Atom transfer radical polymerization (ATR)is one of the most promising industrial application methods of “living”/controlled radical polymerization. For recent years, the extensive research on ATRP has been focusing on “simplifying the operation of polymerization” and “minimizing the amount of metal catalyst”. Several new ATRP techniques with different catalyst systems have been developed at the same time, such as, reverse atom transfer radical polymerization (RATRP), simultaneous reverse and normal initiation ATRP (SR&NI ATRP), initiators for continuous activator regeneration ATRP (ICAR ATRP), activators generated by electron transfer for ATRP (AGET ATRP) and activators regenerated by electron transfer for ATRP (ARGET ATRP). This paper reviewed the development and basic principles of these ATRP systems.

Contents
1. Introduction
2. Overview of ATRP
2.1. Normal ATRP
2.2. RATRP
2.3. SR&NI ATRP
2.4. ICAR ATRP
2.5. AGET ATRP
2.6. ARGET ATRP
3. Conclusion

Due to its unique structural characteristics (the high specific surface area, tailoring structure properties and 100% utilization of exposed metal ions), metal organic framework (MOF) materials have drawn great attention on catalysis in recent years. However, the drawbacks of no open metal ions and poor thermal stability limit their application in catalysis. This tutorial review presents recent developments of the emerging field of MOF based catalysis. We summarize four distinct strategies: pre-synthesis method, post-synthesis modification, impregnation method and precipitation method, which have been utilized to create catalytic active sites in MOF. Examples of the catalytic reactions based on the created active sites in the MOF are then followed. It has been shown that the pre-synthesis method has been widely used in creating catalytic active sites in the MOF. MOF with active sites created by the pre-synthesis and the post-synthesis modification method in the MOF may act as “shape selective catalysis” as zeolite. Usually as a Lewis acid catalyst, MOFs are capable of being very active for many reactions, especially at temperatures below 100 ^oC. A critical comment on these methods and catalytic explorations has been addressed in order to guide the newcomer to this field.

 Contents
1 Introduction
2 The method of creating active sites in MOF and its application in catalysis
2.1 Pre-synthesis method and catalytic explorations
2.2 Post-synthesis modification and catalytic explorations
2.3 Impregnation method and catalytic explorations
2.4 Precipitation method and catalytic explorations
3 Conclusion and outlook

CO₂-induced switchable solvents, solutes and surfactants represent a novel family of smart compounds appeared recently. When bubbling and removing CO₂, the properties of these compounds can be reversibly switchable. The progress on CO₂ switchable solvents, solutes and surfactants were reviewed in this article, including their structures, properties and future development. The existing problems, the development prospect and potential applications of such switchable compounds were outlooked.

Contents
1 CO₂ switchable solvents
1.1 Switchable polarity solvents
1.2 Switchable hydrophilicity solvents
2 CO₂ switchable solutes
3 CO₂ switchable surfactants
3.1 Conventional switchable surfactants
3.2 CO₂ switchable surfactants
4 Conclusion and prospective

In past few years, we have witnessed the discovery and synthesis of graphene — a kind of ideal two-dimensional flat carbon nanomaterials. Owing to its novel and unique physical and chemical properties, graphene has been attracting more and more attention from scientific community and nowadays has become a sparkling rising star on the horizon of nanomaterials science. The graphene-based inorganic nanocomposites, derived from the decoration of graphene sheets with inorganic nanoparticles, are emerging as a new class of exciting materials that hold promise for many applications. So far, numerous inorganic nanocomposites based on graphene have been successfully synthesized and show desirable combinations of these properties that are not found in the individual components. Herein, we briefly introduce the structure, properties and preparation methods of graphene, and then highlight the advance in the synthesis of inorganic nanomaterials/graphene composites, especially focusing on the metal/graphene and semiconductor/graphene nanocomposites. The potential applications of these nanocomposites are also discussed. These results underscore the exciting opportunities of developing next-generation graphene-based inorganic nanocomposites.

