Issn: CN 22-1128/O6
Director:Chinese Academy of Sciences
Host:Changchun Institute of Applied Chemistry, Chinese Academy of Sciences
Heavy metals are difficult to biodegrade and pose a serious threat to the environment and human life and health. Hence， the detection and treatment of heavy metal pollution is vital. In recent years， electrochemical methods for the detection of heavy metal ions have become a research hotspot in the field of heavy metal detection because of their high sensitivity， fast analysis speed and the ability to detect multiple metal ions simultaneously. This paper reviews the detection principles and development status of common electrochemical detection methods， and describes the detection effects of potentiometric analysis， potentiometric stripping analysis and voltammetry by introducing the parameters of linear range， detection limit and recovery. Finally， the review outlines the advantages and disadvantages of various methods， and points out the future research directions in order to provide a basis for the application of electrochemical sensors.
Layered transition metal oxide cathode materials for sodium-ion batteries have the characteristics of low price and high specific capacity， which is an important support for energy transition in the future and has great development potential. In the process of charging and discharging， the typical layered oxide cathode materials with the most promising development and application will produce a series of changes affecting their electrochemical properties with the insertion and extration of sodium-ion. Therefore， the modification of cathode materials is particularly important. The current mainstream failure mechanism， modification methods， challenges and key problems to be solved in the future development are summarized and put forward.
Lignin is one of the most abundant and significant natural polymeric materials in the world， and its position is only second to cellulose. In woody plants， lignin content accounts for about 25%. Due to its chemical inertness and structural complexity， the application of lignin is very limited. Therefore， the chemical modification of lignin is the key method to transform lignin into functional materials， which is of great significance for the sustainable development of resources and environment. In this review， the research progress on the development of chemical modification of lignin and its applications， including wastewater treatment， heterogeneous catalysis and other aspects， are summarized. Furthermore， discussions on challenges and perspectives in the field of lignin modification are also presented.
The effect of hydroxyapatite （HA） samples in different quality states on X-ray diffraction （XRD） results has been investigated systematically. The effects of sample state （block， layered and powder， etc.）， experimental method selection （powder polycrystalline diffraction and thin film grazing incidence diffraction， etc.） and detection environmental conditions （temperature， humidity and X-ray irradiation） on XRD detection are investigated. The results show that， compared with the block sample of HA， the intensity of the characteristic XRD peak of the powder sample after grinding and sieving treatment is significantly enhanced. For HA multi-layered growth samples， the phase analysis of each layer can be accurately achieved by combining grazing incidence and conventional powder diffraction. The particle size， amount， and filling method of the HA powder sample can also affect the XRD detection. The results show that the characteristic peak intensity of the HA powder sample with a particle size of 37 μm is about twice that of the sample with a particle size of 137 μm. In addition， the vacant sample preparation in the middle of a small amount of samples can cause the peak position of the characteristic peak to shift from 31.8 to 31.4（°）， and the peak intensity decreases from 11213.68 to 601.65. Moreover， appropriate storage and detection methods can prevent and avoid erroneous detection and result analysis for samples with poor stability to ambient temperature and humidity. Thus， ensuring high-quality XRD detection data and ensuring experimental data quality requires comprehensive quality control.
Solid oxide fuel cells （SOFCs） are energy conversion devices with high conversion efficiency， environmental friendliness， and wide fuel adaptability. As the place of electrochemical reactions， electrodes play a key role in the performance of SOFCs. Compared with the conventional electrode materials， the electrode with nanoparticles exsolved on the surface show stronger catalytic activity and excellent electrochemical performance. In this article， the investigations of in situ exsolution of perovskite-type electrode materials are summarized. Firstly， the effect of the crystal structure of perovskite on exsolution of electrode is discussed. Secondly， the influences of defects in perovskite on the exsolution of nanoparticles are introduced in detail. And then two main methods for in situ exsolution are compared and different exsolved products are analyzed. Finally， the difficulties and challenges faced to the in situ exsolution investigation for the SOFC electrode are put forward on the basis of the existing research， which points out the direction for future study.
The purity， microstructure and uniformity of ceramic powders will affect the final performance of ceramic products. Therefore， achieving the controlled synthesis of SiC powders is the current research focus of silicon carbide preparation. Herein， SiC is used as the main material to summarize its main preparation methods. Under the normal pressure sintering system， the specific effects of temperature， raw materials， catalysts， gas supersaturation and other factors on SiC products are discussed based on the growth mechanism of Vapor-Liquid-Solid （VLS） mechanism and the Vapor-Solid （VS） mechanism. The controllable synthesis of SiC ceramic powder has important theoretical value and guiding significance for the large-scale production， application and subsequent preparation of ceramic products.
