Polyurethane (PU) is an indispensable polymer material widely used in daily life. However, its flammability (limiting oxygen index LOI < 20%) and release of toxic smoke during combustion restrict its application in emerging fields such as smart wearables and robotic skins. Therefore, overcoming the limitations of traditional flame-retardant strategies has become an urgent issue in materials science. This review systematically summarizes key advances from 2021 to 2025, focusing on new flame-retardant paradigms based on biomimetic structural design and intelligent response mechanisms. Multiscale biomimicry includes macro-shape mimicry, such as sunflowers and cacti, and micro-structural mimicry, such as nacre-like layering and lotus-leaf superhydrophobic surfaces. This approach effectively balances flame retardancy with mechanical properties and introduces additional functions like oil-water separation, solar ice melting, and underwater antibacterial performance. Furthermore, this paper presents the concept of intelligent active protection. Integrating self-healing, fire early warning, and shape memory creates a synergistic system that forms a closed-loop protection mechanism covering sensing, alerting, and action. This advances flame-retardant technology from static, passive defense toward dynamic, adaptive response. Nevertheless, this field still faces three major challenges. First, environmental adaptability is limited, as most self-healing and shape memory behaviors require specific activation conditions. Second, complex biomimetic nanostructures are difficult to fabricate on a large scale at low cost. Third, the long-term cyclic stability and durability of coatings and composites need improvement. To address these challenges, future work should integrate artificial intelligence for material pre-design, combine animal and plant features to build multi-level defense systems, and develop biomass-based green closed-loop solutions across the material life cycle. These efforts will promote the development of biomimetic intelligent flame-retardant polyurethanes that can coexist sustainably with the environment.

Contents

1 Introduction

2 Bionic flame retardant

2.1 Shape bionics

2.2 Structural bionics

2.3 Surface coating

3 Intelligent flame retardant

3.1 Self-healing

3.2 Fire warning

3.3 Shape memory

4 Conclusion and outlook

Sodium-ion batteries (SIBs) have attracted increasing attention as a promising alternative to conventional lithium-ion batteries owing to their abundant resources, low cost, and improved safety. Among various cathode systems for SIBs, P2-type layered transition metal oxides stand out due to their relatively simple crystal structures, mature synthesis processes, and fast Na⁺ diffusion kinetics, rendering them highly attractive for practical applications. Nevertheless, their commercialization is still hindered by several intrinsic challenges, including frequent structural phase transitions during cycling, insufficient air stability, and limited reversible capacity. To address these issues, extensive efforts have been devoted to performance optimization strategies such as ionic doping, composite structure design, surface coating, and morphology regulation, among which ionic doping has emerged as an effective and versatile approach. Despite numerous reports, existing studies are predominantly organized according to dopant species or material systems, while a systematic understanding from the perspective of coordination environment regulation remains lacking. In this review, recent advances in ionic doping strategies for P2-type layered oxide cathodes are comprehensively summarized with an emphasis on coordination environments, and the roles of dopant ions located in the alkali metal layers, transition metal layers, and anionic frameworks are systematically discussed, with particular attention to their mechanisms in stabilizing crystal structures, suppressing unfavorable phase transitions, and enhancing electrochemical performance. Furthermore, the key challenges and limitations associated with ionic doping strategies are critically analyzed, their practical applicability is evaluated, and perspectives on future research directions and development opportunities for P2-type layered cathode materials are provided.

Contents

1 Introduction

2 The challenges of P2-type cathode materials

2.1 Irreversible transition

2.2 Low air stability

2.3 Low reversible capacity

3 Alkali metal layer doping modification

4 Transition metal layer doping modification

4.1 Single metal P2 cathode material

4.2 Binary metal P2 cathode material

4.3 Ternary and polymetallic P2 cathode materials

5 Anion oxygen layer doping modification

6 Conclusion and outlook

Novel and efficient techniques for low-cost and environmentally-friendly energy storage systems are imminent, in regard to the excessive consumption of non-renewable fossil energy. Hydrogen shows the advantages of high energy density, carbon neutrality and pollution-free, so it has been considered as a promising energy carrier to replace fossil fuels. However, the practical application of hydrogen is challenged by the low density, difficult storage and transportation. Therefore, efficient hydrogen storage materials for hydrogen are of great significance. Liquid organic hydrogen carriers (LOHCs) promote the release and absorption of hydrogen through chemical reactions, so it has attracted increasing attention. Lignin is the most abundant aromatic source of natural, renewable organic carbon on Earth. The technologies of converting lignin into LOHCs through catalytic upgrading meet the demands of "carbon neutrality" and have huge application potential. Therefore, we summarized here the recent research progress in the hydrodeoxygenation of lignin and its derivatives to LOHCs. The effects of different catalyst carriers on the catalytic performance for producing LOHCs were demonstrated. The application of the saturated products from lignin and its derivatives, which are considered to be promising LOHCs, was also reviewed. In addition, we also provided a prospect on the future technical development of the production of liquid hydrogen storage materials from lignin and its derivatives.

