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The role of seed mucilage in the moist environments of monsoonal subtropics is poorly understood. We studied germination of six forb species from subtropical monsoonal China. Mucilage presence had little to no effect on germination percentage (G%), except for a significant decline for the large-seeded Prunella vulgaris. Dark treatments reduced G% for all species, while the combination of mucilage removal and high temperatures delayed the mean germination time (MGT). Seed fresh mass was negatively correlated with G%, but only for intact seeds incubated at 12/12 hours of 25/35 °C. The MGT of de-mucilaged seeds varied with seed shape index, also under the warmer temperature regime. Temperature and light are fundamental to drive germination processes, and the presence of mucilage influences MGT of subtropical monsoonal species. Presence or absence of mucilage had little to no difference in germination percentage, but can be important to drive germination timing, also promoting water uptake and seed adhesion to soil.

The transcription factor ABSCISIC ACID INSENSITIVE5 (ABI5) plays a crucial role in abscisic acid (ABA) signaling during seed germination. However, how ABI5 is regulated during this process is poorly understood. Here, we report that the ubiquitin E3 ligase MIEL1 and its target transcription factor MYB30 modulate ABA responses in Arabidopsis thaliana during seed germination and seedling establishment via the precise regulation of ABI5. MIEL1 interacts with and ubiquitinates ABI5 to facilitate its degradation during germination. The transcription factor MYB30, whose turnover is mediated by MIEL1 during seed germination, also interacts with ABI5 to interfere with its transcriptional activity. MYB30 functions downstream of MIEL1 in the ABA response, and both are epistatic to ABI5 in ABA-mediated inhibition of seed germination and postgerminative growth. ABA treatment induces the degradation of MIEL1 and represses the interaction between MIEL1 and ABI5/MYB30, thus releasing both ABI5 and MYB30. Our results demonstrate that MIEL1 directly mediates the proteasomal degradation of ABI5 and inhibits its activity via the release of its target protein MYB30, thus ensuring precise ABA signaling during seed germination and seedling establishment.

Aim: To evaluate the correlation of long noncoding RNAs (lncRNAs) expression in circulating exosomes and the cancerous and noncancerous tissues in patients with non-small-cell lung carcinoma. Methods: The relative expression of the four lncRNAs including LUADT1, MALAT1, NEAT1 and MIAT between tumor tissue, adjacent noncancerous tissues and circulating exosomes were evaluated by quantitative reverse transcription PCR. Results & conclusion: The relative expression of the lncRNAs, including LUADT1, MALAT1 and NEAT1, was upregulated and MIAT was downregulated in tumor tissue compared with noncancerous tissue samples. The expression of lncRNAs in circulating exosomes was not significantly different from cancerous tissue. Our results indicate that the studied exosomal lncRNAs have a good potential to be further evaluated as prognostic/diagnostic biomarkers in patients with non-small-cell lung cancer.

Aqueous battery-supercapacitor hybrid devices (BSHs) are of great importance to enrich electrochemical energy storage systems with both high energy and power densities. However, further improvement of BSHs in aqueous electrolytes is greatly hampered by operating voltage and capacity limits. Different from the conventional intercalation/de-intercalation mechanism, Bi2O3 implements charge storage by a reversible phase conversion mechanism. Herein, taking Bi2O3 electrode with wide potential window (from −1.2 to 1 V vs. saturated calomel electrode) and high capacity as battery-type anode, we propose that the overall performance of aqueous BSHs can be greatly upgraded under neutral condition. By paring with stable layer-structured δ-MnO2 cathode, a sodium-ion Bi2O3//MnO2 BSH with an ultrahigh voltage of 2.4 V in neutral sodium sulfate electrolyte is developed for the first time. This hybrid device exhibits high capacity (~215 C g−1 at 1 mA cm−2), relatively long lifespan (~77.2% capacity retention after 1500 cycles), remarkable energy density (71.7 Wh kg−1@400.5 W kg−1) and power density (3204.3 W kg−1@18.8 Wh kg−1). Electrochemical measurements combining a set of spectroscopic techniques reveal the reversible phase conversion between bismuth oxide and metallic bismuth (Bi2O3 ⇋ Bi0) through Bi2+ transition phase in neutral sodium sulfate solution, which can deliver multielectron transfer up to 6, leading to the high-energy BSHs. Our work sheds light on the feasibility of using Bi2O3 electrode under neutral condition to address the issue of narrow voltage and low capacity for aqueous BSHs.

