Oxidation Research Articles

Integrated metabolomic and transcriptomic strategies to reveal adaptive mechanisms in barley plant during germination stage under waterlogging stress.

Barley (Hordeum vulgare L.) is an important cereal crop used in animal feed, beer brewing, and food production. Waterlogging stress is one of the prominent abiotic stresses that has a significant impact on the yield and quality of barley. Seed germination plays a critical role in the establishment of seedlings and is significantly impacted by the presence of waterlogging stress. However, there is a limited understanding of the regulatory mechanisms of gene expression and metabolic processes in barley during the germination stage under waterlogging stress. This study aimed to investigate the metabolome and transcriptome responses in germinating barley seeds under waterlogging stress. The findings of the study revealed that waterlogging stress sharply decreased seed germination rate and seedling growth. The tolerant genotype (LLZDM) exhibited higher levels of antioxidase activities and lower malondialdehyde (MDA) content in comparison to the sensitive genotype (NN). In addition, waterlogging induced 86 and 85 differentially expressed metabolites (DEMs) in LLZDM and NN, respectively. Concurrently, transcriptome analysis identified 1776 and 839 differentially expressed genes (DEGs) in LLZDM and NN, respectively. Notably, the expression of genes associated with redox reactions, hormone regulation, and other biological processes were altered in response to waterlogging stress. Furthermore, the integrated transcriptomic and metabolomic analyses revealed that the DEGs and DEMsimplicated in mitigating waterlogging stress primarily pertained to the regulation of pyruvate metabolism and flavonoid biosynthesis. Moreover, waterlogging might promote flavonoid biosynthesis by regulating 15 flavonoid-related genes and 10 metabolites. The present research provides deeper insights into the overall understanding of waterlogging-tolerant mechanisms in barley during the germination process.

Highly efficient bifunctional zeolitic imidazolate framework-derived carbon-supported platinum-based nanocatalysts for enhancing methanol oxidation reaction and oxygen reduction reaction

Highly efficient bifunctional zeolitic imidazolate framework-derived carbon-supported platinum-based nanocatalysts for enhancing methanol oxidation reaction and oxygen reduction reaction

Inhibitors of NADH-O-methylquinone compound a class of antitubercular drugs.

Disruption of the mycobacterial redox homeostasis leads to irreversible stress induction and cell death. Hydroquinone scaffolds, as a new type of redox cycling anti-tuberculosis chemotypes, exhibit potent bactericidal activity against non-replicating, nutrient-deprived phenotypically drug-resistant bacteria. Evidences from microbiological, biochemical, and genetic studies indicate that the redox-driven mode of action relies on the reduction of quinones by type II NADH dehydrogenase (NDH2), generating reactive oxygen species (ROS) of bactericidal level. This study demonstrates that (S)-Peniphenone D possesses significant resistance to Mycobacterium marinum (M. marinum) infection, as it enables redox cycling within M. marinum cells, ROS production, and reduction of intracellular NADH levels. The results suggest that hydroquinone compounds, due to their distinctive biological activities, could serve as novel sources for antibacterial drugs, particularly in developing scaffolds for new anti-tuberculosis agents.

Operando Synchrotron X-Ray Absorption Spectroscopy: A Key Tool for Cathode Material Studies in Next-Generation Batteries.

Rechargeable batteries are central to modern energy storage systems, from portable electronics to electric vehicles. The cathode material, a critical component, largely dictates a battery's energy density, capacity, and overall performance. This review focuses on the application of operando X-ray absorption spectroscopy (XAS) to study cathode materials in Li-ion, Na-ion, Li-S, and Na-S batteries. Operando XAS provides real-time insights into the local electronic structure, oxidation states, and coordination environments, which are crucial for understanding complex electrochemical processes, such as redox reactions, phase transitions, and structural degradation. The review highlights the strengths of hard and soft XAS techniques in probing transition metal (TM) and anionic redox processes, particularly in layered oxide cathodes, where reversible oxygen redox and TM behavior are pivotal. The role of operando XAS is also explored in analyzing conversion-type S-based cathodes, where it helps unravel the intricate reaction mechanisms. Furthermore, the review addresses the challenges of in situ cell design for operando XAS, especially under ultrahigh vacuum conditions for soft XAS. By discussing recent advancements and future directions, this review underscores the critical role of operando XAS in driving innovation and improving the design and performance of next-generation battery technologies.

