Functional analyses of TRAF6 gene in Argopecten scallops.

The tumor necrosis factor (TNF) receptor-associated factor (TRAF) family has been reported to be involved in many immune pathways. In a previous study, we identified 5 TRAF genes, including TRAF2, 3, 4, 6, and 7, in the bay scallop (Argopecten irradians, Air) and the Peruvian scallop (Argopecten purpuratus, Apu). Since TRAF6 is a key molecular link in the TNF superfamily, we conducted a series of studies targeting the TRAF6 gene in the Air and Apu scallops as well as their hybrid progeny, Aip (Air ♀ × Apu ♂) and Api (Apu ♀ × Air ♂). Subcellular localization assay showed that the Air-, Aip-, and Api-TRAF6 were widely distributed in the cytoplasm of the human embryonic kidney cell line (HEK293T). Additionally, dual-luciferase reporter assay revealed that among TRAF3, TRAF4, and TRAF6, only the overexpression of TRAF6 significantly activated NF-κB activity in the HEK293T cells in a dose-dependent manner. These results suggest a crucial role of TRAF6 in the immune response in Argopecten scallops. To investigate the specific immune mechanism of TRAF6 in Argopecten scallops, we conducted TRAF6 knockdown using RNA interference. Transcriptomic analyses of the TRAF6 RNAi and control groups identified 1194, 2403, and 1099 differentially expressed genes (DEGs) in the Air, Aip, and Api scallops, respectively. KEGG enrichment analyses revealed that these DEGs were primarily enriched in transport and catabolism, amino acid metabolism, peroxisome, lysosome, and phagosome pathways. Expression profiles of 28 key DEGs were confirmed by qRT-PCR assays. The results of this study may provide insights into the immune mechanisms of TRAF in Argopecten scallops and ultimately benefit scallop breeding.

Core-Shell CoS2@MoS2 with Hollow Heterostructure as an Efficient Electrocatalyst for Boosting Oxygen Evolution Reaction.

It is imperative to develop an efficient catalyst to reduce the energy barrier of electrochemical water decomposition. In this study, a well-designed electrocatalyst featuring a core-shell structure was synthesized with cobalt sulfides as the core and molybdenum disulfide nanosheets as the shell. The core-shell structure can prevent the agglomeration of MoS2, expose more active sites, and facilitate electrolyte ion diffusion. A CoS2/MoS2 heterostructure is formed between CoS2 and MoS2 through the chemical interaction, and the surface chemistry is adjusted. Due to the morphological merits and the formation of the CoS2/MoS2 heterostructure, CoS2@MoS2 exhibits excellent electrocatalytic performance during the oxygen evolution reaction (OER) process in an alkaline electrolyte. To reach the current density of 10 mA cm-2, only 254 mV of overpotential is required for CoS2@MoS2, which is smaller than that of pristine CoS2 and MoS2. Meanwhile, the small Tafel slope (86.9 mV dec-1) and low charge transfer resistance (47 Ω) imply the fast dynamic mechanism of CoS2@MoS2. As further confirmed by cyclic voltammetry curves for 1000 cycles and the CA test for 10 h, CoS2@MoS2 shows exceptional catalytic stability. This work gives a guideline for constructing the core-shell heterostructure as an efficient catalyst for oxygen evolution reaction.

Hierarchically Structured Graphene Aerogel Supported Nickel-Cobalt Oxide Nanowires as an Efficient Electrocatalyst for Oxygen Evolution Reaction.

