Iron nanoparticles surface decorated MXene via molten salts etching as selenium host for ultrafast sodium ion storage.

Sodium-selenium (Na-Se) batteries have gained attention due to their high energy density and power density, resulting from the liquid-liquid reaction at the interface in the dimethoxyethane electrolyte. Nevertheless, the pronounced shuttle effect of polyselenides causes low coulomb efficiency and inadequate cycling stability for Na-Se batteries. Herein, the iron nanoparticles surface modified accordion-like Ti3C2Tx MXene (MXene/Fe) synthesized via the molten salt etching is utilized as the host of Se species for high-performance Na-Se battery cathode. Benefiting from the layered structure and chemical adsorption of accordion-like MXene, the shuttle effect of the cathode is effectively inhibited. Simultaneously, electrochemical kinetics is boosted due to the catalytic effect of Fe nanoparticles, which facilitate the transformation of polyselenide from long-chain to short-chain, contributing to pseudocapacitive capacity. Consequently, the Se-based cathode delivers a steady capacity of 575.0 mA h g-1 at 0.2 A/g, and even a high capacity of 500 mAh/g at 50 A/g based on the mass of Se@MXene/Fe electrode, indicating the ultrafast Na+ ion storage. Most notably, this structure demonstrated remarkable long-term cycling stability for 5000 cycles with a high capacity retention of 97.4 %. The electrochemical energy storage mechanism is further revealed by in situ Raman. Herein, the confinement-catalysis structure shines light on inhibiting shuttling and facilitating ultrafast ion storage.

MoP quantum dots based multifunctional efficient electrocatalyst for stable and long-life flexible lithium-sulfur batteries.

The commercialization of lithium-sulfur (Li-S) batteries is challenging, owing to factors like the poor conductivity of S, the 'shuttle effect', and the slow reaction kinetics. To address these challenges, MoP quantum dots were decorated on hollow carbon spheres (MoPQDs/C) in this study and used as an efficient lithium polysulfides (LiPSs) adsorbents and catalysts. In this approach polysulfides are effectively trapped through strong chemisorption and physical adsorption while simultaneously facilitating LiPSs conversion by enhancing the reaction kinetics. MXene serves as a flexible physical barrier (MoPQDs/C@MXene), further enhancing the confinement of LiPSs. Moreover, both materials are conductive, significantly facilitating electron and charge transfer. Additionally, the flexible MoPQDs/C@MXene-S electrode offers a large specific surface area for sulfur loading and withstand volume expansion during electrochemical processes. As a result, the MoPQDs/C@MXene-S electrode exhibits excellent long-term cyclability and maintains a robust specific capacity of 992 mA h g-1 even after 800cycles at a rate of 1.0C (1C = 1675 mA g-1), with a minimal capacity decay rate of 0.034 % per cycle. This work proposes an efficient strategy to fabricate highly efficient electrocatalysts for advanced Li-S batteries.

Anomalous water molecular gating from atomic-scale graphene capillaries for precise and ultrafast molecular sieving.

The pressing crisis of clean water shortage requires membranes to possess effective ion sieving as well as fast water flux. However, effective ion sieving demands reduction of pore size, which inevitably hinders water flux in hydrophilic membranes, posing a major challenge for efficient water/ion separation. Herein, we introduce anomalous water molecular gating based on nanofiltration membranes full of graphene capillaries at 6 Å, which were fabricated from spontaneous π-π restacking of island-on-nanosheet graphitic microstructures. We found that the membrane can provide effective ion sieving by suppressing osmosis-driven ion diffusion to negligible levels (~10-4 mol m-2 h-1); unexpectedly, ultrafast bulk flow of water (45.4 L m-2 h-1) was still functional with ease, as gated on/off by adjusting hydrostatic pressures within only 10-2 bar. We attribute this seemingly incompatible observation to graphene nanoconfinement effect, where crystal-like water confined within the capillaries hinders diffusion under osmosis but facilitates high-speed, diffusion-free water transport in the way analogous to Newton's cradle-like Grotthus conduction. This strategy establishes a type of liquid-solid-liquid, phase-changing molecular transport for precise and ultrafast molecular sieving.

Application of Inorganic Quantum Dots in Advanced Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have emerged as one of the most attractive alternatives for post-lithium-ion battery energy storage systems, owing to their ultrahigh theoretical energy density. However, the large-scale application of Li-S batteries remains enormously problematic because of the poor cycling life and safety problems, induced by the low conductivity , severe shuttling effect, poor reaction kinetics, and lithium dendrite formation. In recent studies, catalytic techniques are reported to promote the commercial application of Li-S batteries. Compared with the conventional catalytic sites on host materials, quantum dots (QDs) with ultrafine particle size (<10 nm) can provide large accessible surface area and strong polarity to restrict the shuttling effect, excellent catalytic effect to enhance the kinetics of redox reactions, as well as abundant lithiophilic nucleation sites to regulate Li deposition. In this review, the intrinsic hurdles of S conversion and Li stripping/plating reactions are first summarized. More importantly, a comprehensive overview is provided of inorganic QDs, in improving the efficiency and stability of Li-S batteries, with the strategies including composition optimization, defect and morphological engineering, design of heterostructures, and so forth. Finally, the prospects and challenges of QDs in Li-S batteries are discussed.

