Molecular sieves are artificially synthesized hydrated aluminosilicates or natural zeolites with molecular sieving properties. They have uniformly sized pores and well-arranged channels and cavities in their structure. Molecular sieves of different pore sizes can separate molecules of different sizes and shapes. They possess functions such as adsorption, catalysis, and ion exchange, which give them tremendous potential applications in various fields such as petrochemical engineering, environmental protection, biomedical, and energy. In 1925, the molecular separation effect of zeolite was first reported, and zeolite acquired a new name — molecular sieve. However, the small pore size of zeolite molecular sieves limited their application range, so researchers turned their attention to the development of mesoporous materials with larger pore sizes. Mesoporous materials (a class of porous materials with pore sizes ranging from 2 to 50 nm) have extremely high surface area, regularly ordered pore structures, and continuously adjustable pore sizes. Since their inception, mesoporous materials have become one of the interdisciplinary frontiers. For molecular sieves, particle size and particle size distribution are important physical parameters that directly affect product process performance and utility, particularly in catalyst research. The crystal grain size, pore structure, and preparation conditions of molecular sieves have significant effects on catalyst performance. Therefore, exploring changes in molecular sieve crystal morphology, precise control of their shape, and regulating and enhancing catalytic performance are of great significance and have always been important aspects of molecular sieve research. Scanning electron microscopy provides important microscopic information for studying the structure-performance relationship of molecular sieves, aiding in guiding the synthesis optimization and performance control of molecular sieves. ZSM-5 molecular sieve has an MFI structure. The product selectivity, reactivity and stability of MFI-type molecular sieve catalysts with different crystal morphologies may vary depending on the morphology. Figure 1(a) MFI skeleton topology The following are images of ZSM-5 molecular sieve captured using the CIQTEK High-Resolution Field Emission Scanning Electron Microscope SEM5000X. Figure 1(b) ZSM-5 molecular sieve/500V/Inlens SBA-15 is a common silicon-based mesoporous material with a two-dimensional hexagonal pore structure, with pore sizes typically ranging from 3 to 10 nm. Most mesoporous materials are non-conductive, and the commonly used pre-treatment method of coating (with Pt or Au) may block the nanoscale pores, affecting the characterization of their microstructure. Therefore, such samples are usually not subjected to any coating pre-treatment, which requires the scanning electron microscope to have ultra-high resolution imaging capability even at extr...
View MorePorous adsorbents play an important role in the fields of environmental purification, energy storage and catalytic conversion due to their unique porous structure and properties. Porous adsorbents usually have high specific surface area and rich pore distribution, which can effectively interact with molecules in gas or liquid. Using static gas adsorption method to accurately characterize parameters such as BET and Pore Distribution, can help to gain a deeper understanding of the properties and adsorption performance of porous adsorbents. BET and Pore Distribution of porous adsorbents Porous adsorbents are a type of material with high specific surface area and rich pore structure, which can capture and fix molecules in gas or liquid through physical or chemical adsorption. There are many types of them, including inorganic porous adsorbents (activated carbon, silica gel, etc.), organic Polymer adsorbents (ion exchange resins, etc.), coordination polymers (MOFs, etc.) and composite porous adsorbents, etc. A thorough understanding of the physical properties of porous adsorbents is critical to optimizing performance and expanding application areas. The application directions of BET Surface Area & Porosimetry Analyzer in the porous adsorbent industry mainly include quality control, research and development of new materials, optimization of separation processes, etc. By accurately testing the specific surface area and pore distribution, the performance of porous adsorbents can be improved in a targeted manner to meet specific application needs and improve the selective adsorption of target molecules. In summary, analyzing the specific surface area and pore distribution of porous adsorbents through gas adsorption characterization is beneficial to evaluate the adsorption capacity, selectivity and efficiency, and is of great significance in promoting the development of new high-efficiency adsorbents. Characterization of gas adsorption properties of MOFs materials Metal-organic framework materials (MOFs) have become a new type of adsorption material that has attracted much attention due to its high porosity, large specific surface area, adjustable structure and easy functionalization. Through the synergistic regulation of functional group modification and pore size adjustment, the CO2 capture and separation performance of MOFs materials can be improved to a certain extent. UiO-66 is a widely used MOFs adsorbent, often used in gas adsorption, catalytic reactions, molecular separation and other fields. The following is a case of characterization of UiO-66 material using the CIQTEK V-3220&3210 BET Surface Area & Porosimetry Analyzer. As shown on the left side of Figure 1, the specific surface area of UiO-66 is 1253.41 m2/g. A high specific surface area can provide more active sites, which is beneficial to improving its adsorption performance. It can be seen from t...