MnO nanoparticles confined in N,S co-doped porous C are prepared by employing acrylamide monomers as the chelating agents and carbon source. When serving as a zinc-ion battery cathode, it can exhibit enhanced rate performance and a long lifespan.

The highly active and robust bifunctional non-noble electrocatalysts for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are urgently demanded for rechargeable metal-air batteries. Engineering heterointerfaces between metals and metal compounds is an attractive strategy for fabricating high-performance electrocatalysts. However, most reported metal/metal compound heterostructures were designed by partially converting the metal into corresponding metal compound on a one-metal basis. Herein, a facile “coordination construction-thermal decomposition” strategy is developed to construct Co/MnO heterointerface embedded in N-doped carbon nanowires by employing nitrilotriacetic acid as chelating agents to stabilize different metal ions and construct the nanowire structure. The in situ generated Co nanocrystals not only create highly conductive heterointerfaces with MnO, but also facilitate the formation of graphitic carbon as the conductive agent. The resultant Co/MnO@NC exhibits extraordinary bifunctional oxygen electrocatalytic activities and durability with a reversible oxygen overpotential of only 0.66 V. Density functional theory calculations reveal that the formation of Co/MnO heterostructure leads to optimized adsorption energy for oxygen-containing intermediates in OER and ORR. As the air-cathode, the assembled aqueous zinc-air battery (ZAB) can provide a remarkable peak power density of 146 mW cm−2 and an impressive discharge/charge stability for 400 h/600 cycles at 20 mA cm−2. The Co/MnO@NC-based quasi-solid-state ZAB also exhibits outstanding mechanical flexibility in addition to high battery performance. This strategy can be extended to prepare Fe/MnO@NC and Ni/MnO@NC electrocatalysts with other iron group elements, which paves a new way for development of efficient and robust electrocatalysts for energy conversion and storage.

Background: Venous malformations (VMs) are the most common vascular malformations. VMs can be classified as focal, multifocal, or diffuse types. Focal venous malformations with muscle involvement is not well defined.Objective: The aim of our study was to characterize characteristics of focal VMs and classify them based on position that are associated with invasion of muscle.Methods: This is a single-center, retrospective review of patients treated for focal VMs between February 2021 and February 2022.Results: We assessed 26 patients focal VMs with 47 lesions; 18 (69%) were unifocal, 3 (12%) were dual-focal and 5（19%）were multifocal type VMs, and 29（62%) were intramuscular VMs. Of all focal VMs, 32 (68%) lesions arose in the extremities, 10 (21%) in the head and neck region and 5 (11%) in the torso. The three groups were no statistical difference for the intramuscular VMs, 19 (68%) arose in extremities, 6 (21%) in the head and neck region and 3 (11%) in the torso. But the lower limbs intramuscular VMs had a signifificantly elevated risk of focal VMs(relative risk [RR],1.7; 95% confidence interval [CI], 1.148-2.394). Limitations: Retrospective, single-institution study.Conclusion: Intramuscular involvement of the body should be considered in focal VMs. The lower limbs intramuscular VMs had a signifificantly elevated risk of focal VMs.

NiFe based (oxy)hydroxides demonstrate promising electrocatalytic activity toward the oxygen evolution reaction (OER) in alkaline media. To further improve their electrocatalytic performance, it is critical to maximize the density of active sites on the surface while maintaining a high structural order level of the NiOOH host. In this work a unique photochemical–electrochemical strategy is reported to fabricate an active Fe-doped Ni oxyhydroxide electrocatalyst on a three-dimensional carbon cloth scaffold (Fe–NiOOH@CC). Raman depth profiling suggests abundant Fe-containing active sites on the surface of the NiOOH matrix, and NiOOH itself remains highly crystalline with a low structural disorder level in the as-synthesized Fe–NiOOH@CC. Due to this compelling property, it exhibits higher OER catalytic activity than RuO2 and other NiFe analogues and maintains its activity for at least 55 h at ∼150 mA cm−2. This photochemical–electrochemical method is applicable to other transition metals and substrates, thus offering a unique while universal strategy for synthesis of OER electrocatalysts.