Contents

1 Introduction

2 LOHCs

2.1 Aromatic compounds

2.2 Dehydrogenation and hydrogenation of liquid hydrogen storage materials

3 Influence of catalyst carriers on the performance of lignin-based liquid hydrogen storage materials production

3.1 Carbon material

3.2 Metallic oxide

3.3 Molecular sieve

4 Conclusion and outlook

Bioactive materials, with their superior osteoinductive and tissue-integration capabilities, are progressively overcoming the limitations of traditional bioinert materials in tissue repair, emerging as a key development direction in bone tissue engineering. This article reviews recent progress in the application of metals, bioceramics, polymers, and their composites in inducing bone-like apatite formation and bone regeneration, with a focus on elucidating the mechanisms by which these materials regulate bone regeneration through dynamic interactions with the host microenvironment. Studies demonstrate that the surface chemical composition, micro-nano topological features, and interfacial energy state of materials synergistically induce biomimetic mineralization, oriented deposition, and structural evolution of bone-like apatite, thereby activating osteogenic signaling pathways and enhancing stem cell adhesion, proliferation, differentiation, and angiogenesis. Moreover, the diversity in crystal morphology and biological functionality of bone-like apatite induced by different material systems significantly impacts the efficiency and quality of bone regeneration. However, current research faces several challenges, including insufficient control over the mineralization process, difficulties in optimizing the coupling of bioactivity and mechanical properties, and the impact of individual variability on therapeutic consistency in clinical translation. Therefore, systematic breakthroughs are urgently needed in material design, manufacturing technologies, and in vivo response mechanisms. Future research should focus on the integrated development of multiscale biomimetic bone materials, leveraging in situ dynamic characterization, molecular simulations, and artificial intelligence algorithms to deeply elucidate the temporal regulation mechanisms of material-induced biomineralization, thereby advancing the clinical translation and application of smart responsive scaffolds and persona. Therefore, systematic breakthroughs are urgently needed in material design, manufacturing technologies, and in vivo response mechanisms. By focusing on the development of multiscale biomimetic bone materials, leveraging in situ dynamic characterization, molecular simulation dynamics to deeply elucidate the temporal regulation mechanisms of material-induced biomineralization, thereby advancing the clinical translation of smart responsive scaffolds and personalized bone repair strategies in regenerative medicine.

Contents

1 Introduction

2 In vitro mechanisms of bone-like apatite formation on material surfaces

2.1 Bone-like apatite formation induced by metallic materials

2.2 Bone-like apatite formation induced by polymeric materials

2.3 Bone-like apatite formation induced by bioceramics

3 Bone-like apatite coating characteristics in bone regeneration

3.1 Metallic materials and surface-engineered implants

3.2 Bioactive polymers and polymer-based composite scaffolds

3.3 Bioceramics including calcium phosphates and bioactive glasses

4 Conclusion and outlook

Carbonylation reactions represent an important approach for producing high-value-added chemicals by introducing carbonyl groups (C=O) into molecules. Owing to their high atom economy and compliance with green and sustainable development requirements, these reactions have found widespread applications in fields such as organic synthesis, medicinal chemistry, and materials science. Although numerous catalysts for carbonylation reactions have been developed to date, most fail to meet the requirements for industrial application. In recent years, significant progress has been made in the research of cobalt-based catalysts for carbonylation reactions, which have attracted considerable attention due to their low cost, abundant resources, and environmental friendliness. Through strategies like ligand design and support optimization, the activity, selectivity, and stability of cobalt catalysts have been significantly enhanced. This review systematically summarizes the latest advances in cobalt-based catalysts for reactions including hydroesterification, hydroformylation, aminocarbonylation, and hydrocarboxylation, discusses the impacts of ligand design, reaction mechanisms, and heterogenization strategies on catalytic performance, and prospects their development prospects in green chemistry and industrial applications.

Contents

1 Introduction

2 Hydrogen esterification reaction

3 Hydroformylation reaction

4 Amine carbonylation reaction

5 Hydrocarboxylation reaction

6 Conclusion

Proton exchange membrane fuel cells (PEMFCs), characterized by their high energy efficiency and environmental friendliness, are widely regarded as one of the most promising energy conversion technologies. However, the degradation and failure of the proton exchange membrane (PEM) remain key factors limiting the long-term durability and large-scale application of PEMFC systems. This study systematically reviews the three primary degradation modes of PEM—mechanical, thermal, and chemical degradation—from the perspectives of underlying mechanisms and mitigation strategies, with particular attention to their synergistic effects. The causes of these degradation modes during practical fuel cell operation, their impacts on the physicochemical structure of the membrane and on cell performance, as well as the current mitigation strategies and their limitations, are comprehensively analyzed. The results highlight that gas crossover serves as a critical link among different degradation processes: mechanical fatigue and crack propagation increase gas permeability, which intensifies chemical degradation through accelerated radical formation, while chemical degradation of the polymer backbone weakens the mechanical strength of the membrane, thereby promoting further mechanical failure and forming a vicious cycle. Finally, the study summarizes the existing challenges in PEM degradation research and proposes future directions, including the development of multi-stress coupled accelerated aging protocols, the establishment of quantitative correlations between gas permeability and membrane aging, the design of gradient composite membranes that combine durability with high electrochemical performance, and the optimization of system operation strategies to substantially extend overall lifetime and operational stability.

