Carbon fiber reinforced silicon carbide (C/SiC) ceramic matrix composites have comprehensive properties such as low density, high strength, high temperature resistance and wear resistance, and have become one of the important thermal structural material systems. At present, it has been successfully applied to aero-engine thermal structural components, aircraft thermal protection systems, braking systems and nuclear structural components. In this paper, the research progress in preparation and application of C/SiC ceramic matrix composites is reviewed. A series of representative preparation methods of C/SiC composites are introduced, with emphasis on the hybridization process combining various preparation methods. The applications of C/SiC composites in the fields of aerospace thermal structure and thermal protection, brake materials and space camera structures are summarized. A more excellent hybrid preparation process and a new composite material system for different application requirements are prospected. The paper is expected to provide a reference for further research on C/SiC ceramic matrix composites in the future.

At present, the transformation of the global energy structure is accelerating the construction of green, safe and sustainable development. The energy conversion is one of the most important. The exploration of efficient catalyst is an important branch to solve this problem. Cerium dioxide(CeO₂), as a rare earth oxide catalyst or an excellent carrier of heterogeneous catalysts, has unique geometric and electronic structural properties (such as rich oxygen site, Ce valence tautomization(Ce³⁺↔Ce⁴⁺), etc.), which can effectively affect the performance of catalysts through geometric and electronic effects. In recent years, CeO₂-based supported catalysts have been widely explored and applied in chemical, energy, environment, materials and other fields, effectively helping to solve urgent problems such as energy conversion, environmental pollution. Although there have been reviews on CeO₂-based supported catalysts, they mainly focus on single catalytic directions(such as electrocatalysis or thermal catalysis)and lack a systematic overview. In this paper, the research progress of CeO₂-based supported catalysts is summarized from two aspects: (Ⅰ) preparation and synthesis of CeO₂ and CeO₂-based supported catalysts; (Ⅱ) study on the structure-activity of various CeO₂ catalysts in electrocatalysis, photocatalysis, thermal catalysis and photothermal catalysis. A comprehensive review of CeO₂-based supported catalysts will be helpful for its practical application in various fields.

Organic-inorganic hybrid perovskite materials have been widely used in the area of photovoltaic, display devices and sensors because of their excellent photoelectric properties. In recent years, the key technology of perovskite solar cells (PSCs) has developed rapidly, and there are many breakthroughs that have been made in photoelectric conversion efficiency and devices area. However, the stability of perovskite mate-rials and devices has not been fundamentally solved, which seriously restricts the practical performance and commercialization of perovskite photovoltaic devices. The instability of PSCs derived from the perovskite active layer, the charge transport materials and the electrode materials. The causes mainly include environmental factors such as light, water, temperature and oxygen. Therefore, it is crucial to understand the mechanism of each factor on the stability of PSCs. In addition, compared with crystalline silicon solar cells and other thin-film solar cells, PSCs have great differences in material properties and device structures. At present, the stability evaluation methods and testing methods of crystalline silicon cells and other thin film cells are not fully applicable to PSCs. A standard stability tests procedure is required in order to compare the stability test results of perovskite cells between the various institutions.
In this paper, the factors affecting the stability of perovskite materials and photovoltaic devices are firstly summarized. Then the mechanism of environmental factors such as light, moisture, temperature and oxygen on the stability of perovskite devices are analyzed, and the methods to improve the stability of PSCs are summarized. Finally, the stability evaluation and testing methods, as well as the future development direction of PSCs are analyzed and forecasted, which provide a new idea for the commercial application of PSCs.

With the introduction of the concept of peak carbon dioxide emission and carbon neutrality, solar energy as a renewable green energy has attracted much attention. Monocrystalline silicon is main photovoltaic material, and its quality determines the efficiency of solar cells. High-quality monocrystal silicon is required to reduce costs and increase production capacity. Czochralski (CZ) method is main preparation method for monocrystalline silicon, with high production efficiency and automation. The market share of CZ-Si exceeds 90%. At present, it is developing toward large size, N-type, flake, low oxygen, and low carbon. However, as the size of crystal rod increases, the thermal field changes become more complex, and the existing CZ process is difficult to meet the market demand. In the future, reducing the cost of kilowatt-hour electricity is still the driving force for the development of crystalline silicon photovoltaic, and the development of photovoltaic should be promoted through technological innovation, industrial standardization, cost control, and other means. In this paper, the basic principle and growth process of monocrystalline silicon using CZ are first summarized. Defect control, thermal field optimization, and oxygen content control are analyzed. Finally, the process and future prospects of developing monocrystalline silicon using CZ are presented.

With the rapid development of the Internet of things, there is an increasing demand for monitoring volatile organic chemicals in various fields. Metal-oxide semiconductor (MOS) gas sensors based onadvanced micro-electro-mechanical systems (MEMS) technology have significantly developed in the past few decades. The diverse design of micro hot plates, the diversification of MOS nanostructures, and the emergence of machine learning algorithms have promoted the sensing performance of MEMS sensors and their intelligent sensing systems. This paper will summarize the latest advances in the classification, preparation, and application of MEMS gas sensors and the sensor array. Finally, the deve-lopment prospect of MEMS-based gas sensors is summarized.

Maintaining thermal comfort is crucial for sustaining normal human physiological functions. Utilizing fibers and textiles for personal thermal regulation not only enhances thermal comfort but also contributes to reducing building energy consumption. However, traditional textiles often fail to meet diverse human thermal comfort needs, necessitating the development of novel wearable thermal management materials. Thanks to advancements in material chemistry, physics, and nanotechnology, numerous fibers and textiles with outstanding thermal management properties have been developed. This article reviews innovative strategies for temperature regulation and the latest advancements in wearable thermal management materials, focusing on various advanced passive and active thermal management materials. It aims to enhance understanding of the mechanisms behind these materials and provide a comprehensive reference for researchers in the field. It begins with an introduction to the phy-siological basis of human thermal regulation, followed by a detailed exploration of passive and active thermal management fibers and textiles, discussing their operational principles, advantages and disadvantages in various application scenarios. Finally, from a commercial perspective, the article discusses the future prospects and challenges of wearable thermal management fibers and textiles.

