Iron Monomers or Trimers on Nitrogen-Doped Carbon: Which Is Better for the Electrocatalytic Nitrogen Reduction Reaction?

The electrocatalytic nitrogen reduction reaction (NRR) presents an alternative method for the Haber-Bosch process, and single-atom catalysts (SACs) to achieve efficient NRR have attracted considerable attention in the past decades. However, whether SACs are more suitable for NRR compared to atomic-cluster catalysts (ACCs) remains to be studied. Herein, we have successfully synthesized both the Fe monomers (Fe1) and trimers (Fe3) on nitrogen-doped carbon catalysts. Both the experiments and DFT calculations indicate that compared to the end-on adsorption of N2 on Fe1 catalysts, N2 activation is enhanced via the side-on adsorption on Fe3 catalysts, and the reaction follows the enzymatic pathway with a reduced free energy barrier for NRR. As a result, the Fe3 catalysts achieved better NRR performance (NH3 yield rate of 27.89 µg h-1 mg-1cat. and Faradaic efficiency of 45.13%) than Fe1 catalysts (10.98 µg h-1 mg-1cat. and 20.98%). Therefore, our research presents guidance to prepare more efficient NRR catalysts.

Efficient Electrocatalytic Ammonia Synthesis via Theoretical Screening of Titanate Nanosheet-Supported Single-Atom Catalysts.

The electrocatalytic nitrogen reduction reaction (NRR) for synthesizing ammonia holds promise as an alternative to the traditional high-energy-consuming Haber-Bosch method. Rational and accurate catalyst design is needed to overcome the challenge of activating N2 and to suppress the competitive hydrogen evolution reaction (HER). Single-atom catalysts have garnered widespread attention due to their 100% atom utilization efficiency and unique catalytic performance. In this context, we constructed theoretical models of metal single-atom catalysts supported on titanate nanosheets (M-TiNS). Initially, density functional theory (DFT) was employed to screen 12 single-atom catalysts for NRR- and HER-related barriers, leading to the identification of the theoretically optimal NRR catalyst, Ru-TiNS. Subsequently, experimental synthesis of the Ru-TiNS single-atom catalyst was successfully achieved, exhibiting excellent performance in catalyzing NRR, with the highest NH3 yield rate reaching 15.19 µmol mgcat-1 h-1 and a Faradaic efficiency (FE) of 15.3%. The combination of experimental results and theoretical calculations demonstrated the efficient catalytic ability of Ru sites, validating the effectiveness of the constructed theoretical screening process and providing a theoretical foundation for the design of efficient NRR catalysts.

A "solo-solvent de novo liquid-phase" method for synthesizing sulfide solid electrolyte Li6PS5Cl.

We report a "solo-solvent de novo liquid-phase" method of synthesizing a highly-favored sulfide electrolyte (Li6PS5Cl) for developing all-solid-state lithium batteries. The key chemistry for such a successful method is that tetrahydropyrrole enables in situ synthesis of the critical precursor Li2S from cheap and air-stable precursors of lithium chloride and sodium sulfide.

Ultrahigh Lithium Selective Transport in Two-Dimensional Confined Ice.

Inspired by selective ion transport in biological membrane proteins, researchers developed artificial ion channels that sieve monovalent cations, catering to the increasing lithium demand. In this work, we engineered an ion transport channel based on the confined ice within two-dimensional (2D) capillaries and found that the permselectivity of monovalent cations depends on the anisotropy of the confined ice. Particularly, the 2D confined ice showed an anomalous lithium selective transport along the (002) direction in the vermiculite capillary, with the Li+/Na+ and Li+/K+ permselectivity reaching up to 556 ± 86 and 901 ± 172, respectively, superior to most ion-selective channels. However, the 2D confined ice along the (100) direction showed less Li+ permselectivity. Additionally, the anisotropy of 2D confined ice can be tuned by adjusting the interlayer spacing. By providing insights into the ion transport in the 2D confined ice, our work may inspire more design of monovalent ion-selective channels for efficient lithium separation.