Indium (In)-based materials are considered promising electrocatalysts for CO2 reduction to formic acid, but their performance is usually limited by low current density and poor stability. Here, we describe In/ZnO@C hollow nanocubes (NCs), derived from In(OH)3-doped Zn-MOF (i.e. ZIF-8) solid nanocubes, as high-performance CO2-reduction electrocatalysts. The unique nanocube morphology of Zn-MOF makes it an ideal matrix for dispersing In(OH)3 which can avoid aggregation. The formation of a hollow structure is associated with metallic In formation and CO2/CO gas release, resulting from the carbothermal reduction reaction between In(OH)3 and the carbon matrix. In/ZnO@C NCs exhibit excellent catalytic activity and selectivity for formate production, reaching a partial current density of 23.5 mA cm−2 with a Faradaic efficiency of 90% at −1.2 V vs. RHE in 0.5 M aqueous KHCO3 solutions, which is greatly superior to In-free ZnO@C NCs and simple In nanoparticles. Solar-driven electrochemical CO2/H2O splitting can be realized by coupling the In/ZnO@C cathode with a RuO2 anode, offering a promising route to the storage of renewable energy. As a promising technique for CO2 fixation/utilization and energy conversion/storage, an aqueous rechargeable Zn–CO2 battery with In/ZnO@C as the cathode is also constructed. It can output electrical energy with an open-circuit voltage of 1.35 V and a peak power density of 1.32 mW cm−2 while simultaneously realizing CO2 conversion to formate. The Zn–CO2 battery with In/ZnO@C inspires the development of green energy conversion and storage systems combining eco-efficient CO2 utilization.

Exploring bifunctional oxygen electrocatalysts with low cost and high performance is critical to the development of rechargeable zinc-air batteries, but it still remains a huge challenge. In this work, a "coordination construction-pyrolysis/self-catalyzed growth" approach was employed to fabricate branches@trunks-like, N-doped carbon nanotubes@nanowires superstructure with uniformly incorporated CoFe alloy nanoparticles (CoFe@CNTs-NWs). The rational design of such hierarchical architecture could effectively enlarge the exposure of active sites, modulate their electronic structure, and assist the electron transfer and mass diffusion, thus benefiting both ORR and OER. The resultant CoFe@CNTs-NWs displayed prominent bifunctional electrocatalytic activity and stability with a minimized oxygen overpotential of 0.71 V. When used as a cathode for zinc-air batteries, it provided a high peak power density of 131 mW cm

A simple sequence repeat (SSR) marker was used to assess the genetic diversity and population structure of an endangered relic species Emmenopterys henryi Oliv., endemic to China. A total of 124 samples from six populations were analyzed using eight pairs of SSR primers. Total 114 alleles were detected with an average of 14.3 alleles per locus. The presence of null alleles can result in low genetic diversity parameters (He and allelic richness) for all loci and mostly likely caused the deviation from Hardy–Weinberg equilibrium (HWE). The Polymorphism information content (PIC) values were higher which indicates that selection of SSR markers were suitable choice for assessing the genetic diversity in E. henryi. Our results revealed that the natural populations of E. henryi have a high degree of genetic diversity. Genetic diversity amongst the six E. henryi populations in decreasing order were: GJY > LS > DWS > WYS > HS > JGS. Further, genetic structure and the Neighbor-Joining (NJ) cluster analysis indicated that there were cross-mixing among the 124 samples. Four populations (i.e., HS, DWS, JGS and WYS) were clustered in one group, whereas LS and GJY population were clustered separately as two groups. A Principal Component Analysis (PCA) also showed a similar clustering trend. The results of Fst (0.085) and AMOVA indicated that the genetic variation resided within the populations and existence of frequent gene exchanges among populations. Based on these results, populations with abundant genetic variation and rare alleles should be conserved in situ and ex situ. Furthermore, seeds from the different populations with high levels of genetic diversity could be collected and propagated in order to capture the maximum available genetic diversity. The present study on genetic diversity of E.henryi could be helpful in expanding the understanding on species survival and also for developing an effective long term conservation strategy.

