The Chinese pine genome and methylome unveil key features of conifer evolution.

Conifers dominate the world's forest ecosystems and are the most widely planted tree species. Their giant and complex genomes present great challenges for assembling a complete reference genome for evolutionary and genomic studies. We present a 25.4-Gb chromosome-level assembly of Chinese pine (Pinus tabuliformis) and revealed that its genome size is mostly attributable to huge intergenic regions and long introns with high transposable element (TE) content. Large genes with long introns exhibited higher expressions levels. Despite a lack of recent whole-genome duplication, 91.2% of genes were duplicated through dispersed duplication, and expanded gene families are mainly related to stress responses, which may underpin conifers' adaptation, particularly in cold and/or arid conditions. The reproductive regulation network is distinct compared with angiosperms. Slow removal of TEs with high-level methylation may have contributed to genomic expansion. This study provides insights into conifer evolution and resources for advancing research on conifer adaptation and development.

Modification Strategies of Hexagonal Boron Nitride Nanomaterials for Photocatalysis.

Although hexagonal boron nitride (h-BN) was initially considered a less promising photocatalyst due to its large band gap and apparent chemical inertness, its unique two-dimensional lamellar structure coupled with high stability and environmental friendliness, as the second largest van der Waals material after graphene, provides a unique platform for photocatalytic innovation. This review not only highlights the intrinsic qualities of h-BN with photocatalytic potentials, such as high stability, environmental compatibility, and tunable bandgap through various modification strategies but also provides a comprehensive overview of the recent advances in h-BN-based nanomaterials for environmental and energy applications, as well as an in-depth description of the modification methods and fundamental properties for these applications. In addition, we discuss the challenges and prospects of h-BN-based nanomaterials for future photocatalysis.

An all-in-one FeOx-rGO sponge fabricated by solid-phase microwave thermal shock for water evaporation and purification.

Developing high-efficiency photothermal seawater desalination devices is of significant importance in addressing the shortage of freshwater. Despite much effort made into photothermal materials, there is an urgent need to design a rapidly synthesized photothermal evaporator for the comprehensive purification of complex seawater. Therefore, we report on all-in-one FeOx-rGO photothermal sponges synthesized via solid-phase microwave thermal shock. The narrow band gap of the semiconductor material Fe3O4 greatly reduces the recombination of electron-hole pairs, enhancing non-radiative relaxation light absorption. The abundant π orbitals in rGO promote electron excitation and thermal vibration between the lattices. Control of the surface hydrophilicity and hydrophobicity promotes salt resistance while simultaneously achieving the purification of various complex polluted waters. The optimized GFM-3 sponge exhibitedan enhanced photothermal conversion rate of 97.3% and a water evaporation rate of 2.04 kg/(m2·hr), showing promising synergistic water purification properties. These findings provide a highly efficient photothermal sponge for practical applicationsof seawater desalination and purification,as well as develop a super-rapid processing methodology for evaporation devices.

Scalable Production of Thin and Durable Practical Li Metal Anode for High-Energy-Density Batteries.

Utilization of thin Li metal is the ultimate pathway to achieving practical high-energy-density Li metal batteries (LMBs), but its practical implementation has been significantly impeded by formidable challenges of poor thinning processability, severe interphase instability and notorious dendritic Li growth. Here we report a practical thin (10-40 µm) Li/Mo/Li2Se with concurrently modulated interphase and mechanical properties, achieved via a scalable mechanical rolling process. The in situ generated Li2Se and Mo not only enhance the mechanical strength enabling the scalable fabrication of thin Li metal, but also promote homogeneous Li electrodeposition. Significantly, the Li/Mo/Li2Se demonstrates ultrahigh-rate performance (15 mA cm-2) and ultralong-lifespan cycling sustainability (2700 cycles) with exceptional anti-pulverization capability. The Li|LiFePO4 cells show substantially prolonged cyclability over 1200 cycles with an ultralow decay rate of ~0.01 % per cycle. Moreover, the Li|LiNi0.8Co0.1Mn0.1O2 pouch cells deliver enhanced cycling stability even under the extremely harsh conditions of low negative-to-positive-capacity (N/P) ratio of ~1.2 and lean electrolyte of ~0.95 g Ah-1, showing an exceptional energy density of 329.2 Wh kg-1. This work sheds light on facile pathway for scalable production of durable thin Li metal anode toward reliable practicability.

Surface, Interface and Structure Optimization of Metal-Organic Frameworks: Towards Efficient Resourceful Conversion of Industrial Waste Gases.