Portulaca oleracea L. （PO） contains various active chemicals. PO is a medicine and food homologous to traditional Chinese medicine， which has high medicinal and edible value. In recent years， it has been widely used in the field of the chemical industry， especially in the field of cosmetics. Cosmetic companies have developed facial masks， essence， skin care water， cleanser and other cosmetic products that have been added the active ingredient extracted from PO. However， the related commercial cosmetics of PO mainly contain the ethanol extracts， while there are few cosmetic products involving its aqueous extracts， such as polysaccharide and polyphenol. The emergence of new dosage forms has enriched the research on the percutaneous delivery system of PO in cosmetics， and new carriers such as liposomes， delivery bodies， and β-cyclodextrins can be developed in the future. The chemical composition， function， mechanism， and application of Portulaca oleracea in cosmetics are summarized， and some suggestions and prospects are put forward on the development and application of Portulaca oleracea in cosmetics.
Novel oil-soluble fluorescent carbon quantum dots （o-CDs） are prepared by pyrolysis with citric acid， glutathione and oleamine as raw materials. The o-CDs have good photochemical properties and optical stability. The maximum excitation wavelength and emission wavelengths are located at 375 and 440 nm， respectively， and the fluorescence quantum yield is 0.48. A fluorescence sensor with high sensitivity and selectivity for detection of oxytetracycline is established based on the fluorescence quenching effect. The o-CDs based fluorescence sensor exhibits a good linear relationship between the relative fluorescence intensity and the concentration of oxytetracycline （0.77~16.12 μg/mL） with the detection limit of 0.14 μg/mL. Furthermore， the sensor has the potential to determine oxytetracycline in milk samples. The spiked recoveries are in the range of 97.13%~104.18%， and the RSD value is less than 5%. The accuracy of the method is verified. The o-CDs is capable of monitoring oxytetracycline in food industry.
Gunpowder is one of the four great inventions of ancient China， which once had an important impact on the world pattern and development process. However， after the late Ming Dynasty and the early Qing Dynasty， gunpowder firearms gradually declined in China. Gunpowder moved to the West with the war and became black powder， which promoted the birth and development of modern chemical science. The development of chemical science is of great significance to the dynamite family. The brilliant achievements of China's modern king of dynamite revitalize the glory of Chinese gunpowder. This paper reviews the legendary development course and the groundbreaking role of dynamite， describes the properties， rich types and unique working principles of its special chemical energy， and tries to trace the internal mechanism of gunpowder combustion and explosion. It aims to highlight the importance of scientific thinking mode and the development of chemistry discipline to the study of explosives， so as to continuously enrich the knowledge connotation of chemistry students， stimulate their enthusiasm for innovative thinking， enhance their professional confidence， cultural confidence and national confidence， and promote the spirit of scientists.
In the context of the development of new energy sources to reduce carbon emissions and achieve carbon neutralization， power batteries represented by lithium-ion batteries are given higher expectations. The development of electrode materials with high capacity， high multiplicity and high stability is a key step to achieve this goal. Graphite cathodes and silicon carbon cathodes are relatively mature at present， and maintain their respective advantages. Black phosphorus has two-dimensional layered structure and high lithium potential， which shows outstanding advantages in realizing extremely fast charging， but there are also some problems such as volume expansion. In view of the problems of black phosphorus anode， researchers studied the optimization from various dimensions， including structure optimization， surface interface optimization and the pre-lithiation strategy. In this paper， the possibility that black phosphorus can be used as anode electrode of extremely fast charging lithium ion battery is demonstrated， the optimization progress of black phosphorus negative electrode is then reviewed， and its own views and suggestions are put forward. The challenges and development direction of black phosphorus anode electrode are pointed out， and the development prospect of black phosphorus anode electrode is prospected.
Polygalolide A and B are two new phenolic compounds isolated from the rhizome of the medicinal plant Polygala Falax Hemsl. They have a complex tetracyclic cageframe work， including a highly oxidized cycloheptanone， three oxygen-containing heterocycles and two adjacent bridge carbon centers. This review summarizes the central tetracyclic was constructed by （5+2） cycloaddition， intramolecular （3+2） cycloaddition and intramolecular nucleophilic substitution. These lay a foundation for the study of the molecular biological activity
Active packaging can prolong the shelf life of food by releasing functional additive. Polyvinyl alcohol （PVA） has attracted extensive interest for its excellent performance. However， there are some problems such as too strong hydrophilicity and low mechanical properties that limit its application in active packaging. Based on the performance requirements of packaging materials， PVA-CC obtained by cross-linking PVA and cellulose nanofiber （CNF） with citric acid （CA）， and eugenol （EUG） as a typical antibacterial agent is loaded in PVA-CC polymer network， and then the composite film PVA-CCE is obtained. It has demonstrated that PVA-CCE shows great mechanical properties， water resistance， thermal stability and antibacterial properties. The swelling ratio of the composite film with CA cross-linking could be reduced from 495.74% to 72.00%， exhibiting excellent water resistance. Compared to the PVA film， the melting temperature of PVA-CCE is reduced by 11 ℃， and the decomposition temperature is increased by 20 ℃， which indicates that the processing performance of PVA is obviously improved after covalent cross-linking. Additionally， there are free CA in the polymer network to play a plasticizing role for improving comprehensive properties. Moreover， free CA could play a synergistic role with EUG to improve antibacterial properties of PVA-CCE. These results suggest that the prepared PVA-CCE film has an extensive application prospect in active packaging.
