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The electronic structure of active sites is critically important for electrochemical reactions. Here, the authors report a facile approach to independently regulate the electronic structure of Fe in Ni0.75Fe0.25Se2 by P doping. The resulting electrode exhibits superior catalytic performance for the oxygen evolution reaction (OER) showing a low overpotential (238 mV at 100 mA cm−2, 185 mV at 10 mA cm−2) and an impressive durability in an alkaline medium. Additionally, the mass activity of 328.19 A g−1 and turnover frequency (TOF) of 0.18 s−1 at an overpotential of 500 mV are obtained for P─Ni0.75Fe0.25Se2 which is much higher than that of Ni0.75Fe0.25Se2 and RuO2. This work presents a new strategy for the rational design of efficient electrocatalysts for OER. The precise electronic structure regulation of Fe in Ni0.75Fe0.25Se2 by P doping leads to the P─Ni0.75Fe0.25Se2 electrode with remarkable electrocatalytic activity and stability for oxygen evolution reaction (OER).

Rechargeable aqueous zinc‐ion batteries (ZIBs) show promise for use in energy storage. However, the development of ZIBs has been plagued by the limited cathode candidates, which usually show low capacity or poor cycling performance. Here, a reversible Zn//(Na,Mn)V8O20·nH2O system is reported, the introduction of manganese (Mn) ions in NaV8O20 to form (Na,Mn)V8O20 exhibits an outstanding electrochemical performance with a capacity of 377 mA h g−1 at a current density of 0.1 A g−1. Through experimental and theoretical results, it is discovered that the outstanding performance of (Na,Mn)V8O20·nH2O is ascribed to the Mn2+/Mn3+‐induced high electrical conductivity and Na+‐induced fast migration of Zn2+. Other cathode materials derived from (Na,Mn)V8O20·nH2O by substituting Mn with Fe, Co, Ni, Ca, and K are explored to confirm the unique advantages of transition metal ions. With an increase in Mn content in NaV8O20, (Na0.33,Mn0.65)V8O20 ·nH2O can deliver a reversible capacity of 150 mA h g−1 and a capacity retention of 99% after 1000 cycles, which may open new opportunities for the development of high‐performance aqueous ZIBs. Mn‐doped NaV8O20 is synthesized via a one‐step hydrothermal reaction. The Mott–Schottky plots, Tafel curves and calculation results are given to explain the improved cycling performance of Mn‐doped NaV8O20. Other cathode materials derived from (Na,Mn)V8O20·nH2O by substituting Mn with Fe, Co, Ni, Ca, and K are explored to confirm the unique advantages of transition metal ions in NaV8O20.

Understanding the breakdown mechanisms of polymer-based dielectrics is critical to achieving high-density energy storage. Here a comprehensive phase-field model is developed to investigate the electric, thermal, and mechanical effects in the breakdown process of polymer-based dielectrics. High-throughput simulations are performed for the P(VDF-HFP)-based nanocomposites filled with nanoparticles of different properties. Machine learning is conducted on the database from the high-throughput simulations to produce an analytical expression for the breakdown strength, which is verified by targeted experimental measurements and can be used to semiquantitatively predict the breakdown strength of the P(VDF-HFP)-based nanocomposites. The present work provides fundamental insights to the breakdown mechanisms of polymer nanocomposite dielectrics and establishes a powerful theoretical framework of materials design for optimizing their breakdown strength and thus maximizing their energy storage by screening suitable nanofillers. It can potentially be extended to optimize the performances of other types of materials such as thermoelectrics and solid electrolytes. Polymer dielectrics are promising for high-density energy storage but dielectric breakdown is poorly understood. Here, a phase-field model is developed to investigate electric, thermal, and mechanical effects in the breakdown process for a range of polymer dielectrics, and analytical expression for breakdown strength is provided by machine learning.

