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Transition metal dichalcogenides (TMDs) constitute a class of materials wherein transition metals coordinated by bridging chalcogenides form two-dimensional layers that stack via van der Waals (vdW) interactions along the crystallographic c axis. This lamellar structure enables a diverse range of species, including transition metals, to be intercalated into these vdW interfaces. With open-shell intercalants, local magnetic moments can be introduced into the lattice, thereby inducing long-range magnetic order. The versatility of potential intercalants and host lattices has long made this class of materials an appealing choice as tunable platforms for investigating the interplay among composition, structure, and magnetism. More recently, there has been a growing appreciation for the influence of defects and domain structures in these intercalated compounds on exchange interactions and magnetic correlations. This recognition has led to the acknowledgment of complex magnetic phase spaces, highlighting the intricate interplay between structural features and magnetic properties.We design a spin glass with strong spin frustration induced by magnetic disorder by exploiting the distinctive structure of Fe intercalated ZrSe2, where Fe(II) centers are shown to occupy both octahedral and tetrahedral interstitial sites and to distribute between ZrSe2 layers without long-range structural order. Notably, we observe behavior consistent with a magnetically frustrated and multidegenerate ground state in these FexZrSe2 single crystals, which persists above room temperature. Moreover, this magnetic frustration leads to a robust and tunable exchange bias up to 250 K. These results not only offer important insights into the effects of magnetic disorder and frustration in magnetic materials generally, but also highlight as design strategy the idea that a large exchange bias can arise from an inhomogeneous microscopic environment without discernible long-range magnetic order. In addition, these results show that intercalated TMDs like FexZrSe2 hold potential for spintronic technologies that can achieve room temperature applications.Since Fe intercalated ZrSe2 is semiconducting which provides us a knob to tune its physical and chemical properties electrochemically inserting a foreign species (Li+ ions) into their interlayer spacing. We discover substantial enhancement of light transmission and electrical conductivity in thin (∼30 nm) Fe intercalated ZrSe2 nanosheets after Li intercalation due to changes in band structure and the injection of large amounts of free carriers. We also capture the first in situ optical observations of Li intercalation FexZrSe2, shedding light on the dynamics of the intercalation process. The high reversibility of the intercalation process might be attributed to the enhanced stability of the structure induced by the intercalated Fe ion between the host lattice layers. The enhancement of electron transport upon the Li intercalation in the materials lays down a robust groundwork for electrostatic control over spin polarization. We also briefly explore the effect of semiconducting spin glass FexZrSe2 on generating and manipulating spin current in heavy metal, which highlights the potential application of the materials in spintronic technology.Together, we study the interplay among composition, structure, and magnetism of Fe intercalated ZrSe2, explore the impact of electrostatic and electrochemical strategies to manipulate the properties of FexZrSe2, lay down the robust cornerstone for the application of FexZrSe2 in spintronic technology, and inspire the research interest in expanding the knowledge of the magnetic ion intercalated TMDs to diverse 2D heterostructures and twist moiré patterns.

Organic room temperature phosphorescent (ORTP) materials provide an exciting research direction for phosphorescent oxygen (O2) sensors due to their high sensitivity and rapid response to O2. However, most pure ORTP materials are tightly-packed aromatic compound crystals in a face-to-face manner, which largely prohibits effective O2 diffusion for sensing. Thus, how to solve this contradiction still faces huge challenges. Here, the use of organic phosphorescent indicator carbon dots (CDs), inorganic matrix layered double hydroxides (LDHs) and polymers (PVA) successfully prepared an ultra-long RTP composite film whose phosphorescence decay intensity is linearly related to O2 concentration. More importantly, the use of the abundant O2 defects (Vo) on the surface of the inorganic matrix LDHs to adsorb O2, which further accelerates the phosphorescence quenching of the thin film and improves the O2 response. This strategy will provide the possibility to develop high-sensitivity phosphorescent O2 sensors from a new perspective.

SnO2 has been extensively used in the detection of various gases. As a gas sensing material, SnO2 has excellent physical-chemical properties, high reliability, and short adsorption-desorption time. The application of the traditional SnO2 gas sensor is limited due to its higher work-temperature, low gas response, and poor selectivity. Nanomaterials can significantly impact gas-sensitive properties due to the quantum size, surface, and small size effects of nanomaterials. By applying nanotechnology to the preparation of SnO2, the SnO2 nanomaterial-based sensors could show better performance, which greatly expands the application of SnO2 gas sensors. In this review, the preparation method of the SnO2 nanostructure, the types of gas detected, and the improvements of SnO2 gas-sensing performances via elemental modification are introduced as well as the future development of SnO2 is discussed.

