2D MoB MBene: An Efficient Co-Catalyst for Photocatalytic Hydrogen Production under Visible Light.

Highly active and low-cost co-catalysts have a positive effect on the enhancement of solar H2 production. Here, we employ two-dimensional (2D) MBene as a noble-metal-free co-catalyst to boost semiconductor for photocatalytic H2 production. MoB MBene is a 2D nanoboride, which is directly made from MoAlB by a facile hydrothermal etching and manual scraping off process. The as-synthesized MoB MBene with purity >95 wt % is treated by ultrasonic cell pulverization to obtain ultrathin 2D MoB MBene nanosheets (∼0.61 nm) and integrated with CdS via an electrostatic interaction strategy. The CdS/MoB composites exhibit an ultrahigh photocatalytic H2 production activity of 16,892 µmol g-1 h-1 under visible light, surpassing that of pure CdS by an exciting factor of ≈1135%. Theoretical calculations and various measurements account for the high performance in terms of Gibbs free energy, work functions, and photoelectrochemical properties. This work discovers the huge potential of these promising 2D MBene family materials as high-efficiency and low-cost co-catalysts for photocatalytic H2 production.

Charge-orbital synergistic engineering of TM@Ti3C2O1-xBx for highly selective CO2 electrochemical reduction.

Inspired by MXene nanosheets and their regulation of surface functional groups, a series of Ti3C2-MXene-based single TM atom electrocatalysts with a doped boron (B) atom (TM@Ti3C2O2-xBx, TM is V, Cr, Mn, Fe, Co or Ni, x = 0.11) are proposed for achieving a high performance catalytic CO2 reduction reaction (CO2RR). The results reveal that the doped B atom involves in the adsorption reaction of CO2 molecules and CO intermediates in the CO2RR. The TM-to-C and B-to-C π-back bonding contribute to the activation of the CO2 molecules and CO intermediates in the CO2RR. Enough electrons from the single TM atom and B atom occupied orbitals can be injected into the CO2 molecules and *CO intermediates through direct bonding interactions, which effectively alleviates the difficulty of the first hydrogenation reaction step and further helps CO reduction towards CH4. The calculated values of ΔG for the first hydrogenation reaction and the formation of *CHO on Ti3C2O2-xBx are significantly smaller than those of other single-atom catalysts (SACs). Fe@Ti3C2O2-xBx is found to have the highest electrocatalytic activity with a limiting potential of ∼0.40 V and exhibits a high selectivity for obtaining CH4 through the CO2RR compared with the hydrogen evolution reaction. This work is expected to open a research path for engineering the charge-orbital state of the innate atoms of a substrate based on mechanistic insights, which guides the rational design of highly selective MXene-based CO2RR electrocatalysts.

In Situ 1D Carbon Chain-Mail Catalyst Assembly for Stable Lithium-Sulfur Full Batteries.

The main obstacles for the commercial application of Lithium-Sulfur (Li-S) full batteries are the large volume change during charging/discharging process, the shuttle effect of lithium polysulfide (LiPS), sluggish redox kinetics, and the indisciplinable dendritic Li growth. Especially the overused of metal Li leads to the low utilization of active Li, which seriously drags down the actual energy density of Li-S batteries. Herein, an efficient design of dual-functional CoSe electrocatalyst encapsulated in carbon chain-mail (CoSe@CCM) is employed as the host both for the cathode and anode regulation simultaneously. The carbon chain-mail constituted by carbon encapsulated layer cross-linking with carbon nanofibers protects CoSe from the corrosion of chemical reaction environment, ensuring the high activity of CoSe during the long-term cycles. The Li-S full battery using this carbon chain-mail catalyst with a lower negative/positive electrode capacity ratio (N/P < 2) displays a high areal capacity of 9.68 mAh cm-2 over 150 cycles at a higher sulfur loading of 10.67 mg cm-2 . Additionally, a pouch cell is stable for 80 cycles at a sulfur loading of 77.6 mg, showing the practicality feasibility of this design.

Highly NH3 Sensitive and Selective Ti3C2O2-Based Gas Sensors: A Density Functional Theory-NEGF Study.

Ammonia (NH3) detection at the early stage is an important precaution for human health and agricultural production. However, conventional sensing materials are difficult to achieve all the targeted operational performances such as low power consumption and high selectivity. MXenes are a type of graphene-like emergent material equipped with abundant surface sites benefiting gas-sensing applications. In the work, we discuss the sensing performance of Ti3C2O2 to anticipate harmful and polluting NH3 gases by density functional theory and nonequilibrium Green's function. The adsorption geometry, charge difference density, and partial density of states are discussed to understand the nature of interactions between gas molecules and Ti3C2O2. The theoretical results show that only NH3 adsorbs onto the nanosheet through chemisorption. Then, a two-electrode Ti3C2O2-based gas sensor device is built to unravel the transport properties. Current under different bias voltages indicates the Ti3C2O2-based sensor could maintain extremely high sensitivity, demonstrating that Ti3C2O2 has great potential for the NH3 sensor with high selectivity, excellent sensitivity, and low energy consumption. Upon external electric fields, the adsorption energy and charge transfer can be tuned effectively, suggesting that Ti3C2O2 is a versatile agent as an ammonia-sensing material.