View MoreScanning electron microscope as a commonly used microscopic analysis tools, can be observed on all types of metal fracture, fracture type determination, morphology analysis, failure analysis and other research. What is a metal fracture? When a metal is broken by an external force, two matching sections are left at the fracture site, which is called a "fracture". The shape and appearance of this fracture contains a lot of important information about the fracture process. By observing and studying the morphology of the fracture, we can analyze the cause, nature, mode, mechanism, etc., and also understand the details of the stress condition and crack expansion rate at the time of fracture. Like a "scene", the fracture retains the whole process of fracture occurrence. Therefore, for the study of metal fracture problems, observation and analysis of fracture is a very important step and means. Scanning electron microscope has the advantages of large depth of field and high resolution, and has been widely used in the field of fracture analysis. Application of Scanning Electron Microscope in Metal Fracture Analysis There are various forms of failure of metal fracture. Categorized by the degree of deformation before fracture, they can be divided into brittle fracture, ductile fracture, and mixed brittle and ductile fracture. Different fracture forms will have characteristic microscopic morphology, which can be characterized by SEM to help researchers to quickly perform fracture analysis. Ductile Fracture Ductile fracture is a fracture that occurs after a large amount of deformation of a member, which is mainly characterized by significant macroplastic deformation. The macroscopic morphology is a cup-and-cone fracture or a pure shear fracture, and the fracture surface is fibrous and consists of tough nests. As shown in Figure 1, microscopically its fracture is characterized by: the fracture surface consists of a number of tiny wineglass-shaped microporous pits, usually referred to as tough fossa. Toughness fossa is the trace left on the fracture surface after plastic deformation of the material in the range of micro-region generated by the micro-void, through the nucleation/growth/aggregation, and finally interconnected to lead to fracture. Fig. 1 Metal ductile fracture fracture/10kV/Inlens Brittle Fracture Brittle fracture is the fracture of a member without significant deformation. There is little plastic deformation of the material at the time of fracture. While macroscopically it is crystalline, microscopically it includes fracture along the crystal, disintegration fracture or quasi-disintegration fracture. As shown in Fig. 2, a mixed brittle-ductile fracture fracture of the metal, in the ductile fracture region, a distinctive toughness nest feature can be observed. In the brittle fracture region, it belongs to along-crystalline brittle fracture, which refers to the fract...
View More5A molecular sieve is a kind of calcium-type aluminosilicate with cubic lattice structure, also known as CaA-type zeolite. 5A molecular sieve has developed pore structure and excellent selective adsorption, which is widely used in the separation of n-isomerized alkanes, the separation of oxygen and nitrogen, as well as natural gas, ammonia decomposition gas, and the drying of other industrial gases and liquids. 5A molecular sieve has an effective pore size of 0.5 nm, and the determination of the pore distribution is generally characterized by gas adsorption using a physical adsorption instrument. The effective pore size of 5A molecular sieve is about 0.5 nm, and its pore size distribution is generally characterized by gas adsorption using physical adsorption instrument. The specific surface and pore size distribution of 5A molecular sieves were characterized by CIQTEK EASY-V series specific surface and pore size analyzers. Before testing, the samples were degassed by heating under vacuum at 300℃ for 6 hours. As shown in Fig. 1, the specific surface area of the sample was calculated as 776.53 m2/g by the multi-point BET equation, and then the microporous area of the sample was obtained as 672.04 m2/g, the external surface area as 104.49 m2/g, and the volume of the microporous as 0.254 cm3/g by t-plot method, which showed that the microporous area of this molecular sieve accounted for about 86.5%. In addition, the analysis of the N2 adsorption-desorption isotherm plot of this 5A molecular sieve (Fig. 2, left) reveals that the adsorption isotherm shows that the adsorption amount increases sharply with the increase of the relative pressure when the relative pressure is small, and the filling of micropores occurs, and the curve is relatively flat after reaching a certain value, which suggests that the sample is rich in micropores. The microporous pore size distribution calculation using the SF model (Fig. 2, right panel) yielded a concentrated microporous pore size distribution at 0.48 nm, which is consistent with the pore size of 5A molecular sieves. Fig. 1 Specific surface area test results (left) and t-Plot results (right) of 5A molecular sieve Fig. 2 N2-sorption and desorption isotherms (left) and SF-pore size distribution plots (right) of 5A molecular sieve samples CIQTEK Automatic BET Surface Area & Porosimetry Analyzer | EASY-V 3440 EASY-V 3440 is the BET specific surface area and pore size analysis instrument developed independently by CIQTEK, using the static volumetric method. ▪ Specific surface area testing, range 0.0005 (m2/g) and above. ▪ Pore size analysis: 0.35 nm-2 nm (micropore), micropore size distribution analysis; 2 nm-500 nm (mesopore or macropore). ▪ Four analysis stations, simultaneous testing of 4 samples. ▪ Equipped with the molecular pump.
