With the fabrication of single atom catalysts (SACs) as a new concept, researches on catalysts have deep into smaller scale, which can make it available to dissect complex heterogeneous catalysis on atomic lever, simultaneously provide vast opportunities for applications in industrial catalysis because of their predominant performances. Based on the previous achievements, the main components of this research are as follows: the performance characteristics of SACs are summarized, the preparation, characterizations and theoretical approaches about SACs are introduced, the research developments of applications in CO oxidization, selective hydrogenation and photoelectrocatalysis reaction, etc. are illustrated, the influences of the exceptive electronic structure of SACs on catalytic performance and reaction mechanism are analyzed, the breakthroughs and the shortages of SACs system are pointed out. All these discussions contribute to the profound understanding on principles of SACs, improvement of both theoretical and experimental researches, and furthermore put forward suggestions and prospective for expanding its application range and achieving industrial applications.

Contents
1 Introduction
2 Fabrication and properties of SACs
2.1 Selection of substrates
2.2 Preparation methods
2.3 Catalytic characteristics
3 Structural characterization of SACs
3.1 Characterization methods
3.2 Structual characterization
4 Theoretical methods
4.1 Configuration prediction
4.2 Exploration of reaction mechanism
5 Application of SACs
5.1 Oxidation reaction
5.2 Hydrogenation reaction
5.3 Photoelectrocatalysis reaction
5.4 Other reactions
6 Conclusion

The ultra-slippery surface is fabricated by infiltrating functionalized micro/nano surface structures with low-surface energy, chemically inert lubricating oil. The lubricating oil is locked by micro/nano structures due to the capillary effect, and a dynamic oil film is formed on the surface. Therefore, the liquid-solid interface is replaced by liquid-liquid interface, leading to the significant reduction of flow resistance. Compared with traditional superhydrophobic surfaces and superoleophobic surfaces with similar low sliding angles, air trapped in the pores is replaced by the lubricating oil, which can provide better pressure stability. Furthermore, ultra-slippery surfaces possess appealing self-healing ability due to the capillary flow of lubricating oil. Because of these significant advantages, recently they have drawn much attention and become a research focus all over the world. So far ultra-slippery surfaces have been investigated for various applications such as anti-icing, heat transfer enhancement, drag reduction, anti-biofouling, microfluidics, etc. However, there are still some important challenges which limit their applications, for example, how to avoid or alleviate the performance deterioration caused by the evaporation of lubricating oil, and how to choose proper process to fabricate various micro/nano structures on different kinds of material. This paper reviews the recent progress of the fabrication and applications of ultra-slippery surfaces, discusses the existing problems, and provides outlook of development tendency.

Contents
1 Introduction
2 Design principles of SLIPS
3 Fabrication technologies of SLIPS
3.1 Overview of fabrication methods
3.2 Chemical reaction
3.3 Spray coating
3.4 Self-assembly fabrication
4 Applications of SLIPS
4.1 Anti-icing application
4.2 Heat transfer enhancement
4.3 Pipeline transportation
4.4 Droplet manipulation
4.5 Marine anti-biofouling
4.6 Bioengineering application
4.7 Sediment removal
5 Conclusion

Ultralight materials are a kind of novel materials whose densities are less than 10 mg/cm³. These materials exhibit excellent physical properties, chemical properties and mechanical properties derived from both constituent and structure, which possess high specific strength and specific stiffness. With the excellent properties of ultralight materials, great effort has been devoted to studying ultralight materials. The components of the existed ultralight materials mainly include silica, metal and oxidizing materials, ceramic, polymers, carbon and compounds. Ultralight materials play an important role in the field of aerospace, due to their unique properties such as acoustic absorption, energy absorption, shock absorption and thermal insulation. The effective properties of ultralight materials are defined both by their cellular architecture and the properties of the solid, such as the spatial configuration of voids and solids, the stiffness and strength of solids. They all have significant influence on the properties of materials. In this review, ultralight materials are classified into three types by different structures: aerogel, foam and microlattice. Also, the fabrication methods and constituent of the ultralight materials created in recent work are summarized. In addition, The research prospects and directions of ultralight materials in the future are also briefly discussed by comparison of all kinds of materials.