An Upper Bound Visualization of Design Trade-Offs in Adsorbent Materials for Gas Separations: CO2 , N2 , CH4 , H2 , O2 , Xe, Kr, and Ar Adsorbents.

The last 20 years have seen many publications investigating porous solids for gas adsorption and separation. The abundance of adsorbent materials (this work identifies 1608 materials for CO2 /N2 separation alone) provides a challenge to obtaining a comprehensive view of the field, identifying leading design strategies, and selecting materials for process modeling. In 2021, the empirical bound visualization technique was applied, analogous to the Robeson upper bound from membrane science, to alkane/alkene adsorbents. These bound visualizations reveal that adsorbent materials are limited by design trade-offs between capacity, selectivity, and heat of adsorption. The current work applies the bound visualization to adsorbents for a wider range of gas pairs, including CO2 , N2 , CH4 , H2 , Xe, O2 , and Kr. How this visual tool can identify leading materials and place new material discoveries in the context of the wider field is presented. The most promising current strategies for breaking design trade-offs are discussed, along with reproducibility of published adsorption literature, and the limitations of bound visualizations. It is hoped that this work inspires new materials that push the bounds of traditional trade-offs while also considering practical aspects critical to the use of materials on an industrial scale such as cost, stability, and sustainability.

The deformation of short-range order leading to rearrangement of topological network structure in zeolitic imidazolate framework glasses.

In recent years, the study of the glassy structure of zeolitic imidazolate frameworks (ZIFs) has been a key breakthrough in glass science. Yet the theoretical understanding of the structure of these complex materials is still in its infancy, especially the short-range structure. The short-structural disorder of two ZIFs and their corresponding molten structure, namely, ZIF-4 and ZIF-62 are studied, using ab initio simulations. Changes in short-range order are investigated, particularly the changes in bond length, bond angle, and tetrahedral unit volume. Furthermore, the asymmetric distribution of organic groups caused by the benzimidazole functional group leads to the difference in short-range disorder between ZIF-4 and ZIF-62 glasses, which contribute to the glass-forming ability difference.

Facile Melting-Crystallization Synthesis of Cs2NaxAg1-xInCl6: Bi Double Perovskites for White Light-Emitting Diodes.

Lead-free double perovskites (DPs) have outstanding luminescent properties, which make them excellent candidates for wide use in optoelectronics. Herein, a solvent-free melting-crystallization technique, which can produce kilogram-scale DP microcrystals (DP-MCs) in one batch, is invented to synthesize the Cs2NaxAg1-xInCl6: Bi (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) DP-MCs. The structure and composition analysis confirmed the products are pure Cs2NaxAg1-xInCl6 DP-MCs. Affected by Jahn-Teller distortion of AgCl6 octahedra, self-trapped excitons appear in the excited state, resulting in the broadband emission (400-850 nm) of Cs2Ag1-xNaxInCl6: Bi DP-MCs. The enhancement of the photoluminescence quantum yield can be realized by introducing Na+ to break the parity-forbidden transition in the Cs2AgInCl6 DP. Optimized Cs2Na0.4Ag0.6InCl6: Bi DP-MC phosphors combined with commercial blue and green phosphors were coated on ultraviolet chips (365 nm) to fabricate white light-emitting diodes (WLEDs) from warm white (2930 K) to cold white (6957 K). An ultrahigh color rendering index of 97.1 and a CCT of 5548 K as well as Commission Internationale de l'Eclairage color coordinates of (0.331, 0.339) have been demonstrated. This kilogram-scale synthesis technique could stimulate the industrial development of WLEDs for general lighting based on DP-MC phosphors.

Shedding light on the energy applications of emerging 2D hybrid organic-inorganic halide perovskites.

Unique performance of the hybrid organic-inorganic halide perovskites (HOIPs) has attracted great attention because of their continuous exploration and breakthrough in a multitude of energy-related applications. However, the instability and lead-induced toxicity that arise in bulk perovskites are the two major challenges that impede their future commercialization process. To find a solution, a series of two-dimensional HOIPs (2D HOIPs) are investigated to prolong the device lifetime with highly efficient photoelectric conversion and energy storage. Herein, the recent advances of 2D HOIPs and their structural derivatives for the energy realms are summarized and discussed. The basic understanding of crystal structures, physicochemical properties, and growth mechanisms is presented. In addition, the current challenges and future directions to provide a roadmap for the development of next generation 2D HOIPs are prospected.