Effects of Spinach Extract and Licorice Extract on Growth Performance, Antioxidant Capacity, and Gut Microbiota in Weaned Piglets.

Anemia and weaning stress are important factors affecting piglet growth performance. Spinach extract and licorice extract have been used to improve anemia and antioxidant capacity, respectively. However, whether they have synergistic effects has not been reported. To evaluate the effects of mixed spinach extract and licorice extract on growth performance, serum biochemistry, antioxidant capacity, and gut microbiota in weaned piglets, a total of 160 weaned piglets were randomly allotted to four treatments with four replications of 10 piglets each. The four treatments were as follows: control (CON) group (basal diet), spinach extract (SE) group (basal diet + 1.5 kg/t spinach extract), licorice extract (LE) group (basal diet + 400 g/t licorice extract), and spinach extract and licorice extract (MIX) group (basal diet + 1.5 kg/t spinach extract + 400 g/t licorice extract). The results showed that, compared with the CON group, diets supplemented with spinach extract and licorice extract significantly increased the average daily gain (p < 0.05), while considerably reducing the feed-to-gain ratio (p < 0.05). Moreover, the MIX group exhibited a significant up-regulation of serum total protein, globulin, albumin, glucose, and triglyceride levels in comparison to the CON group (p < 0.05). Meanwhile, both the anemia and antioxidant capacity of piglets were effectively improved. Notably, the MIX group achieved even better results than the individual supplementation in terms of enhancing growth performance, which could potentially be attributed to the increased abundance of the Rikenellaceae_RC9_gut_group. These results demonstrated that the supplementation of diets with spinach extract and licorice extract improves the absorption of nutrients from the diet and antioxidant capacity in weaned piglets.

Performance Enhancement of the Li6PS5Cl-Based Solid-State Batteries by Scavenging Lithium Dendrites with LaCl3-Based Electrolyte.

Li6PS5Cl (LPSC) is a very attractive sulfide solid electrolyte for developing high-performance all-solid-state lithium batteries. However, it cannot suppress the growth of lithium dendrites and then can only tolerate a small critical current density (CCD) before getting short-circuited to death. Learning from that a newly-developed LaCl3-based electrolyte (LTLC) can afford a very large CCD, a three-layer sandwich-structured electrolyte is designed by inserting LTLC inside LPSC. Remarkably, compared with bland LPSC, this hybrid electrolyte LPSC/LTLC/LPSC presents extraordinary performance improvements: the CCD gets increased from 0.51 to 1.52 mA cm-2, the lifetime gets prolonged from 7 h to >500 h at the cycling current of 0.5 mA cm-2 in symmetric cells, and the cyclability gets extended from 10 cycles to >200 cycles at the cycling rate of 0.5 C and 30 °C in Li|electrolyte|NCM721 full cells. The enhancing reasons are assigned to the capability of LTLC to scavenge lithium dendrites, forming a passive layer of Ta, La, and LiCl.

Making the Unfeasible Feasible: Synthesis of the Battery Material Lithium Sulfide via the Metathetic Reaction between Lithium Sulfate and Sodium Sulfide.

Lithium sulfide (Li2S) is a highly desired material for advanced batteries. However, its current industrial production is not suitable for large-scale applications in the long run because the process is carbon-emissive, energy-intensive, and cost-ineffective. This article demonstrates a new method that can overcome these challenges by reacting lithium sulfate (Li2SO4) with sodium sulfide. This approach, which seems unfeasible initially because Li2SO4 is barely soluble in ethanol at room temperature, becomes feasible when heated ethanol and an excess amount of Li2SO4 are used. More interestingly, product purification is easier than that in other metathetic reactions, thanks to the poor solubility of Li2SO4. In order to further minimize the overall costs of producing Li2S, the concomitant byproduct LiNaSO4 and the unfinished precursor Li2SO4 are converted into more valuable materials, Li2CO3 and Na2SO4. Moreover, the homemade Li2S is competitive with the commercial Li2S in cathode performance and gains further enhancement when being composited with the Co9S8 catalyst. Thus, this Li2SO4-based metathesis of Li2S has great potential for practical applications.

