Applications

Electron spin sensors have high sensitivity and can be widely used to probe various physicochemical properties, such as electric field, magnetic field, molecular or protein dynamics, and nuclear or other particles. These unique advantages and potential application scenarios make spin-based sensors a hot research direction at present. Sc3C2@C80 has a highly stable electron spin protected by a carbon cage, which is suitable for gas adsorption detection within porous materials. Py-COF is a recently emerged porous organic framework material with unique adsorption properties, which was prepared using a self-condensing building block with a formyl group and an amino group. prepared with a theoretical pore size of 1.38 nm. Thus, a metallofullerene Sc3C2@C80 unit (~0.8 nm in size) can enter one of the nanopores of Py-COF.   A nanospin sensor based on metal fullerene was developed by Taishan Wang, a researcher at the Institute of Chemistry, Chinese Academy of Sciences, for detecting gas adsorption within a porous organic framework. The paramagnetic metal fullerene, Sc3C2@C80, was embedded in the nanopores of a pyrene-based covalent organic framework (Py-COF). The adsorbed N2、CO、CH4、CO2、C3H6 and C3H8 within the Py-COF embedded with the Sc3C2@C80 spin probe were recorded using the EPR technique ( CIQTEK EPR200-Plus).It was shown that the EPR signals of the embedded Sc3C2@C80 regularly correlated with the gas adsorption properties of the Py-COF. The results of the study were published in Nature Communications under the title "Embedded nano spin sensor for in situ probing of gas adsorption inside porous organic frameworks".     Probing gas adsorption properties of Py-COF using molecular spin of Sc3C2@C8     In the study, the authors used a metallofullerene with paramagnetic properties, Sc3C2@C80 (~0.8 nm in size), as a spin probe embedded into one nanopore of pyrene-based COF (Py-COF) to detect gas adsorption within Py-COF. Then, the adsorption properties of Py-COF for N2、CO、CH4、CO2、C3H6 and C3H8 gases were investigated by recording the embedded Sc3C2@C80 EPR signals. It is shown that the EPR signals of Sc3C2@C80 regularly follow the gas adsorption properties of Py-COF. And unlike conventional adsorption isotherm measurements, this implantable nanospin sensor can detect gas adsorption and desorption by in situ real-time monitoring. The proposed nanospin sensor was also used to probe the gas adsorption properties of metal-organic framework (MOF-177), demonstrating its versatility.     Relationship between gas adsorption properties and EPR signals     Effect of gas pressure on EPR signal     EPR signal line width analysis   Spin-based sensors have attracted considerable attention owing to their high sensitivities. Herein, we developed a metallofullerene-based nano spin sensor to probe gas adsorption within porous organic frameworks. For this, spin-...

Environmental catalysts are broadly defined as all catalysts that can improve environmental pollution. In recent years, environmental protection has become more and more popular, and the research and application of environmental catalysts have become more and more in-depth. The environmental catalysts for processing different reactants have corresponding performance requirements, among which the specific surface area and pore size are one of the important indexes for characterizing the properties of environmental catalysts. It is of great significance to use gas adsorption technology to accurately characterize the physical parameters such as the specific surface area, the pore volume and the pore size distribution of the environmental catalysts for the research and optimization of their performance.   01Environmental protection catalyst   Currently, oil refining, chemical and environmental protection industries are the main application fields of catalysts. Environmental catalysts generally refer to the catalysts used to protect and improve the surrounding environment by directly or indirectly treating toxic and hazardous substances, making them harmless or reducing them, broadly speaking, catalysts capable of improving environmental pollution can be attributed to the category of environmental catalysts. Environmental catalysts can be divided into exhaust gas treatment catalysts, wastewater treatment catalysts and other catalysts according to the direction of application, such as molecular sieve catalysts that can be used for the treatment of exhaust gases such as SO2, NOX, CO2, and N2O, activated carbon that can be used as a typical adsorbent for the adsorption of liquid/gas-phase pollutants, as well as semiconductor photocatalysts that can degrade organic pollutants, and so on.   02 Specific surface and pore size analysis and characterization of environmental catalysts   Catalyst surface area is one of the important indexes to characterize catalyst properties. The surface area of catalyst can be divided into outer surface area and inner surface area. Since the majority of the surface area of environmental catalyst is inner surface area and the active center is often distributed on the inner surface, generally, the larger the specific surface area of environmental catalyst is, the more activation centers are on the surface, and the catalyst has a strong adsorption capacity for reactants, which are all favorable to the catalytic activity. In addition, the type of pore structure has a great influence on the activity, selectivity and strength of the catalyst. Before the reactant molecules are adsorbed, they must diffuse through the pores of the catalyst to reach the active center on the inner surface of the catalyst, and this diffusion process is closely related to the pore structure of the catalyst, and different pore structures show different diffusion laws and apparent reaction kinetics, for example, the strong selectivity of ...