Exploring efficient electrodes toward the hydrogen evolution reaction (HER) remains a great challenge for large-scale hydrogen production. Owing to its high earth abundance, low electrical resistivity, and small density, vanadium carbide (VC) is a promising HER electrode candidate but has been rarely explored. In this work, VC nanoparticles encased in nitrogen-doped carbon matrix on carbon cloth (VC@NC/CC) were prepared as a binder-free HER cathode through electropolymerization followed by carbothermal reduction under argon. In the first step of pyrrole electropolymerization, the VO4 3- anions, serving as both vanadium source and supporting electrolyte, were homogeneously incorporated in the positively charged polypyrrole (PPy) framework through coulombic interaction. The electropolymerization was effective for preparation of binder-free metal carbide materials with various polymer monomers as carbon source, which was favorable for the high performance of metal carbide electrodes. During the pyrolysis process, the polymeric hybrids were converted to VC nanoparticles and entrapped in the PPy-derived N-doped carbon matrix. The optimized VC@NC/CC electrode exhibited high catalytic activity and durability in both acidic and alkaline media. The use of VC for efficient HER is remarkable, and such a convenient and versatile electropolymerization-assisted method is appealing for the fabrication of industrially scalable large-area VC electrodes for efficient hydrogen production.

Metal selenides attract great research interest as oxygen evolution reaction (OER) electrocatalysts. Herein, we report heterostructured bimetallic cobalt–iron diselenide nanoparticles with abundant...

Rational design and construction of highly efficient and durable bifunctional non-noble metal electrocatalysts for reversible oxygen reduction (ORR) and evolution reactions (OER) are urgently required yet challenging for rechargeable Zn–air batteries. We develop here a facile and scalable “delignification–impregnation–carbonization” strategy to fabricate uniformly dispersed NiFe alloy nanoparticles anchored on bamboo stick-derived N-doped carbon fibers (NiFe@N-CFs) as an air cathode for flexible Zn–air batteries. Benefiting from the inherent cellulose fibers with abundant macroporous structures in the raw bamboo stick, the lignified carbon fibers possess an interconnected porous structure. In addition to having high electrical conductivity endowed by one-dimensional carbon fibers, this porous structure is favorable for exposure of more active surface sites for electrochemical reactions and fast mass transport. Moreover, the strong metal–support interaction between NiFe nanoparticles and N-doped carbon and their synergistic effect may also contribute to the catalytic performance. Consequently, the resultant electrocatalyst displays excellent catalytic activity and stability toward oxygen electrocatalysis with a remarkably small potential gap (ΔE) of 0.71 V between the half-wave potential (E1/2) of the ORR and the potential at 10 mA cm−2 (Ej=10) of the OER. When employed as a bifunctional air cathode in a liquid Zn–air battery, the NiFe@N-CF based device can achieve a peak power density of 102 mW cm−2 and specific capacity of 729 mA h gZn−1 and can be steadily cycled for 150 h at 10 mA cm−2, which is extraordinary. The NiFe@N-CFs can also be used as a self-supporting air cathode in a flexible quasi-solid-state Zn–air battery, showing high round-trip efficiency and mechanical stability. This work provides a new avenue for the development of energy-related devices by converting biomass into advanced electrodes.

Herein, three-dimensionally ordered macroporous (3DOM) bimetal phosphides were fabricated by a templating method combining solid-phase phosphorization treatment. The resultant materials are composed of interconnected periodic macropore channels with texture mesopores, which can provide high electrical conductivity, efficient mass transport and abundant active sites during electrocatalytic water splitting. Benefiting from the unique multiscale pore structure, the 3DOM Ni3Fe phosphide as a bifunctional electrocatalyst exhibits high activities for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The experimental results suggest that the phosphorization treatment of Ni3FeOx to Ni3Fe–P leads to a roughened surface and enhanced affinity with aqueous electrolyte, accounting for the greatly improved catalytic performance. An alkaline electrolyzer is constructed using 3DOM Ni3Fe–P as both the anode and cathode, which can realize overall water splitting at a significantly low overpotential of only 420 mV for delivering a current density of 10 mA cm−2. The template-assisting method is versatile which is readily applied to fabricate a CoFe–P electrocatalyst. The effective construction of a 3DOM structure by the templating method has been discussed in terms of the compatibility between the PMMA template and metal sources. This study provides a unique and versatile strategy to prepare various 3DOM materials for application in energy conversion and storage systems.