Toward High-Quality Sulfide Solid Electrolytes: A Liquid-Phase Approach Featured with an Interparticle Coupled Unification Effect.

Sulfide solid electrolytes (SSEs) are highly wanted for solid-state batteries (SSBs). While their liquid-phase synthesis is advantageous over their solid-phase strategy in scalable production, it confronts other challenges, such as low-purity products, user-unfriendly solvents, energy-inefficient solvent removal, and unsatisfactory performance. This article demonstrates that a suspension-based solvothermal method using single oxygen-free solvents can solve those problems. Experimental observations and theoretical calculations together show that the basic function of suspension-treatment is "interparticle-coupled unification", that is, even individually insoluble solid precursors can mutually adsorb and amalgamate to generate uniform composites in nonpolar solvents. This anti-intuitive concept is established when investigating the origins of impurities in SSEs electrolytes made by the conventional tetrahydrofuran-ethanol method and then searching for new solvents. Its generality is supported by four eligible alkane solvents and four types of SSEs. The electrochemical assessments on the former three SSEs show that they are competitive with their counterparts in the literature. Moreover, the synthesized SSEs presents excellent battery performance, showing great potential for practical applications.

Direct Electrochemical Synthesis of Acetamide from CO2 and N2 on a Single-Atom Alloy Catalyst.

The electrochemical conversion of carbon dioxide into value-added compounds not only paves the way toward a sustainable society but also unlocks the potential for electrocatalytic synthesis of amides through the introduction of N atoms. However, it also poses one of the greatest challenges in catalysis: achieving simultaneous completion of C-C coupling and C-N coupling. Here, we have meticulously investigated the catalytic prowess of Cu-based single-atom alloys in facilitating the electrochemical synthesis of acetamide from CO2 and N2. Through a comprehensive screening process encompassing catalyst stability, adsorption capability, and selectivity against the HER, W/Cu(111) SAA has emerged as an auspicious contender. The reaction entails CO2 reduction to CO, C-C coupling leading to the formation of a ketene intermediate *CCO, N2 reduction, and C-N coupling between NH3 and *CCO culminating in the production of acetamide. The W/Cu(111) surface not only exhibits exceptional activity in the formation of acetamide, with a barrier energy of 0.85 eV for the rate-determining CO hydrogenation step, but also effectively suppresses undesired side reactions leading to various C1 and C2 byproducts during CO2 reduction. This work presents a highly effective approach for forming C-C and C-N bonds via coelectroreduction of CO2 and N2, illuminating the reaction mechanism underlying acetamide synthesis from these two gases on single-atom alloy catalysts. The catalyst design strategy employed in this study has the potential to be extended to a range of amide chemicals, thereby broadening the scope of products that can be obtained through CO2/N2 reduction.

Synthesis of Deliquescent Lithium Sulfide in Air.

In the field of lithium-sulfur batteries (LSBs) and all-solid-state batteries, lithium sulfide (Li2S) is a critical raw material. However, its practical application is greatly hindered by its high price due to its deliquescent property and production at high temperatures (above 700 °C) with carbon emission. Hereby, we report a new method of preparing Li2S, in air and at low temperatures (∼200 °C), which presents enriched and surprising chemistry. The synthesis relies on the solid-state reaction between inexpensive and air-stable raw materials of lithium hydroxide (LiOH) and sulfur (S), where lithium sulfite (Li2SO3), lithium thiosulfate (Li2S2O3), and water are three major byproducts. About 57% of lithium from LiOH is converted into Li2S, corresponding to a material cost of ∼$64.9/kg_Li2S, less than 10% of the commercial price. The success of conducting this water-producing reaction in air lies in three-fold: (1) Li2S is stable with oxygen below 220 °C; (2) the use of excess S can prevent Li2S from water attack, by forming lithium polysulfides (Li2Sn); and (3) the byproduct water can be expelled out of the reaction system by the carrier gas and also absorbed by LiOH to form LiOH·H2O. Two interesting and beneficial phenomena, i.e., the anti-hydrolysis of Li2Sn and the decomposition of Li2S2O3 to recover Li2S, are explained with density functional theory computations. Furthermore, our homemade Li2S (h-Li2S) is at least comparable with the commercial Li2S (c-Li2S), when being tested as cathode materials for LSBs.