The rational design of a heterostructure electrocatalyst is an attractive strategy to produce hydrogen energy by electrochemical water splitting. Herein, we have constructed hierarchically structured architectures by immobilizing nickel-cobalt oxide nanowires on/beneath the surface of reduced graphene aerogels (NiCoO2/rGAs) through solvent-thermal and activation treatments. The morphological structure of NiCoO2/rGAs was characterized by microscopic analysis, and the porous structure not only accelerates the electrolyte ion diffusion but also prevents the agglomeration of NiCoO2 nanowires, which is favorable to expose the large surface area and active sites. As further confirmed by the spectroscopic analysis, the tuned surface chemical state can boost the catalytic active sites to show the improved oxygen evolution reaction performance in alkaline electrolytes. Due to the synergistic effect of morphology and composition effect, NiCoO2/rGAs show the overpotential of 258 mV at the current density of 10 mA cm-2. Meanwhile, the small values of the Tafel slope and charge transfer resistance imply that NiCoO2/rGAs own fast kinetic behavior during the OER test. The overlap of CV curves at the initial and 1001st cycles and almost no change in current density after the chronoamperometric (CA) test for 10 h confirm that NiCoO2/rGAs own exceptional catalytic stability in a 1 M KOH electrolyte. This work provides a promising way to fabricate the hierarchically structured nanomaterials as efficient electrocatalysts for hydrogen production.

Synergistic Engineering of CoO/MnO Heterostructures Integrated with Nitrogen-Doped Carbon Nanofibers for Lithium-Ion Batteries.

The integration of heterostructures within electrode materials is pivotal for enhancing electron and Li-ion diffusion kinetics. In this study, we synthesized CoO/MnO heterostructures to enhance the electrochemical performance of MnO using a straightforward electrostatic spinning technique followed by a meticulously controlled carbonization process, which results in embedding heterostructured CoO/MnO nanoparticles within porous nitrogen-doped carbon nanofibers (CoO/MnO/NC). As confirmed by density functional theory calculations and experimental results, CoO/MnO heterostructures play a significant role in promoting Li+ ion and charge transfer, improving electronic conductivity, and reducing the adsorption energy. The accelerated electron and Li-ion diffusion kinetics, coupled with the porous nitrogen-doped carbon nanofiber structure, contribute to the exceptional electrochemical performance of the CoO/MnO/NC electrode. Specifically, the as-prepared CoO/MnO/NC exhibits a high reversible specific capacity of 936 mA h g-1 at 0.1 A g-1 after 200 cycles and an excellent high-rate capacity of 560 mA h g-1 at 5 A g-1, positioning it as a competitive anode material for lithium-ion batteries. This study underscores the critical role of electronic and Li-ion regulation facilitated by heterostructures, offering a promising pathway for designing transition metal oxide-based anode materials with high performances for lithium-ion batteries.

Potential roles of IFI44 genes in high resistance to Vibrio in hybrids of Argopecten scallops.

Vibrio bacteria are often fatal to aquatic organisms and selection of Vibrio-resistant strains is warranted for aquaculture animals. In this study, we found that hybrids between bay scallops and Peruvian scallops exhibited significantly higher resistance to Vibrio challenge, but little is available on its mechanism. Interferon induced protein 44 (IFI44), a member of the type I interferon (IFN) family, plays an important role in the IFN immune response in invertebrates, which may also participate in the resistance to Vibrio in scallops. To explore the roles of IFI44 genes in the resistance to Vibrio, they were identified and characterized in the bay scallop (designated as AiIFI44), the Peruvian scallop (designated as ApIFI44), and their reciprocal hybrids (designated as AipIFI44 and ApiIFI44, respectively). Their open reading frame (ORF) sequences were all 1434 bp, encoding 477 amino acids, but with large variations among the four genes. The AipIFI44 and ApiIFI44 exhibited higher similarity with ApIFI44 than with AiIFI44. All four genes have a TLDc structural domain with significant variations in sequences among them. Predicted differences in conformation and posttranslational modifications may lead to altered protein activity. We further demonstrated that the AiIFI44, AipIFI44 and ApiIFI44 expressed in all the tested tissues, with the highest expression in the gills and hepatopancreas. In response to Vibrio anguillarum challenge, the profile of mRNA expression of IFI44 gene differed among the bay scallops and the two hybrids. In the bay scallops, it increased at 6 h but dramatically decreased after 12-48 h. However, the mRNA expression of both AipIFI44 and ApiIFI44 decreased at 6 h but continuously increased thereafter and reached the highest value at 48 h. The results in the present study suggest the immune responds of IFI44 in scallops and it may be related to the higher resistance to Vibrio bacterial in hybrids.