Industrial waste gas emissions from fossil fuel over-exploitation have aroused great attention in modern society. Recently, metal-organic frameworks (MOFs) have been developed in the capture and catalytic conversion of industrial exhaust gases such as SO2 , H2 S, NOx , CO2 , CO, etc. Based on these resourceful conversion applications, in this review, we summarize the crucial role of the surface, interface, and structure optimization of MOFs for performance enhancement. The main points include (1) adsorption enhancement of target molecules by surface functional modification, (2) promotion of catalytic reaction kinetics through enhanced coupling in interfaces, and (3) adaptive matching of guest molecules by structural and pore size modulation. We expect that this review will provide valuable references and illumination for the design and development of MOF and related materials with excellent exhaust gas treatment performance.

Highly Stable and Ultrahigh-Rate Li Metal Anode Enabled by Fluorinated Carbon Fibers.

The advanced energy storage of an Li metal substituted for graphite anode can provide a significant enhancement in a battery's energy density. Nevertheless, the practical implementation of metallic Li has seriously been fettered by the notorious Li dendrite growth and the huge volumetric variation of Li metal inducing poor cycling performance and safety concerns. In this regard, constructing a robust SEI layer combined with a 3D host to stabilize the Li metal is strongly in demand. Herein, a highly stable hosted Li with an LiF dominated SEI has successfully been achieved through metal-free fluorinated carbon fibers (FCF) with strong lithiophilicity. The metal-free design is cost-effective and can retain the energy density of the Li metal, minimizing the unnecessary energy sacrifice from the extra high gravimetric density lithiophilic sites. The FCF hosted Li delivers a promoted high Coulombic efficiency, homogeneous Li deposition, and ultrahigh rate stable cycling over 1000 cycles at 20 mA cm-2 with a much lower voltage polarization (≈220 mV). Moreover, half cells coupled with LiNi0.8 Co0.1 Mn0.1 O2 , sulfur or even thick LiCoO2 cathode demonstrate superior rate performances and enhanced cycling stability even under a lean electrolyte. This work proves the feasibility of FCF hosted Li for practical usage and provides a novel approach toward cost-effective and high performance lithium metal batteries.

Flexible fiber-shaped supercapacitors based on graphene/polyaniline hybrid fibers with high energy density and capacitance.

Fiber-shaped supercapacitors (FSCs) are promising energy storage devices for portable and wearable electronics due to their miniaturized size, flexibility, and knittability. Despite the significant progress in this area, it is still a challenge to develop large capacitance and high energy density FSCs for practical applications. In this work, a hybrid fiber composed of reduced graphene oxide and polyaniline nanoparticles (r-PANI-GOF) is synthesized viain situsynthesis of polyaniline nanoparticles both on the surface and inside of graphene fibers. The areal specific capacitance of a single r-PANI-GOF electrode is as large as 1755 mF cm-2in the three-electrode system. The r-PANI-GOF hybrid fibers were also used as electrodes for making an all-solid-state FSCs. This whole device has a specific areal capacitance of up to 481 mF cm-2and a high areal energy density of 42.76µWh cm-2. The hybrid fiber electrodes with a high capacitance, and excellent flexibility may become new candidates for the development of fiber-shaped high-performance energy storage devices.

Preparation and Electrical Properties of Polyacrylonitrile Based Porous Carbon by Different Activation Methods.

Polyacrylonitrile (PAN)-based porous carbon was prepared by different methods of activation with PAN polymer microsphere as precursor. The morphology, structure and electrical properties for supercapacitor of the porous carbon were investigated. It was found that the morphology of PAN nanospheres tended to be destroyed in the process of one-step activation (activation and carbonization were carried out simultaneously, and could only be retained when the amount of activating agent KOH was small). While the spherical morphology could be well reserved during the two-step activation method (carbonization and activation sequentially). The specific surface area and pore volume increased first and then decreased, with the increase in activation holding time for both one-step and two-step activation methods. The specific surface area reached the maximum value with 2430 m2 g-1 for the one-step activation method and 2830 m2 g-1 for the two-step activation method. Additionally, their mass-specific capacitances were 178.8 F g-1 and 160.2 F g-1, respectively, under the current density of 1 A g-1. After 2000 cycles, the specific capacitance retentions were 92.9% and 91.3%.

Examining K-12 teachers' feelings, experiences, and perspectives regarding online teaching during the early stage of the COVID-19 pandemic.

