MIL-101(Fe) is a typical Fe-based metal-organic framework (Fe-MOF), which demonstrates the advantages of flexible structure, large specific surface area, large porosity, and adjustable pore size. In recent years, MIL-101(Fe) and its composites have been extensively studied in the field of water pollution remediation, especially in the hexavalent chromium (Cr(Ⅵ)) reduction and advanced oxidation processes for removing organic pollutants in water. The water stability, light absorption activity and the carrier separation efficiency can be significantly improved by functional modification with specific functional materials. In this review, the preparation strategies of MIL-101(Fe) and its composites, as well as their application as heterogeneous catalysts for photocatalysis, H₂O₂ activation, and persulfate activation were introduced. The future development of MIL-101(Fe) and its composites as catalysts for water purification is prospected.

1 Introduction

2 Preparation of MIL-101(Fe) and its composites

2.1 MIL-101(Fe)

2.2 MIL-101(Fe) composites

3 MIL-101(Fe) and its composites for reduction of Cr(Ⅵ)

4 Advanced oxidative degradation of organic pollutants in wastewater by MIL-101(Fe) and their composites

4.1 Photocatalysis

4.2 Activation of H₂O₂

4.3 Activation of persulfate

5 Water stability and biotoxicity of MIL-101(Fe)

6 Conclusions and prospective

With the proposal of "peak carbon dioxide emissions" and "carbon neutral" strategic objectives, developing clean energy and promoting the development of new energy industry has become the consensus of the whole society. Lithium battery as the candidate for new generation of energy storage equipment due to its remarkable advantages such as high energy density, high power density, long cycle life and environmental friendliness. Its development plays a significant role in alleviating energy crisis, driving the conversion of old kinetic energy into new and achieving the strategic goal of "carbon peaking and carbon neutrality". In order to further improve the energy density of lithium batteries, the most effective strategy is to use high voltage or high specific capacity cathode materials. However, due to the low oxidation stability and narrow electrochemical window of traditional carbonate ester electrolytes, they are prone to oxidative decomposition when the working voltage exceeds 4.2 V, which cannot be cycled stably at high voltages, so it is particularly important to broaden the electrochemical window of electrolytes. This paper mainly discusses the mechanism of organic solvents and additives in high-voltage electrolytes, explores effective methods to broaden the electrochemical window of new electrolytes, summarizes the characteristics of aqueous electrolytes, solid electrolytes, and polymer gel electrolytes, and finally; summarizes and outlooks the future development and prospects of high-voltage electrolytes to provide scientific basis for the design and development of high-voltage electrolytes for lithium batteries.

Metal oxides have been widely investigated in experimental and industrial catalysis due to their excellent activity, selectivity and stability in many important reactions, especially in some redox reactions, such as CO₂ reduction, water-gas shift (WGS) reaction, reduction of nitrogen, oxygen evolution reaction. It has been proved that metal oxides usually contain many defects, which are the active sites in catalytic reactions, and oxygen vacancies (OVs) are one of the most representative species among them. OVs affect crystal structure and electronic structure of the materials, thus affecting the catalytic activity, so they have great significance to be studied. In this review, we firstly introduce the classification and regulation strategies of OVs based on the formation of them in metal oxides. Secondly, the characteristics and mechanisms of OVs in thermocatalysis, electrocatalysis and photocatalysis were discussed. Finally, the potential applications and future challenges were summarized and prospected.

Aqueous zinc-ion batteries (AZIBs) have great advantages in terms of safety, low cost, high theoretical capacity and element abundance, which shows great potential in large-scale energy storage applications. The development of high-performance AZIBs has become a widely interesting topic recently. Although much progress has been made in AZIBs, the low energy density, poor ionic dynamics and short cycling life limit the commercialization of AZIBs. This review summarizes the challenges, recent progress and corresponding strategies for the development of cathodes, anodes, electrolytes, and energy storage mechanisms of AZIBs. It provides useful guidance for researchers in the battery area to design and develop high performance AZIBs.