Contents
1 Introduction
2 Aerogel
2.1 Silica aerogel
2.2 Carbon aerogel
3 Foam
3.1 Metal foam
3.2 Carbon foam
3.3 Polymer foam
4 Microlattice
4.1 Metal microlattice
4.2 Carbon microlattice
4.3 Ceramic microlattie
5 Conclusion

Lithium-oxygen battery is a metal-air battery using lithium as the negative electrode, oxygen in the air as the positive electrode reactant. Because it has high theoretical specific energy and environmentally friendly advantages, the lithium-oxygen battery has been studied in recent years. In this work, it shows the latest research progress of key technology for lithium-oxygen battery, including positive electrode materials, catalysts, electrolyte, negative electrode and structure of battery. And on this basis, we outlook its future development, providing new ideas and methods for the research of other metal-air battery.

Contents
1 Introduction
2 Working principle of lithium-oxygen battery
3 Positive electrode
3.1 Carbon material
3.2 Composite material
3.3 Non-carbon material
3.4 Coating
4 Catalyst of positive electrode
5 Electrolyte
6 Negative electrode
7 Conclusion and outlook

Molecular shuttle, as a kind of molecular machines, is one of the research intriguing interest in supramolecular chemistry. Molecular shuttles are mostly based on the host-guest recognition. They have potential applications in many areas such as nano-structured functional materials, molecular switches, molecular logic gates, memory devices and so on. In this paper, the progress in molecular shuttles is systematically reviewed, including the conception, mechanisms and potential applications, focusing on the molecular shuttles driven by external-stimuli. According to the difference of external-stimuli, molecular shuttles can be classified into light-driven, pH-driven, redox-driven and multi-mode-driven molecular shuttles. The structure characteristics, motion law and progress of molecular shuttles driven by different external-stimuli, are elaborated. The problem of responsive molecular shuttles researches is analyzed, and the future development of responsive molecular shuttles is prospected.

Contents
1 Introduction
2 Mechanism of molecular shuttles
3 Molecular shuttles driven by different external-stimuli
3.1 Light-driven molecular shuttles
3.2 pH-driven molecular shuttles
3.3 Redox-driven molecular shuttles
3.4 Multi-mode-driven molecular shuttles
4 Potential applications of molecular shuttles
4.1 Potential applications in molecular logic gates
4.2 Potential applications in molecular switches
4.3 Potential applications in energy transfer
5 Prospects

Due to the special optical, electronic properties, particular physical/chemical properties, thiolate protected gold nanoclusters (Au_m(SR)_n, in which m and n are the numbers of Au and SR) have potential applications in nanocatalysis, biomedicine and optical devices. Two breakthroughs in Au_m(SR)_n clusters are the crystal structure determinations of Au₁₀₂(SR)₅₄ and Au₂₅(SR)₁₈^- clusters, which uncover the new Au-S chemical bonding features as well as the new atomic packing structures in Au_m(SR)_n clusters. In this paper, major advances of the Au_m(SR)_n clusters in the experimentally determined crystal structures are generalized. This is followed by the introduction of the progresses in the experimentally synthesized Au_m(SR)_n clusters with mass spectroscopy and the progresses made by the density functional theory predictions. We combine our study subject to generalize superatom complex model, superatom-network model and super valence bond model which are used to interpret the stability and chemical bonding patterns of Au_m(SR)_n clusters. Moreover, we take several Au_m(SR)_n clusters as examples to introduce the applications of the three models. Finally, we give future outlook of the Au_m(SR)_n clusters.