This paper illustrates how R. B. Woodward introduces physical instruments to organic chemistry， and alteres the way of chemical thinking and organic synthesis. This paper proposes that Woodward changes chemistry from empirical research to rationally planned endeavor， in which chemists begin to investigate the chemical structures and reactivity of molecules with scientific instruments.
Selective electrochemical detection of berberine in biological fluids is challenging due tothe high overpotential for berberine electrooxidation （＞1.1 V vs.Ag/AgCl）. By taking advantage of the non-covalent interactions between bromothymol blue （BTB） and berberine， and the reversible and low-potential electrochemical redox properties of polymerized BTB （poly-BTB）， we report a new electrochemical method for berberine detection using poly-BTB as both the recognition unit for berberine and electrochemical probe， in which poly-BTB is generated by electropolymerization of BTB immobilized onto the GC electrode surface via single-walled carbon nanotubes （SWNTs）. The strong affinity of poly-BTB toward berberine leads to the binding of berberine onto the electrode surface and consequently causes the decrement in the peak current of poly-BTB/SWNTs-modified electrode upon berberine being introduced， which validates berberine detection using the current decrease of the poly-BTB/SWNTs/GC electrode as the signal readout. Under the optimized conditions， the method shows linear concentration of berberine in the range of 0.05~1 μmol/L and 1~100 μmol/L with a detection limit of 0.022 μmol/L based on 3σ. As for the animal experiments， the electrochemical method has been demonstrated to be selective and effective for berberine level qualification in rat plasma and liver homogenates. This study offers a facile electrochemical method for berberine detection in biological fluids with less technical demanding and simple operating procedures， which holds a great promise for more applications in physiological and pathological researches associated with berberine.
An “off-on” fluorescence probe （4a） based on N，N-（dimethylamino）naphthalenyl flavone （3） is designed and synthesized for detection of butyrylcholinesterase （BChE） by using resorcinol as starting materials. The structure of the probe is identified by nuclear magnetic resonance spectroscopy （NMR） and high resolution mass spectrometry （HRMS）. The results show that probe 4a could react rapidly and specifically with BChE， and its fluorescence intensity increases obviously at 574 nm in PBS of pH 8.0. Meanwhile， the color change of the solution can be seen by naked eyes. The response mechanism is explored through high performance liquid chromatography （HPLC） and HRMS. The results reveal that BChE catalyzes the cleavage of the ester bond， and strongly fluorescent flavone 3 is released. In addition， probe 4a could be used for fluorescence imaging of BChE in living human hepatocellular carcinoma （HepG2） cells.
The separation and recovery of N，N-dimethylformamide （DMF） from the liquid containing high mass fraction of DMF is studied by continuous extraction in a pulsed disc and doughnut extraction column （PDDC）， which combines with a distillation process. For the feed liquid with 38.46% DMF， chloroform is used as the extraction agent and DMF is extracted in a PDDC. The effects of the extraction operation parameters such as oil-water ratio， flow rate and pulse conditions on the DMF extraction are studied. The results show that the extraction efficiency of DMF increases with the addition of pulsation， the increase of oil-water ratio and the increase of two phase flow rate. Under the optimized conditions， the highest extraction ratio of DMF ias 99.94%， and the DMF mass fraction in raffinate is less than 0.5%. Furthermore， batch distillation experiments and simulation calculations are carried out for the separation of chloroform solution loaded with DMF. The results show that effective separation and recovery of chloroform and DMF can be achieved through continuous distillation.
Among many hydrogen production technologies， electrolysis of water has many obvious advantages， such as environmentally friendly， simple and easy to operate. Industrial-scale hydrogen production is typically carried out at high current density. A great number of H2 bubbles will generate on the electrode surface during the process of hydrogen production. The aggregation and adhesion of bubbles on the electrode surface will lead to a large number of active sites being covered， resulting in the reduction of the efficiency. Therefore， regulating bubble wetting behavior is crucial for industrial electrolysis of water. In recent years， superaerophobic materials have attracted much attention due to their unique wetting capabilities. Superwetting interface materials can be constructed by controlling the chemical composition of the electrode surface and constructing rough structure at micro and nano scales. This type of material has a superhydrophilic/superaerophobic interface structure， which facilitates the effective infiltration of aqueous electrolyte and accelerates the release of in-situ generated bubbles， thus enhancing the water splitting performance of the catalyst. This paper systematically introduces the water splitting catalysts with superhydrophilic/superaerophobic interfacial structures reported in recent years， outlines the synthetic design strategies and catalytic performance of the catalysts， and the current research status， challenges and application prospects of superwetting water splitting catalysts are summarized and prospected.
