Journal of Porous Materials最新文献

Cu(I)-based adsorbents are currently the most commonly used CO adsorbents due to their high adsorption capacity and adsorption selectivity for CO. In order to achieve a facile preparation and improved antioxidant performance of Cu(I)-based adsorbents, in this work, a series of Cu(I) based CO adsorbents were designed and prepared by choosing CuCl₂ as the precursor, ultra-stable Y-type molecular sieves (USY) as the support, and methyl cellulose (MC) as a solid reductant. The MC introduction not only can reduce the precursor CuCl₂ to the active component CuCl, but also play a key role in improving the antioxidant performance of the adsorbent. The optimized adsorbent CuCl(5.0)@USY-MC(8%) exhibits an excellent antioxidant performance, maintaining 76% of CO adsorption capacity of fresh adsorbent after being placed in the air for 24 h. In addition, the adsorbent shows the high adsorption capacity, adsorption selectivity and good cycling stability for CO. The excellent CO adsorption performance as well as good antioxidant ability make the developed adsorbent a promising candidate for the efficient CO adsorption and separation from the gas mixture.

We report first time preparation and crystal structure of NH₄⁺ exchanged form of highly disordered gallosilicate zeolite with natrolite framework (NAT) by ion exchange method from K-gallosilicate zeolite with natrolite framework. K⁺ exchanged form was obtained by ion exchange with hydrothermally prepared highly disordered sodium gallosilicate zeolite with natrolite framework. Phase purity, degree of ion exchange, particle morphology, elemental mapping and thermal behaviour of Na-, K-, NH₄-gallosilicate zeolites were investigated using various instrumental techniques. Crystal structures of Na-, K-, NH₄-gallosilicate zeolites were obtained by Rietveld analysis of powder X-ray diffraction data collected using synchrotron source of X-rays. Refined structural models of hydrated Na-, K-, NH₄-gallosilicate zeolites were compared. NH₄-gallosilicate zeolite was calcined at 450 °C to obtain its H-form. The structure collapse of H-gallosilicate zeolite with natrolite framework is commented finally based on the structural characterization data.

A series of binary In₂O₃/S (S = Al₂O₃, SiO₂, and MgO) catalysts were fabricated by an incipient-wetness impregnation method, which were firstly applied in the ethylbenzene dehydrogenation under the presence of CO₂ (EBDH-CO₂). The synthesized catalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption isotherm, temperature-programmed desorption of NH₃ and CO₂ (NH₃/CO₂-TPD), temperature-programmed reduction of H₂ (H₂-TPR), and X-ray photoelectron spectroscopy (XPS). It is found that the support can strongly impact on the crystalline phase, the dispersity, and the reduction properties of In₂O₃. The catalytic tests during the EBDH-CO₂ show that as compared to In₂O₃/MgO and In₂O₃/SiO₂ with the merely existence of bulk In₂O₃ particles, the In₂O₃/Al₂O₃ catalyst gives the highest catalytic activity and good stability, which can be principally ascribed to the synergistic effect of the bulk In₂O₃ and in situ metallic In formed by the reduction of the well-dispersed In₂O₃ on the Al₂O₃ surface. It therefore affirms that attaining an appropriate support to disperse the active phase In₂O₃ becomes the decisive factor to achieve both superior catalytic activity and satisfied selectivity towards styrene.

Shuttle effect of lithium polysulfides in lithium sulfur batteries greatly influenced their commercialization. Therefore, it is urgent to develop a cheep and effective way to alleviate the shuttle effect. Fe is an active transition element which has good catalytic ability, in this work, a simple wet impregnation method was used to make Fe ions infiltrate into the pores of BP2000 (a kind of commercial conductive carbon), then it was calcined in N₂ atmosphere to get a Fe₂O₃/BP2000 composite and used as a separator modification layer. The Fe₂O₃ nano particles were decorated in the pores of BP2000 which greatly enhanced the absorption ability on lithium polysulfides, additionally it also showed excellent catalytic effect on lithium polysulfides, thus the Fe₂O₃/BP2000 layer can be served as a secondary collector to re-engage the polysulfides in the cathode reaction. In this way, the lithium sulfur batteries equipped with the Fe₂O₃/BP2000 modified separator showed impressive electrochemical performances.

In this work, the dielectric and electrical properties of the complex oxides La_0.5Ba_0.5MnO₃ and La_0.97Ba_0.03MnO₃ were studied. The studies were carried out at a temperature T = 25–225 °C and a frequency f = 20–10⁶ Hz ranges. For these compounds, the values of physical parameters (dielectric constant, dielectric losses, dielectric constant and electrical conductivity) characterizing dielectric and electrical properties are determined. From the temperature and frequency dependence of the parameters, it was established that with increasing temperature and frequency, the value of electrical conductivity in these compounds increases. A semiconductor–metal phase transition was detected in this compound at a temperature T ~ 140 °C. Oxide materials are used in a variety of processes due to their interesting chemical properties. It is known that in the process of condensation of methane with oxygen, along with ethane and ethylene, heavy hydrocarbons are also obtained. Nd₂O₃/MgO, La₂O₃/MgO, oxides of alkali and alkaline earth metals, as well as PbO oxide are used as catalysts for this process. Recently, BaSnO₃ and MnTiO₃ compounds with a perovskite structure have been used as catalysts in these processes. Therefore, it is very important to obtain new perovskite materials and study their physical and chemical properties.