The Atomic Structure and Mechanical Properties of ZIF-4 under High Pressure: Ab Initio Calculations.

The effects of pressure on the structural and electronic properties and the ionic configuration of ZIF-4 were investigated through the first-principles method based on the density functional theory. The elastic properties, including the isotropic bulk modulus K, shear modulus G, Young's modulus E, and Poisson's ratio ν of the orthorhombic-type structure ZIF-4 were determined using the Voigt-Reuss-Hill averaging scheme. The results show that the ZIF-4 phase is ductile according to the analysis of K/G and Cauchy pressure. The Debye temperatures obtained from the elastic stiffness constants increase with increasing pressure. Finally, the pressure-dependent behaviors of the density of states and ionic configuration are successfully calculated and discussed.

Improving the Catalytic CO2 Reduction on Cs2AgBiBr6 by Halide Defect Engineering: A DFT Study.

Pb-free double halide perovskites have drawn immense attention in the potential photocatalytic application, due to the regulatable bandgap energy and nontoxicity. Herein, we first present a study for CO2 conversion on Pb-free halide perovskite Cs2AgBiBr6 under state-of-the-art first-principles calculation with dispersion correction. Compared with the previous CsPbBr3, the cell parameter of Cs2AgBiBr6 underwent only a small decrease of 3.69%. By investigating the adsorption of CO, CO2, NO, NO2, and catalytic reduction of CO2, we found Cs2AgBiBr6 exhibits modest adsorption ability and unsatisfied potential determining step energy of 2.68 eV in catalysis. We adopted defect engineering (Cl doping, I doping and Br-vacancy) to regulate the adsorption and CO2 reduction behavior. It is found that CO2 molecule can be chemically and preferably adsorbed on Br-vacancy doped Cs2AgBiBr6 with a negative adsorption energy of -1.16 eV. Studying the CO2 reduction paths on pure and defect modified Cs2AgBiBr6, Br-vacancy is proved to play a critical role in decreasing the potential determining step energy to 1.25 eV. Finally, we probe into the electronic properties and demonstrate Br-vacancy will not obviously promote the process of catalysis deactivation, as there is no formation of deep-level electronic states acting as carrier recombination center. Our findings reveal the process of gas adsorption and CO2 reduction on novel Pb-free Cs2AgBiBr6, and propose a potential strategy to improve the efficiency of catalytic CO2 conversion towards practical implementation.

Riemerella anatipestifer infection affects intestinal barrier structure and immune reactions in the duck caecum.

Riemerella anatipestifer (RA) infection causes high mortality and poor feed conversion, leading to great economic losses to the duck industry. This study investigated the effects of RA on the intestinal morphology and immune response of ducks. Histological examination showed that RA infection caused intestinal injury, including significantly reduced mucosal thickness on days 2, 3 and 5, significantly reduced villus height on days 1, 2, 3 and 5 (P < 0.05) and significantly reduced villus height to crypt depth ratios on days 2, 3, 5 and 9 of RA infection (P < 0.05). The expression of intestinal mucosal layer construction-associated genes and tight junction genes was significantly altered on at least one time point (day 1, 2, 3, 5, 9 or 14) after RA infection. Quantitative real-time polymerase chain reaction revealed that RA infection affected intestinal mucosal immune function. The genes encoding TLR4 (toll like receptor-4), TRAF6 (TNF receptor-associated factor 6), MYD88 (myeloid differentiation factor 88), IFN-γ (interferon-γ), IL (interleukin)-4 and IL-8 were significantly upregulated on day 2 of RA infection. Taken together, these results indicate that RA infection negatively affects intestinal barrier function in ducks due to impaired mucosal and villus-crypt structure and alters the mRNA expression of mucous layer construction-, intestinal tight junction-, and intestinal mucosal immunity-related genes.

Effects of ammonia on intestinal microflora and productive performance of laying ducks.