Contents
1 Introduction
2 Preparation of graphene
3 Metal/graphene nanocomposites
3.1 Composites of graphene sheets and platinum metals
3.2 Composites of graphene sheets and silver
3.3 Composites of graphene sheets and gold
3.4 Composites of graphene sheets and other metal
4 Semiconductor/graphene nanocomposites
4.1 Composites of graphene sheets and titanium dioxide
4.2 Composites of graphene sheets and cobalt oxide
4.3 Composites of graphene sheets and tin oxide
4.4 Composites of graphene sheets and zinc oxide
4.5 Composites of graphene sheets and sulfide semiconductor
4.6 Composites of graphene sheets and other semiconductor
5 Graphene/ceramic nanocomposites
6 Graphene-based magnetic nanocomposites
7 Carbon/graphene nanocomposites
8 Conclusions and outlook

This review presents current research activities concerning preparation and application of Co₃O₄ nanoparticles with various morphologies. The Co₃O₄ nanostructures are synthesized with various methodes, including thermal deposition, hydrothermal method, solvothermal method, chemical spray pyrolysis, chemical vapor deposition, and sol–gel methods. These methods result in various morphologies such as nanospheres, nanocubes, nanotubes, nanorods, nanaoplates nanofibers, and mesoporous structures. As an important magnetic p-type semiconductor, Co₃O₄ is often used in the fields of lithium batteries, supercapacitors, electrochromic devices, magnetic materials, gas sensors, and catalysts.

Contents
1 Introduction
2 Preparation of Co3O4 nanostructures
2.1 Thermal deposition
2.2 Hydrothermal method
2.3 Solvothermal method
2.4 Sol–gel method
3 Application of Co3O4 nanostructures
3.1 Lithium batteries
3.2 Supercapacitors
3.3 Magnetic materials
3.4 Electrochromic devices
3.5 Gas sensors
3.6 Catalysts
4 Conclusions and Outlook

The by-product of Knoevenagel reaction is water, and the synthetic methods assisted with physical technologies, such as microwave (MW), ultrasound (US) and grinding have many advantages including high efficiency, saving energy, and environmental friendliness, both make the Knoevenagel reaction assisted with physical technologies meet the request of green chemistry very much. Now, Knoevenagel reaction has been widely used in organic synthesis, and the emergence of a variety of physical assistive technologies has increasingly important effects on Knoevenagel reaction, especially in the fields of increasing the reaction yield, simplifying the experimental operation, and expanding its application scope. At the same time, the importance has been attached to the exploration on the industrialization of Knoevenagel reaction via grinding. Based on the classification of different physical assistive technologies, such as MW, US and grinding, the recent progress in Knoevenagel reaction, especially the new application of Knoevenagel reaction in the synthesis of multi-heterocyclic compounds via multi-component reactions (MCR) or tandem reaction including in Knoevenagel reaction has been reviewed. In the future, in order to make Knoevenagel reaction more environmentally friendly, both synthetic methodology research and industrialization research of Knoevenagel reaction based on the above physical assistive technologies are noteworthy in the research on Knoevenagel reaction.

Contents
1 Introduction
2 Knoevenagel reaction assisted with microwave
3 Knoevenagel reaction assisted with ultrasound
4 Knoevenagel reaction assisted with grinding
5 Conclusion

