Search

Zinc‐air batteries (ZABs) have the advantages of high energy density and rich zinc raw materials. It is a low‐cost, green and sustainable energy storage device. At present, one of the key technologies that hinder the large‐scale application of ZABs is the design and fabrication oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) bifunctional catalysts with excellent performance, especially the non‐platinum‐based catalysts. Here N‐doped carbon‐coated Fe‐based selenium oxide catalyst Fe2O(SeO3)2/Fe3C@NC with high performance has been fabricated by a one‐step pyrolysis and then the electrochemical oxidization. The experimental results confirmed that the existence of Fe−O−Se bonds in Fe2O(SeO3)2 crystal phase of Fe2O(SeO3)2/Fe3C@NC, and the Fe−O−Se bonds could obviously enhance ORR and OER catalytic performance of Fe2O(SeO3)2/Fe3C@NC. Density functional theoretical calculations (DFT) confirmed that the Fe2O(SeO3)2 in Fe2O(SeO3)2/Fe3C@NC had a higher d‐band center of Fe atom and a lower p‐orbital coupling degree with its own lattice O atom than Fe2O3, which leads to Fe site of Fe2O(SeO3)2 being more likely to adsorb external oxygen intermediates. The Fe−O−Se bonds in Fe2O(SeO3)2 results in the modification of coordination environment of Fe atoms and optimizes the adsorption energy of Fe site for oxygen intermediates. Compared with Fe2O3/Fe3C@NC, the Fe2O(SeO3)2/Fe3C@NC showed the obvious enhancements of ORR/OER catalytic activities with a half‐wave potential of 0.91 V for ORR in 0.1 M KOH electrolyte and a low overpotential of 345 mV for OER at 10 mA cm−2 in a 1.0 M KOH electrolyte. The peak power density and specific capacity of Fe2O(SeO3)2/Fe3C@NC‐based ZABs are higher than those of Pt/C+RuO2‐ZABs. The above results demonstrate that the asymmetrical Fe−O−Se bonds in Fe2O(SeO3)2 plays a key role in improving the bifunctional catalytic activities of ORR/OER for ZABs. [ABSTRACT FROM AUTHOR]

In recent years, with the global response to the emission reduction pressure caused by climate change, global awareness of green hydrogen has progressively grown. Electrolysis of water is the only way to create green hydrogen. Among them, one of the semi-reactions of the electrolysis of water is the oxygen evolution reaction (OER). One of the bottlenecks limiting the total energy efficiency of green hydrogen production from water electrolysis is its intricate four-electron transfer process. Developing highly efficient oxygen evolution catalysts is essential to increasing the efficiency of the water electrolysis process. Therefore, researchers have been exploring high-performance OER catalysts. In recent years, heterostructured electrocatalysts have shown surprisingly good performance in OER processes due to their unique structural characteristics, including synergistic effects, strain effects, and electronic interactions. This paper reviews the reaction mechanism of the OER in various pH environments, highlights the advantages of heterostructure catalysts, and provides an overview of OER heterostructure electrocatalysts. This review focuses mainly on the overall facilitating effect of heterostructures on the OER process. The aim is to emphasize the advantages of heterostructure catalysts over one-component catalysts. The paper discusses the preparation of heterostructures and explores the relationship between their structures and electrochemical properties. By providing new insights into the interfacial chemistry of OER heterostructure electrocatalysts, this review sheds light on the future opportunities and challenges for developing OER heterostructure catalysts, both in terms of fundamental understanding and practical applications. [ABSTRACT FROM AUTHOR]