Electrochemical synthesis of hydrogen peroxide （H2O2） via two-electron oxygen reduction reaction （2e-ORR） is featured with cost effectiveness and environmental friendliness， and enables on-site production of H2O2 on demand. One of the key technologies is the development of safe， economical and efficient 2e-ORR catalysts. Here， the research progress in precious-metal-based catalytic materials for the synthesis of H2O2via 2e-ORR in recent ten years is reviewed. This review starts with the fundamental mechanism of ORR， pointing out the tuning knobs of reaction pathway on precious-metal surfaces， namely， *OOH binding energy and O2 adsorption mode. The regulating methodologies of geometric structure and electronic structure of precious-metal materials are summarized and exemplified， emphasizing the importance of balanced optimization of catalytic activity and selectivity. We have also briefly introduced the lab-scale methods for performance evaluation of 2e-ORR catalysts. Finally， the challenges and prospects of H2O2 synthesis catalyzed by precious metals are discussed， especially the catalyst stability and the objective evaluation of cost. This review is expected to provide a reference for rational design of novel 2e-ORR catalysts.
Sulfuric acid， nitric acid， phosphoric acid and perchloric acid are usually used as catalysts for the preparation of organic peroxides. Due to the corrosion of strong acid to the equipment， the catalyst can not be reused， the amount of waste water after treatment is large， and the post-treatment cost is very high. The preparation of organic peroxides with heterogeneous catalysts has been paid more and more attention. Heterogeneous catalysts have the advantages of high activity， good stability and reusability， simple post-treatment， less equipment corrosion， and less environmental pollution. In this paper， on the basis of a brief introduction of the homogeneous preparation process of organic peroxides， the heterogeneous catalysts for the preparation of organic peroxides， including ion exchange resins， molecular sieves， phase transfer catalysts， metal oxides， polymer carrier catalysts and carbon-based support catalysts are summarized. The reactors and preparation processes are discussed， and the development direction of heterogeneous catalytic synthesis of organic peroxides is described. The study has strong reference value and guiding significance for understanding the progress in the preparation of organic compounds by heterogeneous catalysis， developing heterogeneous catalysts with excellent performance， and optimizing the production process of organic peroxides.
Herein， under the modulation of an ionic liquid 1-tetradecyl-3-methylimidazole bromide （［C14mim］Br）， Pt-Pd bimetallic nanomaterials are prepared in one-pot at 90 ℃ in aqueous solution with polyvinylpyrrolidone （PVP） as the stabilizer. The morphology， structure， components and valence states of the products are characterized and analyzed in detail by transmission electron microscopy （TEM）， scanning electron microscopy （SEM）， high-angle annular dark-field scanning transmission electron microscopy （HAADF-STEM）， energy dispersive X-ray spectroscopy （EDS）， X-ray diffractometry （XRD） and X-ray photoelectron spectrometer （XPS）. The results show that except for pure Pd sample， Pt-Pd bimetallic nanomaterials with other Pt/Pd ratios have porous structures. ［C14mim］Br plays an important role in regulating the synthesis of Pt-Pd porous nanomaterials. For the ionic liquids ［C n mim］Br with the alkyl chain length≥C12， it is beneficial for the formation of porous Pd@Pt spherical structures. In the experiment of the ammonia borane hydrolysis， Pt-Pd bimetallic nanomaterials with various ratios show higher catalytic activities than commercial Pd/C， among which Pt3Pd7 nanomaterials have the best catalytic performance. The hydrogen generation reaction can be quickly achieved within only 6 min and the hydrogen yield is up to 100%. At 25 ℃， the activation energy （Ea） and the turnover frequency （TOF） values are calculated to be 36.15 kJ/mol and 35.72 mol/（mol·min）， respectively. Furthermore， the reaction for the five catalytic cycles can be achieved within 51 min， and the yield can still reach 100%， indicating that the catalyst has high activity and good stability.
Urea as an effective hydrogen carrier can be used in urea electrolysis （UE） for hydrogen production and direct urea fuel cells （DUFC）. In urea electrolysis， the coupling of urea oxidation reaction （UOR） at the anode and hydrogen evolution reaction （HER） at the cathode to produce hydrogen is more cost-effective than water electrolysis， with energy consumption reduced by about 30% and economic cost reduced by about 36%. In the direct urea fuel cells， urea as fuel at the anode and coupled with oxygen reduction at the cathode can convert chemical energy directly into electrical energy. As the basis of these two energy conversion technologies， UOR has received more and more attention. This review discusses the reaction principle and performance description parameters of UOR in alkaline electrolytes and introduces the application of UOR in UE and DUFC. Attention is also given to the principles of UE and DUFC and the development status of some catalysts， and finally， the challenges faced in the development of UE and DUFC are also commented. Hopefully， this review will be helpful for understanding the basics of UE and DUFC.