This paper focuses on the research achievements of our laboratory in the last 20 years in the field of long-persistent luminescence materials. Starting from the key issues of long persistent luminescence materials, this paper makes a detailed analysis and summary of the matrix selection of materials, the exploration methods of doping and solid solution, the discussion on the mechanism of material lasting glow, and the extended research on special lasting glow phenomena. The future research direction of long-persistent luminescence materials has also been prospected. The future research direction of long-persistent luminescence materials has also been prospected, which is purpose on providing a reference for researchers in this field.

Cement is an essential building material for society’s infrastructure around the world. However, the cement industry is responsible for an unacceptable increase in CO₂ emissions. To mitigate these emissions, several approaches have been proposed, including improving energy efficiency, using alternative raw materials and/or alternative fuels, utilizing CCUS technology and developing low-carbon binders. In the long term, low-carbon binders are expected to play an important role in CO₂ emission reduction of the cement industry. In this review, we summarize the research progress on four types of low carbon binders, viz. low clinker cements, low calcium cements, carbon fixation cements and alkali activated binders, introduce the preparation methods and properties of low-carbon binders, compare and analyze CO₂ emissions of traditional Portland cement and low-carbon binders. Finally, we point out the issues on the development of low-carbon binders, and put forward proposals on their further research.

Thermoelectric material is a kind of functional material, which realizes the mutual conversion between thermal energy and electrical energy. It can recycle waste heat generated in the process of fossil fuel combustion and industrial production, and shows good application prospects in small thermoelectric generators, solar cells, and smart sensors, etc. Thermoelectric materials are gradually applied to small wearable devices with the development of modern technology, which puts forward new requirements for safety, non-toxicity, stable high conversion efficiency and flexibility of thermoelectric materials. Compared with electronic thermoelectric materials, ionic thermoelectric materials have the advantages of high Seebeck coefficient, flexible stretchability, low toxicity and low pollution, and have good application potential in both thermoelectric power generation devices and small wearable devices. In this paper, the research progress of ion gel-based thermoelectric materials in energy harvesting devices such as thermogenic batteries and ionic thermoelectric capacitors are discussed. The problems and challenges faced by ionic thermoelectric materials in the application of wearable energy conversion devices are analyzed, in order to provide new directions for the preparation of safe, pollution-free, stable and efficient new flexible wearable devices.

Gate-all-around (GAA) transistors are the most competitive device structure to replace existing fin field effect transistors(FinFET) below the sub-3 nm node, effectively improve the short-channel effect caused by the continuous shrinking of device size along Moore's Law. In the process flow of GAA device preparation, inner spacer preparation and channel release are newly introduced process modules relative to FinFET, and both require SiGe selective etching technology. SiGe is required to be removed as a sacrificial layer by selective etching with as little damage as possible to the Si channel. This paper presents a review of the SiGe selective etching techniques required in the gate-all-around (GAA) transistor fabrication process. Firstly, we analyze the development trend of device structure and the application of SiGe selective etching. Secondly, the development of conventional SiGe selective etching methods and new selective etching techniques are categorized and reviewed. After that the advantages and shortcomings of each technique are summarized. Finally, this study analyzes the challenges faced by SiGe selective etching technology, and prospects the possible future development trends.

The second-generation rare-earth (RE) permanent magnets (PMs), 2∶17-type Sm-Co-Fe-Cu-Zr magnets, are the strongest high-temperature PMs, which have wide applications in advanced industries. However, the fundamental interest in REPMs was moved from 2∶17-type magnets to the third-generation Nd-Fe-B magnets in 1980s, leaving some fundamental questions unsettled. One of the fundamental issues is the long-standing dispute on phase decomposition mechanism, which cannot provide clear guidance to develop high-performance 2∶17-type magnets. With the advanced techniques, such as in-situ high-energy synchrotron X-ray diffraction (HES-XRD) and Cs-HRTEM, the detailed decomposition process of supersaturated solid solutions into multi-phase coexisting cellular nanostructure has clearly been revealed, clarifying this dispute. In this short review, the latest advances in solid-state phase transformation mechanism, defects formation and dissociation processes, correlation between defects and magnetic properties, and defects-control oriented fabrication methods of 2∶17-type Sm-Co-Fe-Cu-Zr magnets were briefly reviewed. We hope that this review article can be helpful for the community, from the understanding of fundamental contributions to the future development of high-performance magnets.

Directional freeze casting is a method that uses the "liquid-solid-gas" phase transformation of solvents to obtain porous materials by uniformly mixing raw materials, solvents and additives. It has the advantages of simple operation and green environmental protection. Different from the usual pore-making technology, it offers a high degree of control over the physical, chemical and mechanical properties of materials, where the materials prepared by this technology have oriented pores and hierarchical structures at different levels. Because of these characteristics, this technique is widely used in anisotropic porous inorganic, organic, hybrid and carbonaceous materials. This method can also be extended to simulate the structures of natural materials to assemble porous composites with excellent mechanical and physical properties. Finally, the method offers wide application prospects in fields such as environmental science, energy, thermal management and biology.
In this paper, based on the origins and principles of directional freezing technology, the formation mechanism of a directional structure is revealed based on the force model of single and multiple particles. The effects of the solute, solvent, temperature gradient, and additives on a structure and on the properties of the materials are analyzed. In addition, according to the different means of doping modification of precursor materials, the characteristics of directional structures prepared by one-step and two-step methods are introduced. Simultaneously, the research progress of directional freezing technology in pollutant adsorption, energy storage and conversion, structural materials, thermal management, and biomaterials are summarized. Finally, the problems that must be solved in the current research are briefly described, and future developmental directions are proposed.