Contents
1 Introduction
2 Experiments and theoretical predictions of Au_m(SR)_n clusters
2.1 Au_m(SR)_n clusters with single crystal structures
2.2 Au_m(SR)_n clusters with mass spectroscopy
2.3 Au_m(SR)_n clusters by DFT structural predictions
3 Theoretical models for Au_m(SR)_n clusters
3.1 Superatom complex (SAC) model
3.2 Superatom-network (SAN) model
3.3 Super valence bond (SVB) model
4 Conclusion and outlook

Endowed with high charge transporting capabilities and formation of unique phase-separated microstructure, fullerenes and their derivatives have been playing a predominant role as electron acceptor in bulk hetero-junction devices. However, they also suffer from unconquerable drawbacks, such as poor absorption in visible light region, difficult modification and high cost, which limit the performance improvement and scalable application of organic solar cells. More interests are focused on the non-fullerene small-molecule acceptors. It is reasonable to regulate the molecular energy levels of non-fullerene materials through diversiform chemical approaches, especially for small organic molecules and their oligomers. And electron acceptors with specific aggregated-state morphologies and excellent properties could be accessible by virtue of diverse synthetic methods. In the review, the recent advances on non-fullerene acceptors are summarized with outstanding performance for solution-processed bulk-heterojunction solar cells. These non-fullerene acceptors mainly consist of perylenetetracarboxylic diimide acceptors including its monomers, dimers and quasi-3D-structured acceptors, diketopyrrolopyrrole acceptors, benzothiadiazole-based acceptors, as well as other miscellaneous high-performance small-molecule acceptors. The performance of these acceptors is analyzed from the view of molecular structures and their matching with the related donors. Finally, critical challenges that influence photovoltaic performance and the perspectives of small-molecule acceptors are discussed and addressed.

Contents
1 Introduction
2 High-performance small molecule acceptors for organic solar cells
2.1 Perylenetetracarboxylic diimide-based acceptors
2.2 Diketopyrrolopyrrole-based acceptors
2.3 Benzothiadiazole-based acceptors
2.4 Other small molecule acceptors
3 Conclusion and outlook

With the development of nanotechnology in recent years, there are many micro- and nano-reactors. The micro- and nano-reactor could provide a nano-sized reaction environment, so that reaction occurred in that environment is influenced by nano-confined space. Finally the resulting product with special structure is obtained. There are also many micro- and nano-reactor carriers with confined space for olefin polymerization. The carriers play a double role in the polymerization not only being the catalyst's carrier but also providing a confined geometry in which the polymerization reaction can occur. With the effect of nano scale the process of olefin polymerization changes, so that some polyolefin products with special structure and properties (such as high melting point, high molecular weight, and fibrous) will be obtained. In this paper, we mainly focus on recent research on olefin polymerization in confined space, and classify them according to different types of polymer structure, and then the influence of confined space on the morphology of the polyolefin product, the polymerization kinetic and activity, the primary structure of the product, the secondary structure of the product, the condensed matter structure and the property of the product are relatively introduced. Finally, the researches on olefin polymerization in confined space are also prospected.

Contents
1 Introduction
2 The effect of polymerization in confined space on the morphology of product
3 The effect of polymerization in confined space on the polymerization kinetic and activity
4 The effect of polymerization in confined space on the primary structure of the product
5 The effect of polymerization in confined space on the secondary structure of the product
6 The effect of polymerization in confined space on the condensed matter structure and the property of the product
7 Conclusion

Combining the optoelectronic characteristics of the conjugated polymers and the self-assembling behavior of the block polymers, all-conjugated block copolymers have been developed as a new class of optoelectronic functional materials with unique self-assembling behavior in recent years. Researching on the relationship among its assembling structure, the mechanism of self-assembly and the photophysical properties has significant impacts on the manipulating nanoscale morphology patterns of conjugated polymers and the development of organic photovoltaic devices. This paper reviews the development of the synthesis process of all-conjugated block copolymers including conjugated polyelectrolytes. Their unique behavior of self-assembly in solution and thin-film state is discussed. Finally, the application of conjugated polymers in optoelectronic devices is introduced, and its future research and development are prospected.