This mixed-methods study explored K-12 teachers' feelings, experiences, and perspectives regarding online teaching during the COVID-19 pandemic. The study also examined teachers' perspectives of the "new normal" after COVID-19 and of what should be done to better prepare teachers for future emergencies. Both quantitative and qualitative data were collected from an online survey and follow-up interviews. A total of 107 teachers from 25 different states in the United States completed the online survey, and 13 teachers from 10 different states participated in the follow-up interviews. The results revealed teachers' feelings about online teaching and various strategies and tools they used during the early stage of the COVID-19 pandemic. The major challenges faced by teachers during the pandemic included lack of student participation and engagement (or lack of parental support), students without access to technology, concerns about students' well-being, no face-to-face interactions with students, no work-life balance, and learning new technology. Four major themes emerged regarding how to better prepare teachers for future emergencies: (1) professional development for online learning, (2) technology access, (3) technology training for both teachers and students, and (4) action plans and communication. Regarding teachers' perspectives of the "new normal," five major themes emerged: (1) more online or blended learning, (2) rethinking normal, (3) hygiene and social distancing, (4) smaller classes and different school schedules, and (5) uncertainty and concerns about the "new normal."

Graphene oxide induced assembly and crumpling of Co3O4 nanoplates.

Cobalt (II, III) oxide (Co3O4) has been widely studied and applied in various fields, however, it suffers from slow mass and electron transfer during applications. Herein, crumpled Co3O4 and Co3O4/reduced graphene oxide (rGO) with tunable 2D-in-3D structures were prepared by combining spray pyrolysis with a graphene oxide (GO) template. The 2D Co3O4 nanoplates were interconnected with each other to form a 3D ball with many wrinkles, resulting in defect enrichment on the abundant boundaries of the nanosheets, which provided more active sites for catalytic reactions. In addition, the unique 2D-in-3D structure allowed fast mass transfer and structural stability. Furthermore, the assembled structure could be understood as being composed of uniformly distributed oxygen-containing functional groups pinning metal cations on the GO surface through electrostatic interaction, and the 2D structure of the GO enabled the in situ converted Co3O4 to grow along the GO surface with excellent dispersion. Taking advantage of the above, the Co3O4/rGO balls demonstrated an excellent oxygen evolution reaction performance, an overpotential of 298 mV at a current density of 10.0 mA cm-2 and a current density of 115.9 mA cm-2 at the overpotential of η = 500 mV.

Molecule-Driven Nanoenergy Generator.

A large potential can be generated when one end of 1D and/or 2D semiconducting nanostructures such as zinc oxide (ZnO) and molybdenum disulfide is exposed to a wide spectrum of chemical molecules. A nanoenergy generator that comprises vertically aligned ZnO nanowires and poly(vinyl chloride-co-vinyl-co-2-hydroxypropyl acrylate) is fabricated, and it can generate electricity from various molecules including gaseous species exhaled from human breath. The generated voltage, which depends sensitively on the molecular dipole moment of adsorbed chemical species and surface coverage, is significantly larger than the streaming or piezoelectric potentials and is powerful enough to directly drive a single carbon nanotube field-effect transistor. It is demonstrated that the notion of voltage generation through molecule-surface interactions bears general implications to other semiconducting materials, and has the advantages of simplicity, cost-effectiveness, fast response to a wide range of molecules, and high power output, making our approach a promising tool for energy conversion and sensing applications.

Visible-Light Driven TiO2 Photocatalyst Coated with Graphene Quantum Dots of Tunable Nitrogen Doping.

Nitrogen doped graphene quantum dots (NGQDs) were successfully prepared via a hydrothermal method using citric acid and urea as the carbon and nitrogen precursors, respectively. Due to different post-treatment processes, the obtained NGQDs with different surface modifications exhibited blue light emission, while their visible-light absorption was obviously different. To further understand the roles of nitrogen dopants and N-containing surface groups of NGQDs in the photocatalytic performance, their corresponding composites with TiO2 were utilized to degrade RhB solutions under visible-light irradiation. A series of characterization and photocatalytic performance tests were carried out, which demonstrated that NGQDs play a significant role in enhancing visible-light driven photocatalytic activity and the carrier separation process. The enhanced photocatalytic activity of the NGQDs/TiO2 composites can possibly be attributed to an enhanced visible light absorption ability, and an improved separation and transfer rate of photogenerated carriers.

Graphene-Like Porous ZnO/Graphene Oxide Nanosheets for High-Performance Acetone Vapor Detection.

In order to obtain acetone sensor with excellent sensitivity, selectivity, and rapid response/recovery speed, graphene-like ZnO/graphene oxide (GO) nanosheets were synthesized using the wet-chemical method with an additional calcining treatment. The GO was utilized as both the template to form the two-dimensional (2-D) nanosheets and the sensitizer to enhance the sensing properties. Sensing performances of ZnO/GO nanocomposites were studied with acetone as a target gas. The response value could reach 94 to 100 ppm acetone vapor and the recovery time could reach 4 s. The excellent sensing properties were ascribed to the synergistic effects between ZnO nanosheets and GO, which included a unique 2-D structure, large specific surface area, suitable particle size, and abundant in-plane mesopores, which contributed to the advance of novel acetone vapor sensors and could provide some references to the synthesis of 2-D graphene-like metals oxide nanosheets.

