摘要 : Engineering binary transitional metal sulfides (BTMSs)-based electrode materials with a rationally designed constituent architecture is a viable strategy for improving their rate capability and electrochemical durability, which provides a possibility for their application in supercapacitors (SCs). Herein, a novel three-dimensional (3D) flower bud-like phosphorus and tungsten co-doped NiCo 2 S 4 and MoS 2 composites (P, W-NCS@MS) is prepared on conductive carbon cloth using the hydrothermal method. The effects of P, W-doping, or MoS 2 -combination on the morphology, structure and electrochemical properties of NiCo 2 S 4 -based electrode materials are systematically studied. The designed P, W-NCS@MS achieves a high specific capacity of 1250C g −1 at 1 A g −1 and a satisfactory capacity retention of 80 % after 10, 000 cycles. In addition, the asymmetric supercapacitor (ASC) constructed through P, W-NCS@MS and activated carbon electrodes delivers a high energy density of 65.0 Wh kg −1 at the power density of 400 W kg −1 and shows satisfactory cycling stability of 85 % capacitance retention after 20, 000 cycles. Notably, the assembled ASC device successfully powered electronic devices in a serial circuit, highlighting its prospective applications in energy storage. This work offers a viable design approach for heteroatom doping and hierarchical interface structures in composite electrode materials toward high-performance SCs.

摘要 : Pyrethroids are widely used insecticides worldwide, while their on-site and rapid detection still faces technological challenges. Herein, an innovative detection mechanism was designed for deltamethrin, a typical kind of type II pyrethroids, based on a dual-emitting fluoroprobe consisting of NH 2 -SiQDs and Eu 3+ . Deltamethrin can rapidly hydrolyze into 3-phenoxybenzaldehyde (3-PBD) and react specifically with fluoroprobe, causing fluorescence quenching of SiQDs while maintaining the fluorescent stability of Eu 3+ . Building upon the above fluorescence-responsive principle, SiQDs@Eu 3+ provided satisfactorily dual-emitting signals, realizing the highly-selective and sensitive detection of deltamethrin. Correlation between the surface structure of SiQDs and their absorption spectra was in-depth unraveled by TD-DFT calculation and FT-IR analysis. As for the analytical performance, the recovery and LOD of deltamethrin in lettuce, provided by SiQDs@Eu 3+, were comparable or even superior over conventional chromatographic analysis. Meanwhile, an innovative smartphone-based optical device was developed, which greatly decreased errors caused by the previously reported smartphone-based fluorescence detection.

摘要 : The main challenges (sluggish electron transfer, low energy density) hinder the future application of enzymatic biofuel cells (EBFCs), which urgent to take effective measures to solve these issues. In this work, a composite of Au nanoparticles decorated graphdiyne (AuNPs@GDY) is fabricated and employed as the carrier of enzyme (G6PDH), and a mechanism based on π-π interaction of electron transfer is proposed to understand bioelectrocatalysis processes. The results show that the AuNPs@GDY composite exhibits the highest current density among the three materials (GDY, AuNPs, and AuNPs@GDY), which is 3.4 times higher than that of GDY and 2.5 times higher than that of AuNPs. Furthermore, the results reveal that the AuNPs could increase the loading of enzymes and provide more active site for reaction, while GDY provides highly π-conjugated structure and unique sp/sp 2 -hybridized linkages interface. This work provides new insights to explore a theoretical basis for the development of more efficient bioelectrocatalytic systems.

摘要 : Bi 2 S 3 is regarded as one of the most promising thermoelectric materials because of its abundance, cost-effectiveness and environmentally friendly characteristics. This work delves into the impact of interstitial Cu on the composition, microstructure, and thermoelectric properties of the Cl-doped Bi 2 S 3 bulks. The introduction of interstitial Cu as donors generates free electrons without compromising electron mobility. The excessive Cu induces the precipitation of Cu/Bi-rich phase and the Cu ions dynamically diffuse from these precipitates into the Bi 2 S 3 lattice with increasing temperature. This effect significantly enhances electrical conductivity and power factor across a broad temperature range. Intriguingly, dense nanodomains are successfully constructed in the Bi 2 S 3 sample. This unique defect, coupled with interstitial Cu, nanodomains, precipitates, and dislocations, establishes the hierarchical structures, leading to a low lattice thermal conductivity of 0.34 W m −1 K −1 . Notably, the sample incorporating 4 at% Cu achieves an exceptional peak ZT value of 0.67 at 673 K.

摘要 : Nickel-iron based (Ni-Fe) catalysts are widely used in the electrolysis of water due to their high activity and low cost. However, the development of highly active non-precious metal catalysts is still a great challenge. Herein, self-supported nickel–iron phosphide is fabricated through a sulfurization/phosphorization approach (Ni-Fe-P-S-1/Ni-Fe-P-S-2). The prepared catalysts show excellent catalytic performance and stability. The HER performance of Ni-Fe-P-S-1 reaches 500 mA cm −2 with small overpotentials of 289 mV in alkaline freshwater. Meanwhile, the Ni-Fe-P-S-2 requires 312 and 375 mV to reach 500 mA cm −2 in alkaline freshwater and alkaline seawater for OER. Remarkably, at the current density of 500 mA cm −2, the Ni-Fe-P-S-1||Ni-Fe-P-S-2 electrolyzer requires only 1.85 V in alkaline. Interestingly, sustainable energies can power the electrolyzer effectively. The work provides methods for potentially promising and cost-effective electrocatalysts.