The purpose of this short communication is to demonstrate the importance of numerical analysis and wavelength increment selection when characterizing fluorescent dissolved organic matter (FDOM) using fluorescence excitation–emission matrix (EEM) regional integration. A variety of water samples, representing a landscape gradient and different types of FDOM, were analyzed for their percentage distribution of five operationally defined FDOM fractions (aromatic protein I, aromatic protein II, fulvic acid–like, soluble microbial byproduct–like, and humic acid–like) using three numerical methods in integrating volume under the surface of the fluorescence EEMs: Riemann summation, composite trapezoidal rule, and composite Simpson's rule. The influence of wavelength increment was also examined for the precision of the percentage distribution of each fraction. Our results show that the FDOM fraction estimated by Riemann summation with a 10‐ or 5‐nm excitation wavelength can cause >40% or >5% errors, respectively, when compared with the best estimated values obtained by averaging results from composite trapezoidal rule and composite Simpson's rule with 1‐nm excitation wavelength at the same emission increment. Also, our experiments show that fluorescence matrix regional integration could underestimate the two aromatic protein fractions but could overestimate the soluble microbial byproduct–like and humic acid–like fractions if improper increment and integral methods are used. The error can be reduced if a smaller wavelength increment is used. The smallest increment in a spectrofluorometer and composite Simpson's rule should be used for scanning fluorescence EEMs and calculating the percentage distribution of each FDOM fraction. Alternatively, 5‐nm wavelength increments with composite Simpson's rule could be cost effective, and the error of each FDOM fraction commonly falls within 5% compared with those estimated by 1‐nm increments.

Forest soil organic carbon (SOC) is one of the largest reservoirs of terrestrial carbon (C) and is a major component of the global C cycle. Yet there is still uncertainty regarding how ecosystems, and the SOC they store, will respond to changes due to anthropogenic processes. Current and future reactive nitrogen (N) deposition to forest soils may alter biogeochemical processes and shift both the quantity and quality of stored SOC. We studied SOC storage and molecular-level composition after 22 years of N additions (100 kg N ha⁻¹ y⁻¹) in a temperate deciduous forest. SOC storage in surface soils increased by 0.93 kg m⁻² due to a decline in microbial biomass (phospholipid fatty acids) and litter decomposition. N additions resulted in the selective preservation of a range of plant-derived compounds including steroids, lignin-derived, cutin-derived, and suberin-derived compounds that have anti-microbial properties or are non-preferred microbial substrates. This overall shift in SOC composition suggests limited sustainability and a decline in soil health. The reduction in microbial biomass and increase in specific SOC components demonstrate that long-term N fertilization negatively alters fundamental C cycling in forest soils. This study also demonstrates unequivocally that anthropogenic impacts on C and N cycling in forests at the molecular-level must be considered more holistically.

Fine roots constitute a significant source of plant productivity and litter turnover across terrestrial ecosystems, but less is known about the quantitative and qualitative profile of phenolic compounds within the fine‐root architecture, which could regulate the potential contribution of plant roots to the soil organic matter pool. To understand the linkage between traditional macro‐elemental and morphological traits of roots and their molecular‐level carbon chemistry, we analyzed seasonal variations in monomeric yields of the free, bound, and lignin phenols in fine roots (distal five orders) and leaves of Ardisia quinquegona. Fine roots contained two‐fold higher concentrations of bound phenols and three‐fold higher concentrations of lignin phenols than leaves. Within fine roots, the concentrations of free and bound phenols decreased with increasing root order, and seasonal variation in the phenolic profile was more evident in lower order than in higher order roots. The morphological and macro‐elemental root traits were decoupled from the quantity, composition and tissue association of phenolic compounds, revealing the potential inability of these traditional parameters to capture the molecular identity of phenolic carbon within the fine‐root architecture and between fine roots and leaves. Our results highlight the molecular‐level heterogeneity in phenolic carbon composition within the fine‐root architecture, and imply that traits that capture the molecular identity of the root construct might better predict the decomposition dynamics within fine‐root orders.

Transition metal alloys have emerged as promising electrocatalysts due to their ability to modulate key parameters, such as d-band electron filling, Fermi level energy, and interatomic spacing, thereby influencing their affinity towards reaction intermediates. However, the structural stability of alloy electrocatalysts during the alkaline hydrogen evolution reaction (HER) remains a subject of debate. In this study, we systematically investigated the structural evolution and catalytic activity of the c-Co/Co3Mo electrocatalyst under alkaline HER conditions. Our findings reveal that the Co3Mo alloy and H0.9MoO3 exhibit instability during alkaline HER, leading to the breakdown of the crystal structure. As a result, the cubic phase c-Co undergoes a conversion to the hexagonal phase h-Co, which exhibits strong catalytic activity. Additionally, we identified hexagonal phase Co(OH)2 as an intermediate product of this conversion process. Furthermore, we explored the readsorption and surface coordination of the Mo element, which contribute to the enhanced catalytic activity of the c-Co/Co3Mo catalyst in alkaline HER. This work provides valuable insights into the dynamic behavior of alloy-based electrocatalysts, shedding light on their structural stability and catalytic activity during electrochemical reduction processes.

