized using a thermal conductivity meter. The oil yield from the pyrolysis of rich oil shale was also used to evaluate the thermal performance of carbon foam materials. The results revealed that, compared to Fe and Be, Ni was found to be more suitable for graphitization among the tested catalysts. Furthermore, the optimal conditions for achieving the best graphitization effect on carbon foam material were determined to be a nickel nitrate (Ni(NO₃)₂·6H₂O) concentration of 2 mol/L and a graphitization temperature of 1000 °C. The thermal conductivity of the graphitized carbon foam material prepared under this condition was increased by 25.3% from 0.2016 W·m⁻¹·K⁻¹ to 0.2526 W·m⁻¹·K⁻¹, and the tar yield was increased by 46.4% when it was applied to oil-rich coal pyrolysis. This preparation process not only saves energy but also yields graphitized carbon materials with excellent thermal conductivity, holding promising prospects for a wide range of applications.

Graphical Abstract

Despite hydrogen being an attractive energy source, there are two challenges to overcome in its use: hydrogen storage and the use of catalysts to optimize its conversion into energy. N-doped carbons are considered promising candidates for hydrogen storage and catalysis. This paper reports a fast and controllable strategy for obtaining porous N-doped carbons with a monolith-type morphology, high surface area, and hierarchical porosity. The presence of nitrogen increases the electron donor and wettability of carbons, making them favorable for use in hydrogen adsorption and electrodes. The method is based on using aniline as a carbon source and polymerizing it in a Pluronic F127 micellar system before carbonization. It is shown that the pore size and pore volume of porous carbon can be effectively tuned by using tetraethyl orthosilicate (TEOS). The relationship between aniline polymerization conditions, surface chemistry, and porous carbon properties has been investigated. Polyaniline permitted a high conversion to carbon (43.5–98.1%) and a nitrogen content of 5% wt in the N-doped carbon. In addition to the well-developed porosity and interesting monolithic morphology, electrochemical characterization showed that increasing the temperature of carbon synthesis improved the electroactive performance due to higher graphitization. In our previous study on hydrogen diffusion, we observed higher rates in our material compared to other carbon materials. This enhanced performance can be attributed to the effective combination of doping and hierarchical porosity, facilitating improved charge transfer and establishing favorable diffusion pathways. Thus, we demonstrate that pore size and surface area impact the electrochemical properties and hydrogen diffusion in this type of carbon.

Hydrotreating of lignin molecules by heterogeneous catalysts has been a significant area of research in recent eras. The current study describes the hydrotreatment of lignin-derived phenol, m-cresol, over ruthenium-incorporated SAPO-11. The developed catalyst hydrogenates m-cresol completely at 160 °C and 10 bar of hydrogen pressure, yielding 22% methyl cyclohexane, 22% methyl cyclohexanol, and 55% methyl cyclohexanone. Temperature-programmed reduction (TPR) studies using hydrogen as probe molecules show that metallic-ruthenium species exist on the SAPO-11. The desorption profile at 147–215 °C reveals the formation of dispersed metallic ruthenium on SAPO-11. The above observation is consistent with the in-situ formation of metallic ruthenium as an active species during the hydrotreating process at 160 °C in a hydrogen environment. The presence of ruthenium species increases the acidity of the ruthenium-incorporated SAPO-11 system, as demonstrated by the ammonia-temperature-programmed desorption profile. The increase in surface acidity and metallic ruthenium on the surface contribute to the hydrogenation of m-cresol via a hydrogen spillover process, as evidenced by hydrogen desorption in TPR using both fresh and reduced catalysts. The catalyst works for several cycles of m-cresol hydrotreating, and the system is easily regenerated, allowing it to maintain its original activity. The ruthenium incorporated SAPO-11 catalyst is a promising system as it can hydrogenate many other model systems, including guaiacol, toluene, anisole, and cumene.

In the foreseeable future, supercapacitors would be the most promising option for energy storage applications. But their widespread use is limited by their low energy storage density and relatively high effective series resistance. To date, however, the highest energy density of a carbon-based solid-state supercapacitor is limited up to 139 Wh kg⁻¹. Here, we report a nitrogen doped sp³ -rich carbon materials-based doublet layer supercapacitors that demonstrated excellent energy density (218.4 Wh kg⁻¹) with excellent cycling stability. This simple approach to low-cost carbonaceous materials with unique architecture and functionality could be a promising alternative to fabrication of hetero atom doped carbon structures for making next generation high capacitive batteries and hence, high energy storage device.