Room temperature phosphorescence (RTP) has arouse much interest due to their unique luminescence properties and wide potential applications in optoelectronics, sensing, bio-imaging and security devices. In recent years, various methods to promote phosphorescence emission at room temperature have been explored. At present, the commonly used methods for constructing room temperature phosphorescent materials with long lifetime and high quantum yield mainly center on the design of phosphorescent molecular structure and the construction of phosphorescent protective matrix. Supramolecular gel, as a new matrix for inducing room temperature phosphorescence, has attracted much attention owing to the advantages of three-dimensional network structure, thermal reversibility and stimulus responsiveness. This review focuses on metal-free room temperature phosphorescent gel and metal-containing room temperature phosphorescent gel, and summarizes current research status in recent years. In addition, a brief prospect for the future development of room temperature phosphorescent gel research is provided.

Carbon dots (CDots) emerging as a nova in carbon nanomaterials are applied in various fields due to their unique optical property, low toxicity, high biocompatibility, and designable flexibility. Several strategies for controlling the optical properties of CDots have been proposed to meet demands, including heteroatom doping, semiconductor quantum dot doping, polymer passivation and modification, and host-guest constructing. Electron donors or electron acceptors are introduced by doping a single heteroatom or multiple heteroatoms to affect the electron density of neighboring carbon atoms, hence enhancing the fluorescence emission intensity. Semiconductor quantum dots can also form composites with CDots to improve the electron hole separation efficiency, thus enhancing fluorescence. In terms of polymer modification, the polymer can passivate and functionalize the CDots' surface, and (cured) polymer film can provide tight spaces to promote the radiation transition on the surface of CDots to enhance the fluorescence. Furthermore, dye-CDots and porous material-CDots represent the main host-guest structures. The former shows positive effects on the fluorescence emission of CDots, especially performing better in red/near-infrared emission. The latter is highly designable and contributes to solid-state fluorescence, paving the way for advanced applications. This review elucidates four types of functionalized CDots and summarizes their optical properties, photoluminescence mechanisms, and potential applications. Finally, the development and current situation of functionalized CDots are discussed, and the future research direction of functionalized CDots has also been prospected.

With the gradual depletion of fossil fuels and the deteriorating environment, it is urgent to develop clean and renewable energy technologies. In recent years, energy conversion and storage technologies, such as water electrolysis and rechargeable metal-air batteries, have attracted tremendous research attention. Oxygen evolution reaction (OER) is the core reaction of them. Remarkable OER electrocatalysts have been widely reported. The fabrication methods of electrocatalytic electrodes play a prominent role in the performance of the catalysts apart from the intrinsic activity of the catalysts. An increasing number of researchers are devoted to exploring the design and fabrication of high-performance OER electrodes. This review introduces the current fabrication strategies of OER electrodes, discusses their advantages and disadvantages with a summary of the latest research progress, and overviews the emerging approaches for new-type electrodes. Finally, future development in this field is prospected.

Electrocatalytic carbon dioxide reduction (ECR) technology offers a potential strategy to achieve the goal of “carbon neutralization”. Transition metal single-atom catalysts have attracted much attention in ECR due to their adjustable electronic structure, high atom utilization and uniform active sites. This review firstly introduces the advantages of transition metal single-atom catalysts in CO₂ reduction, especially in selective CO production. Then, the recent progress on controlling the active sites as well as the catalysis selectivity over Fe, Co, Ni and other single-atom electrocatalysts are reviewed, with special emphasis on the intermediate process control of proton coupled CO₂ reduction to CO reaction path. Finally, the development direction of transition metal single-atom catalysts in ECR is briefly prospected to provide guidance and reference for promoting their large-scale application.