Characterization of TRAF genes and their responses to Vibrio anguillarum challenge in Argopecten scallops.

The tumor necrosis factor receptor-related factor (TRAF) family has been reported to be involved in many immune pathways, such as TNFR, TLR, NLR, and RLR in animals. However, little is known about the roles of TRAF genes in the innate immune of Argopecten scallops. In this study, we first identified five TRAF genes, including TRAF2, TRAF3, TRAF4, TRAF6 and TRAF7, but not TRAF1 and TRAF5, from both the bay scallop A. irradians (Air) and the Peruvian scallop A. purpuratus (Apu). The phylogenetic analysis showed that the TRAF genes in Argopecten scallops (AiTRAF) belong to the branch of molluscan TRAF family, which lacks TRAF1 and TRAF5. Since TRAF6 is a key bridge factor in the tumor necrosis factor superfamily and plays an important role in innate and adaptive immunity, we cloned the ORFs of the TRAF6 gene in both A. irradians and A. purpuratus, as well as in two reciprocal hybrids (Aip for the hybrid Air × Apu and Api for the hybrid Apu × Air). Differences in conformational and post-translational modification resulted from the variation in amino acid sequences may cause differences in activity among them. Analysis of conserved motifs and protein structural domains revealed that AiTRAF contains typical structural domains similar to those of other mollusks and has the same conserved motifs. Tissue expression of TRAF in Argopecten scallops challenged by Vibrio anguillarum was examined by qRT-PCR. The results showed that AiTRAF were higher in gill and hepatopancreas. When challenged by Vibrio anguillarum, the expression of AiTRAF was significantly increased compared with the control group, indicating that AiTRAF may play an important role in the immunity of scallops. In addition, the expression of TRAF was higher in Api and Aip than in Air when challenged by Vibrio anguillarum, suggesting that TRAF may have contributed to the high resistance of Api and Aip to Vibrio anguillarum. The results of this study may provide new insights into the evolution and function of TRAF genes in bivalves and ultimately benefit scallop breeding.

Realizing Ultrafast and Robust Sodium-Ion Storage of Iron Sulfide Enabled by Heteroatomic Doping and Regulable Interface Engineering.

Fe-based sulfides are a promising type of anode material for sodium-ion batteries (SIBs) due to their high theoretical capacities and affordability. However, these materials often suffer from issues such as capacity deterioration and poor conductivity during practical application. To address these challenges, an N-doped Fe7S8 anode with an N, S co-doped porous carbon framework (PPF-800) was synthesized using a template-assisted method. When serving as an anode for SIBs, it delivers a robust and ultrafast sodium storage performance, with a discharge capacity of 489 mAh g-1 after 500 cycles at 5 A g-1 and 371 mAh g-1 after 1000 cycles at 30 A g-1 in the ether-based electrolyte. This impressive performance is attributed to the combined influence of heteroatomic doping and adjustable interface engineering. The N, S co-doped carbon framework embedded with Fe7S8 nanoparticles effectively addresses the issues of volumetric expansion, reduces the impact of sodium polysulfides, improves intrinsic conductivity, and stimulates the dominant pseudocapacitive contribution (90.3% at 2 mV s-1). Moreover, the formation of a stable solid electrolyte interface (SEI) film by the effect of uniform pore structure in ether-based electrolyte produces a lower transfer resistance during the charge-discharge process, thereby boosting the rate performance of the electrode material. This work expands a facile strategy to optimize the electrochemical performance of other metal sulfides.

Efficient Regulation of Polysulfides by Anatase/Bronze TiO2 Heterostructure/Polypyrrole Composites for High-Performance Lithium-Sulfur Batteries.