Double Network Hydrogels are polymer materials composed of two interpenetrating or semi-penetrating three-dimensional networks, and their unique contrast interpenetrating network structure and adjustable network crosslinking method overcome the obstacles in mechanical properties of single-network hydrogels, and are widely used in tissue engineering, intelligent sensors, ion adsorption and other fields with their good mechanical, anti-swelling, self-healing and other mechanical properties. However, the existing technologies suffer from numerous synthesis steps, complicated preparation conditions and the use of toxic and harmful chemical cross-linking, which limit the mass production of double network hydrogels for applications. Therefore, in recent years, the modification of double network hydrogels has received more and more attention, and researchers have carried out a series of structural modification studies mainly around how to improve the mechanical properties of double network hydrogels, aiming to broaden their application in various fields. In this paper, the types of double network hydrogels are reviewed, and the preparation methods, structures and unique properties of different hydrogels are introduced in detail. The research on modification to improve mechanical properties, anti-swelling performance and self-healing properties is analyzed, aiming to break through the current limitations of double network hydrogels and provide ideas and directions for their future development.

With the rapid development of portable electronic devices, electric vehicles, and smart grids, there is an increasing interest in high-energy-density lithium metal batteries. Uneven Li stripping or deposition on the surface of lithium metal will lead to the growth of lithium dendrites, which can easily pierce the separator and cause the short circuit in the battery. Moreover, the highly reactive lithium metal will continue to react with the electrolyte, resulting in an unstable solid electrolyte. interfacial (SEI) film and irreversible capacity loss. Taking high-energy-density and high safety into account is a key scientific problem that needs to be solved urgently in the development and application of lithium metal batteries. The interaction of strong electron withdrawing group (C≡N) in polyacrylonitrile (PAN) polymer and C=O in carbonate solvent can form a more stable SEI film. As a lithium anode coating, PAN can also inhibit the growth of lithium dendrites. In addition, due to the low lowest unoccupied molecular orbital, high electrochemical stability and wide electrochemical window, PAN can be regard as polymer electrolytes for lithium metal batteries, and matched with a high-voltage cathode to achieve both high energy density and safety. Thus, PAN polymer has significant potential application in electrolytes for lithium metal batteries. This review mainly starts from the different states of electrolytes (liquid, gel, and solid state). Recent research development of PAN polymer as separators and lithium anode protective layers in liquid electrolytes, as well as its application in gel electrolytes and solid-state electrolytes are presented. Finally, the review prospects the development trend of PAN polymer in lithium metal battery electrolytes.

1 Introduction

2 The application of PAN in liquid state electrolytes

2.1 As separator

2.2 As lithium anode protective layers

3 The application of PAN in gel electrolytes

4 The application of PAN in solid-state electrolyte

4.1 Monolayer electrolytes containing PAN

4.2 Heterogeneous multilayer electrolytes containing PAN

4.3 PAN electrospinning fiber membrane

5 Conclusion and outlook

With the massive global consumption of fossil fuels, the energy crisis is getting worse and the emission of greenhouse gases such as CO₂ has made the environmental problems become increasingly prominent. Photocatalytic reduction of CO₂ to energy compounds is considered to be one of the best ways to effectively solve this problem. Covalent organic frameworks (COFs) are a new type of crystalline porous organic polymer materials with high stability and pre-design ability, which makes COFs own great potential ability in the field of photocatalytic CO₂ reduction. This paper summarizes the research progress of COFs in the field of photocatalytic CO₂ reduction, including the introduction of different metal ions to provide the active site and increasing the photosensitive functional groups to improve their utilization of visible light. Since the research of COFs as photocatalytic CO₂ reduction catalyst is still an initial field, further exploration of synthesis, modification, and mechanism of COFs for CO₂ reduction is still promising research work.