Contents

1 Introduction

2 Types of membrane degradation

2.1 Mechanical degradation

2.2 Thermal degradation

2.3 Chemical degradation

2.4 Conjoint degradation

3 Conclusion and outlook

Shape memory polymers (SMPs) are a class of intelligent materials that can autonomously return to their predetermined shape in response to external stimuli, such as temperature, light, electric fields, and magnetic fields, etc. By now, SMPs have attracted significant attention due to advancements in science and technology, emerging as a novel and promising smart material. Owing to their structural flexibility and versatility, SMPs exhibit tremendous potential across a variety of fields, including biomedical engineering, textiles, and aerospace, etc. This review will explore the diverse applications of SMPs in various fields, beginning with an overview of their classification, characteristics, and development history, before delving into their application prospects. The article will conclude by examining the current challenges faced by SMPs and offering insights into their future development trends.

Contents

1 Introduction

2 Classification of shape memory polymers

2.1 One-way shape memory polymers

2.2 Two-way shape memory polymers

2.3 Thermadapt shape memory polymers

2.4 Shape memory polymers with programmable recovery onset

3 Applications

3.1 Scaffold and drug release

3.2 Self-tightening sutures and procoagulant foam

3.3 Textile

3.4 Aerospace

3.5 Sensor

3.6 Information safety

3.7 Architecture

4 Conclusion and outlook

Polyvinyl alcohol (PVA)-based hydrogel fibers possess a three-dimensional cross-linked network structure, combining mechanical properties with liquid mass transfer characteristics, and exhibiting excellent flexibility, controllable wettability, and stimulus responsiveness. Due to their low cost, versatile processing methods, and good mechanical properties, these fibers are expected to play a significant role in fields such as wearable devices, human-computer interaction, and precision medicine through structural optimization and functional modification. This paper provides a systematic review of research progress on PVA-based hydrogel fibers, categorizing them into two main types: physically cross-linked and chemically cross-linked. It summarizes various preparation methods, including the mold method, impregnation, electrospinning, wet spinning, microfluidic spinning, and 3D printing. Building on this foundation, the paper elaborates in detail on the application and development of this material in fields such as biomedicine, flexible electronics, smart textiles, self-healing materials, and supercapacitors. Finally, the paper discusses the challenges currently facing research and future development directions, with the aim of providing a reference for in-depth research and expanded applications in this field.

Contents

1 Introduction

2 Generation, direct detection and trace detection of reactive halogen species

2.1 Physically crosslinked gel fiber

2.2 Chemically crosslinked gel fiber

3 Preparation method of polyvinyl alcohol based gel fiber

3.1 Mold method

3.2 Dipping

3.3 Electrospinning

3.4 Wet spinning

3.5 Microfluidic spinning

3.6 3D Printing

4 Application of PVA based gel fiber

4.1 Biomedical

4.2 Flexible electronics

4.3 Smart textiles

4.4 Self repairing materials

4.5 Supercapacitors

5 Conclusion and Prospect

Electromagnetic interference shielding materials can protect the human body from the harm of electromagnetic waves and ensure the normal operation of electronic devices. The electromagnetic interference shielding performance of traditional electromagnetic interference shielding materials is limited by their fixed structure and size, making it difficult to dynamically adjust according to changes in the external environment. Developing electromagnetic interference shielding materials with smart response capabilities is one way to solve this problem. Smart electromagnetic interference shielding materials can respond to various external factors better, adapting to different usage environments. This article provides a comprehensive review of the research work on smart electromagnetic interference shielding materials. Firstly, the smart response electromagnetic interference shielding mechanisms are briefly explained, including the stress response mechanism, temperature response mechanism, humidity response mechanism, chemical stimuli response mechanism, and other response mechanisms (electric response mechanism, cross-angle response mechanism). Secondly, the preparation methods and application performances of different smart electromagnetic interference shielding materials were summarized and analyzed. Finally, the development of smart electromagnetic interference shielding materials is looked forward to in terms of response time, response sensitivity, response mechanisms, and shielding efficiency.

Since the advent of plastics in the 20th century, human life has been greatly facilitated by their excellent properties. However, their non-biodegradable nature has also led to environmental pollution and resource waste. Regarding waste PET and PLA as valuable carbon reservoirs, their upcycling through heterogeneous catalytic hydrogenation has become a central theme in contemporary chemical recycling research. This process can efficiently produce high-value chemicals and new polymer materials under mild conditions, demonstrating excellent atom economy and rich product diversity. This review systematically summarizes the latest progress in the heterogeneous catalytic hydrogenation upcycling of waste polyesters, mainly PET and PLA, deeply analyzes the structure-activity relationship of catalyst active sites, and the synergistic mechanism of hydrogen sources (H₂, alcohols, and endogenous hydrogen). It also explores in detail the two main pathways of depolymerization, hydrogenation and non-depolymerization hydrogenation, as well as their coupling strategies, revealing the significant impact of key factors such as hydrogen sources, reaction temperature, pressure, and solvents on product selectivity and conversion efficiency. Meanwhile, the review comprehensively summarizes the main bottlenecks of current technologies in terms of catalyst stability, impurity compatibility, economy, and environmental performance, and points out that the development of non-precious metal catalysts, efficient utilization of hydrogen sources, and the scaling up and life cycle assessment of processes are key issues that urgently need to be addressed. It aims to provide a comprehensive reference for the in-depth study of polyester degradation mechanisms and the continuous optimization of efficient upcycling technologies, and to contribute to the synergistic realization of plastic circular utilization and the “dual carbon” goals.

