Achieving a Rapid Na+ Migration and Highly Reversible Phase Transition of NASICON for Sodium-Ion Batteries with Suppressed Voltage Hysteresis and Ultralong Lifespan.

Sodium ion batteries have attracted great attention for large scale energy storage devices to replace lithium-ion batteries. As a promising polyanionic cathode material of sodium-ion batteries, Na3V2(PO4)2F3 (NVPF) belonging to NASICON exhibits large gap space and excellent structural stability, leading to a high energy density and ultralong cycle lifespan. To improve its stability and Na ion mobility, K+ cations are introduced into NVPF crystal as in situ partial substitution for Na+. The influence of K+ in situ substitution on crystal structure, electronic properties, kinetic properties, and electrochemical performance of NVPF are investigated. Through ex situ examination, it turns out that K+ occupied Na1 ion, in which the K+ does not participate in the charge-discharge process and plays a pillar role in improving the mobility of Na+. Moreover, the doping of K+ cation can reduce the bandgap energy and improve the electronic conductivity. Besides, the optimal K+ doping concentration in N0.92K0.08VPF/C is found so as to achieve rapid Na+ migration and reversible phase transition. The specific capacity of N0.92K0.08VPF/C is as high as 128.8 mAh g-1 at 0.2 C, and at 10 C its rate performance is excellent, which shows a capacity of 113.3 mAh g-1.

Dual Channel H2O2 Photosynthesis in Pure Water over S-Scheme Heterojunction Cs3PMo12/CC Boosted by Proton and Electron Reservoirs.

Dual channel photo-driven H2O2 production in pure water on small-scale on-site setups is a promising strategy to provide low-concentrated H2O2 whenever needed. This process suffers, however, strongly from the fast recombination of photo-generated charge carriers and the sluggish oxidation process. Here, insoluble Keggin-type cesium phosphomolybdate Cs3PMo12O40 (abbreviated to Cs3PMo12) is introduced to carbonized cellulose (CC) to construct S-scheme heterojunction Cs3PMo12/CC. Dual channel H2O2 photosynthesis from both H2O oxidation and O2 reduction in pure water has been thus achieved with the production rate of 20.1 mmol L-1 gcat. -1 h-1, apparent quantum yield (AQY) of 2.1% and solar-to-chemical conversion (SCC) efficiency of 0.050%. H2O2 accumulative concentration reaches 4.9 mmol L-1. This high photocatalytic activity is guaranteed by unique features of Cs3PMo12/CC, namely, S-scheme heterojunction, electron reservoir, and proton reservoir. The former two enhance the separation of photo-generated charge carriers, while the latter speeds up the torpid oxidation process. In situ experiments reveal that H2O2 is formed via successive single-electron transfer in both channels. In real practice, exposing the reaction system under natural sunlight outdoors successfully results in 0.24 mmol L-1 H2O2. This work provides a key practical strategy for designing photocatalysts in modulating redox half-reactions in photosynthesis.

LINC00525 promotes tumour growth and epithelial-mesenchymal transition as an oncogene in oral squamous cell carcinoma.

OBJECTIVE: Oral squamous cell carcinoma (OSCC) is the most common malignant tumour in the oral cavity. OSCC is aggressive and prone to metastasis; it is associated with high mortality and short survival. In this study, we investigated the function of the long non-coding RNA LINC00525 in OSCC progression and the molecular mechanisms through in vitro and in vivo experiments. MATERIALS AND METHODS: CCK8 assay was used to detect the effect of LINC00525 on cell viability; transwell migration and invasion assays and scratch assay were used to examine the role of LINC00525 in cell migration and invasion. Flow cytometry, RT-PCR and western blot were used to detect apoptosis indexes. Tumorigenic effects were investigated using mouse xenograft tumour models. RESULTS: LINC00525 was associated with OSCC survival and prognosis. LINC00525 knockdown decreased cell viability and epithelial-mesenchymal transition (EMT) properties and increased apoptosis and also shortened the cell cycle of OSCC cells in vitro. The downregulation of LINC00525 reduced the growth of OSCC tumour in vivo. LINC00525 can regulate OSCC cells via the apoptotic signalling pathway. CONCLUSION: Our results indicate that LINC00525 exhibits oncogenic functions in OSCC. LINC00525 may be a new promising and potential target for the treatment of OSCC.