N-Heterocyclic carbene ligands(NHCs) are playing an increasingly important role in many areas such as organometallic, organic synthetic, pharmaceutical, and polymer chemistry since the discovery of the first N-heterocyclic carbene complexes in 1968 by Öfele and by Wanzlick and the isolation of the first stable free carbene in 1991 by Arduengo III et al. While numerous powerful catalytic systems incorporating NHC ligands have been described, methods of synthesizing them have advanced more slowly. This review describes the recent progress of the methods used in the preparation of N-heterocyclic carbene complexes. According to the nature of the NHC precursor and to the activation method employed, the common routes for preparing NHC–metal complexes are insertion of metal ions into the carbon–carbon double bonds of highly electron-rich alkenes, coordination of preformed, isolated free carbenes, deprotonation of an Imidazolium salt with an external base or with metal complex having a basic ligand, thermal decomposition of corresponding carbene adducts, transmetallation from a silver-NHC complex or from a gold-NHC complex, oxidative addition of the C2-X (X = Me, halogen, H) bond of an imidazolium precursor. In addition, our research group firstly found that Iron, Cobalt, Nickel, and Copper complexes of N-heterocyclic carbenes can be directly synthesized by using commercially available metal powders.

Contents
1 Introduction
2 Synthesis of N-heterocyclic carbene complexes by the cleavage of electron-rich olefins
3 Synthesis of N-heterocyclic carbene complexes from preformed, isolated free carbenes
4 Synthesis of N-heterocyclic carbene complexes by deprotonation of an Imidazolium salt with a base
4.1 Deprotonation with an external base
4.2 Deprotonation with metal complex having a basic ligand
5 Synthesis of N-heterocyclic carbene complexes by thermal decomposition of carbene adducts
5.1 Alcohol adduct of N-heterocyclic carbene
5.2 Triethylborane adduct of N-heterocyclic carbene
5.3 Pentafluorobenzene adduct of N-heterocyclic carbene
5.4 CO2 adduct of N-heterocyclic carbene
5.5 Cyanide adduct of N-heterocyclic carbene
6 Synthesis of N-heterocyclic carbene complexes by transmetallation
6.1 Transmetallation from a silver-NHC complex
6.2 Transmetallation from a gold-NHC complex
7 Synthesis of N-heterocyclic carbene complexes by oxidative addition through activating of the C2-X bond
8 Direct synthesis of N-heterocyclic carbene complex by using metal powders
9 Synthesis of N-heterocyclic carbene complexes by other special methods
9.1 Direct synthesis of N-heterocyclic carbene copper complexes via Cu2O.
9.2 Transmetallation of lithiated heterocycles
9.3 Transmetallation from group VI metal carbonyl carbene complexes
10 Conclusions and Outlook

Multi-hydroxyl flavonoids (glycoside and their aglycones) are known to exhibit a variety of physiochemical properties and biological activities. But they are characterized by a low bioavailability and stability in vivo plus nonspecific action in pharmacology. Owing to their importance in pharmaceutics, food and cosmetics, the purpose of this work is an overview of valuable findings concerning hemisynthesis of multi-hydroxyl flavonol (e.g. rutin, quercetin) and dihydroflavone (e.g. Naringenin, Naringin) involving three types of substitutions (Ar-O-substitution, Ar (C)-substitution and glycoside-O-substitution catalyzed by enzymes). And wherein, the comparative analysis was made on the protection approaches for phenolic hydroxyls following by particular discussion for C-substitution by applying a Mannich-type reaction (including effects of substrate, monomer and systematic pH). The results indicate that a reasonable selection of the protection methods for hydroxyl groups and bioactive groups of monomers is critical to obtain desired products combining stability and target-specific bioactivity via selective hemisynthesis. Furthermore, O-substituted reactions for multi-hydroxyl flavonols and dihydroflavone exhibit comparably stronger reactivity than C-substitution but with poor regioselectivity once substitution occurs. In addition, their reactions with long alkyl-chain monomers (C≥12) in general belong to a monosubstitution, and the resultant hydrophobic substitution products, as a class of bisurfactants, exert a broad prospect for research and application.