Contents

1 Introduction

2 Controlled reduction and targeted conversion pathways for polyesters

3 Advances in polyester upcycling

3.1 Reductive upcycling of PET

3.2 Reductive upcycling of PLA

4 Techno-economic analysis and life cycle assessment

5 Conclusion and outlook

Metal-Support Interactions (MSIs) strategy play a critical role in designing and optimizing water-splitting catalysts. This review constructs a comprehensive framework for MSIs research, spanning from theoretical foundations to water-splitting applications. The fundamental concepts and historical evolution of MSIs are clarified, together with a taxonomic classification based on their physicochemical nature. On this basis, it delves into the formation mechanisms of various MSIs and systematically summarizes advanced characterization techniques used to analyze their electronic structures and interfacial properties. This review further explores how support properties, metal morphology, and preparation conditions collectively determine the strength and interaction mode of MSIs. A dedicated section introduces enhancement strategies, summarizing recent approaches for strengthening MSIs effects through defect engineering, interfacial design, and dynamic regulation. The applications of MSIs regulation in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water-splitting systems are comprehensively discussed, along with the corresponding activity-enhancement mechanisms. It also outlines the challenges and future development directions in this field concerning atom-level precision control, operational condition characterization, and large-scale application.

Carbon dots (CDs), as an emerging class of zero-dimensional carbon nanomaterials, have demonstrated significant potential in the field of biomedical imaging due to their unique photoluminescence properties, excellent biocompatibility, and low toxicity. This review systematically summarizes the recent progress in the application of CDs as dual-modal or multimodal probes in computed tomography (CT), magnetic resonance imaging (MRI), and fluorescence imaging (FL). It particularly focuses on the synergistic effects of metal ion and heteroatom doping on the physicochemical properties of CDs, with an emphasis on their optical, magnetic, and X-ray attenuation characteristics. The findings reveal that element doping and surface functionalization can significantly enhance the performance of multimodal imaging. For instance, doping with metal ions or heteroatoms can effectively improve the relaxivity in MRI/FL dual-modal imaging and optimize the X-ray attenuation properties in CT/FL dual-modal imaging. Furthermore, some CD-based nanomaterials have successfully achieved MRI/CT/FL trimodal imaging, providing innovative solutions for precision medicine. Despite the progress made, CDs-based multimodal probes still face several challenges, including the imbalance in multimodal performance and the lack of comprehensive long-term biosafety assessments. For future clinical translation, further optimization of material design and the implementation of standardized toxicological evaluations will be essential. These efforts will significantly advance the diagnosis and treatment of diseases.

Contents

1 Introduction

2 Classification and synthesis of Doped CDs

2.1 Solvothermal method

2.2 Microwave method

2.3 Pyrolysis method

2.4 Other methods

3 Properties of Doped CDs

3.1 Optical properties

3.2 Biocompatibility

3.3 Magnetic properties

3.4 X-ray attenuation properties

4 Advances in multimodal imaging applications

4.1 Doped CDs for CT/FL imaging

4.2 Doped CDs for MRI/FL imaging

4.3 Doped CDs for MRI/CT/FL imaging

4.4 The potential of multimodal imaging for clinical applications

5 Conclusion

Accurate and real-time sensing is fundamental to advancements in health diagnostics, environmental monitoring, and industrial safety. However, conventional sensing materials such as metal oxides, conducting polymers, and carbon-based composites are constrained by intrinsic trade-offs between sensitivity, selectivity, and operational stability. To address these limitations, metal-organic frameworks (MOFs) have emerged as a transformative class of materials, offering unparalleled structural tunability, ultrahigh surface areas, and programmable pore chemistry. This comprehensive review provides an in-depth analysis of MOF-based chemiresistive sensors, moving beyond a simple catalog of examples to establish a mechanistic understanding of how molecular-level design dictates sensing performance. We systematically deconstruct the evolution from often-insulating pristine MOFs to advanced composites where MOFs synergize with conductive fillers like graphene, carbon nanotubes, and polymers and to MOF-derived porous carbons and metal oxides. Each category is critically examined to highlight strategies for overcoming inherent challenges in electrical conductivity, response kinetics, and long-term stability. The review is structured to guide the researcher in the field from fundamental design principles and charge transport mechanisms to performance benchmarking against key metrics such as sensitivity, limit of detection, selectivity, and response/recovery times. A significant focus is placed on the integration of MOFs into next-generation applications, including flexible and wearable electronics, multi-parameter sensor arrays, and intelligent systems that leverage artificial intelligence for pattern recognition and drift compensation. Furthermore, we critically address the pivotal challenges hindering practical deployment, such as hydrothermal/chemical stability, mechanical robustness for wearable formats, and the urgent need for standardized testing protocols. By synthesizing insights from fundamental research and cutting-edge applications, this review serves as a rational design guide and a forward-looking perspective, outlining a concrete roadmap for harnessing the full potential of MOFs in the development of intelligent, reliable, and commercially viable next-generation chemiresistive sensing technologies.

Photoelectrochemical (PEC) biosensors, as an emerging analytical platform, offer significant advantages, including low background signals, high sensitivity, and operational simplicity, due to the inherent separation of the excitation source and the detection signal. The core of achieving high performance in PEC biosensors lies in the development of efficient signal amplification strategies. This review systematically summarizes recent research progress on signal amplification mechanisms in PEC biosensors. Photoelectric †conversion constitutes the basis of PEC sensing, primarily involving three essential processes: light harvesting, charge carrier separation, and interfacial reaction. Based on this, the prevailing signal amplification mechanisms are reviewed from the core processes of photoelectric conversion to the design of signal output. Simultaneously, the design principles and characteristics of these mechanisms are delved. Finally, this review examines the challenges of PEC sensing technologies and explores future trends. This review aims to provide theoretical guidance for the rational design of high-performance PEC biosensors and to promote their further development in applications of analysis.