The increasing clean energy demands have promoted extensive attention on the development of alternative energy conversion technologies with high efficiency. Water splitting is a large-scale and sustainable technology for high-purity hydrogen production. However, the substantial overpotential and unsatisfied stability of oxygen evolution reaction (OER) electrocatalysts are great challenges for the widespread application of water splitting technology. Rational design of the structure of the OER electrocatalyst can significantly optimize its reaction thermodynamics and kinetics, thus improving the energy conversion efficiency of water splitting technology. The surface/interface is regarded as the main place where the electrocatalytic reaction occurs. The electrocatalysts, modified by surface/interface engineering, such as regulating intrinsic properties or designing synergistic interface, can improve their electrocatalytic efficiency and stability effectively. This review summarizes the application of surface/interface modulation strategies in OER, especially focusing on the research progress of layered double hydroxides, perovskite oxides, spinel compounds and alloy based materials. The design principles of high-efficient and stable electrocatalysts for OER are described. Based on the recent progress of surface/interface modulation applied in catalysts for OER,the effects of surface/interface modulation on the microstructure and electronic states of the catalysts are discussed. In addition, the challenges about modifications of above electrocatalysts are discussed. Finally, the opportunities of OER electrocatalysts via surface/interface modulation are prospected.

Due to the existence of unsaturated electrons, it is difficult to synthesize magnetic nanographene directly by the wet chemical method. With the help of surface catalysis in ultra-high vacuum, designed precursor molecules can be transformed into magnetic nanographene. Magnetism of carbon nanomaterials or nanographene possess high magnitudes of spin-wave stiffness, weak spin-orbit coupling, hyperfine couplings and large spin coherence lifetimes comparing with the transition metal, which hold the promise for spintronics construction and basic research. Due to the existence of unsaturated electrons, it is difficult to synthesize magnetic nanographene directly by the wet chemical method. With the help of surface catalysis in ultra-high vacuum, the synthesis of magnetic nanographene by artificial designed precursor molecules has been exploding. Except for the fabrication the magnetic nanographene, the investigation of magnetic ground state of nanographene itself and the magnetic engineering by tip-manipulation and construction of spin chains have been attracting much attentions. The atomic precise chemical and electronic structure and magnetic ground state could be identified by scanning tunneling spectroscopy and CO-decorated tip scanning tunneling microscope image. In this review, based on the recent research on nanographene, we introduce magnetic generations, structural and magnetism characterizations of nanographene as well as the magnetic order control by scanning tunneling microscopy in ultra-high vacuum.

As a new type of biological material, short peptide self-assembled hydrogel holds the advantages of high biocompatibility, low immunogenicity, high water content, degradation products that can be absorbed by the body, and structure similar to natural extracellular matrix. It has broad application prospects in the fields of materials science, biomedicine and clinical medicine. In this review, we mainly introduce several commonly used methods for preparing stable and tough peptide self-assembled hydrogels, including enzyme-catalyzed hydrogelation and chemical/physical cross-linked hydrogelation and photocatalytic hydrogelation. Furthermore, some applications of peptide self-assembled hydrogels in drug delivery and anti-tumor therapy, antibacterial and wound healing, 3D bioprinting and tissue engineering are introduced. We hope that the discussion in this review can arouse more people's attention to peptide self-assembled hydrogels and promote the development of their applications in the biomedical field.

Superwetting membrane can significantly improve the flux of emulsion treatment and effectively alleviate serious membrane pollution problems due to its unique wetting properties of water and oil. Therefore, more and more attention has been paid to the field of emulsion wastewater treatment. In this paper, the design and preparation methods of superhydrophilic membrane, Janus membrane and superwetting membrane with functional sites are summarized, the separation effect is evaluated and the mechanism of action is explored. The membrane is designed and prepared mainly by constructing hydrophilic surface and rough structure. The cross-linked fiber membrane synthesized by electrospinning method has a good application prospect in emulsion separation because it can break through the limitation of membrane pore size caused by screening effect. At the same time, depending on the type of oil/water separation mode and the application of membranes, we induce the filtration demulsification mode of superhydrophilic membrane and the oil gathering demulsification mode of Janus membrane and their characteristic, the former has the characteristics of low operating pressure, high filtration flux and good anti pollution performance, while the latter has the characteristics of high purity oil gathering. The effect of membrane structure and surfactant concentration on emulsion separation efficiency is also analyzed. Then, the vertical and tangential migration and transformation of droplets in the process of emulsion treatment by superwetting membrane are summarized, and the mechanism of droplet penetrating through the membrane in the process of Janus membrane oil gathering and demulsification and its mechanical analysis are discussed. At present, this part of research is mainly based on the prediction of droplet morphology and qualitative analysis of mechanics, the empirical and quantitative mechanical analysis of relevant mechanisms still need to be further studied. On this basis, a new idea and direction for the subsequent treatment of emulsion wastewater is proposed.