Electrochromic devices have the advantages of lightweight, fast response speed, good reusability, and easy preparation of flexible devices. They are widely used in fields such as smart sensors, smart windows, flexible wearable devices, and energy storage devices. Compared to liquid devices that are prone to leakage and have low safety, all solid state electrochromic devices are easy to package and have high safety, making them more versatile for comprehensive applications. This article first introduces the structure of electrochromic devices, provides a detailed overview of the performance and applications of inorganic and organic solid-state electrochromic devices, and compares and analyzes the advantages and disadvantages between the two devices. Finally, the development and application prospects of all solid state electrochromic devices are discussed from the perspectives of performance bottlenecks, process difficulties, and industrialization.

Cellulose-based photonic crystals are photonic crystals with cellulose and its derivatives as the main constituent materials, and their structures are usually composed of periodically arranged cellulose materials with different refractive indices or complexes of cellulose and other mate-rials, which enable effective control of the propagation characteristics of photons. The advantages of cellulose-based photonic crystals lie in the sustainability, biocompatibility and biodegradability of cellulose materials, which make them have a wide range of potential applications in the fields of biosensing, optical devices and chiral photonics. In recent years, cellulose nanocrystals (CNC) have attracted much attention in the preparation and application of photonic crystals due to their fine nanostructures, excellent mechanical properties, low expansion coefficients, as well as excellent plasticity and adhesion. However, there is still insufficient discussion on the research progress of other types of cellulose-based photonic crystals. Starting from the types of cellulose-based photonic crystals, this paper first outlines their optical modulation mechanisms and preparation methods, and further clarifies the applications of different types of cellulose-based photonic crystals in sensor devices, optical anti-counterfeiting and other smart materials. It ends with a prospective discussion on the existing problems and future trends.

Nickel based single crystal superalloy has become the main material for the manufacture of advanced aero-engine and gas turbine blades due to its excellent high temperature mechanical property and microstructure stability. The anisotropy of mechanical property for nickel based single crystal superalloy is very important for the service property, safety and reliability of turbine blades, which has been highly valued by turbine blade designers and manufacturing experts. In order to meet the more stringent application requirements, new nickel based single crystal superalloys have been constantly developed at home and abroad to improve the temperature bearing capacity of aero-engine blades. However, the research on the anisotropy of mechanical property for new alloys is not very comprehensive, and the mechanism of newly added elements needs to be further studied.
In recent years, the research at home and abroad shows that the anisotropy of mechanical property for nickel based single crystal superalloy is related to temperature, stress and other factors. Meanwhile, different single crystal superalloys show different laws of anisotropy. The tensile property of nickel based single crystal superalloy has obvious anisotropy. With the increase of temperature, the ability of atomic diffusion and the number of slip systems increases, and the anisotropy of tensile property decreases. With the increase on the content of refractory elements in the alloy composition, the dislocation cross-section probability or deformation compatibility of the slip system will change, showing different tensile anisotropy. Under the condition of medium temperature and high stress, there is significant anisotropy in creep property. With the increase of stress, the creep property of the alloy with [001] orientation decreases significantly, and the creep property of the alloy with [111] orientation changes little, which is related to the effect of stress change on the number of slip systems. With the increase on the content of refractory elements, it is easier to start the slip systems with different orientations and form stacking faults, which affects the anisotropy of creep property. Under the condition of high temperature and low stress, the anisotropy of creep property is weakened, the creep property of the alloy with [111] orientation is better, and the creep property of the alloy with [001] and [011] orientation is poor. The low cycle fatigue property of nickel based single crystal superalloy also has obvious anisotropy. The fatigue life of the alloy with [001] orientation is the longest, followed by the alloy with [011] orientation, and the alloy with [111] orientation is the shortest. The high cycle fatigue property decreases in the order of [111], [001] and [011] orientation, which is mainly related to the elastic modulus, the number of slip systems and Schmid factor.
This article introduces the research progress on anisotropy of mechanical properties such as tensile, creep and fatigue property of nickel based single crystal superalloys in detail. The failure mechanism of alloys with different crystal orientations is revealed. The problems of the anisotropy of new nickel-based single crystal superalloy are stuclied and its prospects are discussed. The purpose is to provide a useful reference for the application of nickel base single crystal superalloy in aero-engine turbine blades in the future.

Liquid metals are the metals in a liquid state at room temperature or normal temperature, and are also called low melting point metals. Liquid metals have excellent thermal conductivity, electrical conductivity, lubrication and other properties. They are applied to radiators, batteries, 3D printing, flexible robots, magnetic fluid power generation, electromagnetic shielding, biomedical and other fields, and they have broad application prospects. A variety of new researches continue to emerge. The advent of composite materials such as liquid metal-based plastics and alloys has also further promoted the development of liquid metals. However, the development of liquid metals is also facing bottlenecks: corroding other metals, high density, large quality, too few types of raw material reserves and so on. In this paper, the research progress of multifunctional liquid metals is reviewed, and the research direction and application prospect of liquid metals are prospected.