Sodium-ion batteries (SIBs) are poised to revolutionize the global energy storage landscape, offering a cost-effective and resource-abundant alternative to lithium-ion batteries. Within this emerging ecosystem, hard carbon (HC) has secured its position as the premier anode material, prized for its structural stability and low operating voltage. Yet, the transition from academic discovery to GWh-scale manufacturing faces formidable hurdles. The commercial viability of HC is currently compromised by a low initial coulombic efficiency (ICE), which imposes a severe economic penalty by forcing cathode oversizing, and by significant engineering gaps in precursor scalability and full-cell integration. This review aims to bridge the critical gap between the fundamental understanding of sodium storage mechanisms and the practical realities of battery engineering. We begin by consolidating the latest consensus on the adsorption-intercalation-pore filling mechanism, establishing a solid theoretical framework for rational design. Unlike traditional reviews that focus solely on capacity metrics, we critically evaluate the industrial feasibility of advanced synthesis strategies, highlighting the hidden trade-offs between heteroatom doping and efficiency, and addressing the scalability challenges of biomass precursors, such as ash content and consistency. Furthermore, we provide a comprehensive analysis of the ICE challenge, linking it directly to cell cost, and evaluate mitigation strategies including advanced electrolytes and pre-sodiation. Finally, the review addresses specific full-cell failure modes, such as gassing and low volumetric density, offering a pragmatic roadmap for developing robust, commercially viable hard carbon anodes.

Contents

1 Introduction 2

2. Understanding of Na-Ion Storage Mechanism in HC 4

2.1. Fundamentals of Hard Carbon 4

2.2 Sodium Ions Storage Mechanisms 5

2.3. Advanced Characterization Techniques 7

3. Advanced Synthesis and Structural Engineering 7

3.1. Biomass-Derived Hard Carbons 8

3.2. Heteroatom Doping 9

3.3. Morphological and Pore Structure Engineering 10

4. How To Solve the Low ICE 13

4.1. Understanding the Root Causes of Low ICE 13

4.2. Electrolyte Engineering (Mitigation) 14

4.3. Surface Engineering and Coatings (Mitigation) 14

4.4. Pre-Sodiation (Compensation) 15

5. Full-Cell Development: Bridging the Gap to Commercialization 17

5.1. Sodium Inventory Problem 18

5.2. Pouch Cell and Cylindrical Cell Prototyping 18

5.3. Practical Failure Modes 19

6. Challenges and Future Perspectives 19

7. Conclusions 21

Acknowledgement 21

References 22

Flexible mechanical sensors (FMSs) show significant promise for applications including health monitoring, human motion tracking, electronic skin, and human-machine interaction, and have thus emerged as a key research area within flexible electronics and wearable technology. Hydrogels, with their outstanding stretchability, flexibility, and biocompatibility, offer conformal contact with tissues or skin for stable signal acquisition, making them a prime candidate for constructing FMSs. In recent years, the incorporation of different conductive materials has led to the development of various conductive hydrogels, thereby advancing multifunctional FMSs. This review summarizes recent progress in conductive hydrogel-based FMSs (CHFMSs), with a focus on constituent materials (e.g., conductive nanofillers, ionic additives, or conductive polymers), performance characteristics, and conductive mechanisms. A classification of FMSs based on the conduction mechanisms (resistive, capacitive, piezoelectric, and triboelectric) is also provided. Furthermore, the potential applications of FMSs in various practical scenarios are discussed. Finally, the key challenges and prospects in the developing field are outlined.

Contents

1 Introduction

2 Types of CHs

2.1 Nanocomposite-based CHs

2.2 Ionic-based CHs

2.3 Conductive polymer-based CHs

2.4 Hybrid CHs

2.5 Analysis of different types of CHs

3 Classification and performance of CHFMSs

3.1 Classification of CHFMSs

3.2 Multimodal sensing based on CHFMSs

3.3 Performance of CHFMSs

3.4 Interfacial engineering for CHFMSs

4 Application of conductive CHFMSs

4.1 Healthcare monitoring

4.2 Human motion monitoring

4.3 Human-machine interaction

5 Challenges and prospects

Lithium-Air Batteries are considered a strong candidate for next-generation electrochemical energy storage due to their exceptionally high theoretical energy density. However, the inherent issues of liquid electrolytes, such as flammability and uncontrolled lithium dendrite growth, severely restrict the safety and practical application of lithium-air batteries. Therefore, developing polymer electrolytes that combine high safety, good mechanical properties, and favorable interfacial compatibility is a critical path toward realizing practical solid-state lithium-air batteries. This review summarizes the fundamental characteristics, preparation methods, and performance in LABs of three categories of polymer electrolytes: solid polymer electrolytes, gel polymer electrolytes, and composite polymer electrolytes. A particular emphasis is placed on reviewing the roles and mechanisms of active and inert fillers in improving the polymer-filler interface, enhancing ion transport and mechanical strength, and reinforcing interfacial stability. The review concludes by summarizing the major current challenges and proposing future research directions, aiming to promote the system integration and engineering application of solid-state lithium-air batteries toward achieving high energy density and long cycle life.