Application of Anabaena azotica- and Chlorella pyrenoidosa-Based Algal Biotechnology in Green Production of Algae-Rich Crataegi fructus.

Nitrogen-fixing Anabaena and Chlorella pyrenoidosa algal biotechnology are known as new agricultural inputs due to their characteristics and are widely used in the field of agricultural planting. This paper discusses the application of algal biotechnology based on nitrogen-fixing Anabaena sp. The advantages of algal biotechnology based on nitrogen-fixing Anabaena and Chlorella pyrenoidosa in terms of yield, sugar content, polyunsaturated fatty acid content, and high-quality yield of hawthorn were compared.

Earthworm activity optimized the rhizosphere bacterial community structure and further alleviated the yield loss in continuous cropping lily (Lilium lancifolium Thunb.).

The soil microbial community plays a vital role in the biogeochemical cycles of bioelements and maintaining healthy soil conditions in agricultural ecosystems. However, how the soil microbial community responds to mitigation measures for continuous cropping obstacles remains largely unknown. Here we examined the impact of quicklime (QL), chemical fungicide (CF), inoculation with earthworm (IE), and a biocontrol agent (BA) on the soil microbial community structure, and the effects toward alleviating crop yield decline in lily. High-throughput sequencing of the 16S rRNA gene from the lily rhizosphere after 3 years of continuous cropping was performed using the Illumina MiSeq platform. The results showed that Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chloroflexi and Gemmatimonadetes were the dominant bacterial phyla, with a total relative abundance of 86.15-91.59%. On the other hand, Betaproteobacteriales, Rhizobiales, Myxococcales, Gemmatimonadales, Xanthomonadales, and Micropepsales were the dominant orders with a relative abundance of 28.23-37.89%. The hydrogen ion concentration (pH) and available phosphorus (AP) were the key factors affecting the structure and diversity of the bacterial community. The yield of continuous cropping lily with using similar treatments decreased yearly for the leaf blight, but that of IE was significantly (p < 0.05) higher than with the other treatments in the same year, which were 17.9%, 18.54%, and 15.69% higher than that of blank control (CK) over 3 years. In addition, IE significantly (p < 0.05) increased organic matter (OM), available nitrogen (AN), AP, and available potassium (AK) content in the lily rhizosphere soil, optimized the structure and diversity of the rhizosphere bacterial community, and increased the abundance of several beneficial bacterial taxa, including Rhizobiales, Myxococcales, Streptomycetales and Pseudomonadales. Therefore, enriching the number of earthworms in fields could effectively optimize the bacterial community structure of the lily rhizosphere soil, promote the circulation and release in soil nutrients and consequently alleviate the loss of continuous cropping lily yield.

2D Material Nanofiltration Membranes: From Fundamental Understandings to Rational Design.

Since the discovery of 2D materials, 2D material nanofiltration (NF) membranes have attracted great attention and are being developed with a tremendously fast pace, due to their energy efficiency and cost effectiveness for water purification. The most attractive aspect for 2D material NF membranes is that, anomalous water and ion permeation phenomena have been constantly observed because of the presence of the severely confined nanocapillaries (<2 nm) in the membrane, leading to its great potential in achieving superior overall performance, e.g., high water flux, high rejection rates of ions, and high resistance to swelling. Hence, fundamental understandings of such water and ion transport behaviors are of great significance for the continuous development of 2D material NF membranes. In this work, the microscopic understandings developed up to date on 2D material NF membranes regarding the abnormal transport phenomena are reviewed, including ultrafast water and ion permeation rates with the magnitude several orders higher than that predicted by conventional diffusion behavior, ion dehydration, ionic Coulomb blockade, ion-ion correlations, etc. The state-of-the-art structural designs for 2D material NF membranes are also reviewed. Discussion and future perspectives are provided highlighting the rational design of 2D material membrane structures in the future.

Supercritical CO2 synthesis of Co-doped MoO3-x nanocrystals for multifunctional light utilization.

Here, we demonstrate, for the first time, that Co-MoO3-x nanocrystals (NCs) have been synthesized with the assistance of supercritical CO2. Their unique structural features of transition-metal doping and high oxygen vacancy concentrations, lead to synchronous outstanding surface enhanced Raman scattering (SERS) detection and photothermal conversion performances.