Natalisin (NTL) is a conserved neuropeptide, only present in insects, that has been reported to regulate their sexual activity. In this study, we investigated the involvement of NTL in the reproductive behaviors of a major invasive pest, Spodoptera frugiperda. We identified NTL precursor-encoded transcripts, and evaluated their transcript levels in different stages and tissues of S. frugiperda. The results showed that the NTL transcript level was expressed in both male and female pupae and both male and female adults in the later stage. It was highly expressed in male pupae, 3-day-old male and female adults, and 5-day-old male adults. In different tissues, the expression level is higher in the male and female adult brain and male testis. Immunohistochemical staining of the brain of S. frugiperda female and male adults revealed that three pairs of brain neurons of S. frugiperda adults of both sexes secreted and expressed NTL. To study the role of NTL in reproductive behaviors, NTL was silenced in S. frugiperda male and female adults by RNA interference (RNAi) technology, the results showed that silencing NTL could significantly affect the sexual activity behavior of the adults, reducing the calling rate of females, the courtship rate of males, and the mating rate. In summary, this study emphasizes the important role of NTL in regulating the mating behavior and sexual activity of S. frugiperda in both male and female adults, potentially laying a foundation to employ NTL as a new insect-specific target to control populations of pest insects. [ABSTRACT FROM AUTHOR]

Background Dendrobium huoshanense (DHS) is a classic traditional Chinese medicine (TCM) with distinctive medicinal benefits and great economic worth; nevertheless, because of similar tastes and looks, it is simple to adulterate with less expensive substitutes (such as Dendrobium henanense [ DHN ]). Objective This work aimed to develop a reliable tool to detect and quantify the adulteration of DHS with DHN by using UV-Vis-shortwave near-infrared diffuse reflectance spectroscopy (UV-Vis-SWNIR DRS) combined with chemometrics. Methods Adulterated samples prepared in varying concentrations (0–100%, w/w) were analyzed with UV-Vis-SWNIR DRS methods. Partial least-square-discriminant analysis (PLS-DA) and partial least-squares (PLS) regression techniques were used for the differentiation of adulterated DHN from pure DHS and the prediction of adulteration levels. Results The PLS-DA classification models successfully differentiated adulterated and nonadulterated DHS with an over 100% correct classification rate. UV-Vis-SWNIR DRS data were also successfully used to predict adulteration levels with a high coefficient of determination for calibration (0.9924) and prediction (0.9906) models and low error values for calibration (3.863%) and prediction (5.067%). Conclusion UV-Vis-SWNIR DRS, as a fast and environmentally friendly tool, has great potential for both the identification and quantification of adulteration practices involving herbal medicines and foods. Highlights UV-Vis-SWNIR DRS combined with chemometrics can be applied to identify and quantify the adulteration of herbal medicines and foods. [ABSTRACT FROM AUTHOR]

Water electrolysis has become an attractive hydrogen production method. Oxygen evolution reaction (OER) is a bottleneck of water splitting as its four-electron transfer procedure presents sluggish reaction kinetics. Designing composite catalysts with high performance for efficient OER still remains a huge challenge. Here, the P-doped cobalt oxide/NiFe layered double hydroxides (P-CoO X /NiFe LDHs) composite catalysts with amorphous/crystalline interfaces are successfully prepared for OER by hydrothermal-electrodeposition combined method. The results of electrochemical characterizations, operando Raman spectra, and DFT theoretical calculations have demonstrated the electrons in the P-CoO X /NiFe LDHs heterointerfaces are easily transferred from Ni 2+ to Co 3+ because that the amorphous configuration of P-CoO X can well induce Ni-O-Co orbital coupling. The electron transfer of Ni 2+ to the surrounding Fe 3+ and Co 3+ will lead to the unoccupied e g orbitals of Ni 3+ that can promote water dissociation and accelerate * OOH migration to improve OER catalytic performance. The optimized P-CoO X /NiFe LDHs exhibit superior catalytic performance for OER with a very low overpotential of 265 mV at 300 mA cm -2 and excellent long-term stability of 500 h with almost no attenuation at 100 mA cm -2 . This work will provide a new method to design high-performance NiFe LDHs-based catalysts for OER., (© 2024 Wiley‐VCH GmbH.)