Water electrolysis is one of the most efficient and environmentally benign methods for the hydrogen production using renewable but intermittent power sources. Proton exchange membrane （PEM） water electrolyzers hold great significance for renewable energy storage and conversion. The acidic oxygen evolution reaction （OER） is one of the main roadblocks that hinder the practical application of PEM water electrolyzers. Highly active， cost-effective， and durable electrocatalysts are indispensable for lowering the high kinetic barrier of OER to achieve boosted reaction kinetics. To date， a wide spectrum of advanced electrocatalysts has been designed and synthesized for enhanced acidic OER performance， though Ir and Ru based nanostructures still represent the state-of-the-art catalysts. In this Progress Report， recent research progress on novel electrocatalysts with acidic OER performance is reviewed. First， the basic understanding of acidic OER， including the reaction mechanism， is discussed. On this basis， the design and synthesis progress of noble metal acidic OER electrocatalysts are reviewed for noble metal Ir， Ru single atoms， alloys， oxides， etc. Finally， the future development of acidic OER is prospected from the aspects of reaction mechanism research and more efficient electrocatalyst design.
A polyethylene glycol （PEG） derivative PBA-PEG-SA， which connects phenylboronic acid （PBA） with an amide bond at one end and stearic acid （SA） with an ester bond at the other end， is synthesized by substitution reaction and esterification reaction. And a liposome with pH response characteristics is prepared by co-assembly of PBA-PEG-SA with distearyl choline phosphate （DSCP） and cholesterol （CH）. When PBA-PEG-SA， cholesterol and DSCP are assembled at a mass ratio of 1∶3∶10， the particle size of the prepared liposome is 115 nm， and it could maintain good particle size stability within 20 d. In addition， the liposome has good biocompatibility. When the concentration reaches 800 μg/mL， the survival rate of mouse embryonic fibroblast （NIH-3T3）and hepatoma cell （HepG2） can reach more than 90%. At the same time， after loading doxorubicin （Dox）， compared with DSCP liposomes （Lip/Dox）， Fru/PBA/Lip/Dox liposomes modified with PBA and coated with Fru can effectively enhance the cytotoxicity of HepG2， reduce the toxicity to normal cells NIH-3T3， and improve the endocytosis of cells to drug-loaded liposomes due to the selective binding of phenylboronic acid and fructose. Therefore， the liposomes co-assembled by DSCP and PBA-PEG-SA have good pH response performance and enhance the enrichment ability of liposomes in tumor tissue， which will have good application prospects in the field of tumor therapy.
AB2 hydrogen storage alloy has attracted extensive research interest due to its advantages of high theoretical hydrogen storage capacity， long cycle life and high cost performance. However， AB2 hydrogen storage alloy has some disadvantages such as activation difficulty， toxicity and high platform， which hinders its practical application. In recent years， aiming at the defects of AB2 alloy， researchers have carried out a lot of modification studies and made great progress. This paper summarizes the research progress of AB2-type hydrogen storage alloys in the past 30 years， focuses on the methods to improve its hydrogen storage performance， and puts forward the key research directions of AB2-type alloys in the future.
Capacitive deionization （CDI）， an emerging method for water desalination and ion separation， has received much attention due to its advantages of high ion selectivity， high water recovery and low energy consumption. Compared with the traditional carbon electrodes， the emerging Faraday electrode offers a unique opportunity to make the desalination performance of CDI significantly improved through the Faraday reaction of ion capture. Transition metal-based electrodes have received much attention in the field of CDI electrode design due to their highly reversible Faraday response， relatively high conductivity， and excellent theoretical pseudocapacitance values. In this paper， we systematically summarize and sort out the material classification of transition metal-based electrodes in CDI applications， and summarize the modification engineering performed for their intrinsic defects， mainly including conductive material coupling， functional architecture engineering and defect engineering， etc.， and summarize their performance in CDI applications； in addition， the specific applications of transition metal-based electrodes in CDI are particularly introduced in terms of ion selective separation， metal ion removal and nutrient element recovery. Finally， the paper also outlines the remaining challenges and research directions to provide guidance for future development and research of transition metal chemical substance electrodes.