Host Surface-Induced Excitation Wavelength-Dependent Organic Afterglow.

The design and construction of organic afterglow materials is an attractive but formidably challenging task due to the low intersystem crossing efficiency and nonradiative decay. Here, we developed a host surface-induced strategy to achieve excitation wavelength-dependent (Ex-De) afterglow emission through a facile dropping process. The prepared PCz@dimethyl terephthalate (DTT)@paper system exhibits a room-temperature phosphorescence afterglow, with the lifetime up to 1077.1 ± 15 ms and duration time exceeding 6 s under ambient conditions. Furthermore, we can switch the afterglow emission on and off by adjusting the excitation wavelength below or above 300 nm, showing a remarkable Ex-De behavior. Spectral analysis demonstrated that the afterglow originates from the phosphorescence of PCz@DTT assemblies. The stepwise preparation process and detailed experiments (XRD, 1H NMR, and FT-IR analysis) proved the presence of strong intermolecular interactions between the carbonyl groups on the surface of DTT and the entire frame of PCz, which can inhibit the nonradiative processes of PCz to achieve afterglow emission. Theoretical calculations further manifested that DTT geometry alteration under different excitation beams is the main reason for the Ex-De afterglow. This work discloses an effective strategy for constructing smart Ex-De afterglow systems that can be fully exploited in a range of fields.

Electrically Modulated Nanofiltration Membrane Based on an Arch-Bridged Graphene Structure for Multicomponent Molecular Separation.

Tunable regulation of molecular penetration through porous membranes is highly desirable for membrane applications in the pharmaceutical and medical fields. However, in most previous reports additional reagents or components are usually needed to provide the graphene-based membranes with responsiveness. Herein, we report tunable arch-bridged reduced graphene oxide (rGO) nanofiltration membranes modulated by the applied voltage. Under a finite voltage of 5 V, the rGO membrane could completely reject organic/anionic molecules. With assistance of the voltage, the positive-charge-modified rGO membrane realized the universal rejection of both cationic and anionic dyes, also showing the valid modulation in harsh organic solvents. The efficient electrical modulation depended on the synergetic effects of Donnan repulsion and size exclusion, benefiting from the electric field enhancement in arch-bridged rGO structures. Furthermore, multicomponent separation was achieved by our electrically modulated rGO-based membranes, demonstrating their potential in practical applications such as pharmaceutical industries.

"One Stone Two Birds" Strategy of Synthesizing the Battery Material Lithium Sulfide: Aluminothermal Reduction of Lithium Sulfate.

Lithium sulfide (Li2S) is a critical material for clean energy technologies, i.e., the cathode material in lithium-sulfur batteries and the raw material for making sulfide solid electrolytes in all-solid-state batteries. However, its practical application at a large scale is hindered by its industrial production method of reducing lithium sulfate with carbon materials at high temperatures, which emits carbon dioxide and is time-consuming. We hereby report a method of synthesizing Li2S by thermally reducing lithium sulfate with aluminum. Compared with the carbothermal method, this aluminothermal approach has several advantages, such as operation at lower temperatures, completion in minutes, no emission of greenhouse gases, and valuable byproducts of aluminum oxide (Al2O3). The home-made Li2S demonstrates competitive performance in battery tests versus the commercial counterpart. Moreover, using the byproduct Al2O3 to coat the cathode side of the separator can enhance the battery's capacity without influencing its rate capability. Thus, this "one stone two birds" method has great potential for practical applications of developing Li-S batteries.

Green Synthesis for Battery Materials: A Case Study of Making Lithium Sulfide via Metathetic Precipitation.