The construction of a highly sensitive, highly selective sensor for detecting trace analytes has received wide attention from scientific researchers. Molecularly imprinted technology has been widely used in the field of sensor construction due to its highly selective recognition, high-capacity adsorption, fast binding, thermal stability, and low cost. The molecularly imprinted fluorescent sensor constructed with molecularly imprinted polymer as the identification unit combined with fluorescent sensing technology has become a research focus in the detection of environmental pollutants traces. This article mainly introduces the preparation methods of molecularly imprinted polymers. The construction mechanism of molecularly imprinted fluorescent sensors and the application of molecularly imprinted fluorescent sensors in the detection of metal ions, small organic molecules, and biomacromolecules are summarized. The molecularly imprinted sensors to detect one or more target analytes under different numbers of fluorophores are elaborated, including single-target single-fluorophore detection, single-target ratiometric fluorescence detection, and multiplex detection with molecularly imprinted fluorescence sensor. Finally, the current challenges of molecularly imprinted fluorescent sensors and the prospects of molecularly imprinted fluorescent sensors are proposed to accelerate the development of molecularly imprinted fluorescent sensors and to further develop multifunctional molecularly imprinted fluorescent sensors with a wide range of applications.

Block copolymer (BCP) thin films can undergo microphase separation through different annealing techniques into large-scale cylindrical, lamellar, spherical or gyroidal nanopatterns. These long-range ordered nanopatterns have been widely used in many fields such as nanolithography, electronics, etc. At present, effective and rapid annealing methods are still a hot research topic in BCP thin film self-assembly. This article first introduces the commonly used annealing techniques for preparing BCP nanopatterns, then summarizes three new types of rapid annealing techniques, and finally analyzes and summarizes the advantages and disadvantages of these annealing techniques.

Hydrogels are biological materials with various properties. Hydrogels are three-dimensional network polymer with high water content, high tensile strength and biocompatibility. In addition to having excellent properties of hydrogels, conductive hydrogels have good electrical conductivity, adjustable mechanical properties and self-adhesive characteristics. The appearance of conductive hydrogels enrich types of hydrogels, expand performance of hydrogels, and improve practical application value, so that hydrogels have entered into people's daily life. Conductive hydrogels have gradually become the best candidate materials for flexible wearable electronic devices. In recent years, conductive hydrogels with biocompatibility, mechanical flexibility and fatigue resistance have been extensively studied. Conductive hydrogels can monitor and covert a wide variety of physiological signals and physical signals. Flexible wearable electronic devices based on conductive hydrogel can monitor human health status in real time. Conductive hydrogels with exceedingly good performance promote the development of flexible wearable electronic devices. Flexible wearable electronic devices have gradually become main research direction in field of human-computer interaction technology and artificial intelligence. Conductive hydrogels are synthesized by using conductive polymers, conductive fillers, free ions and their mixtures. According to conductive mechanism, manufactured conductive hydrogels can be divided into electron conductive hydrogels, ion conductive hydrogels and mixed electron-ion conductive hydrogels. In this paper, preparation methods of conductive hydrogels are discussed. The research progress and application of conductive hydrogels in aspects of stretchability, conductivity, biocompatibility, self-repairing and other functions in flexible wearable electronic devices are summarized. It is expected that conductive hydrogels will get better development.