1 Introduction

2 Covalent organic frameworks

2.1 Basic information of COFs

2.2 Application of COFs in photocatalysis

3 Basic principles of photocatalytic CO₂ reduction

4 COFs for photocatalytic CO₂ reduction

5 Conclusion and outlook

Carbon dots (CDs), with particle size less than 10 nm, are a new type of zero-dimensional photoluminescence nanomaterials. Due to the obvious advantages of adjustable fluorescence emission and excitation wavelength, light stability, low toxicity, good water solubility and biocompatibility, etc., CDs have been widely researched in recent years. As a treasure of ancient Chinese science, Traditional Chinese medicine (TCM) is rich in various active ingredients and plays a variety of pharmacodynamic effects, which has been used for thousands of years. TCM-CDs prepared with TCM as carbon source can create some special functions, and then may play a greater medicinal value. In this paper, the synthesis of TCM-CDs and its application in biological imaging and medical therapy are reviewed. Firstly, different synthetic methods of TCM-CDs (including hydrothermal, pyrolysis, solvothermal and microwave assisted method) are introduced in detail, and their advantages and disadvantages are compared. Subsequently, the latest research on TCM-CDs in biological imaging and medical treatment is comprehensively analyzed. This paper focuses on the application of imaging different types of cells in vitro and the distribution and uptake of TCM-CDs guided by imaging in vivo (mice, zebrafish, etc.). In addition, the intrinsic pharmacological activities of these TCM-CDs (including antibacterial, anti-inflammatory, hemostatic, antioxidant and anticancer, etc.) and their mechanisms are also discussed in order to improve and promote their clinical application. Finally, the importance of TCM-CDs research, the main problems and challenges in this fields and the future development direction are summarized and outlooked.

Polyurethane, a prevalent polymer, has garnered considerable attention owing to its exceptional overall performance within various applications. However, even minor damages can significantly curtail the service life of polyurethane. Consequently, a promising approach to address this challenge involves conferring self-healing properties upon polyurethane. Among the various healing mechanisms found in self-healing polyurethane, the intrinsic driving force stands out as the most common. This mechanism entails the spontaneous re-entanglement of polyurethane molecular chains through meticulous molecular structure design, obviating the necessity for external healing agents. Intrinsic driving force encompasses reversible covalent bonds (e.g., disulfide bonds, Diels-Alder reactions, and boronic ester bonds) as well as dynamic non-covalent interactions (e.g., hydrogen bonds, ionic bonds, metal coordination bonds, and host-guest interactions). The polyurethane main chain can possess a single intrinsic driving force or multiple intrinsic driving forces concurrently. Nevertheless, while self-healing polyurethane alone presents advantages in terms of extending service life and reducing maintenance costs through damage repair, it still falls short of meeting the usage requirements in certain specialized applications. To further enable the versatile application of self-healing polyurethane while preserving its self-healing properties, the incorporation of new functional groups becomes an enticing prospect. These functional groups can bestow specific properties upon polyurethane, such as shape memory, degradability, antibacterial properties and biocompatibility, thereby achieving functional integration within self-healing polyurethane. Importantly, these functionalized self-healing polyurethanes possess the potential to supplant traditional materials as dielectric materials, substrate materials, or encapsulation materials in the realm of flexible sensors. Consequently, they contribute to enhancing the reliability and durability of flexible sensors. Therefore, this article primarily focuses on elucidating the self-healing mechanism of self-healing polyurethane. Subsequently, it delves into the integration of functionality within self-healing polyurethane and its application within the field of flexible sensors. Lastly, based on these insights, the paper provides a glimpse into the future prospects for the development of self-healing polyurethane.

In recent years, organo-metal halide perovskites materials with ABX₃ crystal structure have shown promising application prospects in the field of photoelectric detection due to their optical and electrical properties such as adjustable bandgap engineering, high absorption coefficient and long carrier transmission distance. Especially, the hybrid perovskite prepared by pure Sn or Sn/Pb mixed cations have excellent near-infrared photoelectroresponse in the range of 760~1050 nm, showing many advantages such as high sensitivity, low dark current and high detection rate. To further broaden the near-infrared and infrared response wavelength range of perovskite, the researchers explored combining organic materials, crystalline silicon/germanium, Ⅲ-Ⅴ compounds, Ⅳ-Ⅵ compounds, upconversion fluorescent materials as complementary light absorption layers with perovskite to prepare heterostructures to construct wide-spectrum response near-infrared photodetectors. Based on the above research, this paper summarizes the current effective ways to broaden the spectrum range of perovskite photodetectors. At the same time, the future development prospect of perovskite material near infrared photodetector is prospected.