cis-Prenyltransferases (cis-PTs) catalyze the sequential head-to-tail condensation of isopentenyl diphosphate (IPP) to allylic diphosphates, producing mixed E-Z prenyl diphosphates of varying lengths; however, the specific enzymes synthesizing cis-C 25 prenyl diphosphates have not been identified. Herein, we present the discovery and characterization of a cis-geranylfarnesyl diphosphate synthase (ScGFPPS) from Streptomyces clavuligerus. This enzyme demonstrates high catalytic proficiency in generating six distinct cis-polyisoprenoids, including three C 25 and three C 20 variants. We determined the crystal structure of ScGFPPS. Additionally, we unveil the crystal structure of nerylneryl diphosphate synthase (NNPS), known for synthesizing an all-cis-C 20 polyisoprenoid. Comparative structural analysis of ScGFPPS and NNPS has identified key differences that influence product specificity. Through site-directed mutagenesis, we have identified eight single mutations that significantly refine the selectivity of ScGFPPS for cis-polyisoprenoids. Our findings not only expand the functional spectrum of cis-PTs but also provide a structural comparison strategy in cis-PTs engineering., (© 2024 Wiley-VCH GmbH.)

The development of efficient urea oxidation reaction (UOR) catalysts helps UOR replace the oxygen evolution reaction (OER) in hydrogen production from water electrolysis. Here, we prepared Fe-doped Ni 2 P/NiSe 2 composite catalyst (Fe-Ni 2 P/NiSe 2 -12) by using phosphating-selenizating and acid etching to increase the intrinsic activity and active areas. Spectral characterization and theoretical calculations demonstrated that electrons flowed through the Ni-P-Fe-interface-Ni-Se-Fe, thus conferring high UOR activity to Fe-Ni 2 P/NiSe 2 -12, which only needed 1.39 V vs RHE to produce the current density of 100 mA cm -2 . Remarkably, this potential was 164 mV lower than that required for the OER under the same conditions. Furthermore, EIS demonstrated that UOR driven by the Fe-Ni 2 P/NiSe 2 -12 exhibited faster interfacial reactions, charge transfer, and current response compared to OER. Consequently, the Fe-Ni 2 P/NiSe 2 -12 catalyst can effectively prevent competition with OER and NSOR, making it suitable for efficient hydrogen production in UOR-assisted water electrolysis. Notably, when water electrolysis is operated at a current density of 40 mA cm -2 , this UOR-assisted system can achieve a decrease of 140 mV in the potential compared to traditional water electrolysis. This study presents a novel strategy for UOR-assisted water splitting for energy-saving hydrogen production.

A long-term goal of rechargeable zinc-air batteries (ZABs) has always been to design bifunctional electrocatalysts that are robust, effective, and affordable for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). It has become a feasible method to construct metal/metal oxide interfaces to achieve superior electrocatalytic performance for ORR and OER by enhanced charge transfer. In this study, Co/Co 3 O 4 heterojunctions were successfully prepared and encased in porous N-doped mesoporous carbon (Co/Co 3 O 4 @NC) via a simple condensation-carbonization-etching method. The extensive specific surface area of Co/Co 3 O 4 @NC facilitates effective interaction between the electrolyte and the catalyst, thereby enabling sufficient exposure of active sites for the ORR and the OER, consequently enhancing the rate of transport of active species. The well-designed Co/Co 3 O 4 @NC delivers superior ORR catalytic activity with a half-wave potential of 0.82 V (vs RHE) and a low overpotential of 347 mV at 10 mA cm -2 for OER in alkaline solution. The power density of Co/Co 3 O 4 @NC-based alkaline aqueous ZAB (156.5 mW cm -2 ) is superior to the commercial Pt/C + IrO 2 -based alkaline aqueous ZAB, and the cycling stability of ZAB is up to 220 h. In addition, Co/Co 3 O 4 @NC-based ZAB shows a high power density (50.1 mW cm -2 ). The construction of metal/metal oxide heterojunction encased in N-doped mesoporous carbon provides a novel route for the design of bifunctional electrocatalysts for high-performance ZABs.