Contents
1 Introduction
2 Characteristics of structural modification for flavonoids
2.1 Non-protection of phenolic hydroxyls
2.2 Protection and deprotection of phenolic hydroxyls
3 O-substituted flavonoid derivatives
3.1 Mono-O-substitution
3.2 Multi-O-substitution
4 C-substituted flavonoid derivatives
4.1 Effect of reactive substrate and monomer
4.2 Effect of systematic pH
5 Flavonoid glycoside-O-substituted derivatives
6 Conclusion and prospects

Supramolecular chemistry is a hot research topic in current chemistry. It is more attractive to build machines in a nanometer scale by mimicking the processes in macro-scale through the supramolecular way. Being different from the traditional “motile” molecular machines, the novel “processing” molecular machines based on the cyclodextrin-fullerene coupling system focus on a “recognition-capture-processing-release” procedure, but not on the position changes in and between molecules. This new molecular machine will supply a new approach in the area of enzyme mimic, biological process research, photo-immobilization, etc. Here, the development of cyclodextrin-fullerene coupling system is reviewed. Firstly, the synthesis of different kinds of cyclodextrin-fullerene coupling systems, including the synthesis clues, approaches methods and characterization, is introduced. Then, the application of the system is emphatically described, including molecular recognition, DNA cleavage and electron transfer, etc. At last, combination of current development of the system, the prospects are pointed out.

Contents 
1.Introduction
2Synthesisi of cyclodextrin-fullerene coupling system
2.1 Synthesisi of the 1:1 cyclodextrin-fullerene coupling system
2.2 Synthesisi of the 2:1 cyclodextrin-fullerene coupling system 
3 Application of of cyclodextrin-fullerene coupling system
3.1 Molecule recognition
3.2 DNA cleavage
3.3 Research of electron transfer 
4 Prospects

In recent years, molecularly imprinted materials (MIMs) based on polysaccharides have attracted great attention due to their abundant raw materials, good biodegradability and biocompatibility. In this paper, the preparation methods of MIMs based on natural polysaccharides such as cyclodextrin, chitosan, cellulose, alginic acid, agarose and starch are reviewed, including direct crosslinking, graft-copolymerization crosslinking and sol-gel technique. Their applications in separation, solid phase extraction, biosensing, drug delivery and protein refolding are discussed. In addition, the development trend of polysaccharide-based MIMs is prospected.

Contents
1 Introduction
2 Preparation methods of MIMs
2.1 Direct crosslinking
2.2 Graft-copolymerization crosslinking
2.3 Sol-gel technique
3 Applications of MIMs
3.1 Metal ion separation
3.2 Chiral separation
3.3 Peptide and protein separation
3.4 Solid phase extraction
3.5 Biosensing
3.6 Drug delivery
3.7 Protein refolding
4 Prospect

Honeycomb-patterned films by breath figure method have received considerable interest in recent years. This method is based on evaporative cooling and subsequent water-droplet templating to form an ordered array of breath figures, which has many advantages, for example, it is simple and cost-saving, and no extra steps are needed to remove the water templates. This review comprehensively summarizes the advances in the functionalization of honeycomb-patterned films. A series of methods are highlighted, which include hierarchical self-assembly, controlled surface grafting, immobilization of bioactive molecules, ultraviolet-induced and chemical crosslinking, template-guided film formation, and surface filling. The functionalized honeycomb-patterned films have been found great potential applications in various fields, such as microreactor, picoliter beaker, template, cell culture media, separation membrane, superhydrophobic surface, refractive-index materials, and photovoltaic materials.

Contents
1 Introduction
2 Functionalization methods for honeycomb-patterned films
2.1 In-situ hierarchical self-assembly
2.2 Controlled surface grafting
2.3 Immobilization of bioactive molecules
2.4 Ultraviolet-induced and chemical crosslinking
2.5 Template-guided film formation
2.6 Surface filling
2.7 Other methods
3 Conclusion and outlook

Quantum dots(QDs) have attracted enormous interest due to their many novel properties such as unique optical, electrochemical and electrochemical luminescence properties. One of the most active trends is the application of QDs in electrochemical and biological sensing, due to their high surface-to-volume ratio, high reactivity and small size. Slight changes in the external environment will lead to significant changes in particle valence and electron transfer. Based on these significant changes, QDs can be used to construct electrochemical biosensor with biological macromolecules, which is characterized by high sensitivity, rapid response and high selectivity. In this article, we review their applications in electrochemical luminescence sensors, immunosensors, DNA sensors, protein sensors, pesticide sensors and carbohydrate sensors. Meanwhile, the prospects and research directions of QDs are given based on the analysis of this research field.