Novel hybrid aerogels, which can be magnetically extracted from water to avoid filtration, were prepared by adding ZnCl2, NiCl2·6H2O, FeCl2·4H2O and FeCl3·6H2O into a suspension of graphene oxide and oxidzed carbon nanotubes followed by co-precipatation under basic condition, crosslinking with polyvinyl alcohol in water and freeze-drying. The hybrid aerogels consist of magnetic Ni0.5Zn0.5Fe2O4 nanoparticles, graphene oxide, carbon nanotubes and polyvinyl alcohol, which have active sites that attract dye molecules and can be extracted from water by applying magnetic field. Under an optimal mass ratio of the components, the optimized hybrid aerogel has a high adsorption capacity (qe=71.03 mg g−1 for methylene blue) and a moderate magnetic strength of MS = 3.519 emu g−1. Its removal efficiencies for methylene blue, methyl orange, crystal violet and their mixture with an equal mass are 70.1%, 4.2%, 8.9% and 11.1%, respectively under the same dye concentration of 0.025 mg. mL−1. It can be reused for 3 regeneration cycles with a regeneration efficiency of over 82%. Also it is not toxic to the living organism, suggesting that it is promising as an adsorbent for treating industrial wastewater.

Fluorescence imaging in the second infrared windows (1000–1700 nm) has emerged as a promising approach to tumor diagnostic. However, the currently available NIR-II imaging agents are based on “alwa...

Potassium-ion batteries (PIBs) are currently recognized as an emerging battery technology because of the rich resources and low cost of potassium. Nevertheless, investigations on exploiting suitable anode materials to meet stable potassium-ions storage remain to be a problem owing to the big radius size of potassium-ions. Herein, we designed N-doped carbon restricted CoP polyhedra embedded into reduced graphene oxide (rGO) sheet (CoP/NC@rGO) through coupling the function of ZIF-67 and rGO. For this composite, nano-scale CoP particles can be encapsulated by ZIF-67 derived carbon matrix, which significantly alleviates the volume change and promotes K+/e− transfer. Additionally, the combination of CoP/NC polyhedra and rGO nanosheets can build a fascinating 3D architecture to further improve the electronic conductivity of materials, as well as effectively preventing the aggregation of CoP/NC polyhedra. As a result, such composites can exhibit remarkable long-cycle performance, maintaining remarkable capacities of 177 mAh g−1 after 2800 cycles at 1 A g−1. This work provides a hopeful strategy that the combination of MOF-derived porous structures with rGO can effectively promote K+/e− transfer and improve the stability of electrode materials.

A low-profile and dual-polarization frequency-selective rasorber (FSR) with an ultra-wide absorption band is proposed. Based on the Mie resonance theory, water blocks with appropriate height are arranged as the lossy layer. The lossless layer is composed of a bandpass frequency-selective surface (FSS) with Jerusalem-cross gaps. Utilizing the high loss of water, this rasorber can obtain an ultra-wideband (UWB) absorption with a power absorptivity over 90% from 4.63 GHz to 100 GHz, and the fractional bandwidth (FBW) regarding the absorption band is over 182%. The insertion loss (IL) is 0.55 dB at 3 GHz under normal incidence and the thickness λ m (λ m being the free-space wavelength at the middle transmission frequency) is 0.077 λ m. The FSR also shows favorable stability of the frequency response over a relatively broad range of oblique incidence angles of 30° for dual-polarization. Compared with formal water-based FSR, this paper places emphasis on the novelty of elimination of the transition band and extended length of absorption band. Ultimately, a low-cost prototype of the presented design is fabricated, simulated and measured to verify the feasibility.

Lithium–sulfur (Li–S) battery is labeled as a promising high-energy-density battery system, but some inherent drawbacks of sulfur cathode materials using relatively complicated techniques impair the practical applications. Herein, an integrated approach is proposed to fabricate the high-performance rGO/VS4/S cathode composites through a simple one-step solvothermal method, where nano sulfur and VS4 particles are uniformly distributed on the conductive rGO matrix. rGO and sulfiphilic VS4 provide electron transfer skeleton and physical/chemical anchor for soluble lithium polysulfides (LiPS). Meanwhile, VS4 could also act as an electrochemical mediator to efficiently enhance the utilization and reversible conversion of LiPS. Correspondingly, the rGO/VS4/S composites maintain a high reversible capacity of 969 mAh/g at 0.2 C after 100 cycles, with a capacity retention rate of 82.3%. The capacity fade rate could lower to 0.0374% per cycle at 1 C. Moreover, capacity still sustains 795 mAh g–1 after 100 cycles in the relatively high-sulfur-loading battery (6.5 mg/cm2). Thus, the suggested method in configuring the sulfur-based composites is demonstrated a simple and efficient strategy to construct the high-performance Li–S batteries.