Formaldehyde (HCHO) is one of the major pollutants in indoor air; therefore, its removal is vital to safeguarding human health since people spend most of their time indoors. Various methods have been developed for the removal of indoor HCHO, including physical adsorption, chemical adsorption, thermocatalysis, photocatalysis, plasma-based methods, and microbial purification. In this review, the principles, advantages, and disadvantages of these methods as well as their applications in air purification are summarized. Among the abovementioned methods, physical adsorption is the most widely applied because of its simplicity and low cost. However, the main disadvantage of this method is the low adsorption saturation level of most adsorbents, resulting in regular regeneration/replacement of the adsorbent, which in turn limits the application of this method. The development of novel adsorbents with high adsorption capacities which are easy to regenerate is the future direction for physical adsorption. Thermocatalysis is the most extensively investigated approach in recent years. Supported noble metal catalysts achieve higher conversions of HCHO to carbon dioxide and water at room temperature than non-noble metal catalysts, which justifies their widespread use in air purifiers. However, the high costs of noble metals limit their practical application in this regard. The synthesis of highly efficient, durable, and low-cost catalysts is very important to use thermocatalysis in the removal of HCHO. Plasma-based methods achieve high removal efficiencies for HCHO and various other volatile organic compounds (VOCs), making them specifically suitable for the removal of HCHO that coexists with a high concentration of VOCs in places such as furniture factories. However, the application of plasma-based methods can cause secondary pollution due to the formation of ozone, carbon monoxide, and other by-products. Additional catalytic beds are often required to eliminate these by-products. Photocatalysis offers a high removal efficiency for low concentrations of HCHO; therefore, it is suitable for application in places that receive abundant sunshine and have low concentrations of HCHO (such as closed glass rooms receiving abundant sunshine). The development of highly efficient, stable, and visible-light-responsive photocatalytic materials is the future direction for photocatalysis. Additionally, the high equipment requirements of plasma and photocatalysis restrict their vast practical application. Owing to the coexistence of HCHO with particulate matter and other VOCs in indoor air, the combination of adsorption, filtration, and thermocatalysis has important application potential for the removal of HCHO in air purifiers.

Titanium (Ti) and its alloys are widely used in various fields due to their low density, high strength, and excellent corrosion resistance. However the relatively high cost of Ti limits its further application. By forming titanium coatings on the substrate, the cost can be greatly reduced, while still obtaining the desirable properties of Ti. Additionally, Ti coatings exhibit superior durability and mechanical properties compared to the conventional organic coatings, leading to the increasingly intensifying research in this field. This paper systematically clarifies the mainstream technologies for the preparation and post-treatment of Ti coatings, and summarizes worldwide researches of Ti coating with applications in the fields such as marine engineering, biomedical engineering, aerospace, etc. The paper ends with a prospective discussion about the existing challenges and the future trends with respect to the development of Ti coatings.

Cracks and the reduction of water tightness after cracking are the important factors leading to the decrease of durability of cementitious mate-rials. Superabsorbent polymers (SAP) can relieve the self-shrinkage and improve the freeze-thaw resistance, impermeability after cracking, and self-healing ability of cementitious materials. The above functions of SAP rely on its absorption, desorption and re-swelling behavior in cementitious materials. In this paper, the mechanism of the absorption and desorption of SAP and its key influencing factors were first summarized. Then, the evolution mechanism of the re-swelling behavior of SAP in cracks was reviewed. In solutions, the osmotic pressure between the gel and solutions is the driving force for SAP swelling. Ca²⁺, as the key ion, can complex with the carboxyl group on the polymer chains and increase the ionic crosslinking density of SAP. A high ionic crosslinking density will produce a reverse osmotic pressure and induce the desorption of SAP. In cementitious materials, the key factors influencing the desorption rate of SAP are osmotic pressure and capillary force. Reducing the desorption under osmotic pressure and improving the desorption under capillary force can enhance the internal curing efficiency of SAP. Compared with AA SAP, AA-co-AM SAP has a more excellent internal curing effect due to its stronger water restraint ability. The re-swelling capacity of SAP in cracks of cementitious materials is lower than that in solutions, because the restraint effect of cracks and the high ion concentration in cracks inhibit the re-swelling of SAP. Designing new SAP based on the crack characteristics, mix designs and hydration process of cementitious materials may help to enhance the application effect of SAP.

Aqueous nitrate (NO₃^-) contamination is an ubiquitous environmental problem because of the extensive application of the relevant chemicals;the remediation of water polluted by nitrate via economic and effective methods, evenly realizing complete harmlessness is crucial. Nanoscale zero-valent iron (nZVI) is a typical engineered nanomaterial that is potentially used in environmental remediation of nitrate pollution.
In this paper, based on the application and development of nZVI technology in nitrate reduction, the prior studies mainly focus on the following:(1) improving its synthesis method or combining with other remediation techniques to improve its efficiency in in-situ remediation and enhance its resilience towards high concentration nitrate wastewater;(2) investigating the effects of environmental conditions including temperature, dissolved oxygen, solution pH, and competitive coexisting ions, to guide its practical applications. Although nZVI technology possesses remarkable potential in NO3-conversion, some difficulties remain, especially the short lifetime, limited mass transfer and adsorption capacity, and low selectivity towards nitrogen as a final product. These hinder the large-scale practical application of the technology. Therefore, functionalized nZVI-based materials, upon suitable modification, have gradually become promising substitutes for bare nZVI.
Herein, these modified materials are classified into three types, namely the supported, bimetallic, and the surface-modification system, especially emphasizing their advantages as compared with bare nZVI and revealing its promotion mechanism and factors affecting nitrate reduction energy efficiency. Finally, the existing problems to be addressed are identified, and future objectives and research areas worthy of exploration in the field of nZVI-based remediation technology are proposed.

Polarization detection technology is a vital optical sensing method characterized by its strong anti-interference capabilities and its effectiveness in enhancing detection range. It plays a significant role in various fields, including optical remote sensing, environmental monitoring, biomedicine, and underwater imaging. However, traditional polarization detection systems encounter challenges, such as bulky size and complex optical paths, which create substantial obstacles for miniaturization and integration. Metasurfaces, comprised of two-dimensional periodic arrays of artificially subwavelength elements, enable precise manipulation of optical fields according to the polarization states of incident light. This capability effectively reduces the size of polarization detection systems while enhancing device integration, offering innovative solutions for miniaturized polarization detection. This review analyzes the optical field manipulation mechanisms related to polarization detection and summarizes photon and photothermal polarization detectors based on metasurfaces. Additionally, it discusses existing challenges and future trends, aiming to provide valuable insights for further research in this field.