Nanometer hydroxyapatite （nHA） and poly（ether-ether-ketone） （PEEK） powder is intensively mixed to develop and prepare nHA/PEEK-AgNPs composite porous scaffolds by fused deposition modeling （FDM） 3D printing technology. Then， dopamine oxidation polymerization and silver nitrate chemical reduction were used to form silver nanoparticle coating on the surface to prepare nHA/PEEK-AgNPs composite porous scaffolds. The scaffold had a unique three-dimensional porous structure with a surface contact angle of about （33.2±3.65）（°）， showing good hydrophilicity. Mechanical test results showed that the maximum compressive strength of nHA/PEEK-AgNPs porous scaffolds was （47.4±3.9） MPa， which was significantly higher than （36.3±7.3） MPa of PEEK group. At the same time， there was no significant difference in the maximum elastic modulus between the PEEK group and the PEEK group， indicating that the mechanical strength of the composite was enhanced compared with that of the PEEK porous scaffold. The antibacterial test showed that the antibacterial rate of Escherichia coli and Staphylococcus aureus was （89.4±2.4）% and （85.8±4.4）%， respectively. The results of cell proliferation assay showed that the nHA/PEEK-AgNPs group had significantly better cell proliferation than the PEEK group at all time points within 7 days （P＜0.05）. In addition， nHA/PEEK-AgNPs had good cell compatibility and osteogenic activity. The results of RT-PCR showed that the expression levels of Runx2 gene and Col1 gene in nHA/PEEK-AgNPs group were up-regulated over time compared with PEEK group within 14 days （P＜0.05）. These results indicated that nHA/PEEK-AgNPs composite scaffolds could significantly improve the expression of osteogenesis-related genes. nHA/PEEK-AgNPs three-dimensional porous scaffolds are expected to be applied in the field of bone tissue engineering and repair.
Raman spectroscopy is a non-destructive analytical technique that provides detailed information on the chemical structure and molecular interactions of a sample. Insitu spectroelectrochemistry combined by spectroscopy and conventional electrochemical methods is a powerful technique for dynamically detecting the structure and phase composition of electrode materials. It has broad application prospects in energy storage and provides information on the micro-structure at the electrode interface. Raman spectroscopy can effectively characterize the change of various cathodic materials and complex ions in aluminum chloride-based electrolytes of rechargeable aluminum-ion batteries （AIBs） during the charging and discharging processes in situ. Combined with characterization techniques， such as XRD and XPS， Raman spectroscopy can effectively reveal the energy storage mechanism of rechargeable aluminum-ion batteries， including the study of electrolytes and electrode materials and insitu monitoring of electrode surface reactions. The study of the nature of electrode materials and interface structures can guide the optimal design of battery materials and microstructures， and the in-situ exploring of electrode surface reactions can help to conduct an in-depth study of the mechanism of electrode interface reactions for guiding the structural optimization of cathode materials and promoting the development of rechargeable aluminum-ion batteries.
Proton donors or acceptors are important participants in several important electrocatalytic reactions， it has been proved that species and concentration of proton donor/acceptor can induce significant impact on the electrocatalytic reaction rate and even product species. Starting from the demonstration of typical reaction mechanisms of electrocatalytic hydrogen evolution， electrochemical reduction of carbon dioxide， electrocatalytic oxygen evolution and alcohol electrooxidation to produce aldehyde/ketone， this mini-review summarized proton donor/acceptor species and proton transfer pathway etc. in these four electrocatalytic reactions， and discussed their effects on the efficiency of the electrocatalytic reactions.
Silicon （Si） has become the most promising anode material for the next generation lithium-ion battery because of its ultra-high theoretical specific capacity. However， the intercalation and removal of lithium-ions will cause a great change in the volume of silicon microparticles（SiMP）， which will lead to the pulverization of SiMP and irreversible attenuation of electrode capacity， which seriously limits the wide application of silicon-based materials. A large number of reports in the past have shown that polymer binder can effectively overcome the “island effect” caused by the volume expansion of SiMP. It could maintain the integrity of the electrode in the charge-discharge process， and then improve the electrochemical performance of the electrode. According to the structure classification of polymer binders， they can be roughly divided into four categories， linear， branched， cross-linked and conjugated. When the binders with different molecular structures are used as silicon-based negative electrode， the electrodes show different electrochemical properties. Particularly， when polymer binders with multiple molecular structures are designed， the practical application of silicon-based negative electrodes will be greatly promoted. By analyzing the effects of various polymer binders on the electrochemical properties of silicon anode， the differences of binders with different molecular structures can be clearly obtained， and then provide ideas for the development of silicon anode polymer binder in the future. Finally， this paper proposes the design direction of the next-generation polymer binder to promote its development towards large-scale application and industrial production.