A nomogram to predict the risk of bleeding after discharge from stent-assisted ruptured aneurysm embolization in a Chinese population.

The occurrence of bleeding events after stent-assisted embolization of a ruptured artery requiring continuous double antiplatelet therapy may seriously affect the prognosis of this group of patients. A nomogram can provide a personalized, more accurate risk estimate based on predictors. We, therefore, developed a nomogram to predict the probability of bleeding events in patients with stent-assisted ruptured aneurysm embolization. We performed a single-center retrospective analysis of data collected from patients undergoing stent-assisted ruptured aneurysm embolization between January 2018 and December 2021. Forward stepwise logistic regression was performed to identify independent predictors of adverse events of bleeding after stent-assisted embolization and to establish nomograms. Discrimination and calibration of this model were performed using the area under the ROC curve (AUC-ROC) and the calibration plot. The model is internally validated by using resampling (1000 replicates). A total of 131 patients were identified, and a total of 118 patients met the study criteria. The predictors included in the nomogram were body mass index (BMI), AAi, and MA-ADP. The model showed good resolving power with a ROC area of 0.893 (95% CI: 0.834 ~ 0.952) for this model with good calibration. The nomogram can be used to individualize, visualize, and accurately predict the risk probability of bleeding events after stent-assisted embolization of ruptured aneurysms.

MARS1 mutations linked to familial trigeminal neuralgia via the integrated stress response.

BACKGROUND: While new genetic analysis methods are widely used in the clinic, few researchers have focused on trigeminal neuralgia (TN) with familial clustering (≥ 2 TN patients in one kindred family). Previous literature suggests that familial trigeminal neuralgia (FTN) may be associated with inherited genetic factors. To date, few next-generation sequencing studies have been reported for FTN. This study investigated the pathogenic mechanism of FTN by using whole-exome sequencing (WES) technology, which may enhance our understanding of human TN pathophysiology.  METHOD: We performed WES for 7 probands from families of FTN. Sanger sequencing was performed for two control groups (FTN family members group and nonfamilial TN subject group) to potentially identify new FTN-related gene mutations. In families where FTN probands carried potentially pathogenic gene mutations, the ribonucleic acid (RNA) of FTN probands and related family members, as well as nonfamilial TN patients were analysed by RNA sequencing (RNA-seq) to confirm differential gene expression. RESULTS: Seven probands were derived from 3 Chinese families. WES and Sanger sequencing identified MARS1 mutation c.2398C > A p.(Pro800Thr) in Family 1. MARS1 mutation was confirmed in 14/26 [53.8%] members of Family 1 in FTN family member group, while none of nonfamilial TN subjects had this MARS1 mutation. RNA-seq showed that 3 probands in Family 1 had higher expression of Fosl1 (Fos-like antigen 1) and NFE2 (Nuclear factor, erythroid 2) than 3 subjects in the nonfamilial TN subject group. Fosl1 and NFE2 are genes related to integrated stress response (ISR). CONCLUSION: MARS1 mutations may cause chronic activation of ISR, contribute to ISR pathophysiological changes in FTN, and cause/accelerate peripheral nerve degeneration. The findings of this study can enrich our knowledge of the role of molecular genetics in TN in humans.

Ionic Exchange of Metal-Organic Frameworks for Constructing Unsaturated Copper Single-Atom Catalysts for Boosting Oxygen Reduction Reaction.