View MoreZeolite imidazolium skeleton (ZIFs) materials as a subclass of metal-organic skeletons (MOFs), ZIFs materials combine the high stability of inorganic zeolites and the high specific surface area, high porosity and tunable pore size of MOFs materials, which can be applied to efficient catalytic and separation processes, so ZIFs and their derivatives have good potential for use in catalysis, adsorption and separation, electrochemistry, biosensor and biomedicine and other fields with good application prospects. The following is a case study of the characterization of ZIF molecular sieves using CIQTEK EASY-V series specific surface and pore size analyzer. As shown in Fig. 3 left, the specific surface area of this ZIF molecular sieve is 857.63 m2/g. The material has a large specific surface area which is favorable for the diffusion of reactive substances. From the N2-adsorption and desorption isotherms (Fig. 3, right), it can be seen that there is a sharp increase in adsorption in the low partial pressure region (P/P0 < 0.1), which is attributed to the filling of micropores, indicating that there is a certain amount of microporous structure in the material, and there is a hysteresis loop within the range of P/P0 of about 0.40 to 0.99, which suggests that there is an abundance of mesoporous structure in this ZIF molecular sieve. The SF-pore size distribution graph (Fig. 4, left) shows that the most available pore size of this sample is 0.56 nm. The total pore volume of this ZIF molecular sieve is 0.97 cm3/g, and the microporous volume is 0.64 cm3/g, with 66% of micropores, and the microporous structure can significantly increase the specific surface area of the sample, but the molecular sieve will limit the catalytic activity under certain conditions due to the smaller pore size. However, under certain conditions, the smaller pore size will limit the diffusion rate of the catalytic reaction, which makes the performance of molecular sieve catalyst limited, however, the mesoporous structure can obviously make up for this defect of the microporous structure, so the structure of the combination of microporous-mesoporous can effectively solve the problem of the limitation of the mass transfer capacity of the traditional molecular sieve with a single pore. Fig. 1 Specific surface area test results (left) and N2-sorption and desorption isotherms (right) for ZIF molecular sieves Fig. 2 SF-pore size distribution (left) and NLDFT-pore size distribution (right) of ZIF molecular sieve
View MoreThe characterization of copper foil morphology by scanning electron microscopy can help researchers and developers to optimize and improve the preparation process and performance of copper foils to further meet the existing and future quality requirements of high-performance lithium-ion batteries. Wide Range of Copper Applications Copper metal is widely used in lithium-ion batteries and printed circuit boards because of its ductility, high conductivity, ease of processing and low price. Depending on the production process, copper foil can be categorized into calendered copper foil and electrolytic copper foil. Calendered copper foil is made of copper blocks rolled repeatedly, with high purity, low roughness and high mechanical properties, but at a higher cost. Electrolytic copper foil, on the other hand, has the advantage of low cost and is the mainstream copper foil product in the market at present. The specific process of electrolytic copper foil is (1) dissolving copper: dissolve raw copper to form sulfuric acid-copper sulfate electrolyte, and remove impurities through multiple filtration to improve the purity of the electrolyte. (2) Raw foil preparation: usually polished pure titanium rolls as the cathode, through electrodeposition of copper ions in the electrolyte is reduced to the surface of the cathode to form a certain thickness of copper layer. (3) Surface treatment: the raw foil is peeled off from the cathode roll, and then after post-treatment, the finished electrolytic copper foil can be obtained. Figure 1 Electrolytic Copper Foil Production Process Copper Metal in Lithium-ion Batteries Lithium-ion batteries are mainly composed of active materials (cathode material, anode material), diaphragm, electrolyte and conductive collector. Positive potential is high, copper is easy to be oxidized at higher potentials, so copper foil is often used as the anode collector of lithium-ion batteries. The tensile strength, elongation and other properties of copper foil directly affect the performance of lithium-ion batteries. At present, lithium-ion batteries are mainly developed towards the trend of "light and thin", so the performance of electrolytic copper foil also puts forward higher requirements such as ultra-thin, high tensile strength and high elongation. How to effectively improve the electrolytic copper foil process to enhance the mechanical properties of copper foil is the main research direction of copper foil in the future. Suitable additive formulation in the foil making process is the most effective means to regulate the performance of electrolytic copper foil, and qualitative and quantitative research on the effect of additives on the surface morphology and physical properties of electrolytic copper foil has been a research hotspot for scholars at home and abroad. In materials science, the microstructure determines its mechanical properties, and the use of scanning electron microscopy to characterize the changes in the surface micro-m...