Air contamination caused by the ammonia slip phenomenon has gradually captured the researcher's extensive attention. An effective strategy for controlling fugitive NH3 is critical to improving the air quality and living environment. In the present work, CuOx/La2Ce2O7 composite as a potential candidate catalyst is synthesized through the electrostatic adsorption method for the selective catalytic oxidation (SCO) of NH3 to N2. The 5% CuOx/La2Ce2O7 exhibits the best catalytic activity (T90 =243 ℃) and ammonia conversion efficiency. The improvement of performance is mainly attributed to the superficial connection of [Ce-O-Cu], which enhances the capturing ability of ammonia molecule and accelerates the dissociating efficiency of N-H bonding for N2 evolution, simultaneously. This work provides a facile method to synthesis pyrochlore composite catalyst of NH3-SCO for solving the problem of ammonia slip pollution in the future.

Due to seasonal climate alterations, the microstructure and permeability of granite residual soil are easily affected by multiple dry-wet cycles. The X-ray micro computed tomography (micro-CT) acted as a non-destructive tool for characterizing the microstructure of soil samples exposed to a range of damage levels induced by dry-wet cycles. Subsequently, the variations of pore distribution and permeability due to dry-wet cycling effects were revealed based on three-dimensional (3D) pore distribution analysis and seepage simulations. According to the results, granite residual soils could be separated into four different components, namely, pores, clay, quartz, and hematite, from micro-CT images. The reconstructed 3D pore models dynamically demonstrated the expanding and connecting patterns of pore structures during dry-wet cycles. The values of porosity and connectivity are positively correlated with the number of dry-wet cycles, which were expressed by exponential and linear functions, respectively. The pore volume probability distribution curves of granite residual soil coincide with the χ2 distribution curve, which verifies the effectiveness of the assumption of χ2 distribution probability. The pore volume distribution curves suggest that the pores in soils were divided into four types based on their volumes, i.e. micropores, mesopores, macropores, and cracks. From a quantitative and visual perspective, considerable small pores are gradually transformed into cracks with a large volume and a high connectivity. Under the action of dry-wet cycles, the number of seepage flow streamlines which contribute to water permeation in seepage simulation increases distinctly, as well as the permeability and hydraulic conductivity. The calculated hydraulic conductivity is comparable with measured ones with an acceptable error margin in general, verifying the accuracy of seepage simulations based on micro-CT results.

Palm biodiesel-ethanol blends could be the better automotive fuel over palm biodiesel alone owing to the high oxygen content and high volatility of ethanol. The evaporation and burning characteristics of palm biodiesel with 10%, 20%, and 30% ethanol by volume concentration respectively, were investigated by using the droplet experiment. Rapid bubble growth and bubble explosions during the heating stage were observed to be substantial for the palm biodiesel droplet added with 30% volume of ethanol (BE30). Adding ethanol in palm biodiesel increased the ignition delay and burn-rate constant by up to 38.6% and 23.2%, respectively whereas, the evaporation duration and burning period decreased by up to 20.6% and 22.5%, respectively. Overall, the relatively shorter evaporation duration and higher burn-rate found for the BE30 droplet could promote high thermal efficiency and has the potential to achieve ultra-low carbon monoxide (CO) and unburned hydrocarbons (UHCs) emissions in diesel and gas turbine engines.

A multifunctional frequency-selective surface reflector (FSSR) is found to be an applicable candidate for the realization of an antenna's radar cross-section reduction in or out of its operating frequency. In this letter, a polarization-selectable in-band switchable FSSR/absorber based on diodes is designed and experimentally demonstrated, which comprises a layer of active frequency-selective surface and a layer of metal-backed frequency-dispersive magnetic material (FDMM). The design realizes the switching functions of broadband absorption band from 3.5 to 12.0 GHz (110% bandwidth) with at least −10 dB reflectivity and a reflection band at 6.2 GHz with two-sided absorption bands (2.2–4.8 GHz, 74.3% bandwidth for the lower absorption band and 7.1–12.9 GHz, 58% bandwidth for the upper absorption band) by manipulating the on and off states of PIN diodes. Besides, due to the use of FDMM, the thickness of the FSSR is only 0.074 λL , making it easy to design the reflective surface of the antenna. A prototype of the proposed FSSR/absorber is fabricated and measured, where reasonable agreement is observed.

Selective photocatalysis is a very promising direction to improve the activities of photocatalysts. Combining the technique of molecular imprinting (MIP) with heterogeneous photocatalysis can be an appealing approach to achieve our aim. Herein, using the MIP technique, the monoclinic MIP-BiVO4 was successfully synthesized by the presence of rhodamine B (RhB) during the hydrothermal synthesis. The synthesized MIP-BiVO4 possessed better adsorptive and photocatalytic activities than pristine BiVO4. RhB added in the synthesis process worked as a template and served a crucial role in the formation of the MIP-BiVO4 morphology. The photoelectrochemical analysis verified the superiority of MIP-BiVO4 sample in the transfer and separation of the electron–hole pairs. Holes played the most crucial role in the degradation of the pollutants. The effective approach combining MIP technique in the synthesis of photocatalysts would provide some guidance to selective photocatalysis field for designing and synthesizing highly efficient photocatalysts.