High Capacity and Ultralong Lifespan Aqueous Lithium-Bromine Batteries Realized by Low-Cost Concentrated Electrolyte Coupled with Dependable Lithium Titanium Phosphate.

Aqueous halogen batteries are gaining recognition for large-scale energy storage due to their high energy density, safety, environmental sustainability, and cost-effectiveness. However, the limited electrochemical stability window of aqueous electrolytes and the absence of desirable carbonaceous hosts that facilitate halogen redox reactions have hindered the advancement of halogen batteries. Here, a low-cost, high-concentration 26 m Li-B5-C15-O6 aqueous solution incorporating lithium bromide (LiBr), lithium chloride (LiCl), and lithium acetate (LiOAc) was developed for aqueous batteries, which demonstrated an expanded electrochemical stability window of ca. 2.5 V. In addition, the electrochemical performance of the electrolyte in various carbonaceous hosts (graphene, activated carbon, and nitrogen-doped activated carbon (NAc)) was systematically investigated. In-depth analysis using X-ray photoelectron spectroscopy and Raman spectroscopy revealed that the NAc host promoted the redox kinetics of active bromine species and improved the delivery capacity of the battery. Results revealed that the electrolyte in the NAc host achieved a discharge specific capacity exceeding 376 mA h g-1 while maintaining a capacity retention rate of up to 97% after 7800 cycles. When paired with hierarchically porous LTP@C/CNTs anode material, a LTP@C/CNTs-NAc full cell was constructed, which delivered a discharge specific capacity of 238.4 mA h g-1 and an average output voltage of 1.24 V. Moreover, it demonstrated a reversible specific capacity of 158.2 mA h g-1 with near-complete Coulombic efficiency over more than 10,000 cycles.

The Pseudomonas ligninolytic catalytic network reveals the importance of auxiliary enzymes in lignin biocatalysts

Lignin degradation by biocatalysts is a key strategy to develop a plant-based sustainable carbon economy and thus alleviate global climate change. This process involves synergy between ligninases and auxiliary enzymes. However, auxiliary enzymes within secretomes, which are composed of thousands of enzymes, remain enigmatic, although several ligninolytic enzymes have been well characterized. Moreover, it is a challenge to understand synergistic lignin degradation via a diverse array of enzymes, especially in bacterial systems. In this study, the coexpression network of the periplasmic proteome uncovers potential accessory enzymes for B-type dye-decolorizing peroxidases (DypBs) in Pseudomonas putida A514. The catalytic network of the DypBs-based multienzyme complex is characterized. DypBs couple with quinone reductases and nitroreductase to participate in quinone redox cycling. They work with superoxide dismutase to induce Fenton reaction for lignin oxidation. A synthetic enzyme cocktail (SEC), recruiting 15 enzymes, was consequently designed with four functions. It overcomes the limitation of lignin repolymerization, exhibiting a capacity comparable to that of the native periplasmic secretome. Importantly, we reveal the synergistic mechanism of a SEC-A514 cell system, which incorporates the advantages of in vitro enzyme catalysis and in vivo microbial catabolism. Chemical analysis shows that this system significantly reduces the molecular weight of lignin, substantially extends the degradation spectra for lignin functional groups, and efficiently metabolizes lignin derivatives. As a result, 25% of lignin is utilized, and its average molecular weight is reduced by 27%. Our study advances the knowledge of bacterial lignin-degrading multienzymes and provides a viable lignin degradation strategy.

A special two-working-electrode system: a summary of recent development in fabrication and application of interdigitated array electrodes.