Metal-organic frameworks （MOFs） material， as a new multifunctional material， has attracted more and more attention in the field of water treatment of catalytic activation in advanced oxidation technology， due to its high surface area， adjustable pore structure， excellent thermal and chemical stability. This paper focuses on the research progress of activating persulfate by MOFs-based catalyst in the field of water treatment in recent five years. In this paper， various MOFs-based catalyst and their common synthesis methods in persulfate activation are introduced. Then， the oxidation mechanisms of MOFs-based catalyst during the activation of persulfate are summarized； the common modification methods of MOFs-based catalyst are introduced. Finally， some suggestions for the future research direction of activated persulfate by MOFs-based catalyst are put forward. This review will help to deepen the understanding of MOFs-based catalyst activating persulfate to degrade organic pollutants， and provide theoretical reference for the development of new heterogeneous MOFs-based catalysts based on PS activation.
Dye-containing wastewater， largely discharged from the textile or printing industries， is one of the well-known sources of water pollution， posing great threats to both human health and the living environment. Although several water treatment technologies including physisorption， chemical oxidation， and biodegradation have been developed， most of them are costly and may produce some by-products with unknown toxicities. Therefore， it is highly desirable to develop economic and effective treatment technologies to reduce water resource consumption and protect the environment. Photocatalysis is a method in that highly reactive transitory species such as superoxide or hydroxyl radicals can be generated by reacting oxygen or water with photocatalysts upon irradiation of light， then degrading the organic dyes. Because the whole photocatalysis process has no chemical input and no secondary pollutants， it is considered to be an environmentally friendly， energy-efficient， and sustainable technique. In this paper， we have reviewed different kinds of photocatalyst systems developed in recent ten years for the degradation of organic pollutes， which cover inorganic semiconductors， metal-organic frameworks， organic small molecules， and conjugated porous polymers. Based on the large surface area and high photocatalytic activity， the conjugated porous polymers can simultaneously adsorb and photodegrade organic dyes under visible light， exhibiting stronger developmental potential compared with other photocatalytic materials.
Cyclic olefin copolymer （COC） is produced through the copolymerization of ethylene and cyclic olefins， and has been used for the manufacturing of optical devices and diagnostic containers due to its high transparency and excellent water vapor barrier. However， COC with high glass-transition temperature usually needs high cycloolefin insertion in copolymer and has increased brittleness， which has significantly hampered its many end uses. The introduction of α-olefin into ethylene/cycloolefin binary copolymers that have been extensively studied is expected to expand the application of cyclic olefin copolymers. In this paper， we report the terpolymerization of ethylene/norbornene/1-octene and ethylene/dicyclopentadiene/1-octene catalyzed by modified cyclopentadienyl scandium complexes 1-3 activated with ［Ph3C］［B（C6F5）4］ and Al i Bu3 because rare earth catalysts have shown excellent catalytic performance towards olefin polymerization. These rare earth catalysts exhibit high catalytic activities （4.4×105~21.4×105 g/（mol（Sc）·h·bar））. The resultant terpolymers show moderate number average molecular weight （Mn=3.8×104~20.3×104） and relatively narrow polydispersity index （PDI=1.2~2.4）. The introduction of 1-octene significantly improves the toughness of ethylene/norbornene/1-octene terpolymers， and the P3 sample （Mn 13.7×104， norbornene 37.1%， 1-octene 11.0%） exhibits 2.0 times higher elongation at break （29.9% vs. 9.9%） than the P1 sample （Mn 14.0×104， NB 42.6%， OCT 6.4%）
The low hot melt adhesive strength of ethylene vinyl acetate （EVA） as a matrix resin is mainly due to its low cohesive strength and low polarity on the bonding surface. To address this issue， polar vinyltri（2-methoxyethoxy）silane （VT2MES） is grafted onto the EVA main chain through a melt grafting method， resulting in the synthesis of ethylene vinyl acetate grafted with vinyltri（2-methoxyethoxy）silane （EVA-g-VT2MES）. The molecular chain structure of the product is characterized using Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance spectroscopy （NMR）， indicating that VT2MES hasbeen successfully grafted onto the EVA molecular chain， with the highest grafting rate of 2.37%. Rheology and melt index tests demonstrate an improvement in the cohesive strength of the grafted product. Adhesive films are prepared from EVA and EVA-g-VT2MES， and steel plates are bonded with them. Compared with EVA， the peel strength of EVA-g-VT2MES is increased by up to 75.21%， confirming that melt grafting of VT2MES onto the EVA molecular chain can significantly improve the adhesion strength of the EVA matrix.
Circularly polarized luminescence （CPL） organic molecules， an important class of chiral optical materials， have received great attention in the fields of organic optics and organic electronics. In this study， we simultaneously incorporate chiral binaphthyl moieties into and construct donor-acceptor electronic structures of double B←N bridged bipyridine. We synthesize a series of chiral tetracoordinate organoborane molecules with donor-acceptor electronic structures. While the molecules containing the diphenylamine and carbazole units exhibit conventional aggregation-caused quenching emission phenomenon， the compound bearing with the 9，9-dimethyl-9，10-dihydroacridine group has unique aggregation-induced emission property. More importantly， incorporation of two axially chiral binaphthyl moieties makes them possess intriguing chiral optical properties， as proved by circular dichroism and CPL measurements. The luminescence dissymmetric factors of their CPL properties are exceeding 1×10-3.