Regulating the coordination environment of atomically dispersed catalysts is vital for catalytic reaction but still remains a challenge. Herein, an ionic exchange strategy is developed to fabricate atomically dispersed copper (Cu) catalysts with controllable coordination structure. In this process, the adsorbed Cu ions exchange with Zn nodes in ZIF-8 under high temperature, resulting in the trapping of Cu atoms within the cavities of the metal-organic framework, and thus forming Cu single-atom catalysts. More importantly, altering pyrolysis temperature can effectively control the structure of active metal center at atomic level. Specifically, higher treatment temperature (900 °C) leads to unsaturated Cu-nitrogen architecture (CuN3 moieties) in atomically dispersed Cu catalysts. Electrochemical test indicates atomically dispersed Cu catalysts with CuN3 moieties possess superior oxygen reduction reaction performance than that with higher Cu-nitrogen coordination number (CuN4 moieties), with a higher half-wave potential of 180 mV and the 10 times turnover frequency than that of CuN4 . Density functional theory calculation analysis further shows that the low N coordination number of Cu single-atom catalysts (CuN3 ) is favorable for the formation of O2 * intermediate, and thus boosts the oxygen reduction reaction.

Largely enhanced dielectric constant of PVDF nanocomposites through a core-shell strategy.

Core-shell structured TiO2@carbon nanowire (TiO2@C NW) hybrids with different carbon shell thicknesses were synthesized by a combination of a hydrothermal reaction and the chemical vapor deposition (CVD) method. Pristine TiO2 NWs with a high aspect ratio were obtained by a hydrothermal reaction and the as-synthesized TiO2 NWs were subsequently employed as the template for carbon shell deposition during the CVD procedure. The obtained TiO2@C NW hybrids have a uniform carbon shell and the thickness of the carbon shell could be precisely designed from 4 nm to 40 nm by controlling the deposition time. With the help of solution and melt blending methods, the TiO2@C NW hybrids were subsequently incorporated into the PVDF matrix to fabricate TiO2@C NWs/PVDF nanocomposites, which exhibit a similar percolative dielectric behavior to that reported in other percolative nanocomposites. Moreover, the dielectric properties of the TiO2@C NWs/PVDF nanocomposites could be accurately adjusted by tuning the carbon shell thickness of the TiO2@C NW hybrids. The highest dielectric constant (2171) of the TiO2@C NWs/PVDF nanocomposites is 80 times larger than those of the pristine TiO2-filled ones at the same filler loading, and 241 times higher than that of the pure PVDF matrix. The enhanced dielectric performance could be attributed to the improved interfacial polarizations of TiO2/C and C/PVDF interfaces. This approach provides an interesting alternative to fabricate high-performance dielectric nanocomposites for practical applications in the electronic industry.

Influence of Thermal Treatments on the Evolution of Conductive Paths in Carbon Nanotube-Al2O3 Hybrid Reinforced Epoxy Composites.

The conductive path formed by carbon nanotubes (CNTs) in a polymer matrix is one of the most attractive topics for developing multifunctional nanocomposites. In this article, we studied the evolution of conductive paths and interactions in the interfacial regions in epoxy-based composites reinforced by an urchinlike hybrid of CNTs and alumina microparticles (µAl2O3). A homogeneous dispersion of CNTs in the epoxy matrix was achieved thanks to the core-shell structures of CNTs-µAl2O3 hybrids, resulting in the interpenetrated epoxy's cross-linking network that strongly bonds with CNTs. Furthermore, thermal treatments at different temperatures around the glass-transition temperature (Tg) were conducted under vacuum on composites near the percolation threshold. It was found that the dielectric behavior and the Tg were shifted in spite of the constant CNT mass fraction used. This was mainly due to the fact that thermal treatment generated the adjustment of the cross-linking network of epoxy, and the distances between adjacent CNTs were reduced gradually. This study can provide insight into the evolution of conductive paths in the interfacial regions from a more straightforward perspective.

Fluorine-ion-regulated yolk-shell carbon-silicon anode material for high performance lithium ion batteries.