The utilization of dual-working-electrode mode of interdigitated array (IDA) electrodes and other two-electrode systems has revolutionized electrochemical detection by enabling the simultaneous and independent detection of two species, accompanied by the exhibition of unique characteristics. In contrast to conventional dual-potential electrodes, such as the rotating ring disk electrodes (RRDE), IDA electrodes demonstrate analogous yet vastly improved performance, characterized by remarkable collection efficiency and sensitivity. Notably, due to the distinctive microscale structure of IDA electrode, the special "feedback" effect makes IDA a unique signal amplifier. In recent decades, the research surrounding IDA electrodes has garnered escalating interest due to their attractive attributes. This review centers its focus on the fabrication and applications of IDA electrodes. In fabrication, two critical breakthroughs are poised for realization: the achievement of reduced dimensions and the diversification of materials. Established fabrication methods for IDA electrodes encompass photolithography, inkjet printing, and direct laser writing, each affording distinct advantages in terms of size and precision in IDA construction. Predominantly employed materials for IDA electrodes include gold, platinum, and carbon, with the selection of fabrication methods guided by considerations such as material properties, desired dimensions, cost-efficiency, and specific application requisites. In terms of applications, IDA electrodes, capitalizing on their distinctive attributes, have found utility in diverse fields. This review summarizes the applications of IDA electrodes based on their fundamental working principles, encompassing redox cycling, resistance modulation, capacitance variations, and more. The potential for further development of this specialized tool to exhibit enhanced properties holds substantial promise.&#xD.

Rational Regulation of High-Entropy Perovskite Oxides through Hole Doping for Efficient Oxygen Electrocatalysis.

Due to the high configuration entropy, unique atomic arrangement, and electronic structures, high-entropy materials are being actively pursued as bifunctional catalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable zinc-air batteries (ZABs). However, a relevant strategy to enhance the catalytic activity of high-entropy materials is still lacking. Herein, a hole doping strategy has been employed to enable the high-entropy perovskite La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 to effectively catalyze the ORR and OER. Hole doping experiments rely on the substitution of Sr2+ for La3+. The optimized La0.7Sr0.3(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 displays remarkable activity for the ORR and the OER, with a low potential difference of 0.880 V between the half-wave potential of the ORR and the OER potential at 10 mA cm-2, exceeding the majority of perovskite bifunctional catalysts. Further analysis of the electronic structures reveals that hole doping could regulate the eg-orbital filling of the transition-metal cations in high-entropy perovskites to an ideal position and thereby generate many highly active sites to promote the redox activity of oxygen. The assembled rechargeable ZAB with the targeted high-entropy perovskite as the cathode affords a specific capacity of 774.5 mAh gZn-1 under 10 mA cm-2 and durability for a period of 300 cycles, comparable to that of the 20%Pt/C + RuO2 ZAB. This work offers an important approach for the advancement of efficient high-entropy perovskites for ZABs.

Intrinsic Mechanical Effects on the Activation of Carbon Catalysts.

The mechanical effects on carbon-based metal-free catalysts (C-MFCs) have rarely been explored, despite the global interest in C-MFCs as substitutes for noble metal catalysts. Stress is ubiquitous, whereas its dedicated study is severely restricted due to its frequent entanglement with other structural variables, such as dopants, defects, and interfaces in catalysis. Herein, we report a proof-of-concept study by establishing a platform to continuously apply strain to a highly oriented pyrolytic graphite (HOPG) lamina, simultaneously collecting electrochemical signals. Notably, we establish, for the first time, the correlation between the surface strain of graphitic carbon and its activation effect on the oxygen reduction reaction (ORR). Our results indicate that while in-plane and edge carbon sites in HOPG could not be further activated by applying tensile strain, a strong and repeatable dependence of catalytic activity on tensile strain was observed when the structure incorporated in-plane defects, leading to a significant ∼35.0% improvement in ORR current density with the application of ∼0.6% tensile strain. Density functional theory (DFT) simulations reveal that appropriate strain on specific defects can optimize the adsorption of reaction intermediates, and the Stone-Wales defect on graphene is correlated with the observed mechanical effect. This work elucidates fundamental principles of strain effects on the catalytic activity of graphitic carbon toward ORR and may lay the groundwork for the development of carbon-based mechano-electrocatalysis.