Tannic acid modified MoS2 nanosheet membranes with superior water flux and ion/dye rejection.

Energy-efficient membranes are urgently needed for water desalination and separation due to ever-increasing demand for fresh water. However, it is extremely challenging to increase membrane water flux and simultaneously achieve high rejection rates of cations or organic dyes. Herein, we report a tannic acid (TA) assisted exfoliation method to fabricate TA-modified MoS2 (TAMoS2) nanosheets with high production yield (90 ±â€¯5%). The TAMoS2 nanosheets membranes show excellent non-swelling stability in water. It is found that a hybrid membrane with 1 wt% of TAMoS2 in MoS2 nanosheets demonstrates overall better performance than pure MoS2 and TAMoS2 membrane. Such a hybrid membrane with a thickness of 5 µm shows fast water flux at around 32 L m-2 h-1 (LMH) and >97% rejection of various cations under static diffusion mode. Under vacuum-driven filtration condition, the as-prepared hybrid membrane demonstrates ultrafast water flux of 15,000 ±â€¯100 L/(m2 h bar) and 99.87 ±â€¯0.1% rejection of multiple model organic dyes. To the best of our knowledge, the above performances are superior to those of all MoS2-based membranes reported previously in terms of water flux and ion/dye rejection. This work represents a leap forward towards the practical applications of 2D TAMoS2 membranes in various engineering and environmental areas.

Effect of Sodium Content on the Electrochemical Performance of Li-Substituted, Manganese-Based, Sodium-Ion Layered Oxide Cathodes.

Li-substituted, manganese-based, layered oxides NaxLi0.18Mn0.66Co0.17Ni0.17O2+δ (x = 0.54, 0.66, 0.78, and 0.90) have been investigated as one kind of high-performance cathode materials for sodium ion batteries (SIBs). Phase compositions and local structures of the cathode materials with varying sodium content were elucidated by powder X-ray diffraction (PXRD) and atomic-scale high angle annular dark field scanning transmission electron microscope (HAADF-STEM), which demonstrates that a Li-O'3 phase was aroused in P2-type sodium layered oxide matrix forming a Na-P2/Li-O'3 hybrid structure. More importantly, the effect of sodium content on the preferential exposure of (102) and (104) facets and surface morphology of the cathode particles has been comprehensively studied, as well as their relationship with electrochemical performance. It reveals that, in addition to the preferential growth of (102) and (104) facets that has been proved to enhance the capacity and rate performance of the layered oxides, the smooth surface finish of the particles also plays a vital role in deciding the electrochemical performance. The layered sodium cathode material with a sodium content of 0.66 possesses sufficient exposure of (102) and (104) facets and smooth side surface, resulting in the superior capacities under various C rates (187 mAh/g at 0.2 C and 114 mAh/g at 5 C) comparing to the cathode materials with all other sodium contents. The mechanism has also been proposed in this study. These findings presented herein open up new strategies to design high performance sodium layered oxide cathode.

Intermolecular and surface forces at solid/oil/water/gas interfaces in petroleum production.

Many challenging issues are encountered along the petroleum production such as the wettability alteration of reservoir solids due to deposition of petroleum materials, stabilization/destabilization of water-in-oil and oil-in-water emulsions and treatment of tailings water. All these problems are essentially driven by the fundamental intermolecular and surface forces among the different components (i.e., water, oil, solid and gas) in the surrounding complex fluid media, and comprehensive understanding of the interactions among these components will pave the way to the development of advanced materials and technologies for improved petroleum production processes. In this work, we have reviewed the quantitative force measurement methods in different petroleum systems by using nanomechanical techniques including surface forces apparatus (SFA) and atomic force microscope (AFM). Interaction forces between petroleum components (e.g., asphaltenes) and mineral solids in both organic solvents and aqueous solutions are reviewed and correlated to the wettability change of the reservoir solids. The recent key progress in quantifying the surface forces of water-in-oil and oil-in-water emulsion drops using AFM drop probe techniques are discussed. The interaction forces of polymer flocculants and colloidal particles are correlated to the performance of tailings water treatment. The current knowledge gap and future perspectives are also presented.

Long-term combined application of manure and chemical fertilizer sustained higher nutrient status and rhizospheric bacterial diversity in reddish paddy soil of Central South China.

