The electron spin sensor has high sensitivity and can be widely used to detect various physical and chemical properties, such as electric field, magnetic field, molecular or protein dynamics, nuclei or other particles, etc. These unique advantages and potential applications make spin-based sensors a hot research direction. Sc3C2@C80, with its highly stable electron spin protected by a carbon cage, is suitable for gas adsorption detection inside porous materials. Py-COF is a recently emerged porous organic framework material with unique adsorption properties. It is synthesized using self-condensation building blocks with formyl and amino groups, and its theoretical pore size is 1.38 nm. Therefore, a metallofullerene Sc3C2@C80 unit (with a size of approximately 0.8 nm) can enter a nanoscale pore of Py-COF. Researcher Wang from the Institute of Chemistry, Academy of Sciences, has developed a nano spin sensor based on metallofullerene for detecting gas adsorption inside porous organic frameworks. Paramagnetic metallofullerene, Sc3C2@C80, is embedded in nanoscale pores of a pyrene-based covalent organic framework (Py-COF). The EPR Spectroscopy (CIQTEK EPR200-Plus) is used to record the EPR signals of the embedded Sc3C2@C80 spin probe for N2, CO, CH4, CO2, C3H6, and C3H8 adsorbed within Py-COF. The study reveals that the EPR signals of embedded Sc3C2@C80 exhibit a regular dependence on the gas adsorption performance of Py-COF. The research findings are published in Nature Communications under the title "Embedded nano spin sensor for in situ probing of gas adsorption inside porous organic frameworks. " Using Sc3C2@C80 as a molecular spin probe to investigate the gas adsorption performance of PyOF In the study, the authors used a paramagnetic metallofullerene, Sc3C2@C80 (size approximately 0.8 nm), as a spin probe embedded in a pyrene-based covalent organic framework (Py-COF) nanocage to detect gas adsorption in Py-COF. The adsorption performance of N2, CO, CH4, CO2, C3H6, and C3H8 gases in Py-COF was investigated by monitoring the embedded Sc3C2@C80 Electron Paramagnetic Resonance (EPR) signal. The study demonstrated that the EPR signal of Sc3C2@C80 was systematically related to the gas adsorption performance of Py-COF. Additionally, unlike traditional adsorption isotherm measurements, this implantable nanoscale spin sensor enabled real-time gas adsorption and desorption monitoring. The proposed nanoscale spin sensor was also utilized to investigate the gas adsorption performance of a metal-organic framework (MOF-177), showcasing its multifunctionality. Relationship Between Gas Adsorption Performance and EPR Signal The effect of gas pressure on EPR signals Analysis of EPR Signal LineWidth Using the molecular spin method of Sc3C2@C80 to investigate the gas adsorption process in MOF-177  ...
View MoreResearch Publications Applied Catalysis B: Environmental: S2-doping inducing self-adapting dual anion defects in ZnSn(OH)6 for highly efficient photoactivity. Application of CIQTEK EPR200-Plus Series AFM: Simultaneous CO2 and H2O Activation via Integrated Cu Single Atom and N Vacancy Dual-Site for Enhanced CO Photo-Production. Application of CIQTEK EPR200-Plus Series Background In the past century, with the massive growth of population and the continuous expansion of industrial scale, large amounts of traditional fossil energy such as oil, coal, and natural gas have been burned, resulting in problems such as resource shortages and environmental pollution. How to solve these problems has always been the direction of research. With the introduction of policies such as "carbon peaking" and "carbon neutrality", limited resources can no longer meet people's growing development needs, and it is of great significance to seek a sustainable solution. Scientists have focused on many sustainable energy sources. Among clean energy sources such as solar energy, wind energy, hydro energy, geothermal energy and tidal energy, solar energy stands out due to its clean, renewable and huge energy. How to make full use of solar energy and in Solving energy shortages and reducing pollution emissions while applying it to the degradation of pollutants has become a research direction that researchers are committed to. At present, photocatalytic materials are roughly divided into two categories: inorganic semiconductor photocatalysts and organic semiconductor photocatalysts. Inorganic semiconductor photocatalysts mainly include: metal oxides, metal nitrides, and metal sulfides; organic semiconductor photocatalysts include: g-C3N4, linear covalent polymers, covalent porous polymers, covalent organic frameworks, and covalent triazines Organic framework. Based on the principle of photocatalysis, photocatalytic semiconductors are used in photocatalytic water splitting, photocatalytic carbon dioxide reduction, photocatalytic degradation of pollutants, photocatalytic organic synthesis, and photocatalytic production of ammonia. Electron paramagnetic resonance (EPR) technology is currently the only method that can directly, in-situ, and non-destructively detect unpaired electrons. EPR technology can directly detect vacancies (oxygen vacancies, nitrogen vacancies, sulfur vacancies, etc.) and doped electrons in photocatalytic materials. The valence state of heterotransition metals. In addition, EPR technology can also detect free radicals such as e-, h+, •OH, O2•-, 1O2, SO3•- generated on the surface of the photocatalyst. EPR Technology Test Examples CN (Cu1/N2CV-CN) photocatalytic carbon dioxide reduction (1) EPR technology directly detects transition metal copper and N2C vacancies in the photocatalytic material CN; (2)EPR technology supports the analysis results of XAFS. The EPR spectrum shows thre...
View MoreEnvironmental pollution is one of the global crises and is affecting the quality of living and health of the entire population. A new class of harmful substances, the environmentally persistent free radicals (EPFRs). These pollutants are pervasive and can be found in air, water, and soil. The EPFRs can be recognized as biohazard since it can produce reactive oxide species (ROS), which causes cell and tissue damages and ultimately cancer. To mitigate and eventually find a solution to this problem, tracing the origin of such pollutants is needed. Electron paramagnetic resonance (EPR) spectroscopy is a powerful tool and can be used for such tasks. What are EPFRs The conventionally recognized free radicals are often transient with a short lifetime. On the contrary, EPFRs can be stable in the environment for tens of minutes to tens of days without being oxidized or quenched. The commonly found EPFRs include, cyclopentadienyl, semiquinone, phenoxy, and other radicals. Common EPFRs Where do EPFRs come from? EPFRs are found in a wide range of environmental media, such as atmospheric particulate matter (e.g. PM 2.5), factory emissions, tobacco, petroleum coke, wood and plastic, coal combustion particulates, soluble fractions in water bodies, and organically contaminated soils, etc. EPFRs have a wide range of transport pathways in environmental media and can be transported through vertical ascent, horizontal transport, vertical deposition to water bodies, vertical deposition to land, and landward migration of water bodies. In the process of migration, new reactive radicals may be generated, which directly affects the environment and are precursors to other pollutants. Formation and Multimediated Transfer of EPFRs (Environmental Pollution 248 (2019) 320-331) Application of EPR Technique for the Detection of EPFRs EPR spectroscopy is extremely sensitive to unpaired electrons, and a directly measurement of signals from these radicals make it an ideal method for monitoring the presence of EPFRs in different samples. . For the detection of EPFRs, EPR (ESR) spectroscopy provides information in both spatial and temporal dimensions. By measuring and analyzing the continuous-wave EPR spectra of samples, the researchers are able to not only verifying the presence of radicals but also obtain g-values and hyperfine coupling constants of electrons, which can be used for inferring electronic structure of measured molecules. The temporal resolution refers to the half-life of EPFRs, which can also be obtained from monitoring their EPR signals over time. Application of EPR Technology in Detecting EPFRs in the Soil Environment Petroleum processing, storage, transportation, and possible leakage from storage tanks are all susceptible to soil contamination. Although thermal treatment techniques can be used to remediate soils contaminated by various volatile, semi-volati...
