Two-dimensional nanofluidic channels are emerging candidates for capturing osmotic energy from salinity gradients. However, present two-dimensional nanofluidic architectures are generally constructed ...by simple stacking of pristine nanosheets with insufficient charge densities, and exhibit low-efficiency transport dynamics, consequently resulting in undesirable power densities (<1 W m
). Here we demonstrate MXene/Kevlar nanofiber composite membranes as high-performance nanofluidic osmotic power generators. By mixing river water and sea water, the power density can achieve a value of approximately 4.1 W m
, outperforming the state-of-art membranes to the best of our knowledge. Experiments and theoretical calculations reveal that the correlation between surface charge of MXene and space charge brought by nanofibers plays a key role in modulating ion diffusion and can synergistically contribute to such a considerable energy conversion performance. This work highlights the promise in the coupling of surface charge and space charge in nanoconfinement for energy conversion driven by chemical potential gradients.
Graphene (G)-based composite materials have been widely explored for the sensing applications ascribing to their atom-thick two-dimensional conjugated structures, high conductivity, large specific ...surface areas and controlled modification. With the enormous advantages of film structure, G-based composite films (GCFs), prepared by combining G with different functional nanomaterials (noble metals, metal compounds, carbon materials, polymer materials, etc.), show unique optical, mechanical, electrical, chemical, and catalytic properties. Therefore, great quantities of sensors with high sensitivity, selectivity, and stability have been created in recent years. In this review, we focus on the recent advances in the fabrication technologies of GCFs and their specific sensing applications. In addition, the relationship between the properties of GCFs and sensing performance is concentrated on. Finally, the personal perspectives and key challenges of GCFs are mentioned in the hope to shed a light on their potential future research directions.
Display omitted
•The fabrication technologies and sensing applications of GCFs were introduced.•The structure features of GCFs with special sensing performances were discussed.•The key challenges and future perspectives of GCFs were mentioned.
2D materials are important building blocks for the upcoming generation of nanostructured electronics and multifunctional devices due to their distinct chemical and physical characteristics. To this ...end, large‐scale production of 2D materials with high purity or with specific functionalities represents a key to advancing fundamental studies as well as industrial applications. Among the state‐of‐the‐art synthetic protocols, electrochemical exfoliation of layered materials is a very promising approach that offers high yield, great efficiency, low cost, simple instrumentation, and excellent up‐scalability. Remarkably, playing with electrochemical parameters not only enables tunable material properties but also increases the material diversities from graphene to a wide spectrum of 2D semiconductors. Here, a succinct and critical survey of the recent progress in this research direction is presented, comprising the strategic design, exfoliation principles, underlying mechanisms, processing techniques, and potential applications of 2D materials. At the end of the discussion, the emerging trends, challenges, and opportunities in real practice are also highlighted.
Electrochemical exfoliation of layered materials has emerged as an important technique to produce solution‐processable 2D materials with high structural integrity or with specific functional groups, which are essential for fundamental studies as well as for practical applications. An insightful summary of the recent achievements is provided and the challenges and opportunities for the future endeavor are highlighted.
Natural vascular plants leaves rely on differences in osmotic pressure, transpiration and guttation to produce tons of clean water, powered by sunlight. Inspired by this, we report a sunlight-driven ...purifier for high-efficiency water purification and production. This sunlight-driven purifier is characterized by a negative temperature response poly(N-isopropylacrylamide) hydrogel (PN) anchored onto a superhydrophilic melamine foam skeleton, and a layer of PNIPAm modified graphene (PG) filter membrane coated outside. Molecular dynamics simulation and experimental results show that the superhydrophilicity of the relatively rigid melamine skeleton significantly accelerates the swelling/deswelling rate of the PNPG-F purifier. Under one sun, this rational engineered structure offers a collection of 4.2 kg m
h
and an ionic rejection of > 99% for a single PNPG-F from brine feed via the cooperation of transpiration and guttation. We envision that such a high-efficiency sunlight driven system could have great potential applications in diverse water treatments.