ABSTACT In-plane anisotropy (IPA) due to asymmetry in lattice structures provides an additional parameter for the precise tuning of characteristic polarization-dependent properties in two-dimensional (2D) materials, but the narrow range within which such method can modulate properties hinders significant development of related devices. Herein we present a novel periodic phase engineering strategy that can remarkably enhance the intrinsic IPA obtainable from minor variations in asymmetric structures. By introducing alternant monoclinic and rutile phases in 2D VO2 single crystals through the regulation of interfacial thermal strain, the IPA in electrical conductivity can be reversibly modulated in a range spanning two orders of magnitude, reaching an unprecedented IPA of 113. Such an intriguing local phase engineering in 2D materials can be well depicted and predicted by a theoretical model consisting of phase transformation, thermal expansion, and friction force at the interface, creating a framework applicable to other 2D materials. Ultimately, the considerable adjustability and reversibility of the presented strategy provide opportunities for future polarization-dependent photoelectric and optoelectronic devices.

Inspired by the relatively recognized performance of transition metal sulfides in the oxidation of hydrazine, the catalytic properties of FeS2 and Fe3S4 are compared via the density functional theory calculations. Due to the different coordination numbers of iron-sulfur, the free energies of the dehydrogenation steps on FeS2 are far less than those on Fe3S4, which led to the much better catalytic performance of FeS2. Accordingly, FeS2 microspheres are rationally proposed as a more efficient electrocatalyst for hydrazine oxidation, which is then prepared by a facile one-step hydrothermal strategy. Such FeS2 microspheres show great activity for hydrazine oxidation with an onset oxidation potential of 0.22 V vs. reversible hydrogen electrode, and a peak current density of 16 mA cm−2. Meanwhile, stability and high faradaic efficiency (3.5e−/N2H4) is obtained for hydrazine oxidation to N2.

Droplet-based microfluidics enables the generation of uniform microdroplets at picoliter or nanoliter scale with high frequency (∼kHz) under precise control. The droplets can function as bioreactors for versatile chemical/biological study and analysis. Taking advantage of the discrete compartment with a confined volume, (1) isolation and manipulation of a single cell, (2) improvement of in-droplet effective concentrations, (3) elimination of heterogeneous population effects, (4) diminution of contamination risks can be achieved, making it a powerful tool for rapid, sensitive, and high-throughput detection and analysis of bacteria, even for rare or unculturable strains in conventional methods. This mini-review will focus on the generation and manipulation of micro-droplets and bacteria detection and analysis carried out by droplet-based microfluidics. Finally, applications with high potential of droplet-based bacteria analysis are briefly introduced. Due to the advantages of rapid, sensitive, high throughput, and compatibility with rare and unculturable bacteria in conventional methods, droplet-based microfluidics has tremendous potential of providing novel solutions for biological medicine, microbiological engineering, environmental ecology, etc.

Polyurea coating and carbon fibre reinforced polymer reinforcing techniques were applied to retrofit a severely damaged urban utility tunnel (UUT). The blast responses of the retrofitted UUT were investigated through in-filed explosion experimental tests, and the displacements, strains, accelerations, and damage were compared. The retrofitted UUT exhibited comparable or even better blast resistance than the intact UUT. Although the polyurea coating was flexible, it exhibited excellent performance in improving the blast resistance of the damaged UUT. As the UUT reinforced with basalt fibre reinforce polymer (BFRP) bars has smaller damage compared with the UUT reinforced with steel bars, its retrofitting is simple, and the cost is low. The roof was simplified as an elastically simple support one-way slab. Euler beam theory was adopted to analyse the dynamic responses of UUT roof considering the interaction between soil and structure, which agree well with the experiments in the first three cases.

High oxygen concentration oxy-fuel circulating fluidized bed (CFB) combustion technology is a high efficiency and low cost oxy-fuel combustion technology, which also has high potential of optimization and efficiency improvement. In this research, energy efficiency is analysed to acquire the effects of flue gas recirculation mode, preheating temperature and oxygen purity on the net efficiency and energy consumption of the 50% oxy-fuel combustion system, so as to obtain the further optimization strategy. The following results are obtained by simulation. The optimal extraction position of recycled flue gas (RFG) is gas preheater outlet, and the net power generation efficiency increases by 0.23% to 25.08%. As the preheating temperature increases from 230 to 400 °C, the net efficiency increases by 1.19% to 26.04%. The net efficiency increases first then decreases as the oxygen purity at ASU outlet increase from 89% to 97.4%, and the optimal value is the 94%. Finally, the optimal system is obtained when RFG is extracted from gas preheater outlet, the preheating temperature is 400 °C and the oxygen purity at ASU outlet is 94%. The net efficiency of the optimization system reaches 27.4%, increasing by 2.55%.

