Journal of Porous Materials最新文献

When it comes to owning pets, pet odor is a major concern for many individuals. Ammonia (NH₃) and hydrogen sulfide (H₂S) are the primary odor components that have negative effects on human life. Therefore, there is an urgent need to develop a deodorizing material with high NH₃ and H₂S adsorption capacity. In this study, Resorcinol-formaldehyde (RF) aerogels containing amine groups (RF-Mx) were prepared using the sol-gel method and atmospheric pressure drying technique. Melamine was used as a modifier. The specific surface area of the modified aerogel was 119 m²/g with an average pore size of 12 nm when the melamine addition was 20%. The adsorption capacity of RF-M20 for odor was the highest (NH₃: 593.8 mg/g, H₂S: 640 mg/g), which was significantly superior to the unmodified sample. In addition, the adsorption capacity of RF-M20 for H₂S exceeded that of commercial activated carbon. The results concluded that the introduction of amine groups and the higher microporous specific surface area benefited the chemical and physical adsorption of gases, effectively improving the adsorbent’s capacity to capture NH₃ and H₂S. The preparation method is not only efficient in enhancing the odor adsorption capacity but also simple and cost-effective to operate, showing promising potential for industrial applications.

The effect of post-treatment of TS-1 zeolite by tetrapropyl ammonium hydroxide aqueous solution under hydrothermal condition was studied in this work. The characterizations of structure, morphology and composition demonstrated that an open and hierarchical porous structure was generated in TS-1 zeolite after the post-treatment. With increasing the alkalinity of TPAOH solution, the hierarchical porosity and hydrophobicity increased and the framework Ti content decreased in the post-treated TS-1 zeolite. Both the pristine and post-treated TS-1 zeolites were employed as the catalysts for the reaction of phenol hydroxylation. It was found that the post-treated TS-1 zeolite possessed a higher catalytic performance than the pristine TS-1 zeolite. The larger the alkalinity of the post-treatment solution was, the higher the catalytic performance of the post-treated TS-1 zeolite was; however, a too high alkalinity of the post-treatment solution also led to the decline in the catalytic performance. This could be a result of the combined influences of the hierarchical porosity, hydrophobicity and framework Ti content on the catalytic performance. The higher levels of hierarchical porosity and hydrophobicity promoted but the lower level of framework Ti content inhibited the catalytic performance of TS-1 zeolite. Accordingly, the controlling to the alkalinity of TPAOH solution for the post-treatment was very important in respect of the catalytic performance of TS-1 zeolite.

Designing inexpensive and efficient absorbent materials derived from waste is still challenging but of great significance to environmental safety and resource protection. Herein, the modified Hummers’ waste liquid was used as a precursor reactant to synthesize the three types of manganese oxides via a chemical precipitation method. The components, microstructure, and adsorption capacities of the manganese oxides for heavy metal ions were investigated in detail. The results show the manganese oxides have porous structures and different crystal phases as manganese dioxide (I-MO), manganese oxide hydroxide (II-MO), and trimanganese tetraoxide (III-MO), respectively. Compared with II-MO and III-MO, I-MO has a specific surface area and pore volume of 142.27 m²·g⁻¹ and 0.622 cm³·g⁻¹, respectively. The experiments reveal that Ι-MO exhibits better adsorption performance of heavy metal ions than II-MO and III-MO. At 298 K, the maximum adsorption amounts of Pb²⁺, Cd²⁺, and Cu²⁺ on the Ι-MO are 304.15, 175.37, and 74.48 mg·g⁻¹, respectively. The experimental findings closely match both the pseudo-second-order model and the Langmuir model. Moreover, I-MO exhibits a satisfactory adsorption capacity for heavy metal ions even after six repetitive cycles. All of these show that I-MO is a cost-effective adsorbent for heavy metal ions elimination in water.