Neurodegenerative disease is a kind of neurological dysfunction disease caused by the progressive lesion or loss of specific nerve cells in the nervous system. With the aging of the global population， its incidence is increasing significantly. At present， the pathogenesis of such diseases is not clear， and there is a lack of effective clinical treatment measures. Ginseng contains a variety of active ingredients and has a very wide range of pharmacological effects in the treatment of neurodegenerative diseases. Based on recent literature reports， this paper first summarizes the active ingredients of ginseng and detection methods. Then， the specific pharmacological effects of ginseng in the prevention and treatment of neurodegenerative diseases are summarized. Finally， the related mechanisms and pathways are summarized and reviewed. At present， there are many kinds of chemical components with preventive and therapeutic activities for neurodegenerative diseases， but more active components and clinical application research still need to be further studied.
Traditional industrial nitrogen fixation （NF） process uses the Haber-Bosch process which requires high temperature and high pressure， causing high energy consumption and serious pollution. Gliding arc plasma （GAP） combines the advantages of thermal plasma and cold plasma， which can efficiently produce active species and improve energy efficiency obviously. It has great application potential in the field of NF， and has received extensive attention in recent years. However， the research on NF via GAP is relatively fragmented at present. It is necessary to summarize the specific content. The research progress of NF via GAP at home and abroad in past 10 years is reviewed in this paper， mainly including GAP discharge mechanism， reactor design， process parameters and NF reaction mechanism. GAP discharge has B-G mode with breakdown following gliding discharge and A-G mode with continuous steady discharge. A-G mode discharge helps to improve nitrogen fixation efficiency. With the continuous development of GAP discharge technology， the electrode structure in GAP reactor has evolved from the traditional 2D blade structure to a variety of 3D cylindrical structures. Based on process optimization， GAP facilitates the vibrational excitation of N2 molecules， thereby promoting the splitting and transformation of N2 molecules. In the last， the research on NF through GAP is prospected.
With the increasing demand for green and efficient energy storage devices， advanced technologies for clean energy conversion have attracted close attention from researchers. Fuel cells with environmental friendliness and high energy conversion efficiency are promising alternatives to traditional energy sources. However， Pt catalysts with high commercialization degrees in the industrial catalysis field have some problems， such as high cost， poor stability and weak anti-toxicity ability， which limits the further development of fuel cells. The development of non-Pt oxygen reduction reaction （ORR） catalysts with abundant reserves， low cost and excellent performance is an effective way to improve the efficiency of fuel cells. In this paper， based on the research results at home and abroad in recent years， various types of non-Pt system ORR catalysts， including non-precious metal and non-metal catalysts， are systematically introduced. The advantages， disadvantages and modification strategies of various catalysts are summarized， and challenges and prospects for the development of ORR electrocatalysts are put forward.
The mural paintings of the Second Tomb of the Southern Tang Dynasty in Nanjing， Jiangsu Province， which is the largest in scale during the Five Dynasties and Ten Kingdoms period in southern China， are selected as the objects of study， on the basis of optimization of the test conditions of the egg white standard samples by using pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS） analysis technique. Eight inorganic mineral pigments such as calcite， lead tetroxide， ochre， cinnabar， azurite， mineral green， orpiment and realgar on the cleavage products are evaluated for the first time and a method is established for the identification of egg whites in the tomb murals. The Py-GC/MS analytical method is developed for the identification of egg whites in tomb murals. The results of the analysis of the artifact samples show that egg whites are added to the mural ground battles， mortars and pigments as cementing materials， and the results of the Py-GC/MS analysis are verified using enzyme-linked immunosorbent assay （ELISA）， further demonstrating that Py-GC/MS is a reliable analytical method for egg white composition in tomb murals. This study provides a methodological reference for the study of organic binding media in tomb murals.
In recent years， some halogen-based flame retardants have been gradually eliminated out for consideration of the environment， and phosphorus-containing flame retardants have received extensive attention as substitutes for halogen-based flame retardants. However， efficient phosphorus-based flame retardants usually produce more smoke while improving flame retardancy， therefore， they need to be used in combination with synergists. This paper introduced the flame-retardant mechanism of phosphorus-containing flame retardants in epoxy resin. The latest research progress of synergists， including inorganic， organic， and organic-inorganic hybrid synergistic agents， with phosphorus-based flame retardants in epoxy resin was summarized. We look forward to the future development trend of the synergistic system of phosphorus-containing flame retardants in epoxy resin.