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In recent years, single‐atom catalysts (SACs) have become the most active part of the catalytic field due to their excellent catalytic activity. Among them, Ru SACs exhibit excellent performance in many catalytic applications due to their high atomic utilization efficiency, catalytic activity and selectivity, and relatively low cost. In order to understand the structure–performance relationship and potential catalytic mechanism of Ru SACs, this review summarizes the research progress of Ru SACs in the fields of electrocatalytic water splitting, fuel cells, nitrogen reduction, and nitrate reduction in recent years. The catalytic process of Ru single atom in different synthesis methods and modification strategies is summarized. Finally, some opportunities and challenges for the future development of Ru SACs are prospected. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing demand for ultra‐thin carbonized wood films (CWF) with high shielding efficiency (SE) to replace non‐renewable alternatives. Researchers aim to enhance electromagnetic (EM) wave absorption and improve electromagnetic interference (EMI) SE in CWF materials to reduce secondary pollution from reflected EM waves. In this work, the carbonized wood composite film (CWF/EP/Co) with a thickness of 120 µm through the process of hot‐pressing and carbonizing wood soaked in a mixed solution of water‐borne epoxy (EP) and Co/Zn‐MOF (ZIF‐67/8) is obtained. The CWF/EP/Co film exhibits excellent conductivity (105 S cm−1) and demonstrates an excellent EMI SE (73 dB) at a 200 µm thickness. Remarkably, the specific EMI shielding effectiveness (SSE/t) of CWF/EP/Co films reached 15833.3 dB·cm2·g−1 in the X‐band, making it the highest reported value among all wood‐derived EMI shielding materials. CWF/EP/Co films have a high absorption coefficient (A) of 0.4, indicating their effectiveness in absorbing EM waves. Furthermore, the EMI shielding effect of the large‐scale wallpaper (170 mm×170 mm) is confirmed by finite element analysis. Additionally, the CWF/EP/Co film exhibits good mechanical properties and effective Joule heating performance. This shielding film shows promise in applications such as buildings and smart homes, providing EMI shielding and warming effects. [ABSTRACT FROM AUTHOR]

The shortage of freshwater resources has become a major obstacle threatening human development, and directly utilizing solar energy by solar evaporators is emerging as a promising method to produce freshwater from the seawater. Compared to many synthetic polymer‐based evaporators, cellulose‐based evaporators are expected to offer more interesting features benefiting from the renewable feature and abundant reserves of cellulose‐contained naturally occurring materials. First, according to the different fabrication methods, cellulose‐based solar evaporators can be divided into two types, i.e., top‐down utilization (wood‐based) and bottom‐up assembled (cellulose composite‐based), respectively. The different fabrication schemes also bring their own unique advantages, such as the bimodal porous structure of wood‐based evaporators and the artificial interconnection microporous network of cellulose composite‐based evaporators. Subsequently, this review further summarizes the most recent advances and highlights of those cellulose‐based solar evaporators, by focusing on their structural regulation strategies (e.g., drilled channel array, asymmetric wettability structure, delignification, 2D waterway, etc.) and evaporation performance improvements (e.g., salt resistance, high evaporation rate, etc.). Finally, the challenges in this field and potential solutions are also discussed, which are anticipated to provide new opportunities toward the future development of cellulose and other kinds of biomass‐based evaporators. [ABSTRACT FROM AUTHOR]

Size regulation of polydopamine nanoparticles (PDA NPs) is vital to melanin‐inspired materials. The general strategy usually focuses on tuning of the reaction parameters which could affect the dopamine (DA) monomer polymerization process, such as pH, temperature, monomer concentration, etc. The reaction between boronic acids and catechols to form boronic esters has been widely applied in many fields, but little attention has been paid in the size regulation of PDA NPs. Here, it is speculated that the fine size regulation of PDA NPs can be directly achieved by using boronic acids and Lewis base molecules. It is found that these issues could indeed significantly affect the stability of the boronic esters formed by boronic acids and DA, which may further inhibit the monomer polymerization kinetics and tune the particle size of the resulting PDA NPs. It is also found that the several intrinsic properties of PDA NPs such as the free radical scavenging ability, UV spectral absorption, photothermal behavior, and structural color all change with the particle size. It is believed that this work can provide new opportunities for fabricating melanin‐inspired PDA NPs with well controlled size and properties. [ABSTRACT FROM AUTHOR]