Recently, element doping has become an effective strategy to improve the gas sensing properties of In₂O₃-based materials by adjusting their electronic structures. Herein, Pt-modified In₂O₃ nanobundles, composed of nanofibers, were prepared using a simple hydrothermal method. The dispersion of Pt nanoparticles on the In₂O₃ surface was achieved through an in-situ reduction process. High-resolution TEM images reveal that the In₂O₃ nanofibers possess an average diameter of 30 nm. Brunauer-Emmett-Teller(BET) indicates that the Pt modification can increase the specific surface area. XPS indicates that the introduction of Platinum(Pt) nanoparticles can both increase the oxygen vacancy ratio, and facilitate to trap the electrons, as a result of improving the sensing performance. The gas sensing tests demonstrate that the Pt decorated In₂O₃ nanobundles show excellent sensitivity (5.12 of 100 ppm) and selectivity towards formaldehyde at the optimized temperature of 180 °C. This shows that the decoration of Pt nanoparticles can lower the optimized working temperature and shorten the response/recovery times, of which the enhanced performance can be attributed to electronic and chemical sensitization.

In order to decouple structural parameters of silica aerogels like particle size, pore size and fractal dimension on the one hand from aerogel properties such as aerogel density, thermal and mechanical characteristics on the other hand, the structural properties were varied in a wide range. It has been a challenging task to find synthesis parameters still resulting in gels, but also covering a wide property space. For this goal, three synthesis routes, based on the classical tetraalkoxysilane route, were chosen. The structural properties of the silica aerogels produced cover more than two orders of magnitude in particle and pore sizes, whereas the variation of density and porosity is limited by the Si-content of the silica source. Due to physical limitations, not all combinations of pore size correlated to an aerogel density are possible, leading to a gap for small densities and small pores as well as for high densities and large pores. For increasing particle sizes, the structure generation mechanism seems to alter from particle generation and subsequent cluster formation to phase separation. Along with that, the mechanical stiffness drops down for larger structures (pores and particles). For the mechanical and thermal properties, only the solid thermal conductivity scales roughly with the Young’s modulus, thus giving the opportunity of decoupling mechanical and thermal conductivity at ambient pressure from each other.

Electrochemical energy technologies are crucial for a sustainable future, promising to transform energy generation, storage and use with improved efficiency and environmental responsibility. In this study, Fe was integrated into the MCM-48 framework to create a modified mesoporous structure to be used as electrodes for electrochemical storage applications. The materials were thoroughly characterized using various spectroscopic and non-spectroscopic techniques, including XRD, XPS, UV-Vis (DRS), FT-IR, N₂ adsorption-desorption analysis, SEM with EDX, ICP-OES, TEM, TGA and DSC. Cyclic voltammetry and galvanometric charge-discharge studies revealed that the Fe-MCM-48 sample with Si: Fe molar ratio of 20 (Fe-MCM-48 (20)) exhibited pseudocapacitive behaviour, showcasing higher capacitance value of up to 787 F g^− 1 at a current density of 1 A g^− 1. The findings undeniably indicate that Fe-MCM-48 (20) holds promise as a highly effective electrode material for advancing energy storage technologies like supercapacitors.

To cater the ever growing energy demand and durability for modern applications like portable electronic gadgets, hybrid electric vehicles, etc., enormous research has been done to develop high capacity electrochemical energy storage devices. Among different allotropes of carbon, graphene, is emerged as an excellent candidate for energy conversion and storage applications because of its unique properties, including high specific surface area (2630 m²/g), good chemical stability and excellent electrical conductivity. To obtain high specific capacitance as well as high rate capability, the use of MnO₂ based composite materials is predicted as potential candidate. Strategies to modify supercapacitor performance of MnO₂ based composites are reported by various research groups. Polyaniline is one of the most studied conducting polymer due to good conductivity, environmental stability, low weight, easy synthesis on large scale and economic importance for industrial applications. In commercial supercapacitors, activated carbon is commonly used as electrode materials. Low energy density of carbon materials cannot be efficient for their effective use in energy storage applications. Thus, preparation of supercapacitors by using hybrid material with incorporation of metal oxides and conducting polymers in graphene can provide exceptional energy as well as power density. Nanocomposite materials have attracted much attention due to the synergetic effects between the components which shows better electrical properties. Further, the improvement in the electrical properties in hybrid materials is attributed to the direct interfacial interaction. In this study, specific capacitance of Polyaniline/MnO₂/Graphene/Graphene oxide composite material was found to be 1882.32 (Fg⁻¹) with symmetric galvanostatic charge/discharge curves and 97.61% capacitance retention after 6063 cycles in cycle performance.