摘要 : Microbial polysaccharides (MPs) are biopolymers secreted by microorganisms such as bacteria and fungi during their metabolic processes. Compared to polysaccharides derived from plants and animals, MPs have advantages such as wide sources, high production efficiency, and less susceptibility to natural environmental influences. The most attractive feature of MPs lies in their diverse biological activities, such as antioxidative, anti-tumor, antibacterial, and immunomodulatory activities, which have demonstrated immense potential for applications in functional foods, cosmetics, and biomedicine. These bioactivities are precisely regulated by their sophisticated molecular structure. However, the mechanisms underlying this precise regulation are not yet fully understood and continue to evolve. This article presents a comprehensive review of the most representative species of MPs, including their fermentation and purification processes and their biomedical applications in recent years. In particular, this work presents an in-depth analysis into the structure-activity relationships of MPs across multiple molecular levels. Additionally, this review discusses the challenges and prospects of investigating the structure-activity relationships, providing valuable insights into the broad and high-value utilization of MPs.

摘要 : Capturing organics from wastewater is recognized as the initial step towards carbon valorization, since the direct valorization of organics in domestic wastewater is limited by the low concentration. An innovative method was proposed in our former research, which utilizes captured organics from wastewater as raw material for producing a coarse flocculant, thereafter, using the coarse flocculant to capture organics from wastewater in a cyclical manner. Hydrothermal processing (HTP) and chemical modification are jointly applied to coarse flocculant production . Besides, the hydrothermal liquid fraction of concentrated organic matter was indicated as the potential effective precursor. However, the role of hydrothermal liquid fraction as precursor for coarse flocculant and the regulatory mechanism remain unclear. Therefore, this study aims to evaluate the characteristics of the hydrothermal liquid fraction under different alkaline addition, temperature and time from the perspective of coarse flocculant preparation. The results demonstrated that the dissolved polymeric substances extracting through HTP and acid precipitation process exhibit a high molecular weight (reaching up to 9929 Da) and abundant functional groups (including C O, C N, OH, C O C, etc.). Furthermore, the addition of NaOH, along with relatively moderate temperature and time were recommended for producing the flocculant precursor. Specifically, this study suggests a temperature of 140 °C and a duration of 30 min for the flocculant precursor producing.

摘要 : Chemical-nose strategy has achieved certain success in the discrimination and identification of pathogens. However, this strategy usually relies on non-specific interactions, which are prone to be significantly disturbed by the change of environment thus limiting its practical usefulness. Herein, we present a novel chemical-nose sensing approach leveraging the difference in the dynamic metabolic variation during peptidoglycan metabolism among different species for rapid pathogen discrimination. Pathogens were first tethered with clickable handles through metabolic labeling at two different acidities (pH = 5 and 7) for 20 and 60 min, respectively, followed by click reaction with fluorescence up-conversion nanoparticles to generate a four-dimensional signal output. This discriminative multi-dimensional signal allowed eight types of model bacteria to be successfully classified within the training set into strains, genera, and Gram phenotypes. As the difference in signals of the four sensing channels reflects the difference in the amount/activity of enzymes involved in metabolic labeling, this strategy has good anti-interference capability, which enables precise pathogen identification within 2 h with 100% accuracy in spiked urinary samples and allows classification of unknown species out of the training set into the right phenotype. The robustness of this approach holds significant promise for its widespread application in pathogen identification and surveillance.

摘要 : Thermodynamic inhibitors may be used to inhibit hydrate formation in industry. Alcohol substances, due to their hydrophilic hydroxyl groups in their molecular structure, are prone to form hydrogen bond with water molecules to inhibit hydrate formation. In this work, sec -butyl alcohol is chosen to study the effects on CO 2 hydrate dissociation equilibrium conditions, where the step-heating method is utilized to obtain hydrate equilibrium conditions. The equilibrium curve of carbon dioxide hydrate dissociation moves to the region of lower temperatures or higher pressures. The higher mass fraction of sec -butyl alcohol, the better effect of inhibiting hydrate formation. Sec-butyl alcohol can be used as a thermodynamic hydrate inhibitor.

摘要 : The polycrystalline Yb 23 Cu 7 Mg 4 -type {Gd, Tb} 23 Ni 7 In 4 compounds (space group P 6 3 / mmc, N 194, hP 68) were prepared by arc melting with following annealing. They exhibit ferromagnetic ordering below Curie temperature T C = 142 K for Gd 23 Ni 7 In 4 and T C = 112 K for Tb 23 Ni 7 In 4, respectively. A field-sensitive antiferromagnetic transformation takes place around 90 K in Gd 23 Ni 7 In 4 and 106 K in Tb 26 Ni 7 In 4, respectively. Down to 10 K, they are soft ferromagnets with magnetizations of 4.7 μ B /Gd for Gd 23 Ni 7 In 4 and 5.7 μ B /Tb for Tb 23 Ni 7 In 4 in 90 kOe. In a field change of 50 kOe around T C, Gd 23 Ni 7 In 4 shows magnetic entropy change of −4.7 J/kg⋅K at 133–143 K, while Tb 23 Ni 7 In 4 shows magnetic entropy change of −5.4 J/kg⋅K at 109 K.