For some future clean-energy technologies (such as advanced batteries), the concept of green chemistry has not been exercised enough for their material synthesis. Herein, we report a waste-free method of synthesizing lithium sulfide (Li2S), a critical material for both lithium-sulfur batteries and sulfide-electrolyte-based all-solid-state lithium batteries. The key novelty lies in directly precipitating crystalline Li2S out of an organic solution after the metathetic reaction between a lithium salt and sodium sulfide. Compared with conventional methods, this method is advantageous in operating at ambient temperatures, releasing no hazardous wastes, and being economically more competitive. To collect the valuable byproduct out of the liquid phases, a "solventing-out crystallization" technique is employed by adding an antisolvent (AS) of low boiling point. The subsequent distillation of the new solution under vacuum evaporates off the AS rather than the high-boiling-point reaction solvent (RS), saving a lot of energy. Consequently, the separated AS and RS containing the unreacted lithium salt can be directly reused. For industrial production, the entire process may be operated continuously in a closed loop without discharging any wastes. Moreover, Li2S cathodes and sulfide-electrolyte Li6PS5Cl derived from the synthesized Li2S show impressive battery performance, displaying the great potential of this method for practical applications.

Breaking the Volcano-Shaped Relationship for Highly Efficient Electrocatalytic Nitrogen Reduction: A Computational Guideline.

The volcano-shaped relationship is very common in electrocatalytic nitrogen reduction reaction (e-NRR) and is usually caused by the competition between the first and last hydrogenation steps. How to break such a relationship to further improve the catalytic performance remains a great challenge. Herein, using first-principles calculations, we investigate a range of transition-metal (TM)-doped Cu-based single-atom alloys (TM1-Cu(111)) as catalysts for e-NRR. When the adsorption of N2 on the catalysts is strong enough, the inert N2 molecules can be effectively activated for the first hydrogenation step. Meanwhile, the last hydrogenation step is not affected by the scaling relationship and remains easy on all of the catalysts due to the unstable top-site adsorption of NH2, resulting in the break of the volcano-shaped relationship in e-NRR. Thus, only the first hydrogenation step is identified as the potential determining step. Four TM1-Cu(111) catalysts (TM = Re, W, Tc, and Mo) are selected as promising catalysts with limiting potential ranging from -0.38 to -0.56 V, showing outstanding e-NRR activity. Besides, the four catalysts also inhibit the competing hydrogen evolution reaction and long-term stability. Our work provides a guideline for breaking the volcano-shaped relationship in e-NRR and significant in the rational design of highly efficient electrocatalysts.

Lithium Sulfide: Magnesothermal Synthesis and Battery Applications.

As a critical material for emerging lithium-sulfur batteries and sulfide-electrolyte-based all-solid-state batteries, lithium sulfide (Li2S) has great application prospects in the field of energy storage and conversion. However, commercial Li2S is expensive and is produced via a carbon-emissive and time-consuming method of reducing lithium sulfate with carbon materials at high temperatures. Herein we report a novel method of synthesizing Li2S by thermally reducing lithium sulfate with the first non-carbon-based reductant Mg. Compared with the commercial carbothermal method, our magnesothermal technique has multiple advantages, such as completion in minutes, operation at lower temperatures, emission of zero amount of greenhouse-gases, and a valuable byproduct MgO. Moreover, the prepared Li2S product demonstrates excellent cathode performance in lithium-sulfur batteries, in terms of cycling stability, activation voltage, and rate capability. Thus, this innovative method opens a new direction for the research of Li2S and has great potential for practical applications.

Physiology-Based Pharmacokinetic Study on 18ß-Glycyrrhetic Acid Mono-Glucuronide (GAMG) Prior to Glycyrrhizin in Rats.