The unique morphology of grass stomata enables rapid responses to environmental changes. Deciphering the basis for these responses is critical for improving food security. We have developed a planta platform of single nucleus RNA-sequencing by combined fluorescence-activated nuclei flow sorting, and used it to identify cell types in mature and developing stomata from 33,098 nuclei of the maize epidermis. Guard and subsidiary cells displayed differential expression of genes, besides those encoding transporters, involved in the abscisic acid, CO2, Ca2+, starch metabolism, and blue light signaling pathways, implicating coordinated signal integration in speedy stomatal responses, and of genes affecting cell wall plasticity, implying a more sophisticated relationship between guard and subsidiary cells in stomatal development and dumbbell-shaped guard cell formation. The trajectory of stomatal development identified in young tissues, and by comparison to the bulk RNA-seq data of the MUTE defective mutant in stomatal development, confirmed known features and shed light on key participants in stomatal development. Our study provides a valuable, comprehensive, and fundamental foundation for further insights into grass stomatal function.

Hanjiang Liu,1,* Yali Yu,1,* Yanli Niu2 1Department of Clinical Laboratory, Zhengzhou Orthopaedics Hospital, Zhengzhou, Henan, 450000, People’s Republic of China; 2School of Basic Medical Science, Henan University, Kaifeng, Henan, 475004, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yanli Niu, School of Basic Medical Science, Henan University, Kaifeng, Henan, 475004, People’s Republic of China, Email 104752140071@vip.henu.edu.cnPurpose: The discrimination of prosthetic joint infection (PJI) from aseptic failure is regarded as a major clinical challenge. The key function of human neutrophil lipocalin (HNL) in regulating bacterial infection rationalizes its potential as a biomarker to diagnose PJI. This work evaluated the accuracy of serum human neutrophil lipocalin as a biomarker to diagnose PJI.Methods: This prospective cohort study enrolled altogether 58 patients suffering from miserable knee or hip arthroplasty and receiving revision surgery from 2018 to 2020. Related laboratory and clinical information of these patients were retrieved. Following the Musculoskeletal Infection Society (MSIS) criteria, the diagnosis of PJI was conducted. Collecting preoperative blood samples, we measured HNL by the standard assay. Thereafter, plotting the receiver-operating characteristic curve (ROC), the area under the curve (AUC) values were calculated to analyze the diagnosis accuracy.Results: According to the MSIS criteria, 38 cases (65.5%) were classified into the PJI group, while 20 (34.5%) into the aseptic loosening group, with age ranging from 38 to 87 (median, 66.9) years. The median serum HNL level of the PJI patients was 199.01 (range, 85.34– 357.79) ng/mL, significantly higher as compared with that of 64.81 (range, 20.73– 157.89) ng/mL of the aseptic loosening group. Using the Youden index, the optimal threshold value was 105.1ng/mL, while the specificity, sensitivity, and AUC were 85.0%, 81.6%, and 0.919, respectively.Conclusion: Serum HNL is the creditable test that can be employed as the laboratory biomarker to screen PJI. The threshold HNL level is 105.1 ng/mL, which may distinguish PJI from aseptic failure.Keywords: prosthetic joint infection, human neutrophil lipocalin, biomarker, arthroplasty

As the most abundant RNA modification, pseudouridylation has been shown to play critical roles in Escherichia coli, yeast and humans. However, its function in plants is still unclear. Here, we characterized leaf curly and small 1 (FCS1), which encodes a pseudouridine synthase in Arabidopsis. fcs1 mutants exhibited severe defects in plant growth, such as delayed development and reduced fertility, and were significantly smaller than the wild type at different developmental stages. FCS1 protein is localized in the mitochondrion. The absence of FCS1 significantly reduces pseudouridylation of mitochondrial 26S ribosomal RNA (rRNA) at the U1692 site, which sits in the peptidyl transferase center. This affection of mitochondrial 26S rRNA may lead to the disruption of mitochondrial translation in the fcs1-1 mutant, causing high accumulation of transcripts but low production of proteins. Dysfunctional mitochondria with abnormal structures were also observed in the fcs1-1 mutant. Overall, our results suggest that FCS1-mediated pseudouridylation of mitochondrial 26S rRNA is required for mitochondrial translation, which is critical for maintaining mitochondrial function and plant development.

Plants face a more volatile environment than other organisms because of their immobility, and they have developed highly efficient mechanisms to adapt to stress conditions. Transcription factors, as an important part of the adaptation process, are activated by different signals and are responsible for the expression of stress-responsive genes. MYB transcription factors, as one of the most widespread transcription factor families in plants, participate in plant development and responses to stresses by combining with MYB cis-elements in promoters of target genes. MYB transcription factors have been extensively studied and have proven to be critical in the biosynthesis of secondary metabolites in plants, including anthocyanins, flavonols, and lignin. Multiple studies have now shown that MYB proteins play diverse roles in the responses to abiotic stresses, such as drought, salt, and cold stresses. However, the regulatory mechanism of MYB proteins in abiotic stresses is still not well understood. In this review, we will focus mainly on the function of Arabidopsis MYB transcription factors in abiotic stresses, especially how MYB proteins participate in these stress responses. We also pay attention to how the MYB proteins are regulated in these processes at both the transcript and protein levels.