The photoelectrochemical (PEC) conversion of organic small molecules offers a dual benefit of synthesizing value-added chemicals and concurrently producing hydrogen (H2). Ethylene glycol, with its dual hydroxyl groups, stands out as a versatile organic substrate capable of yielding various C1 and C2 chemicals. In this study, we demonstrate that pH modulation markedly enhances the photocurrent of BiVO4 photoanodes, thus facilitating the efficient oxidation of ethylene glycol while simultaneously generating H2. Our findings reveal that in a pH = 1 ethylene glycol solution, the photocurrent density at 1.23 V vs. RHE can attain an impressive 7.1 mA cm−2, significantly surpassing the outputs in neutral and highly alkaline environments. The increase in photocurrent is attributed to the augmented adsorption of ethylene glycol on BiVO4 under acidic conditions, which in turn elevates the activity of the oxidation reaction, culminating in the maximal production of formic acid. This investigation sheds light on the pivotal role of electrolyte pH in the PEC oxidation process and underscores the potential of the PEC strategy for biomass valorization into value-added products alongside H2 fuel generation.

Anxiety commonly co-occurs with obsessive-compulsive disorder (OCD). Both of them are closely related to stress. However, the shared neurobiological substrates and therapeutic targets remain unclear. Here we report an amelioration of both anxiety and OCD via the histamine presynaptic H3 heteroreceptor on glutamatergic afferent terminals from the prelimbic prefrontal cortex (PrL) to the nucleus accumbens (NAc) core, a vital node in the limbic loop. The NAc core receives direct hypothalamic histaminergic projections, and optogenetic activation of hypothalamic NAc core histaminergic afferents selectively suppresses glutamatergic rather than GABAergic synaptic transmission in the NAc core via the H3 receptor and thus produces an anxiolytic effect and improves anxietyand obsessive-compulsive-like behaviors induced by restraint stress. Although the H3 receptor is expressed in glutamatergic afferent terminals from the PrL, basolateral amygdala (BLA), and ventral hippocampus (vHipp), rather than the thalamus, only the PrL– and not BLA– and vHipp–NAc core glutamatergic pathways among the glutamatergic afferent inputs to the NAc core is responsible for co-occurrence of anxiety- and obsessive-compulsive-like behaviors. Furthermore, activation of the H3 receptor ameliorates anxiety and obsessive-compulsive-like behaviors induced by optogenetic excitation of the PrL–NAc glutamatergic afferents. These results demonstrate a common mechanism regulating anxiety- and obsessive-compulsive-like behaviors and provide insight into the clinical treatment strategy for OCD with comorbid anxiety by targeting the histamine H3 receptor in the NAc core.

The subthalamic nucleus (STN) is an effective therapeutic target for deep brain stimulation (DBS) for Parkinson's disease (PD), and histamine levels are elevated in the basal ganglia in PD patients. However, the effect of endogenous histaminergic modulation on STN neuronal activities and the neuronal mechanism underlying STN-DBS are unknown. Here, we report that STN neuronal firing patterns are more crucial than firing rates for motor control. Histamine excited STN neurons, but paradoxically ameliorated parkinsonian motor deficits, which we attributed to regularizing firing patterns of STN neurons via the hyperpolarization-activated cyclic nucleotide-gated channel 2 (HCN2) channel coupled to the H2 receptor. Intriguingly, DBS increased histamine release in the STN and regularized STN neuronal firing patterns under parkinsonian conditions. HCN2 contributed to the DBS-induced regularization of neuronal firing patterns, suppression of excessive β oscillations, and alleviation of motor deficits in PD. The results reveal an indispensable role for regularizing STN neuronal firing patterns in amelioration of parkinsonian motor dysfunction and a functional compensation for histamine in parkinsonian basal ganglia circuitry. The findings provide insights into mechanisms of STN-DBS as well as potential therapeutic targets and STN-DBS strategies for PD.