Contents
1 Introduction
2 Synthesis
2.1 Reaction between macromolecular precursors
2.2 Grignard metathesis
2.3 Synthesis of CPEs
3 Self-assembly
3.1 Self-assembly in solution
3.2 Self-assembly in thin film
4 Application
4.1 Application in PSC
4.2 Application in OFET
4.3 Application in PLED
5 Conclusion and outlook

Polymeric hydrogels, as an important class of polymeric materials, have found widespread use in biomedical and pharmaceutical fields due to their excellent physicochemical and biological characteristics. Degradability is an important parameter when considering the application of polymeric hydrogels in the biomedical fields. Stimuli-responsive degradable (SRD) hydrogel is a kind of intelligent materials, whose network structure can be cleaved in response to external environmental triggers, resulting in a gel-sol or swelling-degradation transition behavior. The stimuli-responsive degradability can be realized by incorporation of environment-sensitive labile or cleavable groups into the gel network. Moreover, this characteristic SRD ability has attracted tremendous interests due to the triggered and controlled degradability in space or in time as compared to the conventional hydrolysis and enzymolysis. This review mainly focuses on the design methods, mechanisms of degradation and most recent studies of SRD hydrogels whose bonds responsively broken by pH, photo and redox triggers. Finally, a perspective on the future research directions of the SRD hydrogels is briefly discussed.

Contents
1 Introduction
2 Stimuli-responsive degradable polymeric hydrogels
2.1 pH-responsive degradable polymeric hydrogels
2.2 Photo-responsive degradable polymeric hydrogels
2.3 Redox-responsive degradable polymeric hydrogels
2.4 Others
3 Conclusion and outlook

Conjugated polymers, with π electron systems and highly delocalized conjugated structures, exhibit excellent luminescence properties. The polymer chains can work as molecular wire, which will lead to the amplification of optical signals and thus improve the detecting sensitivity. Aptamer has advantages in specificity, affinity with targets and signal transmission, hence, nucleic acid biosensors based on conjugated polymers have witnessed a rapid development in bio-detection. The applications of nucleic acid biosensors based on conjugated polymers in recent years are summarized. Finally, an outlook of the developing trend for these sensors is given.

Contents
1 Introduction
2 The sensing mechanism of fluorescent sensor
3 FRET
3.1 Detection of complementary DNA
3.2 Real-time monitoring of DNA hybridization
3.3 Real-time monitoring of DNA structure
3.4 Detection of protein and the activity of enzyme
3.5 Detection of specific gene
4 Aggregation and conformation change
4.1 Detection of complementary DNA
4.2 Real-time monitoring of DNA hybridization
4.3 Real-time monitoring of DNA structure
4.4 Detection of enzyme
4.5 Detection of specific DNA sequence
4.6 Detection of metal ion
5 Superquenching
6 Conclusion

Chemical absorption is one of the most mature method for post combustion CO₂ capture. The current paper gives an overview of the development of solvent for CO₂ capture. In addition to ammines, ammonia solutions, amino acid salts, potassium carbonate solutions are typical solvents which have been widely investigated. Many novel solvents have been proposed, for example blended amines, phase change solvents, ionic liquid, nanofluids based absorbent, switchable solvents and designer amines. The advantages and disadvantages of the solvents are introduced and among them blended amine solutions and phase change solvents are the most promising novel solvents which have great potential in decrease energy consumption.

Contents
1 Introduction
2 Technical analysis of CO₂ chemical absorption
2.1 System process of CO₂ chemical absorption
2.2 Characteristics of CO₂ chemical absorption
3 Solvent development
3.1 Typical solvents
3.2 Novel solvents
4 Conclusion and outlook

Over the past three decades, polypropylene in-reactor alloys have been widely used in various fields such as packaging, automotive and construction due to their excellent mechanical properties and good impact resistance. These excellent properties are derived from their complicated compositions and phase structures, which have attracted significant research interest in recent years. Polypropylene in-reactor alloy is a multicomponent system containing PP homopolymer, ethylene-propylene random copolymer (EPR) and ethylene-propylene block copolymers with different sequence lengths (EbP). These complex components form multiphase in the polypropylene in-reactor products. The original products are in the forms of powers or particles and have complicated morphology. After the processing, polypropylene in-reactor alloys will form abundance microstructures which have crucial influence on the impact strength of the final product. However, the relationship between molecular structures, morphology and properties of the product are still not well understood. For example, it was found that the formation of core-shell structure lead to the best balance of rigidity and toughness. However, studies on the formation condition and the composition of the core-shell structure are still limited. In the present review, we aim to highlight the recent progress in the studies on the morphology of polypropylene in-reactor alloys, and the prospective tendency of this field is proposed.