Modulating Electronic Spin State of Perovskite Fluoride by Ni─F─Mn Bond Activating the Dynamic Site of Oxygen Reduction Reaction.

Establishing the relationship between catalytic performance and material structure is crucial for developing design principles for highly active catalysts. Herein, a type of perovskite fluoride, NH4MnF3, which owns strong-field coordination including fluorine and ammonia, is in situ grown on carbon nanotubes (CNTs) and used as a model structure to study and improve the intrinsic catalytic activity through heteroatom doping strategies. This approach optimizes spin-dependent orbital interactions to alter the charge transfer between the catalyst and reactants. As a result, the oxygen reduction reaction (ORR) activity of NH4MnF3 on CNTs is significantly enhanced by partial substitution of Mn sites with Ni, such as a half-wave potential (E1/2) of 0.86V and a limiting current density of 5.26mA cm-2, which are comparable to those of the commercial Pt/C catalysts. Experimental and theoretical calculations reveal that the introduction of Ni promotes lattice distortion, adjusts the electronic states of the active Mn centers, facilitates the transition from low-spin to intermediate-spin states, and shifts the d-band center closer to the Fermi level. This study establishes a novel approach for designing high-performance perovskite-based fluoride electrocatalysts by modulating spin states.

Spiny Co3O4@Hollow Carbon Spheres─Polyacrylonitrile/Carbon Black Fiber-Based Bifunctional Air Electrodes.

In the realm of zinc-air batteries, high bifunctional catalytic efficacy is intimately tied to the evaluation of catalysts. Consequently, the pursuit of proficient bifunctional catalysts that can efficiently catalyze both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a paramount objective in this research area. In this study, the spiny cobalt tetroxide (Co3O4) encapsulated hollow carbon spheres (HCSs) are constructed by anchoring Co3O4 onto HCS via hydrothermal or annealing treatment. The strategic interface design of the HCS encourages an abundance of sites while simultaneously facilitating the proliferation of spiny Co3O4, offering an expansive surface area and abundant active sites. The surface active Co3+ ions and the induction of surface oxygen vacancies in spiny Co3O4 encapsulated HCS endow it with outstanding bifunctional catalytic activity and stability. After spray-coating and subsequent annealing of the spiny Co3O4 encapsulated HCS catalyst on the flexible carbon-based polyacrylonitrile (PAN) nanofiber support, the spiny Co3O4 encapsulated HCS-PAN/carbon black (C) 800 air electrode is successfully integrated. Moreover, the optimized spiny Co3O4 encapsulated HCS-PAN/C 800 air electrode displays a decreased potential difference (ΔE) of 0.77 V for catalyzing the ORR and OER performance. This work introduces a promising candidate approach for exploring innovative bifunctional oxygen electrocatalysts, targeting enhanced efficiency in portable energy storage applications.

Quantifying Asymmetric Coordination to Correlate Oxygen Reduction Activity in Fe-Based Single-Atom Catalysts.

Precisely manipulating asymmetric coordination configurations and examining electronic effects enable to tuning the intrinsic oxygen reduction reaction (ORR) activity of single-atom catalysts (SACs). However, the shortage of a definite relationship between coordination asymmetry and catalytic activity makes the rational design of SACs ambiguous. Here, we propose a concept of "asymmetry degree" to quantify asymmetric coordination configurations and assess the effectiveness of active moieties in Fe-based SACs. A theoretical framework is established where elucidating the volcanic relationship between asymmetry degree and ORR activity by constructing a series of Fe-based SAC models doped with non-metal atoms (B, P, S, Se, and Te) in the first or second coordination sphere, which aligns with Sabatier principle. The predicted ORR activity of Fe asymmetric active moieties is then experimentally validated using asymmetry degree. The combined computational and experimental results suggest that single-atom moiety with a moderate asymmetry degree exhibits optimal intrinsic ORR activity, because breaking the square-planar symmetry of FeN4 can alter the electronic population of the Fe 3d-orbital, thereby optimizing the adsorption-desorption strength of intermediates and thus enhancing the intrinsic ORR activity. This fundamental understanding of catalytic activity from geometric and electronic aspects offers a rational guidance to design high-performance SACs with asymmetric configurations.