Self-lubricating composites are required to have excellent tribological performances and good mechanical properties when they are applied as mechanic parts. However, the brittle nature of most lubricants will weaken the mechanical properties of the composites where in order to get the lubricating ability proper amount of lubricants are usually incorporated, bringing challenges for them to get well-balanced mechanical and tribological properties. In this study, NiCr matrix self-lubricating composites with the addition of WS2 and nano-Ti were prepared via spark plasma sintering. The hard phase of Ni3Ti and the lubricant TiS were formed via in-situ reaction at the interface, which surrounded the soft alloy matrix and developed a heterostructure. Compared with the conventional NiCr-WS2 composite, the heterostructured composite exhibited a high yield strength of 1645 MPa, a low friction coefficient of 0.37 and a wear rate of as low as 2.25 × 10−5 mm3 N − 1 m − 1 when sliding. Finite element analysis demonstrated that the heterostructure plays a key role to balance well the mechanical and tribological properties of the NiCr matrix composites.

The synthesis of high-value multi-carbon products through the electrochemical reduction of carbon monoxide (COER) is one of the promising avenues for carbon utilization and energy storage, in which searching for efficient electrocatalysts that exhibit moderate CO intermediate binding strength and low kinetic barrier for C-C coupling is a key issue. Herein, by means of comprehensive density functional theory (DFT) computations, we theoretically designed three synergistic coupling catalysts by co-doping transition metal (TM = Fe, Co and Ni) and boron (B) into the two-dimensional black phosphorene (BP), namely TM-B@BP for COER to C2 products. DFT computations and ab initio molecular dynamics simulations reveal the good stability and high feasibility of these proposed TM-B@BP catalysts for practical applications and future experimental synthesis. More interestingly, high-value ethylene (C2H4), ethane (C2H6) and ethanol (C2H5OH) products can be obtained on these three designed electrocatalysts with ultra-small limiting potentials (-0.20∼-0.41 V) and low kinetic energy barriers of C-C coupling (0.52∼0.91 eV). Meanwhile, the competitive one-carbon (C1) products and hydrogen evolution reaction can also be effectively suppressed. The promising activity and selectivity of these three designed electrocatalysts render them ideal candidates for CO electroreduction, thus providing a cost-effective opportunity to achieve a sustainable production of high value C2 chemicals and fuels.

Pillararenes are a new type of supramolecular hosts, and they have been widely applied in drug delivery, catalysis, separation process, and sensors. However, they have rarely been used to produce hydrogen. Here, we report that pillararenes were used as functional molecules to explore photocatalysts and efficiently promoted hydrogen production from water. The most common and easily synthesized p-dimethoxy pillar[5]arene (PI-OMe) was employed to form an organic-inorganic hybrid material with titanium dioxide (TiO2), denoted as PI-OMe-TiO2, using a convenient sol-gel method. When the material was loaded with Pt nanoparticles, the resulting Pt/PI-OMe-TiO2 had a good activity and stability in catalyzing water splitting to produce hydrogen under visible light. The optimized catalyst Pt/PI-OMe-TiO2(5.2 wt%) had a photocatalytic hydrogen production rate of 1736 μmol g−1 h−1 under visible light (λ > 420 nm) irradiation. The catalyst with a Pt loading of 0.5 wt% and a PI-OMe content of 5.2 wt% also showed good long-term durability after 10 cycles of 50 h testing. The total amount of hydrogen produced was 65.01 mmol/g, and the corresponding turnover number (TON) value was 2084. Our findings suggest that pillararene derivatives are promising functional molecules to make efficient and stable hybrid photocatalysts with TiO2 and open a new door to hydrogen production using visible light.

In recent years, graphitic carbon nitride (g-C3N4) has been developed greatly in the domain of water treatment. We adopted one-step calcination to enhance the light absorption of g-C3N4 with melamine-sponge (MS). A novel form of photocatalysts (gCNMx, x = 0.1, 0.2 and 0.3) were successfully prepared. The color of gCNMx changed with addition of MS. Experimental analysis demonstrated that C-doping and N vacancies increased the capacity of light absorption of gCNM0.2, and further increased efficiency of photothermal conversion and photogenerated holes. The sterilization efficiency of gCNM0.2 could rival a variety of metal photocatalysts. Moreover, the preparation of gCNM0.2 was cost-effective and environmental-friendly. Interestingly, the inactivation efficacy of gCNM0.2 for S. aureus depended heavily on the photogenerated holes, however, the decisive force toward S. typhimurium was photothermal conversion.

