Search

The polyacrylic acid/tungsten oxide (PAA/WO3) composite films with good electrochromic properties have been prepared by a layer-by-layer method. The porous PAA layers were used as a template for the deposition of WO3, and finally, the composite film showed a network structure with high porosity. The electrochromic performance of the PAA/WO3 composite film was investigated by means of cyclic voltammogram (CV), chronoamperometry (CA), and transmittance measurements. The PAA/WO3 film also exhibited a remarkable electrochromism ability with the reversible color change from transparent colorless to dark blue and the transmittance change from 83% to 24% at 620 nm. This research provided a cost-effective approach for the preparation of PAA/WO3 composite films with controllable microstructure and good electrochromic property.

Hydrogen is regarded as one of the most promising energy sources of the future, due to its low-cost, zero-pollution, and high-heat value. Nevertheless, traditional methods of storing hydrogen are commonly accompanied by the risk of leaks and explosions, so how to store and transport hydrogen safely and efficiently is a critical issue that needs to be addressed. Solid-state hydrogen storage is the most attractive way to store hydrogen in nanomaterials by chemical or physical adsorption, which has the advantages of high energy density and good safety. Here, a rational Ni–Zn bimetallic MOF has been constructed by a straightforward synthetic technique, in which the Zn atom was partially replaced by the Ni atom. The micropore rate of the Ni–Zn bimetallic MOFs is higher than that of ZIF-8. In addition, the presence of Ni provides more unsaturated metal sites and strengthens the bonding between hydrogen molecules and Ni, effectively improving the hydrogen storage capacity of Ni–Zn bimetallic MOFs. The experimental results show that the hydrogen adsorption capacity of Ni–Zn bimetallic MOFs can reach 1.35 wt% at 77 K and 1 bar. [ABSTRACT FROM AUTHOR]

One of the most promising methods for capturing carbon dioxide (CO2) is solid physical adsorption, which is an efficient and simple technique. The key to effective CO2 capture is the development of high-performance solid adsorbents with excellent CO2 adsorption capacity, CO2/N2 selectivity, and rapid adsorption/desorption kinetics. In this paper, a Mg-MOF-74/sodium alginate composite aerogel was prepared by loading Mg-MOF-74 on sodium alginate sheets followed by directional freeze-drying. The composite aerogel exhibited a hierarchical porous structure, in which sodium alginate provided an open mesoporous/macroporous structure that promoted diffusion and contact with the active center of CO2. The Mg-MOF-74 micropores/mesopores promoted the strong interaction between CO2 and the adsorbent in the micropore and rapid mass transfer of CO2 to the adsorbent through the mesopores. The experimental data showed that MSA-6 achieved CO2 adsorption of 2.461 mmol·g–1 at 298 K. Furthermore, the CO2/N2 adsorption selectivity of MSA-6 reached 35.108, indicating its strong CO2 selective adsorption potential. [ABSTRACT FROM AUTHOR]

Rapid and safe disinfection and exudate management are two major challenges in infected wound care. Therefore, in this work, we developed a novel wound dressing via encapsulating ZIF-8-derived carbon nanoparticles in a hydrophilic nanofiber sponge to address severe wound infection and heavy exudate problems. The dressing can effectively kill bacteria through chemo-photothermal synergistic therapy. Meanwhile, the hydrophilic nanofiber sponge can quickly absorb wound exudate around the wound and accelerate the evaporation rate of liquid through the photothermal effect and its own structure; therefore, it is possible to remove excess liquid and regulate its wetness. In this way, it prevents the problem of wound overhydration often caused by hydrophilic dressings. In our experiment, the dressing showed good antibacterial performance and biocompatibility in vitro and could effectively control wound infection, absorb wound exudate and promote skin wound healing in vivo. Its good therapeutic effect is not only due to effective infection control and wound exudate management, but also because the structure of nanofibers similar to an extracellular matrix provides basic physical support and structural signals conducive to skin tissue regeneration. [ABSTRACT FROM AUTHOR]