Biomimetic Nanostructure Engineering of Ultralow Ir-Loading Electrocatalysts for Oxygen Reduction Reaction.

Promoting the rate of the oxygen reduction reaction (ORR) is critical for boosting the overall energy efficiency of the flexible zinc-air batteries (FZABs). Inspired by nature, we designed "branch-leaf" like hierarchical porous carbon nanofibers with ultralow loadings of Ir nanoparticles (NPs) derived from covalent-organic framework/metal-organic framework (COF/MOF) core-shell hybrids. The as-obtained Ir/FeZn-hierarchical porous carbon nanofibers (HPCNFs) showcase enhanced ORR performance, and the ultralow Ir loading reduces the cost while maintaining catalytic capacity. Interestingly, the FZABs assembled with Ir/FeZn-HPCNFs deliver an impressive stable performance. This work provides a feasible approach for designing cost-effective and highly efficient electrocatalysts using in FZABs.

Electrocatalytic Biomass Oxidation via Acid-Induced In Situ Surface Reconstruction of Multivalent State Coexistence in Metal Foams.

Electrocatalytic biomass conversion offers a sustainable route for producing organic chemicals, with electrode design being critical to determining reaction rate and selectivity. Herein, a prediction-synthesis-validation approach is developed to obtain electrodes for precise biomass conversion, where the coexistence of multiple metal valence states leads to excellent electrocatalytic performance due to the activated redox cycle. This promising integrated foam electrode is developed via acid-induced surface reconstruction to in situ generate highly active metal (oxy)hydroxide or oxide (MOxHy or MOx) specieson inert foam electrodes, facilitating the electrooxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA). Taking nickel foam electrode as an example, the resulting NiOxHy/Ni catalyst, featuring the coexistence of multivalent states of Ni, exhibits remarkable activity and stability with a FDCA yields over 95% and a Faradaic efficiency of 99%. In situ Raman spectroscopy and theoretical analysis reveal an Ni(OH)2/NiOOH-mediated indirect pathway, with the chemical oxidation of 5-HMF as the rate-limiting step. Furthermore, this in situ surface reconstruction approach can be extended to various metal foams (Fe, Cu, FeNi, and NiMo), offering a mild, scalable, and cost-effective method for preparing potent foam catalysts. This approach promotes a circular economy by enabling more efficient biomass conversion processes, providing a versatile and impactful tool in the field of sustainable catalysis.

Synthesis, Structure, and Redox Reactivity of Ni Complexes Bearing a Redox and Acid-Base Non-innocent Ligand with NiII, NiIII, and NiIV Formal Oxidation States.

A series of Ni complexes bearing a redox and acid-base noninnocent tetraamido macrocyclic ligand, H4-(TAML-4) {H4-(TAML-4) = 15,15-dimethyl-5,8,13,17-tetrahydro-5,8,13,17-tetraaza-dibenzo[a,g]cyclotridecene-6,7,14,16-tetraone}, with formal oxidation states of NiII, NiIII, and NiIV were synthesized and characterized structurally and spectroscopically. The X-ray crystallographic analysis of the Ni complexes revealed a square planar geometry, and the [Ni(TAML-4)] complex with the formal oxidation state of NiIV was characterized to be [NiIII(TAML-4•+)] with the oxidation state of the NiIII ion and the one-electron oxidized TAML-4 ligand, TAML-4•+. The NiIII oxidation state and the TAML-4 radical cation ligand, TAML-4•+, were supported by X-ray absorption spectroscopy and density functional theory calculations. The reversible interconversions between [NiII(TAML-4)]2- and [NiIII(TAML-4)]- and between [NiIII(TAML-4)]- and [NiIII(TAML-4•+)] were demonstrated in spectroelectrochemical measurements as well as in chemical oxidation and reduction reactions. The reactivities of [NiIII(TAML-4)]- and [NiIII(TAML-4•+)] were then investigated in hydride transfer reactions using NADH analogs. Hydride transfer from 9,10-dihydro-10-methylacridine (AcrH2) to [NiIII(TAML-4•+)] was found to proceed via electron transfer (ET) from AcrH2 to [NiIII(TAML-4•+)] with no deuterium kinetic isotope effect (kH/kD = 1.0(2)). In contrast, hydride transfer from AcrH2 to [NiIII(TAML-4)]- proceeded much more slowly via a concerted proton-coupled electron transfer (PCET) process with kH/kD = 7.0(5). In the latter reaction, an electron and a proton were transferred to the NiIII center and the TAML-4 ligand, respectively. The mechanisms of the ET by [NiIII(TAML-4•+)] and the concerted PCET by [NiIII(TAML-4)]- were ascribed to the different redox potentials of the Ni complexes.