View MoreExpandable microspheres, small thermoplastic spheres encapsulated with gas, consist of a thermoplastic polymer shell and an encapsulated liquid alkane gas. When the microspheres are heated, the shell softens and the internal air pressure increases dramatically, causing the microspheres to expand dramatically to 60 times their original volume, giving them the dual function of a lightweight filler and a blowing agent. As a lightweight filler, expandable microspheres can greatly reduce the weight of products with very low density, and their density measurement is very important. Figure 1 Expandable microspheres Principle of EASY-G 1330 series true density tester EASY-G 1330 series true density tester is based on Archimedes' principle, using small molecular diameter gas as the probe and the ideal gas equation of state PV=nRT to calculate the volume of gas discharged from the material under certain temperature and pressure conditions, so as to determine the true density of the material. The small molecular diameter gas can be used as nitrogen or helium, because helium has the smallest molecular diameter and is a stable inert gas, which is not easy to react with the sample by adsorption, so helium is generally recommended as the replacement gas. Advantages of EASY-G 1330 series true density tester EASY-G 1330 series true density tester uses gas as the probe, which will not damage the test sample, and the sample can be recycled directly; and in the testing process, the gas will not react with the sample, and will not cause corrosion to the equipment, so the safety factor of the use process is high; furthermore, the gas has the characteristics of easy diffusion, good permeability and good stability, which can penetrate into the internal pores of the material more quickly and make the test results more accurate. Experimental Procedure ①Warm-up: Open the cylinder main valve and pressure-reducing table, turn on the power switch at least half an hour in advance, gas pressure-reducing table output pressure: 0.4 ± 0.02 MPa; ②Instrument Calibration: Before the experiment starts, calibrate the instrument with standard steel balls to ensure that the volume of steel balls tested in all pipelines of the equipment are within the standard value before starting the experiment; ③Sample Tube Volume Determination: Install the empty sample tube into the instrument cavity and tighten it, set up the software, determine the sample tube volume, and record the corresponding sample tube volume at the end of the experiment; ④Sample Weighing: In order to reduce the testing error, it is necessary to weigh as many samples as possible, each test shall weigh the sample to about 3/4 of the sample tube volume, weigh the empty tube mass M1, add the sample and weigh M2 to calculate the sample mass; ⑤Sample Processing: All samples were not pretreated in order to achieve consistency w...
View MoreThe electron paramagnetic resonance (EPR or ESR) technique is the only method available for directly detecting unpaired electrons in samples. Among them, the quantitative EPR (ESR) method can provide the number of unpaired electron spins in a sample, which is essential in studying the reaction kinetics, explaining the reaction mechanism and commercial applications. Therefore, obtaining the unpaired electron spin numbers of samples by electron paramagnetic resonance techniques has been a hot topic of research. Two main quantitative electron paramagnetic resonance methods are available: relative quantitative EPR (ESR) and absolute quantitative EPR (ESR). Relative Quantitative EPR (ESR) Method The relative quantitative EPR method is accomplished by comparing the integrated area of the EPR absorption spectrum of an unknown sample with the integrated area of the EPR absorption spectrum of a standard sample. Therefore, in the relative quantitative EPR method, a standard sample with a known number of spins needs to be introduced. The size of the integrated area of the EPR absorption spectrum is not only related to the number of unpaired electron spins in the sample, but also to the settings of the experimental parameters, the dielectric constant of the sample, the size and shape of the sample, and the position of the sample in the resonant cavity. Therefore, to obtain more accurate quantitative results in the relative quantitative EPR method, the standard sample and the unknown sample need to be similar in nature, similar in shape and size, and in the same position in the resonant cavity. Quantitative EPR Error Sources Absolute Quantitative EPR (ESR) Method The absolute quantitative EPR method means that the number of unpaired electron spins in a sample can be obtained directly by EPR testing without using a standard sample. In absolute quantitative EPR experiments, to obtain the number of unpaired electron spins in a sample directly, the value of the quadratic integral area of the EPR spectrum (usually the first-order differential spectrum) of the sample to be tested, the experimental parameters, the sample volume, the resonance cavity distribution function and the correction factor are needed. The absolute number of unpaired electron spins in the sample can be directly obtained by first obtaining the EPR spectrum of the sample through the EPR test, then processing the EPR first-order differential spectrum to obtain the second-integrated area value, and then combining the experimental parameters, sample volume, resonant cavity distribution function and correction factor. CIQTEK Electron Paramagnetic Resonance Spectroscopy The absolute quantification of unpaired electron spins of the CIQTEK EPR (ESR) spectroscopy can be used to obtain the spin number of unpaired electrons in a sample directly without the use of a reference or standard sample. The resonant cavity distribution funct...