Silicon is considered as the next-generation anode material for lithium-ion batteries due to its high theoretical specific capacity and abundant crustal abundance. However, its poor electrical conductivity results in slow diffusion of lithium ions during battery operation. Simultaneously, the alloying process of silicon undergoes a 300 % volume change, leading to structural fractures in silicon during the cycling process. As a result, it loses contact with the current collector, continuously exposing active sites, and forming a sustained solid electrolyte interface (SEI) membrane. This paper presents the design of a fluorine-ion-regulated yolk-shell carbon-silicon anode material, highlighting the following advantages: (a) Alleviating volume changes through the design of a yolk-shell structure, thereby maintaining material structural integrity during cycling. (b) Carbon shell prevents silicon from coming into contact with the electrolyte, simultaneously improving silicon's electrical conductivity and increasing ion/electron conductivity. (c) Utilizing fluorine-ion interface modification to obtain an SEI membrane rich in fluorine components (such as LiF), thereby enhancing its long cycling performance. The F-Si@Void@C exhibits outstanding electrochemical performance, with a reversible capacity of 1166 mAh/g after 900 cycles at a current density of 0.5 A/g.

Dark Tea Wine Protects Against Metabolic Dysfunction-Associated Steatotic Liver Disease In Vivo Through Activating the Nrf2/HO-1 Antioxidant Signaling Pathway.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a complex and multifactorial disease. Dark tea exhibits great potential for various bioactivities for metabolic health. In this study, we aimed to evaluate therapeutic effects and the underlying mechanisms of dark tea wine (DTW) on MASLD with obesity. A rat model of MASLD was established by high-fat diet and administered with different doses of DTW as an intervention. The biomarkers of lipid metabolism and oxidative stress in rats were tested. The weight of organs and adipose tissues and the expressions of nuclear factor erythroid 2-like 2 (Nrf2) and heme oxygenase-1 (HO-1) were investigated based on the pathology and western blot analysis. We found that DTW enhanced antioxidant capacity via activating the Nrf2/HO-1 signaling pathway, further markedly triggering inhibition of weight gain, reduction of lipid dysfunction, and improvement of pathological characteristics to ameliorate MASLD induced by high-fat diet. These results suggest that DTW is a promising functional supplement for prevention and treatment of MASLD and obesity.

Boosted light absorption by WO3-x/Ag/PbS heterostructure for high-efficiency interfacial solar steam generation.

Interfacial solar steam generation is considered a promising approach to address energy and drinking water shortages. However, designing efficient light-absorbing and photothermal-converting materials remains challenging. In this study, we describe a detailed method for synthesising a three-dimensional (3D) hierarchical oxygen defect-rich WO3/Ag/PbS/Ni foam (termed WO3-x/Ag/PbS/NF) composite to realise efficient exciton separation and enhanced photothermal conversion. The 3D heterogeneous ternary photothermal material combines the individual benefits of WO3-x, Ag and PbS, improving charge transfer and promoting photogenerated electron-hole pairs. This enhances light absorption and energy conversion. Theoretical calculations indicate that the increased photothermal conversion efficiency primarily results from the heterojunction between Ag, WO3-x and PbS, facilitating exciton separation and electron transfer. Consequently, the WO3-x/Ag/PbS/NF solar evaporator exhibits exceptional light absorption (98% within the sunlight spectrum), a high evaporation rate of 1.90 kg m-2h-1 under 1 sun and a light-to-heat conversion efficiency of 94%. The WO3-x/Ag/PbS/NF evaporator also exhibits excellent capabilities in seawater desalination and wastewater treatment. This approach introduces a synergistic concept for creating novel multifunctional light-absorbing materials suitable for various energy-related applications.

Clinical analysis of the efficacy of radiation therapy for primary high-grade gliomas guided by biological rhythms.