Anode-free batteries (AFBs) have the potential of ultra-high energy density, but lithium dendrite has largely hindered their practical applications. In this work, an in-situ grown gradient solid electrolyte interface (SEI) layer on pre-designed micro-hole-grid (MHG) Cu reservoir is proposed to guide uniform lithium deposition and propagation, by which the electrode interface is stabilized and the surface stress is considerably decreased endowing the AFBs with outstanding areal capacity and cycling performance. The gradient SEI is confirmed by cryogenic-transmission electron microscopy (Cryo-TEM) and XPS to be composed of (1) an elastic organic top layer to hinder non-Li species migration and withstand volume fluctuation, and (2) a lithophilic LiCl-rich bottom layer to render the rapid lithium supply. Operando electron paramagnetic resonance (EPR) shows a dynamic Li deposition, unambiguously demonstrating a dendrites-free behavior. As a result, the full cells of a gradient SEI modified Cu reservoir paired with a LiFePO4 cathode exhibit high capacity of 95 mAh g–1 and Coulombic efficiency (CE) of 99.5% after 100 cycles, much better than the control cells with planar current collectors (1.6 mAh g–1, 2.6%). These findings are enlightening in engineering better interphases for high energy and safe rechargeable lithium metal batteries.

Free-standing and flexible air electrodes with long-lasting bifunctional activities for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are crucial to the development of wearable Zn-air rechargeable batteries. In this work, we synthesize a flexible air electrode consisting of 3D nanoporous N-doped graphene with trimodal shells and Ni particles through repeated chemical vapor deposition (CVD) and acidic etching processes. Our results indicate that such trimodal graphene morphology significantly enhances the active N-dopant sites and graphene-coated Ni surface, which consequentially boosts both the ORR and OER activities, as well as catalytic durability. First-principles density functional theory (DFT) calculations reveal the synergetic effects between the Ni and the N-doped graphene; namely, the Ni nanoparticles boost the bifunctional activities of the coated N-doped graphene, and in turn the graphene-covering layers enhance the stability of Ni. Thanks to the better protection from the triple graphene shells, our trimodal N-doped graphene/Ni-based Zn-air battery can be stably discharged/recharged beyond 2500 h with low overpotentials. It is reasonable to expect that such free-standing trimodal graphene/Ni would be promising in many flexible energy conversion/storage devices.

Precursor derived ceramic with controllable carbon content has the advantages of high temperature and adjustable dielectric properties, which has significant potential for the research the high temperature microwave absorbing materials. In this contribution, a series of single-source SiBNCx precursors are obtained using NH3, n-butylamine, and dichlorodiphenylsilane with n-butylamine as the carbon source ammonolysis trichlorosilylamino-dichloroborane (TADB) monomer and polymerization. Adjusting the carbon content of precursors directly leads to phase composition and performance differences of SiBNCx ceramics. For SiBNCx ceramics with no carbon or low-carbon content, it had almost no effect on electromagnetic waves. The transmission rate ranged from 98% to 78% in 2–18 GHz. When SiBNCx ceramics with carbon-rich structure, the tanδ of pyrolytic ceramics increased significantly, which has an obvious loss on electromagnetic wave. The minimum reflection coefficient (RCmin) values reached −64.75 dB, and the effective absorption bandwidth (EAB) was 3.8 GHz in the X band at room temperature. Importantly, EAB of the SiBNCx ceramics still cover more than 50% of the X band, RCmin can be as low as −24.9 dB at 600 °C. The strategy offers a new method to accurately control high temperature electromagnetic performance from molecular structure.

Multi-functional host materials possess high conductivity and strong chemical adsorption ability that could directionally catalyze electrochemical conversion of lithium polysulfides, therefore, their rational design is considered to be an effective strategy to solve the notorious “shuttle effect” for Li-S batteries. Herein, ultrafine zirconium boride (ZrB2) nanoparticles of high conductivity is conveniently fabiricated via a solid-state synthesis at relatively low temperature and applied as sulfur host material. The obtained ZrB2/Nitrogen-doped graphene/S (defined as “ZrB2/NG/S”) cathode stably works for 135 cycles at ultrahigh rate of 20 C with capacity of ∼400 mAh g−1. It is worth to note that a long-term cycling performance has been achieved with low decay rate of 0.02 % per cycle within 4000 cycles at 5 C. Moreover, the designed cathode delivers an areal capacity of 6.43 mAh cm−2 upon a high sulfur loading (7.77 mg cm−2) with a lean electrolyte at 1C. Investigations including kinetics analysis, deposition/dissolution of Li2S, in-situ XRD, and density functional theory have been further conducted, and the successfully assembled pouch cell shows a high capacity. The high conductivity, strong chemical adsorption, and bi-functional catalytic ability of ZrB2 based composite endow its high potential for practical application.