What is nano alumina? Nano-alumina is widely used in various fields such as ceramic materials, composite materials, aerospace, environmental protection, catalysts, and their carriers because of its high strength, hardness, wear resistance, heat resistance, and large specific surface area [1]. This has led to the continuous improvement of its development technology. Currently, scientists have prepared alumina nanomaterials in various morphologies from one-dimensional to three-dimensional, including spherical, hexagonal sheet, cubic, rod, fibrous, mesh, flower, curly, and many other morphologies [2].   Scanning electron microscopy of alumina nano-particles   There are many methods for the preparation of nano alumina, which can be divided into three main categories according to the different reaction methods:  Solid-phase, gas-phase, and liquid-phase methods [3]. In order to verify that the results of the prepared alumina nanopowders are as expected, it is necessary to characterize the structure of alumina under each process, and the most intuitive of the many characterization methods is the microscopic observation method.   The scanning electron microscope, as a conventional microscopic characterization equipment, has the advantages of large magnification, high resolution, large depth of field, clear imaging, and strong stereoscopic sense, which is the preferred equipment for characterizing the structure of nano-alumina.   The following figure shows the alumina powder prepared under different processes observed using CIQTEK Field Emission Scanning Electron Microscope SEM5000, which contains alumina nanopowders in the form of cubes, flakes, and rods, and with particle sizes of tens to hundreds of nanometers.     CIQTEK Field Emission Scanning Electron Microscope SEM5000   SEM5000 is a high-resolution, feature-rich field emission scanning electron microscope, with advanced barrel design, in-barrel deceleration, and low aberration non-leakage magnetic objective design, to achieve low-voltage high-resolution imaging, that can be applied to magnetic samples. SEM5000 has optical navigation, perfect automatic functions, well-designed human-machine interaction, and optimized operation, and use process. Regardless of whether the operator has extensive experience, he/she can quickly get started with the task of high-resolution photography.   Electron gun type: high-brightness Schottky-field emission electron gun Resolution: 1 nm @ 15 kV  1.5 nm @ 1 kV   Magnification: 1 ~ 2500000 x   Acceleration voltage: 20 V ~ 30 kV   Sample table: five-axis automatic sample table     References.  [1] Wu ZF. Study on the relationship between the morphology and properties of alumina nanoparticles[J]. Journal of Artificial Crystals, 2020,49(02):353-357. doi:10.16553/j.cnki.issn1000-985x.2020.02.024.  [2] Nie Duofa. A brief discussion on the preparation of nanoalumina...

For centuries, mankind has been exploring magnetism and its related phenomena without pause. In the early days of electromagnetism and mechanics, it was difficult for humans to imagine the attraction of magnets to iron, and the ability of birds, fish, or insects to navigate between destinations thousands of miles apart - amazing and interesting phenomena with the same magnetic origin. These magnetic properties originate from the moving charge and spin of elementary particles, which are as prevalent as electrons.    Two-dimensional magnetic materials have become a research hotspot of great interest, and they open up new directions for the development of spintronics devices, which have important applications in new optoelectronic devices and spintronics devices. Recently, Physics Letters 2021, No. 12, also launched a special feature on 2D magnetic materials, describing the progress of 2D magnetic materials in theory and experiments from different perspectives.    A two-dimensional magnetic material only a few atoms thick can provide the substrate for very small silicon electronics. This amazing material is made of pairs of ultra-thin layers that are stacked together by van der Waals forces, i.e. intermolecular forces, while the atoms within the layers are connected by chemical bonds. Although only atomically thick, it still retains physical and chemical properties in terms of magnetism, electricity, mechanics, and optics.     Two-dimensional Magnetic Materials Image referenced from https://phys.org/news/2018-10-flexy-flat-functional-magnets.html   To use an interesting analogy, each electron in a two-dimensional magnetic material is like a tiny compass with a north and south pole, and the direction of these "compass needles" determines the magnetization intensity. When these infinitesimal "compass needles" are spontaneously aligned, the magnetic sequence constitutes the fundamental phase of matter, thus allowing the preparation of many functional devices, such as generators and motors, magnetoresistive memories, and optical barriers. This amazing property has also made two-dimensional magnetic materials hot. The microelectronics industry has encountered bottlenecks such as low reliability and high power consumption, and Moore's law, which has lasted for nearly 50 years, has also encountered difficulties (Moore's law: the number of transistors that can be accommodated on an integrated circuit doubles in about every 18 months). If two-dimensional magnetic materials can be used in the future in the field of magnetic sensors, random memory, and other new spintronics devices, it may be possible to break the bottleneck of integrated circuit performance.    We already know that magnetic van der Waals crystals carry special magnetoelectric effects, and therefore quantitative magnetic studies are an essential step in the research of two-dimensional magnetic materials. However, quantitative experimental studies on...