View MoreDrug powders are the main body of most pharmaceutical formulations, and their efficacy depends not only on the type of drug, but also to a large extent on the properties of the powders composing the pharmaceutical formulations. Numerous studies have shown that physical parameters such as specific surface area, pore size distribution and true density of drug powders are related to the properties of powder particles such as particle size, hygroscopicity, solubility, dissolution and compaction, and play an important role in the purification, processing, mixing, production and packaging capabilities of pharmaceuticals. Especially for APIs and pharmaceutical excipients, parameters such as specific surface area are important indicators of their performance. The specific surface area of API, as the active ingredient of a drug, affects its properties such as solubility, particle size and solubility. Under certain conditions, the larger the specific surface area of the same weight of API, the smaller the particle size, dissolution and dissolution rate is also accelerated. By controlling the specific surface area of the API, it can also achieve a good uniformity and fluidity, to ensure uniform distribution of drug content. Pharmaceutical excipients, as excipients and additional agents used in the production of drugs and prescriptions, specific surface area is one of the important functional indicators, which is important for diluents, binders, disintegrants, flow aids, and especially lubricants. For example, for lubricants, the specific surface area significantly affects their lubrication effect, because the prerequisite for lubricants to play a lubricating effect is to be able to be uniformly dispersed on the surface of the particles; generally speaking, the smaller the particle size, the larger the specific surface area, and the easier it is to be uniformly distributed during the mixing process. Thus, accurate, rapid and effective testing of physical parameters such as specific surface area and true density of pharmaceutical powders has always been an indispensable and critical part of pharmaceutical research. Therefore, the methods for the determination of specific surface area and solid density of pharmaceutical powders are clearly defined in the United States Pharmacopoeia USP<846> and USP<699>, the European Pharmacopoeia Ph. Eur. 2.9.26 and Ph. Eur. 2.2.42, as well as in the second additions of the physical and chemical analysis contents 0991 and 0992 to the four general rules of the Chinese Pharmacopoeia, 2020 edition. 01 Gas adsorption technique and its application Gas adsorption technique is one of the important methods for material surface property characterization. Based on adsorption analysis, it can accurately analyze the specific surface area, pore volume and pore size distribution, true density and other parameters of APIs, pharmaceutical excipients and drug formulations. In turn, it can do some...