Despite having ultra-high theoretical specific capacity and theoretical energy density, lithium-sulfur (Li-S) batteries suffer from their low Coulombic efficiency and poor lifespan, and the commercial application of Li-S batteries is seriously hampered by the severe "shuttle effect" of lithium polysulfides (LiPSs) and the large volume expansion ratio of the sulfur electrode during cycling. Designing functional hosts for sulfur cathodes is one of the most effective ways to immobilize the LiPSs and improve the electrochemical performance of a Li-S battery. In this work, a polypyrrole (PPy)-coated anatase/bronze TiO2 (TAB) heterostructure was successfully prepared and used as a sulfur host. Results showed that the porous TAB could physically adsorb and chemically interact with LiPSs during charging and discharging processes, inhibiting the LiPSs' shuttle effect, and the TAB's heterostructure and PPy conductive layer are conducive to the rapid transport of Li+ and improve the conductivity of the electrode. By benefitting from these merits, Li-S batteries with TAB@S/PPy electrodes could deliver a high initial capacity of 1250.4 mAh g-1 at 0.1 C and show an excellent cycling stability (the average capacity decay rate was 0.042% per cycle after 1000 cycles at 1 C). This work brings a new idea for the design of functional sulfur cathodes for high-performance Li-S battery.

The impact of support electronegativity on the electrochemical properties of platinum.

Modulating the electronic structure of platinum (Pt) through a support is an important strategy for enhancing its electrocatalytic properties. In this work, to explore the impact of support electronegativity on Pt's catalytic activity for hydrogen evolution, we chose diverse metals with varying electronegativities that are stable in acidic solutions, such as titanium (Ti), molybdenum (Mo), and tungsten (W), as supports. Ti is the optimal support according to density functional theory (DFT) calculations. As expected, the Pt@Ti catalyst demonstrated remarkable efficiency in the hydrogen evolution reaction (HER), displaying a minimal overpotential of 13 mV at -10 mA cm-2, a Tafel slope of 34.5 mV dec-1, and sustained durability over 110 h in a 0.5 M H2SO4 solution. To unravel the metal-support interaction (MSI) between Pt and Ti, a comprehensive exploration encompassing both experimental investigations and DFT calculations was undertaken. The results elucidate that the outstanding HER performance of Pt@Ti stems from robust synergies forged between Pt and Ti atoms within the Ti support. This work not only furnishes a technique for producing electrocatalysts with superior efficiency and stability but also streamlines the process of choosing the most appropriate metal support. Moreover, it enhances comprehension of the interaction between Pt and the metal support.

Transcriptomic profiling of the thermal tolerance in two subspecies of the bay scallop Argopecten irradians.

The bay scallop is a eurythermal species with high economic value and now represents the most cultured bivalve species in China. Two subspecies of the bay scallop, the northern subspecies Argopecten irradians irradians Korean population (KK) and the southern subspecies Argopecten irradians concentricus (MM), exhibited distinct adaptations to heat stress. However, the molecular mechanism of heat resistance of the two subspecies remains unclear. In this study, we compared the transcriptomic responses of the two subspecies to heat stress and identified the involved differentially expressed genes (DEGs) and pathways. More DEGs were found in the KK than in the MM when exposed to high temperatures, indicating elevated sensitivity to thermal stress in the KK. Enrichment analysis suggests that KK scallops may respond to heat stress more swiftly by regulating GTPase activity. Meanwhile, MM scallops exhibited higher resistance to heat stress mainly by effective activation of their antioxidant system. Chaperone proteins may play different roles in responses to heat stress in the two subspecies. In both subspecies, the expression levels of antioxidants such as GST were significantly increased; the glycolysis process regulated by PC and PCK1 was greatly intensified; and both apoptotic and anti-apoptotic systems were significantly activated. The pathways related to protein translation and hydrolysis, oxidoreductase activity, organic acid metabolism, and cell apoptosis may also play pivotal roles in the responses to heat stress. The results of this study may provide a theoretical basis for marker-assisted breeding of heat-resistant strains.

Rhizoma Drynariae-derived nanovesicles reverse osteoporosis by potentiating osteogenic differentiation of human bone marrow mesenchymal stem cells via targeting ERα signaling.