Developments in flexible electronic devices have led to development of flexible displays, solar cells and sensors. Particularly, flexible transpa-rent conductive films (TCFs) form an indispensable part of flexible electronic devices and the demand for these conductive films will increase in the future. At present, scalable, lightweight, flexible, stretchable, and low-cost optoelectronic devices are desired. Indium tin oxide (ITO) is the most widely used TCFs. However, ITO is brittle in addition to requiring complication preparation process. More importantly, indium is a rare metal, which is scarce and expensive. Therefore, substitutes exhibiting high performance for use in flexible TCFs should be developed. Researchers have developed a variety of flexible TCFs that can replace ITO, and films based on metal mesh have demonstrated great potential.
These films have demonstrated excellent photoelectric properties and mechanical flexibility. The line width and spacing of the metal mesh can be changed independently, thus granting a better ability to adjust trade-off between square resistance and transmittance of the film. Many reports have detailed the development of metal mesh-based flexible TCFs with performances, which are comparable to ITO. Most of these reports prepare master plates by photolithography. Consequently, this preparation is combined with electroless plating or electrodeposition to make conductive films. Flexible TCFs prepared by photolithography have good performance. However, photolithography is complicated and expensive. Some reports have detailed the preparation of flexible TCFs using additive manufacturing, electrostatic spinning, photonic sintering, and template method. The flexible TCFs fabricated using additive manufacturing have been commercialized for touchscreen applications and are expected to be developed further.
In this paper, progress in preparation and optoelectronic device applications of metal mesh TCFs is reviewed. Specifically, the photoelectric properties, manufacturing technology, and device applications of metal mesh TCFs and the drawback of these preparation methods are discussed. This paper provides a reference for future research in the TCFs domain.

Rare earth is an important strategic resource, and the rare earth elements (REEs) are a class of 17 elements in the periodic table that include 15 lanthanides (atomic numbers from 57 to 71), scandium (atomic number 21), and yttrium (atomic number 39). Rare earth elements show excellent catalytic performance in many reactions in the field of catalysis due to their special 4f electron configuration, abundant electron structure and flexible coordination numbers. Among all kinds of rare earth catalytic materials, the rare earth oxide based composite catalysts show superior performance in electrocatalytic reactions due to its simple preparation process, versatile structural tunability. However, at present, the relationship between the electrocatalytic activity of rare earth oxides based composite catalyst and their electronic structures is still not clear, which hinders the understanding of REEs in electrocatalytic reactions. Therefore, in this review paper, we tried to summarize and highlight the applications of rare earth oxides based composites in electrocatalytic reactions based on the characteristics of their electronic structures.

Flexible pressure sensors are an important branch of wearable electronics, which have extensive prospects for applications in human-machine interface and health monitoring. The electrical and mechanical properties of flexible pressure sensor are rapidly being improved to meet various application requirements following the development and application of advanced materials and new device preparation strategies.
Capacitive flexible pressure sensors are superiorto other forms of flexible pressure sensors because of their high sensitivity, low power consumption, and fast response. The performance of capacitive flexible pressure sensors can be optimized by changing device structure parameters, such as effective electrode area, electrode distance, effective dielectric constant, etc. The main improvement approaches are using novel nano-materials, adopting new micro-structure designs, and developing advanced composite materials. There are four basic optimization principles:(i) increasing the efficient surface area by increasing the electrode surface roughness; (ii) introducing air to obtain a low elasticity modulus of the electrode or dielectric layer; (iii) optimizing the effective dielectric constant by introducing air or fillers; (iv) producing micro-capacitors to influence the overall capacitance change of the device.
Maintaining high sensitivity over a broad pressure range remains a critical challenge in flexible capacitive pressure sensor research. Devices with ultra-high sensitivity can easily reach compression saturation under a certain pressure. The saturation limits the detection range, resulting in poor linearity. Some recent studies have focused on improving the sensitivity and detection range of flexible capacitive pressure sensors. Gradient structure design and application of hybrid mechanisms have been demonstrated to be effective methods for obtaining a wide detection range without sacrificing sensitivity. However, hysteresis, stability and array optimization are additional problems confronting the practical application of capacitive flexible pressure sensors.
This review focuses on the rapid development of capacitive flexible pressure sensors. Mechanisms of the performance optimization are reviewed, followed by examples of structure design strategies and material optimization methods. The review concludes with a critical reflection of the current status and challenges, and discusses the prospect of the capacitive flexible pressure sensor development. This review can help to improve the design and preparation of personalized capacitive flexible pressure sensors.

The traditional thermal control coating with fixed emissivity is difficult to meet the rapid development of China's aerospace industry, and the VO₂ intelligent thermal control coating, with the advantages of passive adaptation and strong designability, has become a hot spot of research at home and abroad. In this paper, based on the phase transition characteristics of VO₂ metal-insulator, the optical design methods and research progress of VO₂ intelligent thermal control coatings with four structures of F-P resonant cavity, metasurface, photonic crystal and nanocomposite film are reviewed by analyzing the emissivity regulation mechanism of VO₂ intelligent thermal control coatings in infrared band. It extracts the key factors affecting the engineering application of VO₂ smart thermal control coatings due to the decrease in spatial stability, and looks forward to the future development trends of VO₂ smart thermal control coatings.