Strong metal-support interaction has been explored as an efficient way in heterogeneous catalysis to modulate the electronic structure of active metal for enhanced catalytic activity. Herein we report ultrasmall iridium nanoparticles supported on nitrogen-doped graphene sheets (Ir@N-G-750) with boosted electrocatalytic activity and durability toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for highly efficient water electrolysis. As-reported Ir@N-G-750 demonstrates excellent HER and OER activity superior to benchmarking Pt/C and RuO2/IrO2 catalysts, respectively in both acidic and alkaline media; as a bifunctional electrocatalyst, it enables long-term 1.6 V-overall water splitting at 20 mA cm−2 current density when loaded on planar glassy carbon electrode at a total Ir loading of 23 μg cm−2. Detailed investigation unveils abundant Ir–N coordination in Ir@N-G-750, which enhances the electron density and modifies electronic structure of Ir nanoparticles to facilitate the electrochemical reactions. Density functional theory (DFT) calculation indicates that N dopants can stabilize the supported Ir clusters and improve their electrocatalytic activities.

Exploring highly efficient and low-cost electrocatalysts is important for boosting the efficiency of water splitting to obtain clean and renewable energy. In this study, the NiFe layered double hyd...

The development of economical, high-efficiency, and robust bifunctional oxygen electrocatalysts toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly desirable b...

We report here an iron-integrated transparent electrode by a scalable one-pot hydrothermal reaction and its applications as an active electrocatalyst or as a functional electrode substrate for the oxygen evolution reaction (OER). Characterization of the electrode reveals that it is a well-defined, compact β-FeOOH film whose thickness, photoelectric properties, and catalytic performance are controllable by varying synthetic conditions. The direct-growth strategy is beneficial in improving its electrical conductivity compared to that of catalyst-powder-coated electrodes. The integrated electrode exhibits an onset overpotential of 383 mV toward OER and a Tafel slope of 36 mV dec–1 at pH 7, which are impressive results for an iron-based catalyst. Calcination of β-FeOOH at 650 °C gives α-Fe2O3, which allows for a direct comparison of catalysis performance between the two electrodes and for a comparison by density functional theory. The iron-integrated electrode can also serve as an excellent electrode substrat...

In this work, we have adopted a facile three-step method for constructing an intriguing bifunctional electrode of self-supported hollow (Ni,Co)Se2 arrays with a metal–organic framework (MOF) precursor. The triangle-like cobalt-based MOF arrays are first grown on a carbon cloth at room temperature, which is followed by an ion exchange/etching process with Ni(NO3)2 to form a critical hollow nanostructure with an incorporated hetero-metal element. The intermediate is then transformed into the final product through solvothermal selenization treatment. Taking advantages of the structural and compositional merits as well as the self-supporting nature, the resultant (Ni,Co)Se2 electrode exhibits excellent electrochemical activity and stability. When tested as an electrocatalyst for the oxygen evolution reaction (OER), the (Ni,Co)Se2 array electrode displayed a low onset overpotential of 226 mV and a small overpotential of 256 mV to afford a current density of 10 mA cm−2. The (Ni,Co)Se2 electrode is also utilized in a supercapacitor, which delivers a high specific capacitance of 2.85 F cm−2 at 2 mA cm−2 and exhibits excellent cycling stability with a capacitance retention of 80.8% after 2000 charge–discharge cycles at 20 mA cm−2. These results demonstrate the significance of the rational design of electrode materials and disclose the potential of our MOF-derived hollow (Ni,Co)Se2 array electrode for a variety of practical applications in energy conversion and storage.