Dipnictogen Radical Chemistry: A Dithorium-Supported Distibene Radical Trianion.

Although two examples of σ-bonded trans-bent [RSbSbR]•- (R = bulky organo- or Ga-groups) that formally contain the Sb2•3- radical trianion moiety are known in p-block chemistry, d- or f-element Sb2•3- radical trianion complexes, with or without R-substituents, have remained elusive. Here, we report that reduction of a 77:23 mix of [{Th(TrenTIPS)}2(μ-η2:η2-Sb2)] (3a, TrenTIPS = {N(CH2CH2NSiPri3)3}3-):[{Th(TrenTIPS)}2(μ-SbH)] (3b) with 1.5 equiv of KC8 in the presence of 1.1 equiv of 2.2.2-cryptand yields the emerald green Sb2•3- radical complex [K(2.2.2-cryptand)][{Th(TrenTIPS)}2(μ-η2:η2-Sb2)] (4), providing an f-block Sb2•3- radical trianion complex, and the heaviest actinide-N2 radical analogue. When the recrystallization conditions are modified, a small crop of red crystals determined to be [K(2.2.2-cryptand)]3[{Th(TrenTIPS)(μ-η3:η3-Sb3)}2(μ-K)] (5) were also isolated, highlighting the complexity of heavy group 15 homodiatomic reduction chemistry. SQUID magnetometry and EPR spectroscopy suggest that the Sb2•3- radical trianion in 4 is fairly well isolated, due to electrostatic binding to Th, with pseudoaxial g-values reflecting the distinctive Sb2•3- radical trianion side-on bridging π-bonded coordination mode. Spectroscopically validated computational analysis of 3a and 4 confirms the stronger donating capability, and weaker Sb-Sb bond, of Sb2•3- radical trianion compared to the Sb22- dianion form.

Densely populated macrocyclic dicobalt sites in ladder polymers for low-overpotential oxygen reduction catalysis

Dual-atom catalysts featuring synergetic dinuclear active sites, have the potential of breaking the linear scaling relationship of the well-established single-atom catalysts for oxygen reduction reaction; however, the design of dual-atom catalysts with rationalized local microenvironment for high activity and selectivity remains a great challenge. Here we design a bisalphen ladder polymer with well-defined densely populated binuclear cobalt sites on Ketjenblack substrates. The strong electron coupling effect between the fully-conjugated ladder structure and carbon substrates enhances the electron transfer between the cobalt center and oxygen intermediates, inducing the low-to-high spin transition for the 3d electron of Co(II). In situ techniques and theoretical calculations reveal the dynamic evolution of Co2N4O2 active sites and reaction intermediates. In alkaline conditions, the catalyst exhibits impressive oxygen reduction reaction activity featuring an onset potential of 1.10 V and a half-wave potential of 1.00 V, insignificant decay after 30,000 cycles, pushing the overpotential boundaries of ORR electrocatalysis to a low level. This work provides a platform for designing efficient dual-atom catalysts with well-defined coordination and electronic structures in energy conversion technologies.

A Unique Intramolecular Redox Reaction by Unidirectional Migration of Three Hydrogen Atoms: Theoretical Elucidation of the 3H-Transfer Sequence.