Bacteria, as the key component of soil ecosystems, participate in nutrient cycling and organic matter decomposition. However, how fertilization regime affects the rhizospheric bacterial community of reddish paddy soil remains unclear. Here, a long-term fertilization experiment initiated in 1982 was employed to explore the impacts of different fertilization regimes on physicochemical properties and bacterial communities of reddish paddy rhizospheric soil in Central South China by sequencing the 16S rRNA gene. The results showed that long-term fertilization improved the soil nutrient status and shaped the distinct rhizospheric bacterial communities. Particularly, chemical NPK fertilizers application significantly declined the richness of the bacterial community by 7.32%, whereas the application of manure alone or combined with chemical NPK fertilizers significantly increased the biodiversity of the bacterial community by 1.45%, 1.87% compared with no fertilization, respectively. Moreover, LEfSe indicated that application of chemical NPK fertilizers significantly enhanced the abundances of Verrucomicrobia and Nitrospiraceae, while manure significantly increased the abundances of Deltaproteobacteria and Myxococcales, but the most abundant Actinobacteria and Planctomycetes were detected in the treatment that combined application of manure and chemical NPK fertilizers. Furthermore, canonical correspondence analysis (CCA) and the Mantel test clarified that exchangeable Mg2+ (E-Mg2+), soil organic carbon (SOC) and alkali-hydrolyzable nitrogen (AN) are the key driving factors for shaping bacterial communities in the rhizosphere. Our results suggested that long-term balanced using of manure and chemical fertilizers not only increased organic material pools and nutrient availability but also enhanced the biodiversity of the rhizospheric bacterial community and the abundance of Actinobacteria, which contribute to the sustainable development of agro-ecosystems.

Scalable polyzwitterion-polydopamine coating for regenerable oil/water separation and underwater self-cleaning of stubborn heavy oil fouling without pre-hydration.

A facile and scalable polyzwitterion-polydopamine coating strategy has been developed to functionalize substrates and sponges. This approach, for the first time, achieves superior regenerable underwater self-cleaning of stubborn asphaltenes-containing heavy oil fouling without pre-hydration and removal of water residues from heavy oil, with significant implications in many engineering and environmental processes.

Effective carbon and nitrogen removal with reduced sulfur oxidation in an anaerobic baffled reactor for fresh leachate treatment.

The application of an anaerobic baffled reactor (ABR) with four compartments was investigated for the simultaneous removal of carbon and nitrogen from leachate. The nitrified effluent was recycled to compartment 3 of the ABR, thereby avoiding the adverse influence of nitrogen oxides on anaerobic methanogenesis in compartment 1. Nitrified effluent recirculation not only enhanced chemical oxygen demand removal (>95.6%) but also improved the total nitrogen removal efficiency from 12.7% to 67.4% with increasing recirculation ratio from 0.25 to 2. The challenge of insufficient carbon sources for heterotrophic denitrification in compartment 3 with a high recirculation ratio could be overcome by step feeding of leachate. Moreover, various reduced sulfurs (e.g., sulfide, elemental sulfur, and organic sulfur) were involved in nitrate reduction via sulfur-based autotrophic denitrification. The addition of sulfide to compartment 3 further confirmed nitrate reduction using reduced sulfur as an electron donor. The interaction of organic carbon, reduced sulfur, and nitrate in leachate treatment needs further study.

Rechargeable batteries with high energy storage activated by in-situ induced fluorination of carbon nanotube cathode.

High performance rechargeable batteries are urgently demanded for future energy storage systems. Here, we adopted a lithium-carbon battery configuration. Instead of using carbon materials as the surface provider for lithium-ion adsorption and desorption, we realized induced fluorination of carbon nanotube array (CNTA) paper cathodes, with the source of fluoride ions from electrolytes, by an in-situ electrochemical induction process. The induced fluorination of CNTA papers activated the reversible fluorination/defluorination reactions and lithium-ion storage/release at the CNTA paper cathodes, resulting in a dual-storage mechanism. The rechargeable battery with this dual-storage mechanism demonstrated a maximum discharging capacity of 2174 mAh (gcarbon)(-1) and a specific energy of 4113 Wh kg(carbon)(-1) with good cycling performance.

Manganese oxide-based materials as electrochemical supercapacitor electrodes.

Electrochemical supercapacitors (ECs), characteristic of high power and reasonably high energy densities, have become a versatile solution to various emerging energy applications. This critical review describes some materials science aspects on manganese oxide-based materials for these applications, primarily including the strategic design and fabrication of these electrode materials. Nanostructurization, chemical modification and incorporation with high surface area, conductive nanoarchitectures are the three major strategies in the development of high-performance manganese oxide-based electrodes for EC applications. Numerous works reviewed herein have shown enhanced electrochemical performance in the manganese oxide-based electrode materials. However, many fundamental questions remain unanswered, particularly with respect to characterization and understanding of electron transfer and atomic transport of the electrochemical interface processes within the manganese oxide-based electrodes. In order to fully exploit the potential of manganese oxide-based electrode materials, an unambiguous appreciation of these basic questions and optimization of synthesis parameters and material properties are critical for the further development of EC devices (233 references).