The first-principle is a calculation method involving material science, physics, chemistry, computer science and artificial intelligence, which can study the properties of materials from a micro perspective. In recent years, first-principles calculations has been applied to the field of electrochemical corrosion of materials. It can analyze the micro scale mechanism of corrosion and oxidation at the atomic level, explain the nature of corrosion from the electronic level, and open up a new research area for corrosion science. Based on the investigation and analysis of current research, this paper expounds the basic methods of first-principles, and summarizes the research progress of first-principles calculations in the field of corrosion, such as adsorption and diffusion of surface, stability of passive film and interface, element doping and inclusion dissolution, corrosion inhibition and battery electrochemistry, and corrosion of high entropy alloy and amorphous metallic alloy. Besides, we summarize the existing problems in the application of first-principles in fields of corrosion science, and emphasize the urgency of in-depth research on direct cha-racterization of electrochemical process of corrosion, quantitative modeling and calculation of materials, construction model of amorphous structure, cross scale simulation of corrosion process and so on. Finally, the development direction of first-principles calculations in corrosion science is prospected. This paper aims to elaborate the effects of metal surface adsorption on corrosion performance, and discuss the stability and failure mechanism of passive film and interface. It can also reveal the essence of galvanic corrosion induced by element doping and precipitated phase, and understand the anticorrosion mechanism and design new corrosion inhibitors. It has important theoretical guiding significance to describe the dynamic evolution process of local structure in high entropy alloy or amorphous structure. This paper has very important theoretical guiding significance for application of first-principles in corrosion science.

In the rapidly evolving landscape of integrated circuit technology, as process nodes continue to shrink to the nanometer level, the demands placed on interconnect materials and their processing technology are becoming increasingly stringent. Cobalt (Co), an emerging metal material, is gaining traction as a preferred choice forcopper (Cu) interconnect barrier layers and potential interconnect materials due to its exceptio-nal thermal stability, void-free filling ability, and strong adhesion to Cu wiring. However, this heightened interest in cobalt is accompanied by a high demand for surface smoothness and cleanliness, driving extensive research and innovation in chemomechanical polishing (CMP) processes and post CMP cleaning process. This paper aims to review the current application status of Co as Cu interconnect barrier and new interconnect material in integrated circuits, respectively. The impact of various slurry components on the material removal rate, galvanic corrosion, and removal selection ratio in CMP process are analyzed. Furthermore, the crucial role of cleaning solutions is discussed in post CMP cleaning process. Through precise chemical formula design, defects such as nanoparticles and organic residues can be effectively removed to ensure that the Co surface achieves high levels of cleanliness and flatness. Additionally, the review identifies the limitations of current research and offers forward-looking insights into the development of more environmentally friendly and efficient Co CMP and post-CMP cleaning technologies.

The development of railways, buildings and machineries has necessitated the implementation of stringent requirements for the materials of safe and light-weight structures, which can be achieved through the development of strong and tough advanced high strength steels (AHSS). AHSS are characterized by the combinations of multi-phase microstructures achieved through innovative process designs to meet the performance requirements of modern industries. Currently, the third generation AHSS, which include transformation-induced plasticity (TRIP) steel, quenching and partitioning (Q&P) steel, medium Mn steel, and carbide-free bainitic steel, are considered promising candidates for lightweight structural applications, because they possess the ability to induce combinations of excellent mechanical properties. In this paper, firstly we review recent studies on alloying designs, solid-state phase transformations, microstructure adjustments of the third generation AHSS, in particular, the roles of advanced heat treatments, and partitioning of alloying elements in microstructure transformations. AHSS comprise microstructures of martensite, bainite, ferrite, and retained austenite. The amount and stability of retained austenite are crucial factors affecting the mechanical perfor-mance of AHSS. Secondly, the factors affecting the stability of retained austenite and the effect of austenite retention on strength, ductility, toughness, and fatigue properties are discussed. This paper would provide a reference to future research on obtaining a specific volume of metastable retained austenite in multiphase microstructures and exploring the relationship between microstructures and mechanical properties. Finally, the development trend of AHSS is briefly introduced for exploring new methods to improve the mechanical properties of metals.

Molybdenum carbide is formed when carbon atoms are introduced into the crystal lattice of molybdenum. This kind of mesenchymal structure has unique physical and chemical properties. This material has excellent catalytic activity in hydrogenation reaction and hydrogen production reaction, and its catalytic performance can be compared with platinum and palladium. Molybdenum carbide has active chemical properties, so the synthesis method and experimental conditions closely affect the physical and chemical properties of the final product. Small changes in the reaction materials and experimental conditions may result in changes in the crystal phase structure, grain size, and specific surface area of molybdenum carbide, thus changing the catalytic performance of the material.
This paper reviews the research progress of molybdenum carbide. The crystalline phase types and spatial structure of several typical molybdenum carbides are introduced, the electronic properties affecting the structure of molybdenum carbide are analyzed, the synthetic strategies of molybdenum carbide are summarized systematically, and the advantages and disadvantages of different preparation methods are pointed out. Ta-king programmed temperature carbonization as an example, the growth mechanism is emphatically analyzed, and the influence and importance of preparation conditions on the final synthetic material are discussed from three aspects: final temperature of carbonization, heating rate, and carbon source concentration. The applications of molybdenum carbide in hydrogenation reaction, hydrogen production reaction, sensor, and biomedical materials are reviewed. The catalytic mechanism and improvement strategy of molybdenum carbide in electrocatalytic hydrogen evolution and CO₂ hydroconversion are introduced in detail. Finally, based on the existing challenges, the future development direction of molybdenum carbide material is further proposed.