View MoreConductive paste is a special functional material with both conductive and bonding properties, widely used in new energy batteries, photovoltaic, electronics, chemical industry, printing, military and aviation and other fields. Conductive paste mainly includes conductive phase, bonding phase and organic carrier, of which the conductive phase is the key material of conductive paste, determining the electrical properties of the paste and the mechanical properties after film formation. The commonly used materials of conductive phase include metal, metal oxide, carbon materials and conductive polymer materials, etc. It is found that the physical parameters such as specific surface area, pore size and true density of conductive phase materials have an important influence on the conductivity and mechanical properties of the slurry. Therefore, it is particularly important to accurately characterise physical parameters such as specific surface area, pore size distribution and true density of conductive phase materials based on gas adsorption technology. In addition, precise tuning of these parameters can optimise the conductivity of the pastes to meet the requirements of different applications. 01 Conductive paste introduction According to the actual application of different types of conductive paste is not the same, usually according to the different types of conductive phase, can be divided into conductive paste: inorganic conductive paste, organic conductive paste and composite conductive paste. Inorganic conductive paste is divided into metal powder and non-metallic two kinds of metal powder mainly gold, silver, copper, tin and aluminium, etc., non-metallic conductive phase is mainly carbon materials. Organic conductive paste in the conductive phase is mainly conductive polymer materials, which has a smaller density, higher corrosion resistance, better film-forming properties and in a certain range of conductivity adjustable and so on. Composite system conductive paste is currently an important direction of conductive paste research, the purpose is to combine the advantages of inorganic and organic conductive paste, the inorganic conductive phase and organic material support body organic combination, give full play to the advantages of both. Conductive phase as the main functional phase in the conductive paste, to provide electrical pathway, to achieve electrical properties, its specific surface area, pore size and true density and other physical parameters have a greater impact on its conductive properties. Specific surface area: the size of the specific surface area is the key factor affecting the conductivity, within a certain range, a larger specific surface area provides more electronic conduction pathways, reducing the resistance, making the conductive paste more conductive. High conductivity is critical in many applications, such as in electronic devices to ensure efficient conduction of circuits. Pore size: ...
View MoreCeramic materials have a series of characteristics such as high melting point, high hardness, high wear resistance, and oxidation resistance, and are widely used in various fields of national economy such as the electronics industry, automotive industry, textile, chemical industry, and aerospace. The physical properties of ceramic materials depend largely on their microstructure, which is an important application area of SEM. What are ceramics? Ceramic materials are a class of inorganic non-metallic materials made of natural or synthetic compounds through forming and high-temperature sintering and can be divided into general ceramic materials and special ceramic materials. Special ceramic materials can be classified according to chemical composition: oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics, silicide ceramics, etc.; according to their characteristics and applications can be divided into structural ceramics and functional ceramics. Figure 1 Microscopic morphology of boron nitride ceramics SEM helps to study the properties of ceramic materials With the continuous development of society and science and technology, people's requirements for materials have been increasing, which requires a deeper understanding of the various physical and chemical properties of ceramics. The physical properties of ceramic materials are largely dependent on their microstructure [1], and SEM images are widely used in ceramic materials and other research fields because of their high resolution, wide adjustable magnification range, and stereoscopic imaging. The CIQTEK Field Emission Scanning Electron Microscope SEM5000 can be used to observe the microstructure of ceramic materials and related products easily, and in addition, the X-ray energy spectrometer can be used to determine the elemental composition of materials quickly. Application of SEM in the Study of Electronic CeramicsThe largest end-use market of the special ceramics industry is the electronics industry, where barium titanate (BaTiO3) is widely used in multilayer ceramic capacitors (MLCC), thermistors (PTC), and other electronic components because of its high dielectric constant, excellent ferroelectric and piezoelectric properties, and voltage resistance and insulation properties [2]. With the rapid development of the electronic information industry, the demand for barium titanate is increasing, and the electronic components are becoming smaller and more miniaturized, which also puts forward higher requirements for barium titanate.Researchers often regulate the properties by changing the sintering temperature, atmosphere, doping, and other preparation processes. Still, the essence is that the changes in the preparation process cause changes in the microstructure of the material and thus the properties. Studies have shown that the dielectric ferroelectric properties of barium titanate are closely related to the material's mi...
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