As a new two-dimensional (2D) monoelement material in post-graphene era, black phosphorus (BP) has gained broad prospects in photocatalysis due to its extraordinary physicochemical characteristics including unique anisotropic structures, high carrier mobility and thickness-controlled bandgap. Nevertheless, the extremely narrow bandgap of BP (≤ 1.5 eV) is detrimental for the efficient separation of photogenerated electron-hole pairs that limits the photoreactivity. And the isolated BP suffers from the severe degradation upon long-term exposure due to P_xO_y species formed by the reaction between the lone pair electrons onto the BP surfaces and oxygen in ambient environment, then BP will gradually corrode in water through the formation of phosphoric acid. Therefore, the lower photoreactivity and instability of BP material restrict its industrial implementation. To overcome these obstacles, various effective strategies like creating a wide range of plasmonic hybrid nanostructures and mixed-dimensional heterojunctions have been developed. Herein, the recent progress on BP-based nanostructures through hybridization with dissimilar components like metals, semiconductors, carbon materials, etc. has been summarized and its applications in photocatalytic reactions such as water splitting for hydrogen evolution, organic pollutant removal, CO₂ photoreduction and N₂ fixation have also been reviewed, together with the insights into the photocatalytic mechanism for the boosted photoreactivity and good recyclability. Lastly, the challenges and potential directions of BP-based nanostructures toward high-efficiency photocatalytic reactions are analyzed and provided.

The presence of water vapor in gas streams is a significant technical issue for restricting the large-scale development of carbon capture. The polarity of H₂O often leads to the decrease or even failure of CO₂ capture rate of adsorbents. In addition, it also causes parasitic losses such as temperature and pressure drop to the system, and even causes equipment corrosion and adsorbent poisoning, thus greatly increasing the extra energy consumption and cost. In order to solve the above bottleneck, understanding the mechanism of H₂O/CO₂ co-adsorption and developing the highly efficient CO₂ adsorbent with reasonable cost, low regeneration energy consumption and insensitivity to H₂O are the important basis for the realization of effective CO₂ adsorption capture under wet gas streams. At present, due to the dispersion in multiple fields and different emphasis points, there is a lack of summary on the mechanism analysis of the influence of H₂O on CO₂ adsorption, and it is difficult to form a relatively unified view. In this paper, the co-adsorption process of CO₂ and H₂O are reviewed in detail from the macro and micro levels. Firstly, according to the fundamental research of co-adsorption mechanism, the progress in the fields of competitive adsorption, moisture swing adsorption and “breathing effect” are reviewed and briefly evaluated. Secondly, based on the application research of co-adsorption, the status and progress of adsorbent development and technology improvement of wet gas CO₂ adsorption are described. Furthermore, the CO₂ adsorption capture level under different wet gas sources is also briefly evaluated. Finally, the shortcomings of the current research are summarized and the future directions are prospected. This paper attempts to summarize, analyze and compare the CO₂/H₂O co-adsorption processes in various fields, which may provide effective guidance for CO₂ adsorption capture in wet gas source.

MXenes have attracted intensive research attention owing to its unique two-dimensional layered structure, high specific surface area, excellent conductivity, superior surface hydrophilicity and chemical stability. In recent years, selectively etching the A element layers from MAX phases by fluoride-containing etchants (HF, LiF-HCl, etc) is a common method to prepare multilayer MXenes with plentiful surface terminations. Due to the pollution problems of fluoride-containing etchants, at present, many studies have been reported on the use of more green and environmentally friendly fluorine-free etchants (NaOH, ZnCl₂, etc) to etch MAX phases. The properties of MXenes are closely related to its structure. Additionally, it is found that the preparation methods have great impacts on the layer spacing and surface terminations of MXenes, consequently affecting its performance. Hence, this paper summarizes and compares the research progress of the preparation strategies, layer spacing and surface terminations regulation of MXenes. Then the applications of MXenes in electrochemical energy storage are outlined. Finally, the challenges and prospects for the future development of MXenes are also proposed.