Multi-energy field assisted processing is an important direction for the development of advanced manufacturing technology. Electropulsing treatment (EPT) is an innovative technology, which has been used to improve the microstructure and mechanical properties of metallic materials by applying electric pulse current. The EPT has broad promising applications in the manufacturing industry.
Due to the advantages of energy saving and high efficiency that can quickly heat up materials, EPT has preponderance over conventional heat treatment in terms of improving material plasticity, promoting recrystallization and phase transformation. The response of microstructure and mechanical properties of metal materials to EPT has attracted wide attention.
The coupling effects, including joule heating effect, electromigration effect and other electroplastic effects, could enhance the atomic diffusion and dislocation migration to improve the forming ability. In addition, pulse current can significantly promote grain refinement, solid-state phase transition, and texture weakening, so as to obtain excellent comprehensive mechanical properties. In addition, EPT can repair internal porosities and cracks of the material to effectively inhibit the crack propagation and improve the fracture behavior.
Based on the existing research, the effect of EPT on the microstructure and mechanical properties of materials has been summarized and the mechanism is preliminarily analyzed from the aspects of grain refinement, solid-state phase transition, and crack repair. Moreover, the related researches on the formation characteristics and performance of welded joints after EPT are also included in the paper. Finally, the follow-up research on EPT is discussed.

All objects whose temperatures exceed absolute zero emit infrared thermal radiation which relates closely to the objects' emissivities. Due to the constant emissivity, most objects can only present a single thermal function. However, in practical applications, dynamic thermal radiation regulation is of great importance to meet the requirements for different environment and functions. Flexible and electroresponsively emissivity-dynamically-modulatable materials exhibit not only environment-condition-independent high tunability, but also favorable properties such as lightweight, flexibility, and portability, thereby are superior in both usage and storage. This review summarizes the research progress of some typical kinds of flexible and electroresponsively emissivity-dynamically-modulatable materials including conductive polymers, carbon-based materials, and reversibly electrodeposited metals, and outlines the applicative potential of flexible and electroresponsively thermal-radiation-dynamically-regulating devices. The paper ends with a discussion about the challenges and the future trends.

Diamond/SiC composites combine the advantages of SiC and diamond, and have excellent properties such as high thermal conductivity, low thermal expansion coefficient, high specific stiffness, high hardness and wear resistance, which have broad application prospects, and are one of the key research focuses in the field of ceramic matrix composites. Diamond/SiC composites are first prepared by high temperature and high pressure method, which can effectively avoid the harmful effects of graphitization of diamond particles. With the continuous development of technology, a variety of preparation methods have emerged. The properties of diamond/SiC composites are determined by the major phase content, interfacial phase structure and microstructure under different preparation methods. This paper reviews the research and development status of diamond/SiC composites at home and abroad, describes the preparation method, performance characteristics, microstructure and interfacial reaction mechanism, analyzes the current problems of diamond/SiC composites, and gives an outlook on the future development of this composites.

Compared with lithium-ion batteries, sodium-ion batteries have the advantages of low cost, abundant raw materials, good cycle stability and rate performance. Hence, a growing number of researchers have joined the basic research and engineering exploration of sodium-ion batteries because of the increasing demand for low-cost energy storage technologies. With regard to the sodium-ion battery system, the anode materials significantly influence the energy density of the battery, as well as the cycling performance and safety. Recently, anatase titanium dioxide (TiO₂), among many anode materials, has gradually become a research hotspot for sodium-ion battery on account of its low self-discharge, high safety, long cycle life, environmental friendliness and relatively high sodium-ion deintercalation potential. Yet, since TiO₂ is a semiconductor material, the sluggish ionic diffusivity and poor electronic conductivity severely hinder the performance under high rates and long-term cycling conditions. Therefore, anatase TiO₂ needs to be modified to improve its electrical conductivity. This study systematically reviews the effects of different modification methods, such as microstructure adjustment, defects (oxygen vacancy and heteroatom doping) and compounding with conductive matrix. In addition, the research and applications of anatase TiO₂ as sodium-ion anode in the future are also prospected.

The rapid development of nuclear energy technology has brought about hidden dangers of radiation safety. In order to protect the health of personnel and the safety of the surrounding environment, a shield must be used for protection. The complexity of the nuclear facility structure as well as the diversity of application scenarios puts forward higher requirements for the performance of comprehensive shielding materials. Materials not only have excellent neutron and γ-ray shielding functions, but also have remarkable mechanical properties to be used as structural materials. This article briefly describes the design requirements of nuclear radiation comprehensive shielding materials. According to the research status of shielding materials at home and abroad, the research progress of commonly used radiation shielding materials is reviewed. Through comparative analysis of the shielding performance of metallic and non-metallic materials, the research content, characteristics and problems of various substrates and functional filler materials are summarized. It is proposed that the structure/function integrated shielding material has become the development direction. And the application of nickel-based composites containing rare earth elements will become the focus of further research, which provides a reference for the development and application of new radiation shielding materials.

Silicon heterojunction (SHJ) solar cells are an important part of the current photovoltaic industry, and they have attracted wide spread attention because of their high open-circuit voltage (V_oc). The optical and electrical properties of transparent conductive oxide (TCO) films in SHJ solar cells affect the short-circuit current (J_sc) and filling factor (FF), respectively, and the variation of J_sc and FF will further affect the conversion efficiency of the cells. Therefore, the performance of the TCO film layer limits the long-term development of SHJ solar cells. In recent years, the development of TCO films in SHJ cells has mainly focused on improving the performance of doped In₂O₃ systems and doped ZnO systems. In this paper, we firstly describe the different structures of SHJ solar cells, followed by the optoelectronic properties, namely, transmittance, band gap, sheet resistance, carrier concentration, mobility, and work function, of transparent conductive oxide films. The effect of contact properties with each layer on the performance of the cell is then summarized, the application and research status of various transparent conductive oxide films in SHJ solar cells are introduced, and the prospects for their future development trends are reviewed.