Quasi-Emulsion Confined Synthesis of Edge-Rich Ultrathin MoS2 Nanosheets/Graphene Hybrid for Enhanced Hydrogen Evolution.

High-purity hydrogen produced by water splitting is considered as one of the most promising fuels to replace traditional fossil fuels. Developing highly efficient electrocatalysts toward hydrogen evolution is vital for the realization of large-scale H2 generation. Glycerol is used herein in a facile solvothermal process to synthesize edge-rich ultrathin MoS2 /reduced graphene oxide (RGO) composites. The introduction of glycerol plays an important role in the formation of such interesting structures. The MoS2 /RGO electrocatalyst exhibits excellent hydrogen evolution reaction (HER) activity and remarkable stability, owing to the rich active edges and improved electrical conductivity of the catalyst composites. This work provides new insights to engineer the structures of MoSx -based composites and thus achieves more active and efficient electrocatalysts.

Activation of Kagome lattice-structured Cu3V2O7(OH)2·2H2O volborthite via hydrothermal crystallization for boosting visible light-driven water oxidation.

We report a feasible strategy via hydrothermal crystallization to activate Kagome lattice-structured Cu3V2O7(OH)2·2H2O volborthite mineral as a stable visible-light-driven photocatalyst. It was demonstrated to play a crucial role in stimulating absorption ability and photodegradation performance for the removal of methylene blue present in high concentration. In contrast, direct calcination was almost ineffective, whereas post-calcination was significantly detrimental. Moreover, the photocatalytic water oxidation activity of hydrothermally crystallizated volborthite was comparable to that of BiVO4, and it was clearly higher than those of WO3 and g-C3N4 from aqueous NaIO3 solution. By further in situ decoration with an optimum amount of CoOx cocatalysts (i.e., 2 wt%), the oxygen evolution rate of volborthite was greatly enhanced, and it was 1.6-fold, 1.8-fold and 2.9-fold higher than those of BiVO4, WO3 and g-C3N4, respectively. The importance of hydrothermal crystallization can be elucidated in terms of water-Kagome lattice structure interactions involving built-in intrinsic electric field and formation of single hydrogen bonds.

Synthesis of high-purity, layered structured K2Ta4O11 intermediate phase nanocrystals for photocatalytic water splitting.

High-purity K2Ta4O11 (kalitantite) intermediate phase with a layered structure, as a new family member of alkali-metal tantalate semiconductors, was successfully prepared via a simple and cost-effective flux growth technique using potassium chloride (KCl) at a low temperature of 800 °C for only 4 h. The as-synthesized K2Ta4O11 was characterized by XRD, SEM, TEM, STEM/EDS, and UV-Vis DRS, etc. It was found that the K2Ta4O11 single nanocrystals were non-stoichiometric in the size range of 100-500 nm, and the indirect band gap of K2Ta4O11 was correctly determined to be 4.15 eV. The K2Ta4O11 not only exhibited a high and stable photocatalytic H2 generation rate of ∼45.3 µmol h(-1) g(-1) in an aqueous methanolic solution with the photodeposition of Pt as co-catalysts, but also possessed the photocatalytic ability for simultaneous evolution of H2 and O2 in a stoichiometric ratio, with loading of NiO particles as cocatalysts. Thus, it can be mainly attributed to the benefits of KCl flux lowing the reaction temperature, and increasing the surface area and crystallinity of K2Ta4O11, that the charge efficiency and enhancement of the photoreactivity for water splitting are improved.

Structural evolution of 2D microporous covalent triazine-based framework toward the study of high-performance supercapacitors.

A series of nitrogen-containing micropore-donimated materials, porous triazine-based frameworks (PTFs), are constructed through the structural evolution of a 2D microporous covalent triazine-based framework. The PTFs feature predictable and controllable nitrogen doping and pore structures, which serve as a model-like system to more deeply understand the heteroatom effect and micropore effect in ionic liquid-based supercapacitors. The experimental results reveal that the nitrogen doping can enhance the supercapacitor performance mainly through affecting the relative permittivity of the electrode materials. Although microspores' contribution is not as obvious as the doped nitrogen, the great performances of the micropore-dominated PTF suggest that micropore-dominated materials still have great potential in ionic liquid-based supercapacitors.