The intramolecular migration of three hydrogen atoms from one moiety of a gaseous radical cation to the other prior to fragmentation is an extremely rare type of redox reaction. Within the scope of this investigation, this scenario requires an ionized but electron-rich arene acceptor bearing a para-(3-hydroxyalkyl) residue. The precise mechanism of such unidirectional 3H transfer processes, including the order of the individual H transfer steps, has remained unclear in spite of previous isotope labelling and recent infrared ion spectroscopy (IRIS) studies. Herein, the details of this peculiar process have been investigated for ionized 4-(N,N-dimethylaminophenyl)-2-butanol, 2, by state-of-the-art density functional theory (DFT) calculations. The energetically most favorable pathway consists of a sequence of successive 1,4-, 1,6- and 1,5-H steps. During these steps the secondary alcohol functionality is oxidized to a carbonyl group and the radical-cationic aniline ring is reduced to an ionized 2,3-dihydroaniline unit. Several alternative sequences, such as three successive 1,5-H shifts, could be excluded. A concomitant unidirectional 2H migration reaction of the ion 2 was also investigated and the intermediacy of ion-neutral complexes (INCs) enabling sequential hydride and proton transfer was confirmed by the calculations.

Ultrafast Preparation of High-Entropy NASICON Cathode Enables Stabilized Multielectron Redox and Wide-Temperature (-50-60°C) Workability in Sodium-Ion Batteries.

Avoiding severe structural distortion, irreversible phase transition, and realizing the stabilized multielectron redox are vital for promoting the development of high-performance NASICON-type cathode materials for sodium-ion batteries (SIBs). Herein, a high-entropy Na3.45V0.4Fe0.4Ti0.4Mn0.45Cr0.35(PO4)3 (HE-Na3.45TMP) cathode material is prepared by ultrafast high-temperature shock, which inhibits the possibility of phase separation and achieves reversible and stable multielectron transfer of 2.4/2.8 e- at voltage range of 2.0-4.45/1.5-4.45 V versus Na+/Na (the capacity of 137.2/162.0 mAh g-1). The galvanostatic charge/discharge and in-situ X-ray diffraction tests indicate the sequential redox reactions and approximate solid solution phase transition behavior of HE-Na3.45TMP. Density functional theory calculations analyze the migration pathways and energy barriers, further confirming the superior reaction kinetics of HE-Na3.45TMP. Accordingly, the HE-Na3.45TMP exhibits outstanding wide temperature applicability and can operate stably in the temperature range of -50-60°C, accompanied by a capacity retention of 92.8% after 400 cycles at -40°C and a capacity of 73.7 mAh g-1 even at -50°C. The assembled hard carbon//HE-Na3.45TMP full-cell offers an energy density of ≈301 Wh kg-1 based on total cathode and anode active mass, verifying the application feasibility of HE-Na3.45TMP. This work provides an innovative and ultrafast pathway to rationally fabricate high-performance cathodes for SIBs.

Microbial manganese redox cycling drives co-removal of nitrate and ammonium.

Manganese (Mn), abundant in the Earth's crust, can act as an oxidant or a reductant for diverse nitrogen biotransformation processes. However, the functional microorganisms and their metabolic pathways, as well as interactions, remain largely elusive. Here, a microbial consortium was enriched from a mixture of freshwater sediments and activated sludge by feeding ammonium, nitrate and Mn(II), which established manganese-driven co-removal of nitrate and ammonium with removal rates of 5.83 and 2.30mgN L-1 d-1, respectively. The batch tests and metagenomic analyses revealed a nitrate-dependent anaerobic manganese oxidation (NDMO) process mediated by Anaerolineales and Phycisphaerales and a manganese reduction coupled to anaerobic ammonium oxidation (Mnammox) process mediated by Chthonomonadales. Based on identified key genes involved in the nitrogen and manganese metabolic pathways, nitrate was likely reduced to nitrite and nitrogen gas in the NDMO process while ammonium was oxidized to nitrite in the Mnammox process, which in turn fuelled the Anammox process carried out by Candidatus Brocadia. This revealed the microbial interactions of NDMO, Mnammox, and Anammox processes responsible for manganese-driven co-removal of ammonium and nitrate. These findings provide a potential solution for biological nitrogen removal and expand our understanding of the nitrogen and manganese biogeochemical cycles.