In recent years, several nanoparticles have been studied as potential nucleation seeds for cement hydration. Synthetic nano-calcium silicate hydrate (C-S-H), nano-SiO₂, nano-CaCO₃, nano-TiO₂, and carbon nanotubes are investigated to determine their abilities to reduce the nucleation barrier by providing nucleation sites for hydration products, thereby accelerating cement hydration. Among them, the nano C-S-H seeds are found to be a good nucleation substrate for C-S-H gel, and provided the most significant cement-hydration acceleration. Thus, nano C-S-H seeds are attracting increasing attention from both academia and industry.
To date, methods of synthesizing nano C-S-H seeds, as well as the seed nucleation process and mechanism of cement hydration, have all been studied. In many studies, the nano C-S-H suspension is prepared by co-precipitating in the presence of polymer that exhibited nanoscale-sized grains and good dispersion stability which followed a non-classical nucleation mode. After applying it to cement, nano C-S-H seeds, with a high surface area, acted as additional nucleation sites for C-S-H gel, which reduced the nucleation barrier of the C-S-H gel. Thus, the nano C-S-H seeds effectively accelerated the cement hydration rate. The nano C-S-H seeds also enhanced the early strength development of the cement, particularly within the first day of aging. In contrast to traditional cement accelerators, nano C-S-H seeds have the advantages of low dosing requirements, good effect on early strength, and no impact on cement and concrete durability. To a certain extent, these seeds also compensate for the slow early-strength growth of supplementary cementitious materials (SCMs). Therefore, nano C-S-H seeds have promising applications in low-temperature and slipform construction, the production of precast-concrete products, and other projects that require high levels of early strength. Nano C-S-H seeds have the potential to become a widely used hydration accelerator for cement and concrete.
In this review, many studies about nano C-S-H seeds are analyzed and summarized. Including the methods for synthesizing C-S-H seeds, as well their nucleation process, mechanism of interaction with polymers, and effects on the cement-hydration process. Based on theoretical principles and experimental results, current shortcomings are evaluated, and the problems that still need to be addressed are identified. This review provides a theoretical basis and future direction for scientific research and engineering applications of nano C-S-H seeds.

Carbon fibers, as new type of fiber material, contained more than 90% carbon. For their excellent properties such as high-strength, high-modulus, low-density, electric conductivity, temperature-resistance, and chemical stability, carbon fibers were widely used in aerospace and rail transportation as engineering materials. Carbon fiber papers were critical foundational material for electromagnetic wave shielding, friction plate, electric heating, gas diffusion layer (GDL) of fuel cell, electrode of capacitor, which exhibited excellent mechanical, electrical, and chemical stability as well as the uniform porosity, flexibility. Recently, research on the formation process and paper-based functional materials derived from carbon fibers has attracted extensive attention in academia and industry. Herein, the research process of formation process and application of carbon fiber paper from home and abroad were reviewed. The new challenge of wet-laid pulp process for carbon fiber paper was discussed, and the development tendency of carbon fiber paper has been prospected.

The interfacial transition zone (ITZ), a thin layer formed between cement matrix and aggregate, generally has the properties of larger porosity and enrichment of the oriented calcium hydroxide crystals. The formation mechanism of ITZ mainly includes the wall effect, micro-bleeding effect, ion migration and nucleation effect, one-sided growth effect, flocculation effect and syneresis effect, and the synergistic effects of these effects makes the ITZ the weakest point of concrete. Therefore, it will be beneficial for the mechanical properties and durability of concrete if the bonding strength of ITZ can be enhanced. Commonly used methods for improvement of ITZ bonding strength, including incorporation of mineral admixtures or nanomaterials, aggregates modification, biomineralization and carbon dioxide curing, are summarized and compared in this study. This study will provide a reference for the study on formation mechanism and modification of ITZ and its application in practical engineering.

Due to its large specific capacitance, high electrical conductivity, chemical stability and many other advantages, polypyrrole is considered to be the most likely conductive polymer for industrialization. However, bulk polypyrrole is usually deficient in electrical, optical and biological properties, while nano-structured polypyrrole has special electrochemical activity, improved optical properties and good biocompatibility due to its well-defined nanostructure and larger surface area. In addition, with the rapid development of science and technology, single polypyrrole nanomaterials have been insufficient to cope with the application needs of various aspects. However, polypyrrole nanocomposites can retain the function of the individual components and the synergistic effect when integrated with other functional materials, and can simultaneously possess the advantages of several materials, thus greatly broadening the application range of polypyrrole. This article summarizes the research progress of polypyrrole nanocomposites and introduces the five types of polypyrrole nanocomposites. Based on their excellent electrical conductivity and reversible redox properties, the applications of polypyrrole nanocomposites in the fields of energy storage, biomedicine, adsorption and impurity removal, electrocatalysis, wave-absorbing materials, sensors and corrosion protection are presented. Finally, the perspectives on the challenges and opportunities in this emerging area of research are discussed.

The development of novel energy-efficient cooling technologies is of significant importance for the realization of effective building thermal management and energy-saving. Radiation is the most ubiquitous mode of heat transfer in nature, where solar and environmental thermal radiation plays a vital role serving as two critical energy vectors. The photothermal regulation could modulate the solar and thermal radiation properties, thus managing the internal temperature of objects. Materials exhibit varied spectral responses to solar and thermal radiations according to the specific demands of different scenarios, which could be categorized into active and passive photothermal control materials. Active photothermal regulation materials are favored for their high tunability and low energy consumption, while passive photothermal regulation materials are recognized for their zero-energy consumption and robust temperature regulation capabilities, both garnering extensive attention from researchers. This article, exemplifying active control and passive control with electrochromic materials and radiative cooling, respectively, focuses on outlining the regulatory principles of these emerging photothermal control technologies. It reviews the development of electrochromic and radiative cooling materials based on spectral design strategies and principles, and further summarizes the existing challenges and future development directions, providing a comprehensive perspective for researchers in the field of building energy saving.