Although various anti-osteoporosis drugs are available, the limitations of these therapies, including drug resistance and collateral responses, require the development of novel anti-osteoporosis agents. Rhizoma Drynariae displays a promising anti-osteoporosis effect, while the effective component and mechanism remain unclear. Here, we revealed the therapeutic potential of Rhizoma Drynariae-derived nanovesicles (RDNVs) for postmenopausal osteoporosis and demonstrated that RDNVs potentiated osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) by targeting estrogen receptor-alpha (ERα). RDNVs, a natural product isolated from fresh Rhizoma Drynariae root juice by differential ultracentrifugation, exhibited potent bone tissue-targeting activity and anti-osteoporosis efficacy in an ovariectomized mouse model. RDNVs, effectively internalized by hBMSCs, enhanced proliferation and ERα expression levels of hBMSC, and promoted osteogenic differentiation and bone formation. Mechanistically, via the ERα signaling pathway, RDNVs facilitated mRNA and protein expression of bone morphogenetic protein 2 and runt-related transcription factor 2 in hBMSCs, which are involved in regulating osteogenic differentiation. Further analysis revealed that naringin, existing in RDNVs, was the active component targeting ERα in the osteogenic effect. Taken together, our study identified that naringin in RDNVs displays exciting bone tissue-targeting activity to reverse osteoporosis by promoting hBMSCs proliferation and osteogenic differentiation through estrogen-like effects.

Whole-Genome Re-sequencing and Transcriptome Reveal Candidate Genes and Pathways Associated with Hybrid Sterility in Hermaphroditic Argopecten Scallops.

The interspecific hybrid scallops generated from the hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) showed significant heterosis in growth. However, its sterility limits large-scale hybridization and hinders the development of the scallop breeding industry. Hybrid sterility is regulated by plenty of genes and involves a range of biochemical and physiological transformations. In this study, whole-genome re-sequencing and transcriptomic analysis were performed in sterile and fertile hybrid scallops. The potential genetic variations and abnormally expressed genes were detected to explore the mechanism underlying hybrid sterility in hermaphroditic Argopecten scallops. Compared with fertile hybrids, 24 differentially expressed genes (DEGs) with 246 variations were identified to be related to fertility regulation, which were mainly enriched in germarium-derived egg chamber formation, spermatogenesis, spermatid development, mismatch repair, mitotic and meiotic cell cycles, Wnt signaling pathway, MAPK signaling pathway, calcium modulating pathway, and notch signaling pathway. Specifically, variation and abnormal expression of these genes might inhibit the progress of mitosis and meiosis, promote cell apoptosis, and impede the genesis and maturation of gametes in sterile hybrid scallops. Eleven DEGs (XIAP, KAZN, CDC42, MEIS1, SETD1B, NOTCH2, TRPV5, M- EXO1, GGT1, SBDS, and TBCEL) were confirmed by qRT-PCR validation. Our findings may enrich the determination mechanism of hybrid sterility and provide new insights into the use of interspecific hybrids for extensive breeding.

Study of Methane Explosion Suppression Characteristics of N2 and CO2 in Variable Cross-Section Ducts.

To investigate the effect of concentration of N2 and CO2 (0, 10, 20, 30, 40, and 50%) on the flame propagation characteristics of CH4/air premixed gases with stoichiometric ratios in variable cross-section ducts, experiments were conducted in four combinations of ducts at initial conditions of 298 K and 1 atm. The results show that the flame propagation velocity, propagation time, and overpressure are greater in the suddenly contracted duct than in the suddenly expanded duct if the dimensions of the ducts are kept constant. However, an increase in inert gas concentration leads to a decrease in flame propagation speed, an increase in flame propagation time, and changes in flame structure and pressure. "Tulip" flames appeared when a duct with a cross section of 100 mm × 100 mm was combined with a duct with a cross section of 70 mm × 70 mm, whether N2 or CO2 was added or what its concentration was. However, when a duct with a cross section of 140 mm × 140 mm was combined with a 70 mm × 70 mm duct, a "tulip" flame is formed only at a CO2 concentration of 50%. As the concentration of inert gas increases, the explosion pressure first decreases and then stabilizes, while the rate of pressure increase showed a monotonically decreasing trend. The explosion pressure is minimized when the concentration of CO2 and N2 is 30 and 40%, respectively.

An enzyme-based system for extraction of small extracellular vesicles from plants.