To understand that 18ß-Glycyrrhetic acid 3-O-mono-ß-D-glucuronide (GAMG) showed better pharmacological activity and drug-like properties than 18ß-Glycyrrhizin (GL); a rapid and sensitive HPLC-MS/MS method was established for the simultaneous determination of GAMG and its metabolite 18ß-Glycyrrhetinic acid (GA) in rat plasma and tissues after oral administration of GAMG or GL. This analytical method was validated by linearity, LLOQ, specificity, recovery rate, matrix effect, etc. After oral administration, GAMG exhibited excellent Cmax (2377.57 ng/mL), Tmax (5 min) and AUC0-T (6625.54 mg/L*h), which was much higher than the Cmax (346.03 ng/mL), Tmax (2.00 h) and AUC0-T (459.32 mg/L*h) of GL. Moreover, GAMG had wider and higher tissue distribution in the kidney, spleen, live, lung, brain, etc. These results indicated that oral GAMG can be rapidly and efficiently absorbed and be widely distributed in tissues to exert stronger and multiple pharmacological activities. This provided a physiological basis for guiding the pharmacodynamic study and clinical applications of GAMG.

A Low-Cost Liquid-Phase Method of Synthesizing High-Performance Li6PS5Cl Solid-Electrolyte.

Li6PS5Cl is an extensively studied sulfide-solid-electrolyte for developing all-solid-state lithium batteries. However, its practical application is hindered by the high cost of its raw material lithium sulfide (Li2S), the difficulty in its massive production, and its substandard performance. Herein we report an economically viable and scalable method, denoted as "de novo liquid phase method", which enables in synthesizing high-performance Li6PS5Cl without using commercial Li2S but instead in situ making Li2S from cheap materials of lithium chloride (LiCl) and sodium sulfide. LiCl, a raw material needed for making both Li2S and Li6PS5Cl, can be added at a full-scale in the beginning and unrequired to separate when making the intermediate Li3PS4. Such a consecutive feature makes this method time-efficient; and the excess amount of LiCl in the step of making Li2S also facilitates removing the byproduct of sodium chloride via the common ion effect. The materials cost of this method for Li6PS5Cl is ∼ $55/kg, comparable with the practical need of $50/kg. Moreover, the obtained Li6PS5Cl shows high ionic conductivity and outstanding cyclability in full battery tests, that is, ∼2 mS/cm and >99.8% retention for 400+ cycles at 1 C, respectively. Thus, this innovative method is expected to pave the way to develop practical sulfide-solid-electrolytes for all-solid-state lithium batteries.

Green synthesis of the battery material lithium sulfide via metathetic reactions.

We report a synthesis of lithium sulfide, the cost-determining material for making sulphide solid electrolytes (SSEs), via spontaneous metathesis reactions between lithium salts (halides and nitrate) and sodium sulfide. This innovative method is economical, scalable and green. It will pave the way to developing practical SSE-based solid-state lithium batteries.

Influence of socioeconomic development on river water quality: a case study of two river basins in China.

Social and economic development processes require large amounts of natural resources and in some cases seriously deteriorate river water quality. Since the reform and expansion era began, China has vigorously pursued socioeconomic development but neglected environmental protection. However, in recent years, improvements in environmental awareness and the implementation of environmental protection measures have led to a balanced relationship between economic development and the environment. In this study, the Yangtze River Basin and the Yellow River Basin were selected as research areas. We used a combination of canonical correlation analysis (CCA) and a distance-based influence assessment method to quantitatively assess the influence of socioeconomic development on river water quality. The results revealed a strong correlation between socioeconomic development and river water quality. The degree of influence of socioeconomic development on water quality varied not only temporally but also spatially due to differences in socioeconomic development and hydrometeorology in the two basins in North and South China. The average degree of influence in the Yangtze River Basin was between 0.22 and 0.27, and that in the Yellow River Basin was between 0.2 and 0.36. Moreover, the degree of influence in the Yangtze River Basin in the wet season was greater than that in the dry season, whereas the opposite pattern was observed in the Yellow River Basin. The degree of influence in both basins gradually declined after 2011, indicating that the coupling and coordination between socioeconomic development and environmental protection have continuously improved and that the water quality has gradually improved. By analysing the influences of various socioeconomic indicators on water quality, we found that the main factors that influence water quality are per capita GDP and urbanization rate in the Yangtze River Basin and urbanization rate in the Yellow River Basin. The results provide a basis for future sustainable development in the Yangtze River Basin and the Yellow River Basin.