In situ electrospun 3D polyacrylonitrile (PAN) nanofiber-reinforced (EPNR) silica aerogel monoliths were prepared through methyltriethoxysilane–trimethylchlorosilane modification followed by ambient pressure drying (APD). The 3D PAN nanofiber network was built into silica sol by liquid-assisted collection. Homodispersed and intertwined PAN nanofibers were well incorporated into the silica aerogel matrix. The APD-EPNR silica aerogel had a porosity of 90.9% and a BJH pore volume of 2.15 cm³ g⁻¹. Furthermore, the APD-EPNR silica aerogel monolith showed excellent flexibility and revealed a highly hydrophobic surface with a water contact angle of 145º. The APD-EPNR aerogel was suitable for removal of oil from water. The static mass of the APD-EPNR silica aerogel achieved 700%–1500% to various solvents and the aerogel can be recovered without obvious performance decline. The APD-EPNR silica aerogel mat also achieved oil/water separation with a separation efficiency of more than 99%. Hence, the prepared APD-EPNR silica aerogel has promising application for treatment of oil pollution.

This study presents a novel approach for the one-step hydrothermal synthesis of Fe₂O₃/KIT-6 (Korea Advanced Institute of Science and Technology) nanocomposite, demonstrating its remarkable potential as a humidity sensor at room temperature. The nanocomposite, comprised of hydrothermally derived hematite-doped hybrid moieties within a mesostructured siliceous matrix, exhibits outstanding sensitivity to moisture. Through a comprehensive characterization utilizing various techniques including X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscopy, and energy dispersive X-ray analysis, the ordered mesoporous structure and purity of the synthesized nanocomposite are confirmed. Notably, the incorporation of 5 wt% Fe₂O₃ into the KIT-6 framework via hydrothermal synthesis yields superior sensing properties, characterized by minimal hysteresis, rapid response and recovery times (14s/15s), and exceptional stability within a wide relative humidity (RH) range of 11-98%. These findings pave the way for the development of practical moisture detection devices employing the silica-hematite hybrid nanocomposite as a sensing material in resistive-type sensor configurations.

Graphene-based aerogels have garnered significant attention due to their combined advantages derived from both graphene and aerogels. Nevertheless, a key limitation in their practical applications arises from their relatively modest specific surface area and pore volume. In this study, porous graphene materials with high porosity are synthesized through the physical and chemical activation of nitrogen-doped graphene aerogel (NGA) using carbon dioxide and KOH as activating agents. The carbon dioxide-activated NGA (CNGA) maintains the spongy aerogel structure and exhibits a hierarchical porous structure encompassing micropores, mesopores, and macropores. Notably, CNGA exhibits a high specific surface area (2030 m² g^–1) and pore volume (5.4 cm³ g^–1). Given its intriguing properties, the CNGA porous material shows exceptional adsorption capabilities for toluene (2625 mg g^–1) and methanol (2091 mg g^–1) under saturated vapor pressure conditions, making it possible to serve as an efficient gas adsorbent. Furthermore, the CNGA as a sulfur host for lithium–sulfur battery demonstrates good cycling performance, retaining a discharge specific capacity of 719.6 mA h g^–1 even after 200 cycles at a rate of 0.5 C.

In this study, a new metal–organic framework (MOF) based on copper (II) functionalized with graphene oxide (MOF-Cu@GO) was successfully synthesized and applied as an efficient sorbent for dispersive micro-solid phase extraction (D-μSPE) of losartan potassium (LP) from water. The MOF-Cu@GO sorbent was characterized using DRX, FTIR, XPS, TGA, RAMAN, BET, SEM, EDX, and potential Z. The influence of different parameters in the D-μSPE method was studied and optimized using the fractional factorial design 2^5–1 and central composite design. The results indicated that the adsorption process was spontaneous and endothermic followed the pseudo-second order model kinetics and the Freundlich isotherm. The maximum adsorption capacity of MOF-Cu@GO sorbent was 415 mg g⁻¹. The adsorption mechanism proposed of LP onto MOF-Cu@GO proceeded via electrostatic interaction, hydrogen bonds, unsaturated sites of the ligand, and π-π interactions. The microextraction procedure was followed by determination of LP with high performance liquid chromatography (HPLC–UV-Vis). Under optimized conditions, the limits of detection and quantitation were found to be 25 and 80 ng ml⁻¹ respectively, the method exhibited a linear response (r = 0.998) in the concentration range of 0.1–50 µg ml⁻¹ of LP, with a relative standard deviation less than 2% (n = 5). The D-μSPE method showed preconcentration factor of 684.9 and high percentage of LP extraction of 99.78% ± 2.62, the accuracy of the method was demonstrated by studying the recovery of LP from water samples of 100.3 ± 1.06. The material obtained can be used up to 3 cycles with time for the sorption and determination of 30 min indicating good stability and reusability. The MOF-Cu@GO proposed is an efficient and fast sorbent in the D-μSPE for determination of LP from aqueous solutions.