Plant-derived nanovesicles (NVs) and extracellular vesicles (EVs) are the next generation of nanocarrier platforms for biotherapeutics and drug delivery. EVs exist not only in the extracellular space, but also within the cell wall. Due to the limitations of existing isolation methods, the EVs extraction efficiency is low, and a large amount of plant material is wasted, which is of concern for rare and expensive medicinal plants. We proposed and validated a novel method for isolation of plant EVs by enzyme degradation of the plant cell wall to release the EVs. The released EVs can easily be collected. The new method was used for extraction of EVs from the roots of Morinda officinalis (MOEVs). For comparison, nanoparticles from the roots (MONVs) were extracted using the grinding method. The new method yielded a greater amount of MOEVs, and the vesicles had a smaller diameter compared to MONVs. Both MOEVs and MONVs were readily absorbed by endothelial cells without cytotoxic effect and promoted the expression of miR-155. The promotion of miR-155 by MOEVs was dose-dependent. More importantly, we found that MOEVs and MONVs were enriched toward bone tissue. These results support our hypothesis that EVs in plants could be efficiently extracted by enzymatic cell wall digestion and confirm the potential of MOEVs as therapeutic agents and drug carriers.

Potential Involvement of DNA Methylation in Hybrid Sterility in Hermaphroditic Argopecten Scallops.

DNA methylation is an important epigenetic modification factor in regulating fertility. Corresponding process remains poorly investigated in hermaphroditic scallops. The interspecific F1 hybrids between the hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) exhibited significant heterosis in yield, but sterility in hybrids obstructs the utilization of the genetic resources. However, the determination mechanism of hybrid sterility in the hermaphroditic Argopecten scallops is still unclear. In this study, the effect of DNA methylation in the hybrid sterility of hermaphroditic Argopecten scallops was explored. The results showed that the mean methylation level was higher in sterile hybrids than fertile hybrids, especially on chromosome 11 of the paternal parent. A total of 61,062 differentially methylated regions (DMRs) were identified, containing 3619 differentially methylated genes (DMGs) and 1165 differentially methylated promoters that are located in the DMRs of CG sequence context. The hyper-methylated genes were enriched into five KEGG pathways, including ubiquitin-mediated proteolysis, ECM-receptor interaction, non-homologous end-joining, notch signaling, and the mismatch repair pathways. The DMGs might induce hybrid sterility by inhibition of oogenesis and egg maturation, induction of apoptosis, increased ROS, and insufficient ATP supply. Our results would enrich the determination mechanism of hybrid sterility and provide new insights into the utilization of the genetic resources of the interspecific hybrids.

Constructing Abundant Oxygen-Containing Functional Groups in Hard Carbon Derived from Anthracite for High-Performance Sodium-Ion Batteries.

Hard carbon is regarded as one of the greatest potential anode materials for sodium-ion batteries (SIBs) because of its affordable price and large layer spacing. However, its poor initial coulombic efficiency (ICE) and low specific capacity severely restrict its practical commercialization in SIBs. In this work, we successfully constructed abundant oxygen-containing functional groups in hard carbon by using pre-oxidation anthracite as the precursor combined with controlling the carbonization temperature. The oxygen-containing functional groups in hard carbon can increase the reversible Na+ adsorption in the slope region, and the closed micropores can be conducive to Na+ storage in the low-voltage platform region. As a result, the optimal sample exhibits a high initial reversible sodium storage capacity of 304 mAh g-1 at 0.03 A g-1, with an ICE of 67.29% and high capacitance retention of 95.17% after 100 cycles. This synergistic strategy can provide ideas for the design of high-performance SIB anode materials with the intent to regulate the oxygen content in the precursor.

Machine Learning-Assisted Low-Dimensional Electrocatalysts Design for Hydrogen Evolution Reaction.