Three-Dimensional-Bioprinted Bioactive Glass/Cellulose Composite Scaffolds with Porous Structure towards Bone Tissue Engineering.

In this study, three-dimensional (3D) bioactive glass/lignocellulose (BG/cellulose) composite scaffolds were successfully fabricated by the 3D-bioprinting technique with N-methylmorpholine-N-oxide (NMMO) as the ink solvent. The physical structure, morphology, mechanical properties, hydroxyapatite growth and cell response to the prepared BG/cellulose scaffolds were investigated. Scanning electron microscopy (SEM) images showed that the BG/cellulose scaffolds had uniform macropores of less than 400 µm with very rough surfaces. Such BG/cellulose scaffolds have excellent mechanical performance to resist compressive force in comparison with pure cellulose scaffolds and satisfy the strength requirement of human trabecular bone (2-12 MPa). Furthermore, BG significantly increased the excellent hydroxyapatite-forming capability of the cellulose scaffolds as indicated by the mineralization of the scaffolds in simulated body fluid (SBF). The BG/cellulose scaffolds showed low cytotoxicity to human bone marrow mesenchymal stem cells (hBMSCs) in the CCK8 assay. The cell viability reached maximum (percent of the control group) when the weight ratio of cellulose to BG was 2 in the scaffold. Therefore, the 3D-printed BG/cellulose scaffolds show a potential application in the field of bone tissue engineering.

In Situ Trapping Strategy Enables a High-Loading Ni Single-Atom Catalyst as a Separator Modifier for a High-Performance Li-S Battery.

The poor electrochemical reaction kinetics of Li polysulfides is a key barrier that prevents the Li-S batteries from widespread applications. Ni single atoms dispersed on carbon matrixes derived from ZIF-8 are a promising type of catalyst for accelerating the conversion of active sulfur species. However, Ni favors a square-planar coordination that can only be doped on the external surface of ZIF-8, leading to a low loading amount of Ni single atoms after pyrolysis. Herein, we demonstrate an in situ trapping strategy to synthesize Ni and melamine-codoped ZIF-8 precursor (Ni-ZIF-8-MA) by simultaneously introducing melamine and Ni during the synthesis of ZIF-8, which can remarkably decrease the particle size of ZIF-8 and further anchor Ni via Ni-N6 coordination. Consequently, a novel high-loading Ni single-atom (3.3 wt %) catalyst implanted in an N-doped nanocarbon matrix (Ni@NNC) is obtained after high-temperature pyrolysis. This catalyst as a separator modifier shows a superior catalytic effect on the electrochemical transitions of Li polysulfides, which endows the corresponding Li-S batteries with a high specific capacity of 1232.4 mA h g-1 at 0.3 C and an excellent rate capability of 814.9 mA h g-1 at 3 C. Furthermore, a superior areal capacity of 4.6 mA h cm-2 with stable cycling over 160 cycles can be achieved under a critical condition with a low electrolyte/sulfur ratio (8.4 µL mg-1) and high sulfur loading (4.85 mg cm-2). The outstanding electrochemical performances can be attributed to the strong adsorption and fast conversion of Li polysulfides on the highly dense active sites of Ni@NNC. This intriguing work provides new inspirations for designing high-loading single-atom catalysts applied in Li-S batteries.

Interfacial Manipulation via In Situ Constructed Fast Ion Transport Channels toward an Ultrahigh Rate and Practical Li Metal Anode.

The successful substitution of Li metal for the conventional intercalation anode can promote a significant increase in the cell energy density. However, the practical application of the Li metal anode has long been fettered by the unstable solid electrolyte interface (SEI) layer on the Li metal surface and notorious dendritic Li growth. Herein, a stabilized SEI layer with in situ constructed fast ion transport channels has successfully been achieved by a robust In2S3-cemented poly(vinyl alcohol) coating. The modified Li metal demonstrates significantly enhanced Coulombic efficiency, high rate performance (10 mA cm-2), and ultralong life cycling stability (∼4900 cycles). The Li|LiCoO2 (LCO) cell presents an ultralong-term stable operation over 500 cycles at 1 C with an extremely low capacity decay rate (∼0.018% per cycle). And the Li|LCO full cell with the ultrahigh loading cathode (∼25 mg cm-2) and ultrathin Li foil (∼40 µm) also reveals a prolonged cycling performance under the low negative-to-positive capacity ratio of 2.2. Furthermore, the Li|LCO pouch cell with a commercial cathode and ultrathin Li foil still manifests excellent cycling performance even under the harsh conditions of limited Li metal and lean electrolyte. This work provides a cost-effective and scalable strategy toward high performance practical Li metal batteries.