Thermal insulation materials must exhibit superior mechanical properties alongside exceptional thermal insulation conductivity. However, traditional porous ceramics often struggle to meet these dual requirements simultaneously. In high-entropy materials, the phonon scattering induced by lattice distortion effects can significantly reduce the thermal conductivity of ceramics, thus opening new avenues for the design of novel thermal insulation materials. Inspired by the high-entropy effect, this study employed solid-state reaction methods to synthesize (Ce_0.2Zr_0.2Ti_0.2Sn_0.2Ca_0.2)O_2−δ (CZTSC) high-entropy ceramics at various temperatures, investigating their phase constituents, microstructural characteristics, and mechanical properties, while exploring the optimal sintering temperature. Additionally, a pore-forming agent method was utilized to fabricate monophasic CZTSC porous ceramics with different porosities at 1400 °C. Specifically, when the pore-forming agent content was 20 wt%, the sample exhibited an apparent porosity of 42.82%, with a low thermal conductivity of 0.57 W·m^− 1·K^− 1, a low thermal diffusivity of 0.406 mm²·s^− 1, and a relatively high compressive strength of 32.49 MPa. The current investigation underscores the promising prospects of porous CZTSC ceramics in the field of thermal insulation.

The present study reports in-situ synthesis of porous silica-ruthenium composite catalyst for hydrolysis of ammonia borane. The in-situ synthesized catalyst precursors were prepared via sol-gel based methods using surfactant micelles of cethyltrimethylammonium bromide (CTAB) to form well-ordered nanopores in the precursor particles. The precursors consisted of spherical particles with the diameter of ca. 20–60 nm and nanopores with the diameter of ca. 2–3 nm were included in the precursor particles. The specific surface areas and pore volumes decreased with increasing of ruthenium content, while their catalytic activity for hydrogen generation from aqueous ammonia borane solution was the same level regardless of the ruthenium contents. The catalytic activity was effectively improved via reflux procedure of the precursors through removing residual compound probably originated from CTAB with maintaining dispersion of the active ruthenium species after the procedure.

Methylene blue is one of the most common compounds in mutagenic, teratogenic and carcinogenic dye wastewater. Adsorption is a simple and effective method for efficient treatment of organic wastewater. In this study, amine functionalized Al-SBA-15 mesoporous molecular sieves were prepared for adsorption of methylene blue solution. Solid waste fly ash was utilized as a cheap source of silica, which was combined with templating agent P123 to form Al-SBA-15 molecular sieves. Then silane coupling agent (APTES) was used to graft amine groups on the surface of Al-SBA-15 to improve the adsorption performance. The adsorption experiments showed that NH₂-Al-SBA-15 had the best adsorption performance, with 324 mg g⁻¹ against 200 mg L⁻¹ methylene blue solution in 500 min. But the adsorption of Al-SBA-15 was 311 mg g⁻¹. It proved that the functionalization increased the adsorption of methylene blue by the molecular sieve. Then the kinetic study was carried out, which showed that it conformed to the proposed secondary kinetics as well as Langmuir isothermal adsorption model. Then the effects of pH, adsorption temperature and methylene blue concentration on the adsorption performance were investigated. The optimal adsorption performance was obtained, and it resulted in the optimal adsorption pH value of 10, adsorption temperature of 25 °C, methylene blue concentration of 200 mg L⁻¹, and mass of adsorbent of 30 mg.