Contents

1 Introduction

2 Solid polymer electrolytes for Li-air batteries

2.1 Polyethylene oxide

2.2 Polyvinylidene fluoride-co-hexafluoropropylene

2.3 Other polymers

3 Gel polymer electrolytes for Li-air batteries

4 Composite polymer electrolytes for Li-air batteries

4.1 Active filler

4.2 Inert filler

5 Conclusion and outlook

Metal nanoclusters, with their atomically precise structures, unique quantum effects, and tunable optoelectronic properties, have emerged as a crucial bridge connecting discrete metal atoms and bulk metals. As a pivotal material for next-generation high-performance optoelectronic devices, in-depth understanding of their structure-property relationship is necessary for the on-demand design of functional devices. However, conventional characterization techniques predominantly focus on the macroscopic effects induced by collective behaviors of cluster ensembles, making it difficult to precisely resolve the structure-performance relationship of metal nanoclusters at the atomic level, significantly hindering the advancement of metal nanoclusters in atomically precise fabrication and functional integration. With continuous progress of single-molecule electronics, single-cluster devices have emerged as an effective platform for directly revealing the intrinsic electronic structure and quantum transport behavior of metal nanomaterials at the single-cluster scale, largely bypassing the ambiguity in structure-performance relationship caused by averaging effects and structure heterogeneity of cluster ensembles. This review focuses on the single-cluster devices research, systematically summarizing recent progress in precise synthesis of functionalized clusters, fabrication of single-cluster devices, electrical transport behavior of single-cluster devices, and their potential applications in diverse fields. We then conclude our discussion with key challenges and perspectives for the future development of single-cluster devices, aiming at offering an useful reference for design and fabrication of nanodevices at the atomic level.

Contents

1 Introduction

2 Precise synthesis of functionalized metal nanoclusters

2.1 Metal core doping

2.2 Ligand engineering

3 Fabrication of single cluster devices

3.1 Static single-cluster devices - electromigration technique

3.2 Dynamic single-cluster devices

4 Electrical transport properties of single-cluster devices

4.1 Regulation of electrical transport properties of single-cluster junctions at the cluster-electrode interface

4.2 Regulation of electrical transport properties of single-cluster junctions by the intrinsic structure of clusters

5 Applications of single-cluster devices

5.1 Single-cluster switch devices

5.2 Single-cluster transistor devices

5.3 Catalytic characterization platform based on single cluster devices

5.4 Single-cluster light-emitting diode devices

6 Conclusion and outlook

Cell heterogeneity is key to understanding life processes such as embryonic development and disease evolution, while traditional bulk cell RNA sequencing cannot resolve gene expression differences at the single-cell level. Although single-cell RNA sequencing (scRNA-seq) technology can construct transcriptomic maps at single-cell resolution, it faces challenges such as low efficiency in single-cell isolation and capture, and large deviations in trace RNA manipulation. Microfluidic chip technology, through a microscale fluid manipulation system, integrates processes such as single-cell isolation, lysis, reverse transcription, amplification, and sequencing library construction, achieving high-throughput, low sample loss, and automated operations, which significantly improve the efficiency and data reliability of scRNA-seq. This paper outlines the sequencing process of scRNA-seq, including steps such as single-cell isolation and capture, RNA extraction, reverse transcription and amplification, and single-cell sequencing. It analyzes the core advantages of microfluidic chips in adapting to single cells, precisely controlling reaction volumes, and realizing process automation, and briefly describes the technical principles and characteristics of representative platforms such as Fluidigm C1, 10X Genomics Chromium, and BD Rhapsody. Microfluidic chip technology provides an efficient and precise technical platform for scRNA-seq. In the future, with the continuous optimization of chip design and the improvement of multi-omics integrated analysis capabilities, we expect it to play a more profound role in resolving complex biological systems, revealing disease mechanisms, and even promoting precision medicine.

Contents

1 Introduction

2 Single-Cell RNA Sequencing Workflow

2.1 Isolation and Capture of Single Cells

2.2 RNA Extraction, Reverse Transcription and Amplification

2.3 Single-Cell Sequencing

3 Single-Cell RNA Sequencing Technology Based on Microfluidic Chips

3.1 Development history of scRNA-seq based on microfluidic chips

3.2 Core Advantages of Microfluidic Chips in scRNA-seq

4 Representative Microfluidic Single-Cell RNA Sequencing Platforms

4.1 Fluidigm C1 Platform

4.2 10X Genomics Chromium Platform

4.3 BD Rhapsody Platform

5 Summary and Prospects

This article reviews the challenges and recent advancements in the utilization of methane (CH₄) resources via low-temperature electrochemical oxidation (CH₄OR) for producing value-added chemicals. Conventional indirect pathways, including methane reforming, are energy-intensive and operate under harsh conditions. In contrast, thermal catalytic partial oxidation frequently results in over-oxidation, thereby limiting their practical applications. In contrast, electrochemical CH₄OR represents a promising alternative, facilitating efficient methane conversion under mild conditions, compatible with renewable energy sources, and providing advantages in product separation and transport. This review explores the mechanistic aspects of C-H bond activation during CH₄OR, encompassing both direct and radical-mediated indirect pathways.

