染雾Identification of pore size in porous materials: A review of characterization techniques
篇一：Identification of pore size in porous materials: A review of characterization techniques
Introduction:
Porous materials play a crucial role in various fields, including catalysis, filtration, and energy storage. The pore size distribution and pore structure of these materials greatly influence their performance and properties. Therefore, accurate identification and characterization of pore size are essential for understanding the behavior and optimizing the design of porous materials. In this article, we will review various techniques used for the identification of pore size in porous materials.
1. Mercury intrusion porosimetry:
Mercury intrusion porosimetry (MIP) is a widely used technique for pore size characterization. It involves the intrusion of mercury into the pores under controlled pressure. By measuring the volume of mercury intruded at different pressures, the pore size distribution can be determined. MIP has a wide measurement range, typically from nanometers to micrometers, making it suitable for a variety of porous materials.
2. Gas adsorption:
Gas adsorption techniques, such as nitrogen or argon adsorption, are commonly used to determine the pore size distribution in porous materials. The adsorption isotherms obtained at different temperatures and pressures provide valuable information about the pore size and surface area. The Brunauer-Emmett-Teller (BET) theory is often applied to analyze the data and calculate the specific surface area and pore size distribution.
3. Scanning electron microscopy (SEM):
SEM is a powerful imaging technique that can provide valuable information about the morphology and pore structure of porous materials. By capturing high-resolution images of the material's surface, SEM can help identify the pore size and pore shape. Combined with image analysis software, SEM can quantify the pore size distribution and provide insights into the connectivity and arrangement of pores.
4. X-ray diffraction (XRD):
XRD is commonly used to determine the crystalline structure and phase composition of materials. In the case of porous materials, XRD can provide information about the pore size indirectly. By analyzing the broadening of diffraction peaks, which is related to the size of coherent scattering domains, the average pore size can be estimated.
5. Nuclear magnetic resonance (NMR):
NMR techniques, particularly relaxometry and diffusometry, have been used to characterize porous materials. NMR can provide information about the pore size distribution and the surface-to-volume ratio. By analyzing the relaxation or diffusion behavior of the nuclear spins, the size and shape of the pores can be determined.
Conclusion:
Accurate identification of pore size is essential for understanding the behavior and optimizing the design of porous materials. A combination of different characterization techniques, such as MIP, gas adsorption, SEM, XRD, and NMR, provides a comprehensive understanding of the pore size distribution and pore structure in porous materials. Each technique has its advantages and limitations, and the choice of technique depends on the specific requirements and characteristics of the material under investigation.
Identification of pore size in porou 篇三
Identification of pore size in porous SiO2 thin film by positron annihilation
Positron annihilation lifetime and Doppler broadening of annihilation line techniques have been used to obtain information about the small pore structure and size of po
YU Run-Sheng,WANG Qiao-Zhan,WANG Bao-Yi(Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, CAS, Beijing 100049, China)
MA Yan-Yun(China Institute of Atomic Energy, Beijing 102413, China)
刊 名：中国物理C（英文版） ISTIC 英文刊名： CHINESE PHYSICS C 年，卷(期)： 200933(2) 分类号： O4 关键词： A1-Si thin film porous SiO2 thin film positron annihilation