Contents
1 Introduction
2 Synthesis and composition of polypropylene in-reactor alloys
3 Morphology of polypropylene in-reactor alloys
3.1 Morphology of the polypropylene in-reactor alloys original particles
3.2 Influence of thermal treatment and processing on the morphology of the polypropylene in-reactor alloys
3.3 Core-shell structure of the polypropylene in-reactor alloys
4 Summary and outlook

Pressure retarded osmosis (PRO) is one of the most promising membrane technologies, which has attracted much attention in recent years. PRO can be applied in desalination and waste water treatment when combined with forward osmosis or reverse osmosis process, and power generation from salinity gradients energy. This paper systematically summarizes the power generation mechanism, process design, and influencing factors of PRO processes. Then, it introduces PRO membrane materials, membrane types, existing problems and their corresponding solutions. Finally, we give several examples about PRO applications in power generation and water treatment.

Contents
1 Introduction
2 Pressure retarded osmosis process
2.1 Principle of PRO
2.2 PRO process design
2.3 Influencing factors of PRO process
3 Pressure retard osmosis membranes
3.1 Membrane type
3.2 Existing problems and their solutions
4 Applications
4.1 Power generation
4.2 Water treatment
5 Outlooks

Under anaerobic conditions, many microorganisms are capable of extracellular respiration involving electron transfer to or from extracellular substrates such as iron (hydr)oxides and humic substances. Electron shuttling is one of the significant strategies for extracellular electron transfer, however, the involved mechanism has not been thoroughly understood. Electron shuttles can be divided into endogenous electron shuttles that are self-produced by microbes themselves and exogenous electron shuttles that are natural substances or artificially synthesized materials. Electron shuttle-mediated extracellular electron transfer generally involves the following reactions: the oxidized form of electron shuttles (ES_ox) accept electrons from the oxidization of organic matter and become as the reduced form of electron shuttles (ES_red), then ES_red transfer electrons to extracellular electron acceptors and return to ES_ox. Through these steps, electron shuttles can be reversibly oxidized and reduced. This review mainly focuses on the electron transfer mechanisms of different electron shuttles, and the factors affecting extracellular electron transfer such as the molecule diffusion, redox potential and electron transfer capacity of electron shuttles. Electron shuttle-mediated extracellular electron transfer has significant influence on contaminants degradation and microbial electrogenesis, thus the better understanding of their mechanisms is very important to their implications in bioremediation and bioenergy.

Contents
1 Introduction
2 Electron transfer mechanisms of different electron shuttles
2.1 Endogenous electron shuttles
2.2 Exogenous electron shuttles
3 Factors affecting extracellular electron transfer
3.1 Molecule diffusion
3.2 Redox potential
3.3 Electron transfer capacity
4 Environmental implications
4.1 The applications of electron shuttles in pollutant biodegradation
4.2 The applications of electron shuttles in bioelectrochemical systems
5 Conclusion and outlook

Silver nanoparticles have been widely applied in various areas due to their special physical and chemical properties. However, the practical applications are always restricted by aggregation between nanoparticles. The drawbacks can be minimized by dispersing nanoparticles onto a template to generate nanocomposites. The obtained nanocomposites have much better physical and chemical properties over the single component. Electrostatic spinning has already been used as an effective tool to synthesize the nanofiber composites loaded with silver nanoparticles. In this paper we review the studies about synthesis and application of silver nanocomposites by electrostatic spinning in recent years,highlighting the preparation and loading methods of Ag nanoparticles in the process of synthesizing silver composite fibers. The recent developments in the preparation of two kinds of silver composite fibers, organic and inorganic composite fibers, are summarized. In addition, the paper also point out the directions.

Contents
1 Introduction
2 Preparation of Ag-loaded composite fibers
2.1 Preparation of the AgNPs
2.2 Loading of the AgNPs
2.3 Organic Ag-loaded composite fiber
2.4 Inorganic Ag-loaded composite fiber
3 Applications of Ag-loaded composite fiber
3.1 Antibacterial
3.2 Filtrater
3.3 Surface-enhanced Raman scattering
3.4 Catalyst
3.5 Sensor
3.6 Battery material
3.7 Electromagnetic interference shielding
4 Perspectives