The Fe/N–C catalyst is a type of promising catalyst to replace costly Pt/C for oxygen reduction reaction (ORR). The Fe agglomerates in the Fe/N–C catalyst are capable of enhancing the ORR activity, but the effect of the agglomerate composition has not received prior investigation. In this paper, three Fe/N–C catalysts composed of different Fe-based nanoparticles including metal/oxide, carbide, and nitride on nitrogen-doped graphene sheets (denoted as Fe/Fe3O4@N-G, Fe3C@N-G and FexN@N-G, respectively) are synthesized and their oxygen reduction reaction activities are compared. Electrochemical evaluation reveals an order of Fe/Fe3O4@N-G > FexN@N-G > Fe3C@N-G in ORR activity, and the best Fe/Fe3O4@N-G catalyst is even superior to the commercial Pt/C catalyst. Detailed structure and composition analyses suggest that the excellent catalytic performance is tightly associated with the high N (particularly pyridinic-N) dopants and the chemical composition of metal agglomerates in the catalyst. Our work explores a highly active ORR electrocatalyst and also reveals the effect of agglomerate composition on the activity, which may provide valuable insights into the rational design and controllable synthesis of sustainable high-performance ORR electrocatalysts.

The development of noble-metal-free active oxygen evolution reaction (OER) catalysts for efficient water electrolysis is in high demand. In this work a novel self-supported hierarchical OER catalyst comprising vanadium oxide (VO/VO2) nanocrystals embedded in amorphous trinickel disulfide (Ni3S2) nanosheets grown on Ni foam (VOx/Ni3S2@NF, 2 > x > 1) is reported. This VOx/Ni3S2@NF demonstrates excellent OER activity and durability in alkaline media. To achieve an OER current density of 100 mA cm−2, it requires an overpotential of only 358 mV (or 330 mV after 95% iR compensation), which is even much lower than that for commercial RuO2 catalysts (446 mV). Detailed investigation unveils that the excellent OER performance of VOx/Ni3S2@NF is tightly associated with its rationally combined chemical composition and hierarchical nanostructure; remarkably, the presence of vanadium oxide nanocrystals in the Ni3S2 nanosheets boosts the OER activity by strengthening the Ni–O bond. This work opens a new route to the rational synthesis of highly efficient OER electrocatalysts, and may help deepen our understanding of the OER process catalyzed by non-precious metal-based hybrid electrocatalysts.

A highly efficient and low-cost oxygen evolution reaction electrocatalyst is essential for water splitting. Herein, a simple and cost-effective autologous growth method is developed to prepare NiFe-based integrated electrodes for water oxidation. In this method, a Ni(OH)2 nanosheet film is first developed on nickel foam by oxidative deposition in a chemical bath solution. The as-prepared nanosheet electrode is then immersed into a solution containing Fe(III) cations to form an Fe-doped Ni(OH)2 electrode by utilization of the different solubility of metal cations. Benefiting from its unique and integrated nanostructure, this hierarchically structured electrode displays extremely high catalytic activity toward water oxidation. In 1 M KOH, the electrode can deliver a current density of 1000 mA cm−2 at an overpotential of only 330 mV. This work provides a facile way to produce an efficient, durable, and Earth-abundant OER electrocatalyst with no energy input, which is attractive for large-scale water splitting.

Highlights A novel heterostructured bimetallic Co/CoFe nanomaterial supported on nanoflower-like N-doped graphitic carbon (NC) is prepared through a strategy of coordination construction-cation exchange-pyrolysis.The Co/CoFe@NC exhibits high bifunctional activities with a remarkably small potential gap of 0.70 V between oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), which can be used in liquid and flexible quasi-solid-state rechargeable Zn–air batteries.The density functional theory calculations reveal optimized adsorption energies for intermediates of ORR and OER on heterostructured Co/CoFe@NC. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00650-2., Metal–air batteries, like Zn–air batteries (ZABs) are usually suffered from low energy conversion efficiency and poor cyclability caused by the sluggish OER and ORR at the air cathode. Herein, a novel bimetallic Co/CoFe nanomaterial supported on nanoflower-like N-doped graphitic carbon (NC) was prepared through a strategy of coordination construction–cation exchange-pyrolysis and used as a highly efficient bifunctional oxygen electrocatalyst. Experimental characterizations and density functional theory calculations reveal the formation of Co/CoFe heterostructure and synergistic effect between metal layer and NC support, leading to improved electric conductivity, accelerated reaction kinetics, and optimized adsorption energy for intermediates of ORR and OER. The Co/CoFe@NC exhibits high bifunctional activities with a remarkably small potential gap of 0.70 V between the half-wave potential (E1/2) of ORR and the potential at 10 mA cm‒2 (Ej=10) of OER. The aqueous ZAB constructed using this air electrode exhibits a slight voltage loss of only 60 mV after 550-cycle test (360 h, 15 days). A sodium polyacrylate (PANa)-based hydrogel electrolyte was synthesized with strong water-retention capability and high ionic conductivity. The quasi-solid-state ZAB by integrating the Co/CoFe@NC air electrode and PANa hydrogel electrolyte demonstrates excellent mechanical stability and cyclability under different bending states. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00650-2.