Lithium metal is regarded as the most promising anode material for the next-generation lithium batteries due to its high theoretical specific capacity (3860 mAh/g) and lowest electrochemical potential (-3.04 V vs SHE). However, dendrite growth and volume changes in Li metal anodes during battery cycles hinder the industrialization of Li metal anodes severely. Recent research progress has shown that introducing 3D host in Li metal can not only suppress dendrite growth, but also relieve volume changes of Li anode, thus improving cycle performance and safety of lithium metal batteries. Therefore, designing 3D host/Li metal composite anodes is regarded as an emerging strategy that can solve the problem of Li metal anodes effectively. This review summaries the recent progress on 3D host/Li metal composite anodes prepared by thermal infusion strategy. We firstly discuss prelithiation methods of 3D host and analyze influencing factors of host lithiophilicity in thermal molten infusing. Afterwards, different 3D host framework and their features are discussed followed by the improved strategies. Finally, we summarize existing problems of 3D host/Li metal composite anodes and give their future prospects.

The drug delivery systems (DDSs) developed with advanced nanotechnologies can improve the physicochemical properties and therapeutic effects of drugs, while weakening their side effects. Therefore, nanoscale DDSs have become a hot spot and mainstream direction of current pharmacy research. Among them, mesoporous silica nanoparticles (MSNs) have the advantages of large specific surface area, adjustable morphology/structure, easy surface modification and good biocompatibility, thereby have attracted extensive attention of biomedical researchers and provided new design ideas for constructing new smart DDSs. In this paper, the latest research progress of MSNs-based smart delivery systems in construction and disease treatment applications is reviewed. Firstly, the development process, preparation methods and structural characteristics of MSNs are briefly summarized. Secondly, the construction strategies of MSNs-based smart delivery systems in recent years were systematically expounded from the perspectives of drug loading and gate-controlled release. The gatekeepers (such as polymers, inorganic nanoparticles, supramolecular assemblies and biomacromolecules, etc.) and controlled release mechanisms of various stimuli-responsive MSNs-based delivery systems were emphatically introduced. Afterwards, the applications of MSNs-based controlled release system in the treatment of various diseases (including cancer, bacterial infection, diabetes and Alzheimer's disease, etc.) was described in detail. Finally, the challenges in the investigations of MSNs-based smart nanocarriers are summarized, and the prospects of their future development are presented.

Nano zero-valent iron (nZVI/Fe⁰) has attracted tremendous attentions for its excellent catalytic activities and economic applicability. However, tendency to agglomeration and instability normally limit its practical applications. In recent years, a series nZVI composites and/or stabilizers have been fabricated to address the above-mentioned issues with great promotion in preparations, substrates and applications. This review summarized and discussed the related studies on loading methods, stabilizing approaches and aqueous environmental applications in recent five years. The comprehensive reviews and prospects about nZVI composites are discussed from three main aspects: (1) the support frames including polymers, clays, carbons and metal oxides; (2) the new achievements of bimetal/multimetals, surface coating and vulcanizationfor composite stability; (3) the removal of heavy metals and organic pollutants through adsorption, reduction, complexation, co-precipitation, electrochemical reaction, (quasi) Fenton oxidation and other processes, and treatment promotion by the introduction of light, heat, electricity, ultrasound, and microwave.

A dataset of indoor formaldehyde concentrations in more than 10394 decorated houses was collected from literature, containing 27384 rooms monitored from 2003 to 2018 with sample locations in 62 cities throughout 31 Chinese provinces. With respect to regional distribution, change pattern with years, indoor temperature and humidity, seasonal trend, room type, and the time after decoration, the indoor formaldehyde pollution status and the key factors that affect formaldehyde concentrations were analyzed. The results show that formaldehyde-polluted indoor air is widespread in China. Indoor formaldehyde concentrations largely exceeded the national standard GB/T 18883-2002 recommended limit, with most over-standard rates higher than 50%. Indoor formaldehyde concentrations decreased gradually from the enactment of the national standard GB/T 18883-2002 in 2002—2009; nevertheless, a reversal trend occurred from 2013, which demands further attention. Generally, higher indoor formaldehyde concentrations were found in rooms with higher indoor temperatures, more decoration loads, easily formaldehyde emission furnishing materials, a shorter time after decoration, and lower ventilation rates. Different trends of seasonal indoor formaldehyde concentrations were observed between the north and the south; however, whether in the north or in the south, indoor formaldehyde concentrations are higher in seasons with higher indoor temperatures and lower ventilation rates.