OBJECTIVE: High-grade glioma (HGG) patients frequently encounter treatment resistance and relapse, despite numerous interventions seeking enhanced survival outcomes yielding limited success. Consequently, this study, rooted in our prior research, aimed to ascertain whether leveraging circadian rhythm phase attributes could optimize radiotherapy results. METHODS: In this retrospective analysis, we meticulously selected 121 HGG cases with synchronized rhythms through Cosinor analysis. Post-surgery, all subjects underwent standard radiotherapy alongside Temozolomide chemotherapy. Random allocation ensued, dividing patients into morning (N = 69) and afternoon (N = 52) radiotherapy cohorts, enabling a comparison of survival and toxicity disparities. RESULTS: The afternoon radiotherapy group exhibited improved overall survival (OS) and progression-free survival (PFS) relative to the morning cohort. Notably, median OS extended to 25.6 months versus 18.5 months, with P = 0.014, with median PFS at 20.6 months versus 13.3 months, with P = 0.022, post-standardized radiotherapy. Additionally, lymphocyte expression levels in the afternoon radiation group 32.90(26.10, 39.10) significantly exceeded those in the morning group 31.30(26.50, 39.20), with P = 0.032. CONCLUSIONS: This study underscores the markedly prolonged average survival within the afternoon radiotherapy group. Moreover, lymphocyte proportion demonstrated a notable elevation in the afternoon group. Timely and strategic adjustments of therapeutic interventions show the potential to improve therapeutic efficacy, while maintaining vigilant systemic immune surveillance. A comprehensive grasp of physiological rhythms governing both the human body and tumor microenvironment can refine treatment efficacy, concurrently curtailing immune-related damage-a crucial facet of precision medicine.

General negative pressure annealing approach for creating ultra-high-loading single atom catalyst libraries.

Catalyst systems populated by high-density single atoms are crucial for improving catalytic activity and selectivity, which can potentially maximize the industrial prospects of heterogeneous single-atom catalysts (SACs). However, achieving high-loading SACs with metal contents above 10 wt% remains challenging. Here we describe a general negative pressure annealing strategy to fabricate ultrahigh-loading SACs with metal contents up to 27.3-44.8 wt% for 13 different metals on a typical carbon nitride matrix. Furthermore, our approach enables the synthesis of high-entropy single-atom catalysts (HESACs) that exhibit the coexistence of multiple metal single atoms with high metal contents. In-situ aberration-corrected HAADF-STEM (AC-STEM) combined with ex-situ X-ray absorption fine structure (XAFS) demonstrate that the negative pressure annealing treatment accelerates the removal of anionic ligand in metal precursors and boosts the bonding of metal species with N defective sites, enabling the formation of dense N-coordinated metal sites. Increasing metal loading on a platinum (Pt) SAC to 41.8 wt% significantly enhances the activity of propane oxidation towards liquid products, including acetone, methanol, and acetic acid et al. This work presents a straightforward and universal approach for achieving many low-cost and high-density SACs for efficient catalytic transformations.

N-Coordinated Iridium-Molybdenum Dual-Atom Catalysts Enabling Efficient Bifunctional Hydrogen Electrocatalysis.

Achieving effective hydrogen evolution/oxidation reaction (HER/HOR) across a wide pH span is of critical importance in unlocking the full potential of hydrogen energy but remains intrinsically challenging. Here, we engineer the N-coordinated Ir-Mo dual atoms on a carbon matrix by ultrafast high-temperature sintering, creating an efficient bifunctional electrocatalyst for both HER and HOR in both acidic and alkaline electrolytes. The optimized catalyst, Ir-Mo DAC/NC, demonstrates exceptional performance, with a significantly reduced HER overpotential of 11.3 mV at 10 mA/cm2 and a HOR exchange current (i0,m) of 3972 mA/mgIr in acidic conditions, surpassing the performance of Pt/C and Ir/C catalysts. In alkaline conditions, Ir-Mo DAC/NC also outperforms Pt/C, as evidenced by its low HER overpotential of 23 mV at 10 mA/cm2 and a high i0,m of 1308 mA/mgIr. Furthermore, our catalyst exhibits remarkable stability in both acidic and alkaline environments. DFT calculations results reveal that the superior electrochemical performance of Ir-Mo DAC/NC arises from the electronic synergy between Ir and Mo pairs, which regulates the interaction between the intermediates and active sites. These findings present a promising strategy for the development of dual-atom catalysts (DACs), with potential applications in the polymer fuel cells and water electrolyzers.