In this study, we have developed intriguing self-supporting caterpillar-like spinel NiCo2S4 arrays with a hierarchical structure of nanowires on a nanosheet skeleton, which can be used as a self-supporting trifunctional electrocatalyst for the oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and urea oxidation reaction (UOR). The caterpillar-like NiCo precursor arrays are first in situ grown on carbon cloth (NiCo2O4/CC) by a facile hydrothermal reaction, which is followed by an anion exchange process (or sulfuration treatment) with Na2S to form self-supporting spinel NiCo2S4 arrays (NiCo2S4/CC) with a roughened nanostructure. Taking advantage of the bimetallic synergistic effect, the unique hierarchical nanostructure, and the self-supporting nature, the resultant NiCo2S4/CC electrode exhibits high activities toward the OER, HER and UOR, which are highly superior to the monometallic counterparts of NiS nanosheets and Co9S8 nanowires on a carbon cloth substrate. The comparison of the three electrodes also indicates that the hierarchically structured bimetallic electrode combines the morphological and structural characteristics of monometallic Ni-based nanosheets and Co-based nanowires. When assembling a two-electrode electrolytic cell with NiCo2S4/CC as both the anode and cathode, an applied cell voltage of only 1.66 V is required to deliver a current density of 10 mA cm-2 in water electrolysis. By using the same two-electrode setup, the applied voltage for urea electrolysis is further reduced to 1.45 V that produces hydrogen at the cathode with the same current density. This study paves the way for exploring the feasibility of future less energy-intensive and large-scale hydrogen production.

Photoreduction of CO2 to chemical fuels offers a promising strategy for managing the global carbon balance using renewable solar energy. However, the decisive process of oriented photogenerated electron delivery presents a considerable challenge. The performance of most transition metal compounds, as photocatalysts for CO2 reduction, is largely limited by their inherent stacked structure, poor conductivity, and fast recombination of photogenerated electron-hole pairs. Herein, we report the construction of porous nitrogen-doped carbon nanofibers (NCPF) with highly dispersed Ni and molybdenum phosphide nanoparticles (Ni-MoP@NCPF) loaded for photocatalytic CO2 reduction. The porous carbon nanofibers with high conductivity and open ends can effectively promote charge/mass transfer and improve CO2 adsorption. The loaded Ni species exist at a highly dispersed state that are stabilized by formation of coordinating Ni-N bonds with N from pyrrolic nitrogen in NCPF. The incorporation of Ni and its electronic coupling with MoP can adjust the band structure of the resultant material and alter the transfer route of the photogenerated carriers. The Ni-MoP@NCPF exhibits a CO product selectivity up to 98.95% with a rate of 953.33 μmol g−1h−1 under visible light irradiation, which is 9.37 times faster than that of Ni-free MoP@NCPF. These findings provide new insights into photocatalytic CO2 reduction on cost-effective transition metal compounds through combined morphology, composition, and heterointerface engineering.

Molybdenum (Mo) based materials including its phosphides, carbides, nitrides, oxides, dichalcogenides and metallic alloys have received particular interest in recent years for sustainable hydrogen evolution reaction (HER) electrocatalysis. In this study, a novel Mo2C/MoP hybrid nanoparticle embedded N, P co-doped carbon nanofibers on carbon fiber paper (Mo2C-MoP NPC/CFP-800) is successfully prepared as a highly efficient hierarchical HER electrocatalyst. Benefitting from its structural advantages and compositional merits, this Mo2C-MoP NPC/CFP-800 electrocatalyst displays remarkable catalytic activity as well as excellent durability for HER. Only 85 and 146 mV overpotential is required to drive a HER current density of 10 mA cm−2 in acidic and alkaline solution, respectively. Remarkably, this electrocatalyst is also able to fulfill efficient HER even in seawater. Further, this work reveals that the Mo2C/MoP hybrid nanoparticle is superior to MoP nanoparticle under present system in HER electrocatalysis, which may offer valuable clues on further design and synthesis of HER electrocatalysts.