Contents

1 Introduction

2 The mechanism of low-temperature electrooxidation of methane

2.1 Direct activation mechanism of methane dehydrogenation

2.2 Mechanism of methane dehydrogenation activated by reactive oxygen species

2.3 Kinetic and thermodynamic control in the CH₄OR

3 Methane electrooxidation catalyst

3.1 Noble metal catalysts

3.2 Alloy catalysts

3.3 Transition metal oxide catalysts

3.4 MOFs catalysts

3.5 Single atom catalysts

4 Defect engineering: material design strategy for catalytic performance optimization

5 Conclusions and Prospects

Photocatalytic water splitting for hydrogen production is recognized as one of the most promising solutions to alleviate global energy crises and mitigate environmental pollution. As a typical ternary chalcogenide semiconductor with a layered structure, Zn₃In₂S₆ (ZIS) has garnered significant attention in the field of photocatalytic hydrogen evolution, thanks to its favorable energy band structure, excellent visible-light response capability, and abundant surface active sites. This review comprehensively summarizes the latest research progress of ZIS-based nanomaterials in photocatalytic hydrogen production. First, it systematically elaborates on the fundamental properties of ZIS, including its hexagonal layered crystal structure, and its energy band characteristics, as well as the core mechanism of photocatalytic hydrogen production centered on the separation and migration of photogenerated carriers. Then, the review focuses on the application progress of ZIS-based nanomaterials in different photocatalytic hydrogen production systems: overall water splitting (achieving efficient carrier separation via S-scheme heterojunctions), hydrogen production in sacrificial agent systems (optimizing hole consumption paths with agents like lactic acid, formic acid, and triethanolamine to enhance efficiency), and bifunctional coupled reaction systems (including organic pollutant degradation coupled with hydrogen production, selective oxidation of alcohols such as benzyl alcohol and 5-hydroxymethylfurfural coupled with hydrogen production, and hydrogen peroxide synthesis coupled with hydrogen production). For each system, a comparative analysis is conducted on reaction mechanisms, advantages, disadvantages, performance optimization strategies (e.g., heterojunction construction, cocatalyst loading, defect engineering), and technical economy. Finally, the review discusses the current challenges faced by ZIS-based photocatalytic materials, especially in bifunctional coupled reaction systems, such as limited selectivity in organic oxidation, catalyst deactivation, and complex product separation, and proposes future development directions, including the design of atomically dispersed cocatalysts, in-situ mechanism studies using advanced characterization technologies, and integration with practical application scenarios like wastewater treatment. This review provides a systematic reference for the rational design and further development of high-performance ZIS-based photocatalytic materials for hydrogen production.

Contents

1 Introduction

2 Structure and Properties of ZIS-based Nanomaterials

2.1 Crystal Structure

2.2 Optical Properties and Energy Band Structure

3 Mechanism of Photocatalytic Hydrogen Production

4 Research Progress on Photocatalytic Hydrogen Production by ZIS-based Nanomaterials

4.1 Overall Water Splitting for Hydrogen Production by ZIS

4.2 Photocatalytic Hydrogen Production in Sacrificial Agents Systems

4.3 Photocatalytic Degradation of Organic Pollutants Coupled with Hydrogen Production

4.4 Photocatalytic Selective Oxidation of BA/Biomass Alcohols Coupled with Hydrogen Production

4.5 Photocatalytic Hydrogen Production Coupled with Hydrogen Peroxide Synthesis

5 Conclusions, Future Outlook, and Challenges

5.1 Conclusions

5.2 Future Outlook and Challenges

Self-enhanced electrochemiluminescence (SEECL), as an emerging analytical technique, significantly enhances electrochemiluminescence (ECL) efficiency by integrating luminophores and co-reactants into unified nanostructures or molecular frameworks, demonstrating substantial value in the fields of bioanalysis and environmental sensing. Based on the integration mode of luminophores and co-reactants, SEECL structures can be categorized into two types: covalently bonded SEECL and non-covalently bonded SEECL. Covalently bonded SEECL can be further divided into inorganic, organic, and nanoscale covalent bonding SEECL systems, while non-covalently bonded SEECL includes structures such as nanocarrier encapsulation, self-assembly, and metal-organic framework (MOF)-based SEECL. On the basis of summarizing the construction principle of SEECL, this paper summarizes its applications in areas including bioanalysis (protein biomarker detection, nucleic acid analysis, and enzyme activity monitoring), environmental sensing (trace detection of heavy metal ions and organic pollutants), food safety testing, wearable devices, and point-of-care testing (POCT). Additionally, the article addresses unresolved issues such as the stability, biocompatibility of SEECL materials and interference from complex matrices, and prospects its future development directions, providing a reference for subsequent research on SEECL.

Contents

1 Introduction

2 Construction of SEECL systems

2.1 Mechanistic insights into SEECL

2.2 Covalent-bonded SEECL systems

2.3 Non-covalent-bonded SEECL Systems

3 Applications of SEECL

3.1 Bioanalysis

3.2 Environmental sensing

3.3 Other categories

4 Conclusion and prospect

Electrochemical carbon dioxide reduction reactions (CO₂RR) have become an important means of building sustainable energy systems due to their potential to convert carbon dioxide into high-value chemicals under mild conditions, as global carbon dioxide emissions become increasingly serious. This review provides a systematic overview of the research progress in the construction of CO₂RR electrodes, with a focus on the structural design principles of the electrodes. It highlights typical construction strategies for metal-based, carbon-based, and emerging electrode structures, analyzing the effects of conductivity, pore structure, and three-phase interface stability on electron transport, carbon dioxide mass transfer, and product desorption behavior.