Contents

1 Introduction

2 Basic indicators of photodetectors

2.1 Device structure and working principle of photodetectors

2.2 Performance parameters of photodetectors

2.3 Strategy of broadening the spectrum response range of perovskites

3 Pb perovskite for near-infrared photodetectors

3.1 Polycrystalline perovskite materials

3.2 Single crystal perovskite materials

4 Narrow band gap Sn and Sn/Pb Mixed Perovskite- Based near-infrared photodetectors

4.1 Sn-based perovskite near-infrared photodetectors

4.2 Sn/Pb mixed perovskite near-infrared photodetectors

5 Perovskite/inorganic heterojunction near-infrared photodetectors

5.1 Silicon and other classic semiconductors

5.2 Graphene

5.3 Transition metal dichalcogenides

5.4 Ⅲ-Ⅴ compounds semiconductors

5.5 Ⅳ-Ⅳ compounds semiconductors

6 Perovskite/organic heterojunction near-infrared photodetectors

7 Perovskite/upconversion material near-infrared photodetectors

8 Application of near-infrared photodetectors

9 Conclusion and outlook

Wet adhesion plays an important role in the gestation and development of life. The research shows that hydrogel is a kind of intelligent material with both solid and liquid properties. They have been widely used in such areas as wound closure and repair, cell engineering and tissue engineering, owing to their noteworthy versatility and bio-compatibility. However, the physiological environment is usually wet, and the hydration layer on wet tissue surface prevents hydrogel from forming interfacial adhesion bonds with tissue surface. Faced with this challenge, inspired by the fact that the catechol group of DOPA is critical group for the underwater adhesion of mussels, the structure and functional unit design of catechol hydrogel have attracted wide attention. This review introduces the structure and wet adhesion mechanism of mussel foot proteins (Mfps), and the main types of catechol derivatives are classified into natural Mfps or Mfps synthesized by genetic engineering, catechol small molecular compounds, natural polymers modified by catechol groups and synthesized functional polymers containing catechol groups. Nextly, the research progress of catechol hydrogel as wet tissue adhesive in the past decade is summarized, such as tissue wound repair materials, biological coating materials, targeted drug delivery materials and bioelectronic equipment materials. Finally, the opportunities and challenges of catechol hydrogel are prospected.

With the rapid development of current society and economy, as well as the accelerated process of industrialization and urbanization, the complexity and seriousness of environmental pollution issues are becoming increasingly apparent. Beyond traditional pollutants, the appearance of emerging pollutants on a global scale has brought new challenges to environment and public health. China’s “14th Five-Year Plan” and medium and long-term planning put forward “emerging pollutant control”, report of the 20th National Congress of the Communist Party of China also explicitly requested “carry out emerging pollutant control”. In 2022, General Office of the State Council issued “Action Plan for Emerging Pollutant Control”, followed by the Ministry of Ecology and Environment and various provinces, municipalities, and autonomous regions, which released corresponding implementation plans, China has transferred to a new phase of environmental protection that balances the control of both traditional and emerging pollutants. However, management of emerging pollutants is a long-term, dynamic and complex systematic project, which urgently needs to strengthen top-level design as well as scientific and technological support. Conducting systematic research on emerging pollutants not only provides effective scientific guidance for their control and improves the level of environmental quality management, but also assists our country in fulfilling international conventions, enhances the discourse power in global environmental governance, ensures our country environmental security, food security, international trade security, etc., and is of great significance for realizing sustainable development. This review aims to comprehensively explore various aspects of emerging pollutants, including their types and characteristics, production, use and emission, identification and detection, environmental occurrence, migration and transformation, ecotoxicological effects, human exposure, health risks, and management strategies. Furthermore, it looks forward to the future research direction, with a view to providing a scientific basis and decision-making support for control of emerging pollutants in China.