Contents
1 Introduction
2 Quantum dots
2.1 Optical properties of quantum dots
2.2 Electrochemical properties of quantum dots
2.3 Electrochemical luminescence properties of quantum dots
3 Applications of quantum dots based electrochemical biosensors
3.1 Applications of quantum dots based electrochemical luminescence sensors
3.2 Applications of quantum dots based electrochemical Immunosensor
3.3 Applications of quantum dots based electrochemical DNA sensors
3.4 Applications of quantum dots based electrochemical protein sensors
3.5 Applications of quantum dots based electrochemical pesticide sensors
3.6 Applications of quantum dots based electrochemical carbohydrate sensors
4 Conclusions and outlook

Terahertz (THz) technology and its applications are now advancing rapidly. This has resulted in a number of promising applications in the fields of homeland security, information and communications, condensed mater physics, global environmental monitoring, nondestructive evaluation, physical and analytical chemistry, biology and medical sciences and many others. THz technology including terahertz time-domain spectroscopy (THz-TDS) and terahertz imaging has great potential in pharmaceutical industry, because it can provide rich and useful information that helps us to understand the structure and property of molecules from a new electromagnetic wave window. The innovative progresses in the application of THz technology in the pharmaceutical setting in recent years are reviewed with illustrative examples in this paper. THz-TDS has the capability to characterize and quantify the active pharmaceutical ingredients (APIs) in drug materials and final solid dosage forms and to investigate crystallinity, polymorphism, and pseudo-polymorphism. THz functional imaging can be used to nondestructively analyze the tablet matrix physicochemical composition, coating thickness, density and internal structure, and the uniformity and integrity of the coat in solid dosage forms due to the pulsed, coherent and frequency-dependent penetration nature of the radiation. The applications of THz technology in reaction dynamics and as an on-line process analytical technology (PAT) are also discussed in this review.

Contents
1 Introduction
2 Terahertz time-domain spectroscopy
2.1 Investigation of isomers
2.2 Investigation of polymorphism and crystallinity
2.3 Pseudo-polymorphism qualification and quantification
2.4 Quantitative monitoring of reaction processes
3 Terahertz imaging
3.1 Nondestructive analysis of tablet coating
3.2 Nondestructive investigation of druy dissolution performance
3.3 Nondestructive inspection of pharmaceutical ingredients
4. Outlook

Proteomics has become one of the most active fields in life sciences. The study of biological functions of proteins not only relies on high-throughput identification of proteins, but also on quantitative analysis of the dynamic proteins that is termed quantitative proteomics. Quantitative proteomics is anticipated to provide new insights into biological functions, facilitate the identification of prognostic disease markers and contribute to discovery of proteins as therapeutic targets. The available methods for quantitative proteomics are mainly based on the isotope tagging combined with biological mass spectrometry (such as Electrospray Ionization Mass Spectrometry, ESI-MS, and Matrix Assisted Laser Desorption Ionization Mass Spectrometry, MALDI-MS). Recently inductivity coupled plasma-mass spectrometry (ICP-MS), as an attractive complement to ESI-MS and MALDI-MS, has played an increasing role in protein quantification, especially in absolute protein quantification. ICP-MS is an ideal instrument for determination of trace elements in biomolecules because of its unique advantages, such as high sensitivity, wide dynamic range, and minimal matrix effects. This review will selectively discuss the recent advances of ICP-MS based techniques and their applications in protein quantification and immunoassay.