Filtration control is important to ensure safe and high efficient drilling. The aim of the current research is to explore the feasibility of using basil seed powders (BSPs) to reduce filtration loss in water-based drilling fluid. The effect of BSP concentration, thermal aging temperature, inorganic salts (NaCl and CaCl2) on the filtration properties of bentonite/basil suspensions was investigated. The filtration control mechanism of BSP was probed via water absorbency test, zeta potential measurement, particle size distribution measurement, and filter cake morphologies observation by scanning electron microscope. The incorporation of BSPs into the bentonite suspension generated acceptable rheology below 1.0 w/v%. The BSPs exhibited effective filtration control after thermal aging at 120 °C, but less efficiency at 150 °C. After thermal aging at 120 °C, the bentonite suspension containing 1.0 w/v% BSPs could resist NaCl and CaCl2 pollution of 5.0 w/v% and 0.3 w/v% respectively. Besides general filtration control behaviors, the exceptional water retaining capability formed by numerous nanoscale 3D networks in the basil seed gum and considerable insoluble small particles in BSPs might further contribute to the filtration control. The excellent filtration properties bring basil seed a suitable and green candidate for the establishment of high-performance drilling fluids.

To repair the damaged SiC coated C/C composites, a double-layer system including a Sm-doped borosilicate glass external layer and a Si SiC inner layer was prepared by a slurry-based laser cladding technique. Isothermal oxidation experiment and indirect/direct thermal-radiation measurements were performed. The results showed that the absorbance of borosilicate glass to the laser at 900–1200 nm was improved significantly by Sm-doping. Consequently, the repaired coating with a more compact structure and better oxidation resistance was obtained. After oxidation at 1773 K for 10 h, the mass loss of the damaged sample could be reduced by 74.98% with repairing. By increasing laser-absorption and reducing viscosity, the thermal-radiation property of the repaired coating was enhanced to decrease the surface temperature greatly. A repair system with excellent thermal protection performance was achieved.

Background: Great attention has been paid to the environmental pollution by organic dyes, which are difficult to be degraded in the natural environment and have been an unavoidable and urgent global problem. It is essential to develop green wastewater treatment technology with high removal efficiency and low-cost for protecting the surrounding and human health. Objective: The aim of the research is to synthesize lithium bismuthate/bismuth oxide microspheres with good photocatalytic performance for the removal of gentian violet (GV). Methods: Lithium bismuthate/bismuth oxide microspheres were successfully prepared by a sodium ligninsulfonate-assisted hydrothermal synthesis route. The lithium bismuthate/bismuth oxide microspheres were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR), and solid UV-vis diffuse reflectance spectrum. Results: XRD pattern and SEM observation show that the lithium bismuthate/bismuth oxide microspheres are composed of cubic LiBi12O18.50 and monoclinic Bi2O3 with a diameter of 250 nm-1 μm. Irregular microscale and nanoscale particles are formed under low hydrothermal temperature, low sodium ligninsulfonate concentration, and short duration time. By increasing the sodium ligninsulfonate concentration, hydrothermal temperature, and duration time, irregular particles are transferred into microspheres. Lithium bismuthate/bismuth oxide microspheres possess a band gap energy of 1.85 eV, suggesting good visible light absorption ability. The photocatalytic removal ability for GV is enhanced by prolonging light irradiation time and microspheres dosage. GV solution with the concentration of 10 mg•L-1 is able to be totally degraded by 10 mg lithium bismuthate/bismuth oxide microspheres in 10 mL GV solution under solar light irradiation for 6 h. Conclusion: The lithium bismuthate/bismuth oxide microspheres show good photocatalytic removal ability toward GV in wastewater under solar light irradiation.

Nanocrystalline metals often display a high strength up to the gigapascal level, yet they suffer from poor plasticity. Previous studies have shown that the development of hetero-sized grains can efficiently overcome the strength-ductility trade-off of nanocrystalline metals. However, whether this strategy can lead to the fabrication of nanocrystalline nanowires exhibiting both high strength and superplasticity is unclear, similar to the atomistic deformation mechanism. In this paper, we show that ultra-small nanocrystalline Au nanowires comprising grains in both the Hall–Petch and inverse Hall–Petch grain-size regions can exhibit extremely high uniform elongation (236%) and high strength (2.34 gigapascals) at room temperature. In situ atomic-scale observations revealed that the plastic deformation underwent two stages. In the first stage, the super-elongation ability originated from the intergrain plasticity of small grains via mechanisms such as grain boundary migration and grain rotation. This intergrain plasticity caused the grains in the heterogeneous-structured nanowires to grow very large. In the second stage, the super-elongation ability originated from intragrain plasticity accompanied by the diffusion of surface atoms. Our results show that the hetero-grain-sized nanocrystalline nanowires, comprising grains with sizes both in the strongest Hall–Petch effect region and the inverse Hall–Petch effect region, were simultaneously ultra-strong and ductile. They displayed neither a strength-ductility trade-off nor plastic instability.