Atmospheric ammonia is harmful to poultry and human health. The effect of ammonia on the intestinal microflora of laying ducks is still unknown. In this study, the effects of atmospheric ammonia and exposure time on the intestinal microflora of laying ducks were investigated using 16S rDNA sequencing technology. The body weight, ovary weight, spleen weight, liver weight, and productive performance of laying ducks were also recorded, and the relationship between intestinal microflora diversity and productive performance was analyzed. The results showed that Bacteroidetes, Firmicutes, and Proteobacteria were the dominant bacterial phyla. At the phylum and genus levels, with the exception of the phylum Firmicutes and the genus Sutterella, the top 10 most abundant phyla and genera differed significantly when the ammonia concentration was increased from 10 to 75 ppm and/or the exposure time was extended from 10 to 30 D. Laying rate was highly significantly lower in ducks exposed to 75 ppm ammonia for 10 D compared with those exposed to 10 ppm ammonia for 10 D. Body, ovary, and spleen weights also decreased when the ammonia concentration was increased. At the genus level, Flavonifractor was highly significantly positively correlated with ovary weight. Methanocorpusculum and Anaerotruncus were significantly positively correlated with ovary weight. Lactobacillus was significantly positively correlated with spleen weight. Phascolarctobacterium, Sphaerochaeta, Erysipelotrichaceae_UCG.004, and Lactococcus were significantly positively correlated with spleen weight. These results indicated that ammonia affected the diversity of the intestinal microbiota and the productive performance of laying ducks. Several intestinal microbiota genera were also correlated with organ weights.

[Simultaneous extraction and determination of nine chemically synthetic anticoccidial drug multi-residues in chicken meat using high performance liquid chromatography-tandem mass spectrometry].

A high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/ MS) method was developed for the simultaneous extraction and determination of multi-residues of nine chemically synthetic anticoccidial drugs in chicken meat. Toltrazuril-D3 was used as the internal standard. The sample was extracted by 15 mL acetonitrile/dimethyl sulfoxide (4:1, v/ v, containing 2% acetic acid), cleaned-up by a QuEChERS (quick, easy, cheap, effective, rugged and safe) clean-up tube with 150 mg octadecylsilyl (ODS), 100 mg Florisil and 100 mg graphitized carbon black (GCB). After the concentration, the extract was analyzed by HPLC-MS/MS. The results showed that good linearity in the range of 20 - 150 microg/L for each target compound. The recoveries were between 81.5% and 103. 6% with the relative standard deviations lower than 15%. The method is simple, rapid, and suitable to detect the chemically synthetic anticoccidial drug residues with high throughput.

[Comparison of pretreatment methods for the simultaneous determination of diclazuril and toltrazuril residues in chicken tissues].

The effects of four pretreatment methods (acetonitrile extraction-evaporation concentration, acetonitrile extraction-solid phase extraction (SPE), matrix solid-phase dispersion (MSPD) extraction and MSPD-SPE) for the simultaneous analysis of diclazuril and toltrazuril residues in chicken tissues were compared. The average recovery of 70% for the former three methods as achieved. In comparison with other methods, the MSPD method saved more than 60% in time and solvent. So, MSPD as the sample pretreatment method, an MSPD-high performance liquid chromatography with ultraviolet detection (MSPD-HPLC/UV) method was established for the analysis. Under the optimal chromatographic conditions, the linear range was between 50 and 1,000 microg/kg. At the added levels of 50, 500, 1,000 ng/g, the recoveries of diclazuril and toltrazuril in chicken tissues ranged from 71.13% - 84.02% with the relative standard deviations (RSD) in the range of 3.76% - 12.11%, and the RSDs of intra- and interday analyses ranged from 3.70% - 6.77%. The detection limits of diclazuril and toltrazuril were less than 10 microg/kg. The quantitative limits of diclazuril and toltrazuril were less than 20 microg/kg. The method meet the requirements of the residue analysis on accuracy and precision.

[Simultaneous determination of residues of three fluoroquinolones in chicken using high performance liquid chromatography with post-column derivatization and terbium sensitized fluorescence].

A method of high performance liquid chromatography with post-column derivatization and terbium sensitized fluorescence for simultaneous determination of residues of ciprofloxacin, norfloxacin and enrofloxacin in chicken was established, based on the effect that Tb3+ can sensibilize fluorescence of fluoroquinolones. Under the optimal chromatographic condition, three fluoroquinolones were separated on a C18 column with 0.05 mol/L acetic acid/acetate buffer-acetonitrile (89:11, v/v) as the mobile phase, and at a flow rate of 0.8 mL/min; then were derivatized with 8 x 10(-5) mol/L Tb3+ at 40 degrees C, and at a flow rate of 0.5 mL/min; finally were detected using a fluorescence detector (lamda(ex) = 271 nm, lamda(em) = 545 nm). The recoveries of three fluoroquinolones ranged from 66.3%-88.0% at the added levels of 1.0, 10.0, 50.0, and 100.0 ng/g, and the relative standard deviations (RSDs) were less than 15.0%. The linear range for quantitative analysis was between 0.1 and 500 ng/mL. All the RSDs of the inter-day and intra-day analyses were less than 13.0%. The detection limits were 0.05 ng/g for ciprofloxacin and norfloxacin and 0.08 ng/g for enrofloxacin. The method is sensitive for the determination of multi-residues of fluoroquinolones in chicken.