Contents 
1 Introduction
2 Problems of protein quantification 
3 Available methods for protein quantification 
4 The advantages of ICP-MS in proteins quantification 
5 ICP-MS-based methods for protein quantification
5.1 Protein quantification based on element labeling and ICP-MS detection
5.2 ICP-MS-based Immunoassay
6 Conclusions and outlook

The interaction between medicine and biological target in vivo is one of the most important factors that determine the therapeutic activity of the medicine. Screening medicine that can bind with biological target and show well pharmacological effects will promotes the development of new medicine discovery significantly. therefore, several approaches have been developed to screening of combinatorial libraries and natural product extracts for biologically active compounds. Ultrafiltration mass spectrometry is a combination of ultrafiltration equipment and mass spectrometry, which is a valuable approach for the selection, structure analysis, and identification of low molecular weight compounds that interact with biological target in the solution phase. It has been developed as a powerful tool for the determination of the interaction between medicine and biological target because of its high speed, high sensitivity, and its high throughput screening ability. In this paper, the fundamental principles on which the ultrafiltration mass spectrometry is based, and the experimental details that must be considered during the operation of ultrafiltration equipment are introduced. The developments and applications of the ultrafiltration mass spectrometry in the studies on the interaction between medicine and biological target are reviewed. In addition, the developmental trend of the ultrafiltration mass spectrometry are also discussed．

Contents
1 Introduction
2 The fundamental principles of ultrafiltration mass spectrometry
3 The useful discussion of experimental details that must be considered
4 The recent applications of ultrafiltration mass spectrometry
5 Conclusions and outlook

Cells are the fundamental building blocks of life. Single-cell analysis can explain structures and functions of individual cells and uncovers the heterogeneity within populations of cells. It plays an important role in researches of cellular differentiation, physiology, pathology and early clinic diagnosis. As a high efficient separation method, capillary electrophoresis is uniquely suited for single-cell analysis because it needs ultrasmall samples and can be coupled  with sensitive detectors. The recent advances since 2007 in single-cell analysis using capillary electrophoresis are described, including single-cell injection techniques, single-cell lysis techniques, detection methods and applications. Future directions of single-cell analysis by capillary electrophoresis are also predicted. It is shown that capillary electrophoresis is not only suited for single-cell analysis but also still has tremendous development potentials and wide application fields.

Contents
1 Introduction
2 Single-cell injection techniques
3 Single-cell lysis techniques
4 Detection methods
4.1 Optical absorption-based detection
4.2 Laser-induced fluorescence
4.3 Chemiluminescence and electrochemiluminescence
4.4 Electrochemical detection
4.5 MS
5 Applications
5.1 Proteins and proteome
5.2 Metabolome
5.3 Subcellular structures
5.4 Neurotransmitters
5.5 Microorganisms
5.6 Others
6 Conclusions and outlook

This review introduces the research progress of the bio-inspired mineralization process in the gel medium. Bio-inspired mineralization is the leading edge and hotspot of the research in the fields including chemistry, biology and materials science at present. Recently, more and more efforts prove that the biomolecules, such as the protein and polysaccharide, usually form the gelatinous reticular matrix in the organism, which can influence the biomineralization process. Therefore, the research of bio-inspired mineralization processes in the gel medium is important to understand the biomineralization mechanism, and guide the design and synthesis of advanced functional materials. Until now, the bio-inspired mineralization process in the gel media including the natural and man-made macromolecule gel, supermolecule hydrogel, and inorganic gel, and so on, has been investigated. The current experimental results show that the gel media control the morphology of inorganic crystals by primarily inhibiting the diffusion of reactant ions in their network structure and doping into the formed crystals. Moreover, the bio-inspired mineralization in the gel medium cooperating with organic matrices, such as water-soluble additives and self-assembled mono-layers (SAMs), exhibits different characters from that in aqueous solution. In addition, this review also introduces several opinions about the bio-inspired mineralization mechanism of inorganic crystals formed in the gel medium. At last, the development trend of the research and application in this field is expected.