Innovative dual-active sites in interfacially engineered interfaces for high-performance S-scheme solar-driven CO2 photoreduction.

The realization of 2D/2D Van der Waals (VDW) heterojunctions represents an advanced approach to achieving superior photocatalytic efficiency. However, electron transfer through Van der Waals heterojunctions formed via ex-situ assembly encounters significant challenges at the interface due to contrasting morphologies and potential barriers among the nanocomposite substituents. Herein, a novel approach is presented, involving the insertion of a phosphate group between copper phthalocyanine (CuPc) and B-doped and N-deficient g-C3N4 (BDCNN), to design and construct a Van der Waals heterojunction labeled as xCu[acs]/yP-BDCNN. The introduction of phosphate as a charge modulator and efficient conduit for charge transfer within the heterojunction resulted in the elimination of spatial barriers and induced electron movement from BDCNN to CuPc in the excited states. Consequently, the catalytic central Cu2+ in CuPc captured the photoelectrons, leading to the conversion of CO2 to C2H4, CO and CH4. Remarkably, this approach resulted in a 78-fold enhancement in photocatalytic efficiency compared to pure BDCNN. Moreover the findings confirm that the 2D-2D 4Cu[acs]/9P-BDCNN sheet-like heterojunction effectively boosts photocatalytic activity for persistent pollutants such as methyl orange (MO), methylene blue (MB), rhodamine B (RhB), and tetracycline antibiotics (TCs). The introduction of "interfacial interacting" substances to establish an electron transfer pathway presents a novel and effective strategy for designing photocatalysts capable of efficiently reducing CO2 into valuable products.

Improved Energy Density Obtained in Trilayered Poly(vinylidene fluoride)-Based Composites by Introducing Two-Dimensional BN and TiO2 Nanosheets.

Dielectric capacitors with an ultrahigh power density have received extensive attention due to their potential applications in advanced electronic devices. However, their inherent low energy density restricts their application for miniaturization and integration of advanced dielectric capacitors. Herein, a novel composite entirely incorporated with two-dimensional (2D) nanosheets with a topological trilayered construction is prepared by a solution casting and hot-pressing method. The 2D boron nitride nanosheets (BNNS) with a wide band gap that are oriented in a poly(vinylidene fluoride) (PVDF) matrix to form the upper and bottom outer layers would efficiently suppress the leakage current in composites, thus significantly improving the overall breakdown strength. Meanwhile, the 2D anatase-type TiO2 nanosheets (TONS) uniformly distributed in the middle layer can enhance their interfacial compatibility and polarization with the PVDF matrix, leading to a synergistic improvement in both the breakdown strength and dielectric constant of the composite. In particular, a significantly improved dielectric constant of ∼11.42, a reduced dielectric loss of 0.03 at 100 Hz, and a maximum discharge energy density (Udis) of 10.17 J cm-3 at an electric field of 370.1 MV m-1 can be obtained from the trilayered composite containing 3 wt % 2D TONS in the middle layer and 2 wt % 2D BNNS on the outer layer. The finding of this research offers an effective strategy for the preparation of advanced polymer-based composites with an outstanding discharge energy density performance.

Lymphoepithelial carcinoma of the oral cavity and pharynx: a SEER population-based cohort study.