Constructing heterostructure in nanomaterials is a scientific and efficient method to optimize the electrochemical properties of supercapacitors. Carbon aerogels (CAs) can enhance electrical conductivity and ion diffusion because of their three-dimensional porous structure, which is useful for fabricating electrodes. The moderate nanoheterostructures in aerogel nanomaterials have made great contributions to the optimization of application performance. Herein, a simple method for constructing the MnO2 nanoparticle/CA (MnO2/CA) heterostructure is proposed. The MnO2/CA heterostructure exhibits outstanding electrochemical capability in a three-electrode system, with a specific capacitance of 384 F/g, higher than 201 F/g of the CA, at a current density of 0.5 A/g. When MnO2/CA is used as a symmetric supercapacitor, it also exhibits a high energy density and power density, with the highest energy density of 33.78 Wh/kg. The prepared MnO2/CA shows improved performance for synergies in providing a high specific capacity and long cycle life. [ABSTRACT FROM AUTHOR]

The cost of CO2 separation and energy consumption can be decreased through the use of CO2 adsorption. Due to the electron-rich heteroatoms in its network, polyimide (PI) has a remarkable affinity for CO2. Polyethylene glycol (PEG) can increase the layer spacing of polymers, so as to change the mass transfer of CO2 in it. Furthermore, the ether bond (-O-) in PEG has good affinity for CO2. In this study, PEG-1000 was introduced into PI aerogel by mild sol-gel method at low temperature, and freeze-drying was used to produce PI/PEG composite aerogels with directional pore structure. The effect of PEG-1000 content and directional pore structure of the PI/PEG composite aerogels on CO2 adsorption performance were further studied. The L-PI/PEG-4 composite aerogel, which contains 4 g PEG and is directionally frozen in liquid nitrogen, has a CO2 adsorption capacity of 16.76 cm3/g at 25°C and 1 bar. L-PI/PEG-4 aerogel also exhibits high CO2/N2 selectivity and adsorption cycle stability. [ABSTRACT FROM AUTHOR]

Pyrolysis-free metal–organic frameworks (MOFs) with optimized particle sizes were used as capacitive deionization (CDI) materials in oxygenated saline water. Upon decreasing the particle size of the MOFs, excellent cycling stability and higher CDI performance were achieved. This was possibly due to the improvement in charge transfer and electrolyte permeation, uncovering the significance of particle size control in improving CDI performance. [ABSTRACT FROM AUTHOR]

High CO2 concentration in atmosphere causes serious environmental issues, and carbon capture and storage technologies have attracted attention as a means to reduce the atmospheric CO2 concentration. Metal-organic frameworks (MOFs) can potentially be used for CO2 adsorption, but their poor stability and microporosity limit their applications. Herein, a novel strategy was proposed to combine a cellulose aerogel and hierarchically-porous MOFs (HP-MOFs) with larger pores. According to this strategy, a series of microcrystalline cellulose/HP-UIO-66-NH2 hybrid aerogels (MC-HUN-X) was constructed by adding a modulator (monocarboxylic acid, MA), followed by the in-situ growth of HP-UIO-66-NH2 on a cellulose aerogel. By adjusting the chain length of MA, the structure–function relationship between pore size and the CO2 adsorption capacity of MC-HUN-X was explored. The results showed that the CO2 adsorption capacity increased first and then decreased upon increasing the MOFs pore size, while the adsorption selectivity of CO2 continuously increased. Among all samples, MC-HUN-4 with a moderate pore size had the highest CO2 adsorption capacity (1.90 mmol/g at 298 K and 1 bar) and adsorption selectivity (13.02 and 2.40 for CO2/N2 and CO2/CH4). The combination with a cellulose aerogel endowed MC-HUN-X with excellent mechanical stability and reusability. Cellulose/HP-UIO-66-NH2 hybrid aerogel with larger aperture sizes of MOF showed excellent adsorption capacity and selectivity for CO2, and the combination with aerogel could effectively improve the mechanical stability and reusability. [ABSTRACT FROM AUTHOR]

Carbon aerogel (CA) based materials have multiple advantages, including high porosity, tunable molecular structures, and environmental compatibility. Increasing interest, which has focused on CAs as electrocatalysts for sustainable applications including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and CO2 reduction reaction (CO2RR) has recently been raised. However, a systematic review covering the most recent progress to boost CA-based electrocatalysts for ORR/OER/HER/CO2RR is now absent. To eliminate the gap, this critical review provides a timely and comprehensive summarization of the applications, synthesis methods, and principles. Furthermore, prospects for emerging synthesis, screening, and construction methods are outlined. [ABSTRACT FROM AUTHOR]