Contents
1 Introduction
2 Bio-inspired mineralization in gel media
2.1 Natural macromolecule gel
2.2 Man-made macromolecule gel
2.3 Supermolecule hydrogel
2.4 Inorganic gel
3 Effect of organic matrices on bio-inspired mineralization in gel media
3.1 Water-soluble additives
3.2 Self-assembled mono-layers, SAMs
4 Mechanism of bio-inspired mineralization in gel medium
5 Conclusions and outlook

The tissue engineering nanomaterials, which are produced from traditional tissue engineering nanomaterials by nanotechnology, have special biology properties and have been already paid attention to. In recent years, the studies on application of nanomaterials in tissue engineering fields have been of great interest. The applications of nano-phase ceramics, carbon nanotubes, carbon nanowires and nano metallic materials in bone and cartilage tissue engineering, titanium nanomaterials, polylactide-dl-lactide nanomaterials and carbon nanofibers in artery tissue engineering, polypeptide nano bone frameworks, nano-fibrous scaffolds and carbon nanotubes/fibers in neural tissue engineering, nano-structured polymers in bladder tissue engineering, have already been reported. The results indicate that nanomaterials have potential application foreground. This review focuses on the applications and prospects of nanomaterials in bone and cartilage tissue engineering, artery tissue engineering, neural tissue engineering and bladder tissue engineering.

Contents
1 Introduction
2 The applications of nanomaterials in tissue engineering
2.1 The applications of nanomaterials in bone and cartilage tissue engineering
2.2 The applications of nanomaterials in artery tissue engineering
2.3 The applications of nanomaterials in neural tissue engineering 
2.4 The applications of nanomaterials inbladder tissue engineering 
3. Conclusions and outlook

Hydrogen storage is a key to the utility of hydrogen as a renewable energy source. The encapsulation of hydrogen on porous materials has its special advantages. In this review, the fundamentals of the encapsulation are briefly introduced. The relevant porous materials of zeolites, metal coordination compounds, hollow glass microspheres, fullerenes and their derivative, and their characteristics on encapsulation of hydrogen are addressed in details. Recent progresses on the studies of the encapsulation of hydrogen on porous materials are summarized. The differences between the encapsulation and physical adsorption of hydrogen on porous materials are analyzed based on their required operation conditions, material specifications and energy barriers. Finally, the perspectives of the applications and further studies on the encapsulation of hydrogen are discussed.

Contents
1 Introduction
2 Fundamentals of encapsulation
3 Porous materials for hydrogen encapsulation
3.1 Zeolites
3.2 Metal coordination compounds
3.3 Hollow glass microspheres
3.4 Fullerenes and their derivatives
4 Conclusions

Although the highest energy conversion efficiency about 11 % of dye-sensitized solar cell (DSSC) based on the transparent oxide conductive glass (TCO) has been obtained, the heavy, rigid, and expensive TCO substrate need to be substituted with flexible materials such as plastic or metal substrates in order to both decrease the production costs and enlarge the application range. The key problem with plastic substrates is their low temperature tolerance, so some novel fabricating methods need to be developed to enhance the quality of flexible photo electrodes. Whereas with metal substrates, the above problem is not existed due to the high temperature tolerance of them, while a few kinds of metals such as stainless steel, titanium are suitable for substrates owing to the corrosion of iodine-containing electrolyte typically used in DSSC. The key problem for fabricating flexible DSSC with metal substrate photo electrodes is to fabricate the high transparent counter electrodes and use some kinds of low light absorption electrolytes. Taking these accounts in mind, researchers have obtained some significant progresses. Another important research challenge on flexible DSSC is to improve the long-term stability of the cells to suit for consumer applications. Some kinds of quasi or all solid state electrolytes have been used in TCO based DSSC and show excellent long-term stability, if they can be transferred to the flexible DSSC successfully, the problem can be solved.

Contents
1 Introduction
2 Flexible photo electrode
3 Flexible counter electrode
4 Electrolyte
5 Conclusions and outlook