Efficient electrocatalysts are crucial for hydrogen generation from electrolyzing water. Nevertheless, the conventional "trial and error" method for producing advanced electrocatalysts is not only cost-ineffective but also time-consuming and labor-intensive. Fortunately, the advancement of machine learning brings new opportunities for electrocatalysts discovery and design. By analyzing experimental and theoretical data, machine learning can effectively predict their hydrogen evolution reaction (HER) performance. This review summarizes recent developments in machine learning for low-dimensional electrocatalysts, including zero-dimension nanoparticles and nanoclusters, one-dimensional nanotubes and nanowires, two-dimensional nanosheets, as well as other electrocatalysts. In particular, the effects of descriptors and algorithms on screening low-dimensional electrocatalysts and investigating their HER performance are highlighted. Finally, the future directions and perspectives for machine learning in electrocatalysis are discussed, emphasizing the potential for machine learning to accelerate electrocatalyst discovery, optimize their performance, and provide new insights into electrocatalytic mechanisms. Overall, this work offers an in-depth understanding of the current state of machine learning in electrocatalysis and its potential for future research.

Synergistic Structure and Iron-Vacancy Engineering Realizing High Initial Coulombic Efficiency and Kinetically Accelerated Lithium Storage in Lithium Iron Oxide.

Transition metal oxides with high capacity still confront the challenges of low initial coulombic efficiency (ICE, generally <70%) and inferior cyclic stability for practical lithium-storage. Herein, a hollow slender carambola-like Li0.43 FeO1.51 with Fe vacancies is proposed by a facile reaction of Fe3+ -containing metal-organic frameworks with Li2 CO3 . Synthesis experiments combined with synchrotron-radiation X-ray measurements identify that the hollow structure is caused by Li2 CO3 erosion, while the formation of Fe vacancies is resulted from insufficient lithiation process with reduced Li2 CO3 dosage. The optimized lithium iron oxides exhibit remarkably improved ICE (from 68.24% to 86.78%), high-rate performance (357 mAh g-1 at 5 A g-1 ), and superior cycling stability (884 mAh g-1 after 500 cycles at 0.5 A g-1 ). Paring with LiFePO4 cathodes, the full-cells achieve extraordinary cyclic stability with 99.3% retention after 100 cycles. The improved electrochemical performances can be attributed to the synergy of structural characteristics and Fe vacancy engineering. The unique hollow structure alleviates the volume expansion of Li0.43 FeO1.51 , while the in situ generated Fe vacancies are powerful for modulating electronic structure with boosted Li+ transport rate and catalyze more Li2 O decomposition to react with Fe in the first charge process, hence enhancing the ICE of lithium iron oxide anode materials.

Strong electronic metal-support interaction between Pt and stainless mesh for enhancing the hydrogen evolution reaction.

Strong electronic metal-support interaction (EMSI) can tailor the electronic structure of electrocatalysts. Herein, Pt nanoparticles anchored on stainless mesh (SM) via EMSI engineering are reported, exhibiting excellent hydrogen production activity. Theoretical calculations demonstrate that the superior performance stems from the strong EMSI between Pt atoms and Fe atoms in SM.

Optimizing electronic structure of porous Ni/MoO2 heterostructure to boost alkaline hydrogen evolution reaction.

Heterostructure engineering is an efficient strategy to synergisticallyimprove electrocatalytic activity. In this work, Ni/MoO2 heterojunction nanorods with porous structure self-supported on nickel foam (NF) are elaborately designed through a facile solution-evaporationmethod followed by a thermal reduction process. Prominently, the optimal electrocatalyst Ni/MoO2@NF-E delivers an exceptionally low overpotential of 19 mV at the current density of 10 mA cm-2 and a small Tafel slope of 52.3 mV dec-1 toward the hydrogen evolution reaction (HER) in alkaline solution. Concurrently, Ni/MoO2@NF-E also maintains excellent stability after 120 h of electrolysis or 5000 cyclic voltammetry cycles. The experimental and density functional theory (DFT) results indicate that the enhanced HER performance of Ni/MoO2@NF-E should be ascribed to the porous structure in the Ni/MoO2 nanorods providing more active catalytic site, the moderate Gibbs free energy of hydrogen adsorption (ΔGH*), as well as strong synergistic effect between Ni and MoO2. This work provides an efficient route for developing HER electrocatalysts in alkaline media.