The interactions between organelles can maintain normal cell activity. Lysosomes, as waste disposal systems of cells, have many important interactions with the plasma membrane, especially in the repair of cracked plasma membrane. Unfortunately, a way to study the relationship between them synchronously is still lacking. Therefore, in this work, we constructed a dual-targeting probe (Mem-Lyso) to simultaneously visualize the plasma membrane and lysosomes for the first time. Taking advantage of dual-targeting, the probe Mem-Lyso could successfully track and analyze the dynamic changes of the plasma membrane and lysosomes in different bioprocesses. The experimental results demonstrated that, compared to the normal status, there was obvious fusion between the plasma membrane and lysosomes in the apoptosis process. Furthermore, because of the sensitivity to polarity, Mem-Lyso could label the plasma membrane and lysosomes with red and yellow colors in cells, respectively. Moreover, the skeleton and gastrointestinal wall of zebrafish were visualized by dual-color imaging, respectively. More importantly, the dual-targeting property endowed Mem-Lyso with the ability to spatially distinguish the cholesterol (CL) content in the plasma membrane, which provided a potential detection tool for biological research and diagnosis of related diseases. [ABSTRACT FROM AUTHOR]

Developing highly efficient and stable photocatalysts is an effective method to achieve CO2 photocatalytic reduction. Herein, PI/WO3 aerogel photocatalyst was prepared by chemical amide reaction coupled with an ethanol supercritical drying technique. The novel aerogel photocatalysts exhibit excellent photocatalytic performance for reducing CO2 into CO. In particular, PI/WO3-10 aerogel photocatalyst shows the highest yield of CO (5.72 μmol g–1 h–1), which is ca 11-fold higher than that of the pristine PI aerogel. The high CO2 reduction activity can be attributed to the Z-scheme structure, which enhances the separation of photo-generated electron – holes, and induces H2O oxidation on WO3 nanosheets and CO2 reduction on PI aerogel. The photocatalytic reaction mechanism of CO2 when using PI/WO3 aerogel photocatalyst is proposed. [ABSTRACT FROM AUTHOR]

TiO2/SiO2-Based nanocomposites with highly porous structures have received increasing attention due to their excellent photocatalytic activity. In this work, a TiO2/SiO2/Ag ternary composite aerogel with enhanced visible-light photocatalytic activity has been successfully synthesized through a facile sol–gel method combined with a supercritical drying technique. The specific surface area and pore structure of TiO2/SiO2/Ag aerogel could be controlled by adjusting the Si content. The TiO2/SiO2/Ag aerogel with pore size of 9.2 nm achieved the maximum adsorption capacity of oxytetracycline. The presence of SiO2 in TiO2/SiO2/Ag improved the compression strength of the aerogel and thus achieved long-term stability in photocatalysis. Furthermore, the addition of Ag particles in TiO2/SiO2/Ag effectively decreased the recombination of photo-electrons and holes. The photocatalytic degradation rates of oxytetracycline over the TiO2/SiO2/Ag aerogel with a mole ratio of Ag : Si : Ti = 0.1 : 10 : 4 were 3.1 and 2.3 times those over P25 and a TiO2/SiO2 aerogel. The enhanced photocatalytic performance of the TiO2/SiO2/Ag aerogel is attributed to the large specific surface area, 3-D porous structure, high electrical conductivity and compression strength of this novel composite aerogel. [ABSTRACT FROM AUTHOR]