As the material basis of active substances and life activities in living organisms, peptides and proteins play vital roles in basic physiological processes such as signal transmission, energy utilization, immune response, etc. And they are closely related to the occurrence of a variety of diseases. An important prerequisite for studying their structure and biological function and developing related drugs is to obtain a certain number of high pure peptides and proteins. The sources of natural peptides and proteins mainly include tissues and organs of animals and plants, secondary metabolites of microorganisms, etc. Natural extraction, recombinant technology, and chemical synthesis are the main methods to obtain peptides and proteins. Chemical synthesis can conveniently introduce unnatural amino acids or specific types of post-translational modification groups at any site of peptides and proteins compared with the former two, such as glycosylation, phosphorylation, fluorophores, and photorelinking reaction groups, which has greatly promoted the application and development of peptides and proteins in the field of medicine research. This review comprehensively introduces the various chemical synthesis strategies of peptides and proteins, along with the basic principles, advantages and disadvantages, and application values, aiming to provide a novel sight for synthesizing peptides and proteins.

One of the most promising candidates for large-scale energy storage applications is the solid-state sodium ion battery, which replaces conventional organic liquid electrolytes with solid electrolytes and has the advantages of high safety, high energy density, and extended cycle life. Among many solid electrolyte materials, Poly(ethylene oxide) (PEO)-based polymer solid electrolytes are considered promising solid electrolyte materials because of their high safety, easy manufacturing, low cost, high energy density, favorable electrochemical stability, and excellent solubility in sodium salts. However, the high crystallinity of the ethylene oxide (EO) chain segment results in low ionic conductivity at room temperature, which is unable to meet the requirements of practical application. To overcome the aforementioned limitations, researchers have used a variety of strategies to lessen the crystallinity of PEO-based polymer electrolyte and hence increase its ionic conductivity. Common techniques include polymer block copolymerization, blending, crosslinking, adding plasticizers, and adding inorganic fillers. In the review, the physical and chemical properties, preparation methods, and modification techniques of PEO-based polymer electrolytes are evaluated, and the most recent advancements on PEO-based polymer electrolytes are reviewed.

Thermoelectric materials, as one new kind of energy materials, can realize the direct conversion of thermal and electrical energy, which have important applications in power generation and refrigeration. Compared with traditional thermoelectric materials, flexible thermoelectric materials demonstrate excellent application prospects in wearable devices and flexible electronics fields, due to the advantages of being bendable, a lightweight and environmentally friendly. At present, how to further improve the performance of flexible thermoelectric materials is the focus, especially the collaborative optimization of flexibility andthermoelectric properties. In this paper, we have reviewed the research progress of polymer-based flexible thermoelectric materials, carbon-based flexible thermoelectric materials and inorganic semiconductor flexible thermoelectric materials, introduced their characteristics, performance optimization and preparation methods, and summarized the applications of flexible thermoelectric materials in the fields of electronics, medicine and industry. Also, based on the shortcomings of flexible thermoelectric materials, the future research directions are prospected.

1 Introduction

2 Types of flexible thermoelectric materials and their thermoelectric properties

2.1 Polymer-based flexible thermoelectric materials

2.2 Carbon-based flexible thermoelectric materials

2.3 Inorganic semiconductor flexible thermoelectric materials

3 Preparation method of flexible thermoelectric materials

3.1 Physical vapor deposition

3.2 In-situ polymerization

3.3 Electrospinning

3.4 High temperature melting method

4 Applications of flexible thermoelectric materials

5 Conclusion and outlook

Metal-organic frameworks (MOFs) are a new generation of crystalline porous materials with void space structures constructed from metal ions or clusters and organic ligands through coordination bonds, and have been a hot research topic in the field of coordination chemistry over the past two decades. As the novel multifunctional materials, MOFs have been widely used in various fields due to their high porosities, low densities, large surface areas, tunable pore sizes, diverse topological structures and tailorabilities. Although MOFs have many advantages, most of MOFs materials have relatively lower water and chemical stability and cannot maintain their structures under harsh conditions, which greatly restrict their practical applications under moisture-rich conditions. Therefore, chemically stable MOFs materials will have greater application prospects. In recent years, researchers have carried out a lot of exploration in improving the chemical stability of MOFs, and developed some excellent methods to synthesize chemically stable MOFs. This review will mainly focus on the latest research progress in the syntheses of chemically stable MOFs during the past five years.