Nano-zirconia has been widely applied due to its excellent physical and chemical properties (e.g., high strength, corrosion resistance, oxygen ion conductivity). Existing preparation methods of nano-zirconia tend to require long reaction time, and the sizes of final particles are large with uneven distributions. Sub-/supercritical hydrothermal synthesis of nanoparticles is favored by researchers owing to controllable reaction process, uniform particle size distribution, good reproducibility, short reaction time, high conversion rate and harmlessness to environment. In this paper, the characteristics and mechanisms of dissolution, crystallization and growth of nano-zirconia during sub-/supercritical hydrothermal synthesis are systematically reviewed. The influences of process and material parameters on the size and purity of particles are analyzed. Then, the reaction mechanism and product phase transition mechanism during hydrothermal synthesis of zirconia are summarized to provide a theoretical reference for the oriented preparation. Finally, the improvement and commercialization of sub-/supercritical hydrothermal synthesis technology are evaluated, and the future research topics are proposed.

To boost the visible light catalytic performance of typical metal-organic frameworks (MOFs) materials (MIL-68(In)-NH2), a novel stable Z-scheme Ag/Ag3PO4/MIL-68(In)-NH2 plasmonic photocatalyst was constructed by electrostatic attraction, co-precipitation reaction, and in-situ photoreduction reaction methods for the first time. The photocatalytic activities of the photocatalysts are systematically explored by the photocatalytic degradation of bisphenol A (BPA) and reduction of Cr(VI) under visible light. Ag/Ag3PO4/MIL-68(In)-NH2 displays the best photocatalytic performance among the as-prepared photocatalysts. The rate constant of BPA degradation on Ag/Ag3PO4/MIL-68(In)-NH2 is 0.09655 min−1, which is better than many reported photocatalytic materials. It also achieved a maximum rate constant of 0.02074 min−1 for Cr(VI) reduction. The boosted photocatalytic performance is due to the improved absorption caused by localized surface plasmon resonance (LSPR), effective interface charge transfer and separation, and more reactive sites provided by the large specific surface area. Besides, the photocatalytic degradation pathway of BPA is concluded according to GC-MS analysis. Finally, a more reasonable Z-scheme mechanism is speculated and verified through a series of characterizations and simulations, such as time-resolved photoluminescence spectroscopy (TRPL), electron spin resonance (ESR), and finite difference time domain (FDTD) method.

It is a major challenge to combine the advantages of two kinds of two-dimensional materials to construct a heterojunction and achieve efficient photocatalytic antifouling. In this work, we covalently connected two materials MXenes and covalent organic frameworks (COFs) through the Schiff base reaction and anchored Ag nanoparticles (NPs) to prepare a Ti3C2/TpPa-1/Ag composite material with high efficiency bactericidal properties. The covalent bonding between MXene and COF greatly improved the stability of the material. Ti3C2/TpPa-1/Ag composite showed an excellent antibacterial property against S. aureus and P. aeruginosa. The fluorescence spectra of Ti3C2/TpPa-1/Ag proved that the electron transfer channels formed between the ternary materials could greatly improve the efficiency of carrier separation and prolong the life of photogenerated carriers. Density functional theory calculations showed that the synergistic catalytic effect of Ag and Ti3C2 could greatly reduce the work function along the interface, and the built-in electric field between the layers drive carrier fast migration, which effectively improve the catalytic performance.

Hierarchical multi-metal oxide-based gas sensors with high surface area and abundant active sites have attracted intensely research interests for their highly sensitive and fast gas detection performance. Developing synthetic strategies for obtaining novel hierarchical metal oxides with high sensing performance remains eminently challenging. Herein, hierarchial hollow GaFeO3 microcubes were successfully prepared via a Ga3+-modified Fe-based Prussian Blue (PB) mediated template conversion strategy. The microsized morphologies and hollow interior structures of GaFeO3 microcubes can be feasibly modulated by controlling the thermolysis temperatures. The ultrasmall nanoparticle-assembly of GaFeO3 architecture obtained at 500 °C exhibited an optimum response value (Ra/Rg) of 7.4, and rapid response/recovery times (9 s/49 s) toward 200 ppm triethylamine (TEA) at a working temperature of 200 °C, as well as remarkable selectivity and excellent long-term stability (for at least 31 days), which are intrinsically beneficial from the unique interior loose structure with good permeability for diffusion of target gases. This work provides a promising approach for synthesizing various hierarchical multimetal oxides with intriguing nanoparticle-assembled hollow structure and broad prospects for practical gas sensing applications.