Designing energy storage devices from thick carbon electrodes with high areal/volumetric energy density via a simple and green way is very attractive but still challenging. Cellulose, as an excellent precursor for thick carbon electrodes with abundant sources and low cost, is usually activated by a chemical activator and pyrolysis route to achieve high electrochemical performance. However, there are still some problems to be addressed, such as the harsh activation conditions, easy collapse of porous structures, and the high cost. Herein, a 3D self‐supporting thick carbon electrode derived from wood‐based cellulose is proposed for high areal and volumetric energy density of supercapacitor from a mild, simple, and green enzymolysis treatment. Benefiting from the high specific surface area (1418 m2 g−1) and abundant active sites on the surface of wood‐derived hierarchically porous structures and enzymolysis‐induced micropores and mesopores, the assembled symmetry supercapacitor from the thick carbon electrode can realize the high areal/volumetric energy density of 0.21 mWh cm−2/0.99 mWh cm−3 with excellent stability of 86.58% after 15 000 long‐term cycles at 20 mA cm−2. Significantly, the simple and universal strategy to design material with high specific surface area, provides a new research idea for realizing multi‐functional application. [ABSTRACT FROM AUTHOR]

Flexible bioelectronics have attracted increasing research interests due to their wide range of potential applications in human motion detection, personal healthcare monitoring, and medical diagnosis. Recently, design and fabrication strategies integrated with mussel‐inspired polydopamine (PDA) have demonstrated many appealing properties, which meet the structural and functional requirements of high‐performance flexible bioelectronics. The inherent multiple reactive sites and hierarchical interactions within PDA can promote the total electrochemical activities, self‐healing, surface activation, and biocompatibility of the composite system. This review paper strives to provide a comprehensive overview on this emerging area, including the fabrication methodology, the structural and functional contributions of PDA on the whole composites, and various applications of PDA‐based flexible bioelectronics. The current challenges and future outlook in this field are also extensively discussed at the end. This paper aims to serve as a guideline in this emerging area and provide new inspirations toward next‐generation integrated multifunctional flexible PDA bioelectronics with a broad range of healthcare applications. [ABSTRACT FROM AUTHOR]

Ultralight cellular sponges offer a unique set of properties. We show here that solvent uptake by these sponges results in new gel-like materials, which we term spongy gels. The appearance of the spongy gels is very similar to classic organogels. Usually, organogels are formed by a bottom-up process. In contrast, the spongy gels are formed by a top-down approach that offers numerous advantages for the design of their properties, reproducibility, and stability. The sponges themselves represent the scaffold of a gel that could be filled with a solvent, and thereby form a mechanically stable gel-like material. The spongy gels are independent of a time-consuming or otherwise demanding in situ scaffold formation. As solvent evaporation from gels is a concern for various applications, we also studied solvent evaporation of wetting and non-wetting liquids dispersed in the sponge. [ABSTRACT FROM AUTHOR]

This study reports on gold nanoparticles (AuNPs) immobilized in a sponge made of short electrospun fibers (Au-sponge), which show surprisingly high reaction rates at extremely low gold amount. Au-sponges are made by freeze-drying of dispersions of short electrospun fibers with preimmobilization of AuNPs. The resulting Au-sponges show very low densities around 7 mg cm−3 corresponding to a pore volume of about 150 mL g−1, but low surface area and very low amount of AuNPs in the range of 0.29-3.56 wt%. In general, catalysts with immobilized AuNPs show much low reaction rates compared to systems with dispersed AuNPs. By contrast, the Au-sponge catalyst with immobilized AuNPs is discerned here as an extremely efficient catalyst even superior to other systems with dispersed AuNPs. The fidelity of the Au-sponges after reactions is good enough for manifold use and thereby provides a sustainable catalyst design as well. [ABSTRACT FROM AUTHOR]

Ultralight polymer sponges are prepared by freeze-drying of dispersions of short electrospun fibers. In contrast to many other highly porous materials, these sponges show extremely low densities (<3 mg cm−3) in combination with low specific surface areas. The resulting hierarchical pore structure of the sponges gives basis for soft and reversibly compressible materials and to hydrophobic behavior in combination with excellent uptake for hydrophobic liquids. Owing to their large porosity, cell culturing is successful after hydrophilic modification of the sponges. [ABSTRACT FROM AUTHOR]

Coaxial electrospinning is an attractive technology to produce core/sheath and hollow fibers. However, until now, the relatively low productivity has limited its broad applications. In this work, coaxial electrospinning with air‐blowing‐assistance is applied to improve the productivity of core/sheath and hollow fibers. Different core and shell materials are used for this electrospinning. The flow rate and air‐blowing rate during electrospinning are optimized. SEM and TEM are used to confirm the core/sheath and hollow structure of fibers. The results show that air‐blowing‐assisted electrospinning technology can be successfully applied for the large‐scale production of core/sheath and hollow fibers which open the path to new applications of this promising class of materials. [ABSTRACT FROM AUTHOR]