View MorePowders are today's raw materials for the preparation of materials and devices in various fields and are widely used in lithium-ion batteries, catalysis, electronic components, pharmaceuticals, and other applications. The composition and microstructure of the raw material powders determine the properties of the material. The particle size distribution ratio, shape, porosity, and specific surface of the raw material powders can match the unique properties of the material. Therefore, the regulation of the microstructure of the raw material powder is a prerequisite for obtaining excellent performance materials. The use of scanning electron microscopy allows observation of the specific surface morphology of the powder and precise analysis of the particle size to optimize the preparation process of the powder. Application of scanning electron microscopy in MOFs materials In the field of catalysis, the construction of metal-organic backbone materials (MOFs) to substantially improve the surface catalytic performance has become one of the hot research topics today. MOFs have the unique advantages of high metal loading, porous structure and catalytic sites, and have great potential as cluster catalysts. Using the CIQTEK Tungsten Filament Scanning Electron Microscope, it can be observed that the MOFs material shows regular cubic shape and the presence of fine particles adsorbed on the surface (Figure 1). The electron microscope possesses a resolution of up to 3 nm and excellent imaging quality, and uniform high-brightness SEM maps can be obtained in different fields of view, which can clearly observe the folds, pores, and particle loading on the surface of MOFs materials. Figure 1 MOFs material / 15 kV/ETD Scanning electron microscopy in silver powder materials In the manufacture of electronic components, electronic paste, as a basic material for manufacturing electronic components, has certain rheological and thixotropic properties, and is a basic functional material integrating materials, chemical and electronic technologies, and the preparation of silver powder is the key to manufacturing silver conductive paste. Using the SEM5000 field emission scanning electron microscope independently developed by CIQTEK, relying on the high voltage tunneling technology, the space charge effect is drastically reduced, and irregular silver powder clustering with each other can be observed (Figure 2). And the SEM5000 has high resolution, so that details can still be seen even at 100,000x magnification. Figure 2 Silver powder/5 kV/Inlens Scanning electron microscopy in lithium iron phosphate Lithium-ion batteries are rapidly occupying the mainstream market because of their high specific energy, long cycle life, no memory effect, and high safety. The use of electron microscopy to observe the positive and negative electrode morphology of lithium-ion batteries is important to improve t...
View MoreIn recent years, hydrogen energy and carbon capture and utilization-related industries have received extensive attention and development, especially hydrogen storage and CO2 capture and conversion and utilization-related industries. The research of H2, CO2, and other gas storage and separation materials is the key to promoting the development of related industries. Recently, Prof. Cheng Xingxing's group at Shandong University synthesized biomass cellulose carbon aerogel with a three-dimensional network structure from Tetragonum officinale (TO) and further enhanced the energy storage performance of the carbon aerogel with KOH activation.TO cellulose carbon aerogel is characterized by its lightweight (3.65 mg/cm3), superhydrophobicity, and large specific surface area (1840 cm2/g). Due to the excellent microporous volume and abundant functional groups, TO carbon aerogel can be used as a multifunctional adsorbent material in different applications. The material possesses 0.6 wt% hydrogen storage capacity, 16 mmol/g CO2 adsorption capacity, 123.31 mg/g o-xylene, and 124.57 mg/g o-dichlorobenzene adsorption capacity at room temperature. The low-cost, environmentally friendly, and multifunctional TO cellulose carbon aerogels are promising for various applications such as hydrogen storage, carbon sequestration, and dioxin removal. The study provides a new and effective approach for the sustainable design and fabrication of high-performance functional carbon materials from renewable biomass resources, which can be widely used in energy storage and environmental protection industries. The study is entitled "Multifunctional carbon aerogels from typha orientalis for applications in adsorption: Hydrogen storage, CO2 capture, and VOCs removal". Removal" was published in the journal Energy. The CIQTEK EASY-V product line was used in the study. Schematic illustration for the fabrication procedure of TO cellulose carbon aerogels. In addition, in the direction of gas separation materials research, Prof. Ren Xiuxiu's group at Changzhou University successfully prepared composite membranes for H2 separation by doping two-dimensional (2D) molybdenum disulfide (MoS2), which is unique to H2, into grafted microporous organosilica networks derived from 1,2-bis(triethoxysilyl)ethane (BTESE) using the sol-gel method. The research results were published in the journal Industrial & Engineering Chemistry Research under the title "Laminar MoS2 Nanosheets Embedded into Organosilica Membranes for Efficient H2 Separation. Due to their opposite ζ-potentials, the BTESE sols generated by the hydrolysis polymerization reaction and the MoS2 nanosheets formed a continuous surface without lamellar boundary defects. With the increase of MoS2 content, the H2 transmittance of BTESE membranes showed an overall increasing trend in the range of 1.85 ~ 2.89 × 10-7 mol·...
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