It particularly emphasizes the crucial role of surface and interface engineering in enhancing catalytic selectivity and long-term stability, and summarizes cutting-edge construction methods such as 3D printing, bio-inspired modification of electrodes, and the use of derivative materials. Although existing research has made significant progress under laboratory conditions, challenges such as structural stability, construction costs, and large-scale manufacturability remain to be addressed in practical applications. Therefore, this review proposes that future research should be conducted in a coordinated manner in the areas of interface microenvironment control, structural modeling, and manufacturing process simplification to achieve efficient, stable, and scalable CO₂RR electrode systems.

Contents

1 Introduction

2 CO₂RR mechanism

3 CO₂RR Electrode Construction

3.1 Transition metal-based

3.2 Carbon-based

3.3 Emerging Structures and 3D Printed Electrodes

4 Surface and Interface Engineering

5 Conclusion and outlook

Air pollution is a major challenge for the improvement of urban environmental quality. The process of urbanization is an important cause of highly complex air pollution, on the other hand it also provides artificial reinforcement conditions for self-purification of air pollutants in cities. "Environmental catalytic city" refers to the spontaneous catalytic purification of low concentration gaseous pollutants in the atmosphere by catalytic materials coating on the artificial surfaces, such as building surfaces in the city under natural photothermal conditions. "Environmental catalytic city" is of great significance for the control of complex air pollution without additional energy consumption, the continuous improvement of indoor and outdoor air quality, and the scheme and construction of " self-purifying city". Here, we propose the concept of “environmental catalytic city”, and discuss its further improvement, development, and application.

Lignocellulose aerogels possess excellent properties of low density, high porosity, low thermal conductivity and so on, making them widely utilized in thermal insulation, adsorption, catalysis, electromagnetic shielding, biomedical and other fields. Moreover, as a bio-based material, lignocellulose is a green, pollution-free, renewable, and sustainable material. In this paper, the latest research progress of wood-based cellulose and agricultural waste-based cellulose aerogels are reviewed. Then the current research status of lignocellulose aerogel preparation methods including freeze-drying, supercritical drying, and atmospheric drying, is summarized. In addition, for the flammability issues commonly found in lignocellulose aerogels, commonly used methods to improve the flame retardancy of lignocellulose aerogels are discussed in detail. Finally, this paper concludes the main problems in lignocellulose aerogel preparation methods and properties, and the future development direction in this field is proposed.

Water is a clean, safe, environmentally benign chemical reaction medium. Understanding the properties of water and the chemical processes in hydrothermal systems is of vital significance in the research of condensed matter chemistry. The physicochemical features of water under hydrothermal conditions greatly differ from that under normal condition, and thus the hydrothermal technique has been extended to much broader systems. In this review article, we introduce the structures of water and its clusters, the variation of their properties along with conditions, and relevant condensed matters in hydrothermal systems. We also illustrate the hydrothermal chemistry through discussing the preparation of typical materials through hydrothermal methods, hydrothermal organic reactions, and bio-hydrothermal chemistry. By relating condensed matter and hydrothermal chemistry, we hope this review will offer new ideas for comprehending hydrothermal reaction systems from the angle of condensed matter chemistry.

Fuel cell technology and its industrialization have been developed rapidly in China in recent years. However, the high cost of the fuel cell caused mainly by the using of precious Pt catalysts is still one of the most important factors restricting the development of fuel cell commercialization. It is of great significance to develop low Pt catalysts with much higher catalytic efficiency and lower Pt loadings. In recent years, Pt-based catalysts with three-dimensional morphology or nanostructure have been emerged as a type of ultra-important low Pt catalysts, due to their special morphologies/structures, their catalytic activity are usually much higher than that of the widely used Pt/C catalysts. In this paper, the research progress of Pt-based catalysts with special three-dimensional morphology (such as nanoframe structure, flower-like structure, nanocage structure, sea urchin structure, etc.) and their applications in fuel cells are reviewed, meanwhile, some weaknesses and challenges of these catalysts are concluded; Furthermore, the future development and application of these catalysts are prospected.

Photoacoustic (PA) imaging, as a new type of imaging technique that offers strong optical absorption contrast and high ultrasonic resolution, shows great application prospects in the early disease diagnosis for its characteristics of deep tissue penetration and high spatial resolution. However, traditional "always on" PA contrast agents have many disadvantages such as low signal-to-noise ratio, poor selectivity and specificity. In contrast, activatable PA contrast agents, where the imaging signal can be changed in response to pathologic parameters, have shown decreased background signal and improved selectivity and specificity in early disease detection. Moreover, these contrast agents can obtain pathological parameters and information of various diseases at the molecular level by rational design to their structures, providing important guidelines for the optimization of treatment options. Therefore, activatable PA contrast agents hold greater promise in clinical practice than traditional "always on" PA contrast agents. In this review, we describe the recent advances in the development of activatable PA contrast agents. The design mechanisms and proof-of-concept applications of these activatable PA contrast agents are summarized in detail. The use of these activatable probes to detect different pathologic parameters (such as metal ions, enzymes, reactive nitrogen and reactive oxygen) is highlighted. Finally, current challenges and future perspectives in this emerging field are also analyzed.