In recent years, with the rapid advancement and large-scale application of lithium battery technology and electric vehicle, the market demand for lithium resource is growing sharply. However, due to insufficient mining degree and extraction technology, the total production capacity of ore lithium and brine lithium resources is far below the actual market demand. Extracting lithium from surface salt lake brine, deep brine and other liquid resources has the advantages of large resource potential and low extraction cost, which presents an important research direction in the lithium resource extraction field. Among available lithium extraction technologies, adsorption method is suitable for extracting lithium from low concentration and large volume liquid brine resources in China, and selective lithium ion adsorption materials are the core of adsorption method. In this review, we focus on the preparation and application of lithium ion selective adsorption materials for lithium extraction from brine. The preparation methods, adsorption properties and adsorption mechanisms of organic (crown ether), inorganic (aluminum-, manganese- and titanium-based adsorbents) and composite selective lithium adsorption materials are reviewed. This review provides a brief prospect for the design and development of new lithium adsorption materials, which may push forward the efficient extraction and utilization of lithium resources from salt lake brine.

With the widespread use of antibiotics, the problem of water pollution caused by antibiotics is becoming increasingly serious. Currently, technologies for removing antibiotic pollutants from water include physical adsorption, flocculation, and chemical oxidation. However, these processes often leave a large amount of chemical reagents and difficult-to-dispose sediment in water, making post-treatment more difficult. Photocatalytic technology uses photocatalytic materials to decompose antibiotics under light, ultimately forming non-toxic CO₂ and H₂O. Photocatalytic degradation of antibiotics has the advantages of low cost, high efficiency and free secondary pollution. In this paper, the research progress of several commonly used photocatalytic materials for degrading antibiotics is reviewed, and their future researches and applications are also prospected．

The rapid application of big data and artificial intelligence, and the deep intersection of machine learning (ML) and chemistry disciplines have inspired more promising development approaches for the integration of ML technology with battery materials, especially in the material design of battery, performance prediction, structure optimization, and so on. The application of ML can effectively accelerate the selection process of battery materials and predict the performance of lithium batteries (LBs), consequently driving the development of LBs. This review briefly introduces the basic idea of ML and several important ML algorithms in the field of LBs, then the error performance and analysis of the traditional simulation calculation method and ML method are discussed, thereby increasing understanding of ML methods by LBs experts. Secondly, the application of ML in the practical development of battery materials, including cathode materials, electrolytes, multi-scale simulation of materials and high-throughput experiments (HTE), is emphatically introduced to draw out the ideas and means of applying ML methods in the field of batteries. Finally, the recent works of ML in lithium batteries are summarized and their application prospects are foreseen. It is hoped that this review will shed light on the application of ML in the development of LBs and promote the development of advanced LBs.

As a kind of metal-organic framework (MOF) with high valence, titanium-based metal-organic framework (Ti-MOF) has superior chemical stability, appealing photoresponsive properties, low toxicity and so on. However, due to the high reactivity of titanium sources, it brings certain challenges to the synthesis of materials. In this paper, the research progress of Ti-MOF synthesis in recent years is reviewed, and the solvothermal synthesis, post-synthetic modification and in situ SBUs construction methods are introduced in detail. The topological types and crystal structures formed are analyzed, and the synthesis rules of Ti-MOF and the advantages and disadvantages of various methods are summarized. It is pointed out that the control of the metal source and coordination environment is the most important strategy to obtain Ti-MOF, and the construction of Ti-MOF by in-situ formation of SBUs and heterometallic Ti/M-MOF are prospected.