A novel Z‐scheme polyimide (PI)/AgBr@Ag aerogel photocatalyst has been successfully synthesized by combining an in situ precipitation method and a supercritical drying method. The as‐prepared PI/AgBr@Ag‐50 (50 wt % AgBr@Ag in PI/AgBr@Ag) aerogel photocatalyst exhibited excellent photocatalytic activity for oxytetracycline degradation with a rate constant of 0.025 min−1, which was 6.9 and 2.6 times higher than that of the PI aerogel or the AgBr@Ag nanoparticles, respectively. More significantly, the PI/AgBr@Ag‐50 aerogel photocatalyst showed stable cycling, which could be attributed to the high mechanical strength and 3D network of the PI aerogel. The introduction of AgBr@Ag on PI with a heterojunction structure efficiently promoted the separation of electron–hole pairs by a Z‐scheme mechanism. The reduced metallic Ag nanoparticles were found to function as centers for the transfer of electrons from AgBr to PI. This work has revealed a new application for the aerogel PI/AgBr@Ag photocatalyst in environmental protection. Two is better than one: AgBr@Ag nanoparticles were uniformly dispersed on a polyimide (PI) aerogel, and the resultant Z‐scheme PI/AgBr@Ag composite aerogel exhibited excellent photocatalytic activity for oxytetracycline (OTC) degradation under visible light, which can be attributed to the synergy between the AgBr@Ag plasmonic photocatalyst and the PI semiconductor photocatalyst (see figure). [ABSTRACT FROM AUTHOR]

A novel bifunctional Ag@AgSCN nanostructure with excellent photocatalytic degradation and antimicrobial performance has been successfully prepared by a simple precipitation method. Both the presence of PVP and the dropping rate of AgNO3 solution have a great effect on the triangle-shaped Ag@AgSCN nanostructure with exposed {−112} facets. The degradation constant (k) of triangle-shaped Ag@AgSCN (0.28 min−1) is three times as much as that of Ag@AgSCN nanoparticles (0.09 min−1), and also shows better bactericidal activity than Ag@AgSCN nanoparticles. Furthermore, the triangle-shaped Ag@AgSCN exhibits excellent structure stability in the cycling experiments, and reaches six cycles and four cycles in the photocatalytic degradation and antimicrobial experiments, respectively. The novel triangle-shaped Ag@AgSCN structure provided high-index facets with high catalytic activity, increased the adsorption amount of phenol and improved the separation efficiency of the electron–hole pairs, which resulted in more active species being produced over triangle-shaped Ag@AgSCN than Ag@AgSCN nanoparticles. The effect of the active species on the photocatalytic activity is in the order: ṖO2− radicals ＞ h+ ＞ ṖOH radicals. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porous polyimide/carbon quantum dots (CQDs) aerogel was prepared successfully. • CQDs increased light absorption and adjusted band structure of aerogel. • The aerogel possessed large specific surface area and wide visible absorption range. • The aerogel had high photocatalytic activity under visible light. • h+ and ·O 2 – were the main active species to degrade the pollutant. Polyimide was widely studied as semiconductor polymer photocatalyst. However, polyimide photocatalyst suffers from small specific surface area, poor visible light absorption and low charge thansfer efficiency. Herein, porous polyimide/carbon quantum dots aerogel was prepared successfully via supercritical CO 2 drying method. The carbon quantum dots were obtained by a green hydrothermal method. The carbon quantum dots could be anchored intimately on the polyimide aerogel by π -π stacking interactions. The polyimide/carbon quantum dots aerogel had large specific surface area and porous structure. The carbon quantum dots increased the visible light absorption, adjusted the band structure of the polyimide aerogel and facilitated the generation and separation of photogenerated electron and holes. Thus the photocatalytic property of the polyimide/carbon quantum dots aerogel was increased compared to pure polyimide aerogel. h+ and ·O 2 – were the main active species to degrade the pollutant. Finally, the mechanism of the photocatalysis under the visible light was proposed. [ABSTRACT FROM AUTHOR]

The polyaniline was synthesized by the emulsion polymerization and the polyaniline/polyacrylic acid (PANI/PAA) composite films were prepared through a layer-by-layer method. The porous PAA layer was used as a template for the deposition of PANI, and finally the composite film showed a network structure with large surface area and high porosity. The facile process for preparation of PANI/PAA composite films was good for large-scale production and application. The electrochromic performance of the PANI/PAA composite film was investigated by means of cyclic voltammogram, chronoamperometry and transmittance measurements. The composite film showed three typical redox couples, and the response time for reduction and oxidation was 90 and 102 ms, respectively. The PANI/PAA films also exhibited remarkable electrochromism ability with a reversible color change from yellow to purple and a transmittance change from 68 to 27% at 550 nm. [ABSTRACT FROM AUTHOR]