High-performance grade 300 maraging steels were fabricated by selective laser melting (SLM) and different heat treatments were applied for improving their mechanical properties. The microstructural ...evolutions, nanoprecipitation behaviors and mechanical properties of the as-fabricated and heat-treated SLM parts were carefully characterized and analysed. The evolutions of the massive submicron sized cellular and elongated acicular microstructures are illustrated and theoretically explained. Nanoprecipitates triggered by intrinsic heat treatment and amorphous phases in as-fabricated specimens are observed by TEM. High-resolution TEM (HRTEM) images of the age hardened specimens clearly exhibit massive nanosized needle-shaped nanoprecipitates Ni3X (X=Ti, Al, Mo) and 50–60nm sized spherical core-shell structural nanoparticles embedded in amorphous matrix. XRD analyses reveal austenite reversion and probable phase transformations during heat treatments. The hardness and tensile strength of the as-fabricated and age-treated SLM specimens absolutely meet the standard wrought requirements. Furthermore, the lost ductility after aging can be compensated by preposed solution treatments. Relationships between massive nanoprecipitates and dramatically improved mechanical performances of age hardened specimens are elaborately analysed and perfectly explained by Orowan mechanism. This study demonstrates that high-performance grade 300 maraging steels, which is comparable to the standard wrought levels, can be produced by SLM additive manufacturing.
Display omitted
•Evolutions of the typical SLMed microstructures are illustrated and theoretically explained.•Precipitation behavior and phase transformation of SLMed maraging steel are characterized by TEM and XRD.•Significant improvement of strength after solution and aging treatment was evaluated and explained.•Relationships between massive nanoprecipitates and improved mechanical performances are elucidated.
Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most destructive diseases that pose a great threat to wheat production. Wheat landraces represent a rich source of ...powdery mildew resistance. Here, we report the map-based cloning of powdery mildew resistance gene Pm24 from Chinese wheat landrace Hulutou. It encodes a tandem kinase protein (TKP) with putative kinase-pseudokinase domains, designated WHEAT TANDEM KINASE 3 (WTK3). The resistance function of Pm24 was validated by transgenic assay, independent mutants, and allelic association analyses. Haplotype analysis revealed that a rare 6-bp natural deletion of lysine-glycine codons, endemic to wheat landraces of Shaanxi Province, China, in the kinase I domain (Kin I) of WTK3 is critical for the resistance function. Transgenic assay of WTK3 chimeric variants revealed that only the specific two amino acid deletion, rather than any of the single or more amino acid deletions, in the Kin I of WTK3 is responsible for gaining the resistance function of WTK3 against the Bgt fungus.
Two‐dimensional (2D) titanium carbide (Ti3C2) is emerging as an important member of the MXene family. However, fluoride‐based synthetic procedures remain an impediment to the practical applications ...of this promising class of materials. Here we demonstrate an efficient fluoride‐free etching method based on the anodic corrosion of titanium aluminium carbide (Ti3AlC2) in a binary aqueous electrolyte. The dissolution of aluminium followed by in situ intercalation of ammonium hydroxide results in the extraction of carbide flakes (Ti3C2Tx, T=O, OH) with sizes up to 18.6 μm and high yield (over 90 %) of mono‐ and bilayers. All‐solid‐state supercapacitor based on exfoliated sheets exhibits high areal and volumetric capacitances of 220 mF cm−2 and 439 F cm−3, respectively, at a scan rate of 10 mV s−1, superior to those of LiF/HCl‐etched MXenes. Our strategy paves a safe way to the scalable synthesis and application of MXene materials.
A facile fluoride‐free method has been developed to prepare Ti3C2Tx (T=O, OH) sheets by anodic etching of bulk Ti3AlC2 crystals in aqueous electrolyte. The properties of the delaminated sheets are comparable to those made from classic HF etching procedures.
A hole-rich graphene framework (HGF) has been successfully prepared through lyophilization combined with thermal treatment at 200 °C. As the advanced three-dimensional (3D) graphene mesh assembly, ...the monolithic HGF was directly compacted to form capacitive deionization (CDI) electrode without grinding and binder so that the intact 3D structure can be reserved. The presence of original 3D structure combined with hierarchical hole structure in HGF plays important role in improving the CDI performance. The desalination capacities of HGF can reach up to 8.0 mg g−1, 16.9 mg g−1, and 29.6 mg g−1 in NaCl aqueous of 80 mg L−1, 270 mg L−1, and 572 mg L−1 respectively, which significantly exceeds other carbon-based materials at 2.0 V.
Display omitted
Hygroelectricity is proposed as a means to produce electric power from air by absorbing gaseous or vaporous water molecules, which are ubiquitous in the atmosphere. Here, using a synergy between a ...hygroscopic bulk graphene oxide with a heterogeneous structure and interface mediation between electrodes/materials with Schottky junctions, we develop a high-performance hygroelectric generator unit with an output voltage approaching 1.5 V. High voltage (e.g., 18 V with 15 units) can be easily reached by simply scaling up the number of hygroelectric generator units in series, enough to drive commercial electronic devices. This work provides insight for the design and development of hygroelectric generators that may promote the efficient conversion of potential energy in the environmental atmosphere to electricity for practical applications.
PDF