OBJECTIVES: Lymphoepithelial carcinoma (LEC) of the oral cavity and pharynx is a rare cancer, with poorly understood clinicopathological characteristics and prognosis. Only a few case reports or small case series have been reported, so the characteristics and survival of patients with this disease remains unclear. The present study aimed to describe the clinicopathological characteristics and determine the factors associated with survival of this uncommon cancer. METHODS: A population-based study was carried out to investigate clinical characteristics and prognosis of LEC of the oral cavity and pharynx using the data from Surveillance, Epidemiology and End Results (SEER) database. Log-Rank test and Cox regression analysis were performed to determine the prognostic factors, and a prognostic nomogram was further constructed. The propensity-matched analysis was conducted to compare the survival of nasopharyngeal LEC and non-nasopharyngeal LEC patients. RESULTS: Totally, 1025 patients were identified, including 769 nasopharyngeal LEC patients and 256 non-nasopharyngeal LEC patients. The median OS of all patients was 232.0 months (95% CI 169.0-258.0). The 1-, 5-, 10- and 20-year survival rates were 92.9%, 72.9%, 59.3%, and 46.8%, respectively. Surgery significantly prolonedg the survival of LEC patients (P<0.01, mOS: 190 m vs. 255 m). Radiotherapy, as well as radiotherapy after surgery, prolonged the mOS (P<0.01 for both). The survival analysis demonstrated that old age (>60 years), lymph node (N3) and distant metastases were independent factors for poor survival, whereas radiotherapy and surgery were independent factors for favorable survival. The prognostic nomogram was established base on these five independent prognostic factors (C-index = 0.70; 95% CI 0.66-0.74). In addition, no significant difference in survival time between nasopharyngeal LEC and non-nasopharyngeal LEC patients were observed. CONCLUSIONS: LEC of the oral cavity and pharynx is a rare disease, and old age, lymph node and distant metastases, surgery and radiotherapy were significantly associated with prognosis. The prognostic nomogram could be used to make individual predictions of OS.

Influence of coordination structure of Fe-585DV/NxC4-x on the electrocatalytic performance of oxygen reduction reactions.

Fe-N-C material, known for its high efficiency, cost-effectiveness, and environmental friendliness, is a promising electrocatalyst in the field of the oxygen reduction reaction (ORR). However, the influence of defects and coordination structures on the catalytic performance of Fe-N-C has not been completely elucidated. In our present investigation, based on density functional theory, we take an Fe adsorbed graphene structure containing a 5-8-5 divacancy (585DV) defect as a research model and investigate the influence of the coordination number of N atoms around Fe (Fe-NxC(4-x)) on the ORR electrocatalyst behavior in alkaline conditions. We find that the Fe-N4 structure exhibits superior ORR catalytic performance than other N coordination structures Fe-NxC4-x (x = 0-3). We explore the reasons for the improved catalytic performance through electronic structure analysis and find that as the N coordination number in the Fe-NxC(4-x) structure increases, the magnetic moment of the Fe single atom decreases. This reduction is conducive to the ORR catalytic performance, indicating that a lower magnetic moment is more favorable for the catalytic process of the ORR within the Fe-NxC(4-x) structure. This study is of great significance for a deeper understanding of the structure-performance relationship in catalysis, as well as for the development of efficient ORR catalysts.

Efficient industrial-current-density acetylene to polymer-grade ethylene via hydrogen-localization transfer over fluorine-modified copper.

Electrocatalytic acetylene semi-hydrogenation to ethylene powered by renewable electricity represents a sustainable pathway, but the inadequate current density and single-pass yield greatly impedes the production efficiency and industrial application. Herein, we develop a F-modified Cu catalyst that shows an industrial partial current density up to 0.76 A cm-2 with an ethylene Faradic efficiency surpass 90%, and the maximum single-pass yield reaches a notable 78.5%. Furthermore, the Cu-F showcase the capability to directly convert acetylene into polymer-grade ethylene in a tandem flow cell, almost no acetylene residual in the production. Combined characterizations and calculations reveal that the Cuδ+ (near fluorine) enhances the water dissociation, and the generated active hydrogen are immediately transferred to Cu0 (away from fluorine) and react with the locally adsorbed acetylene. Therefore, the hydrogen evolution reaction is surpassed and the overall acetylene semi-hydrogenation performance is boosted. Our findings provide new opportunity towards rational design of catalysts for large-scale electrosynthesis of ethylene and other important industrial raw.

Direct Observation of Transition Metal Ions Evolving into Single Atoms: Formation and Transformation of Nanoparticle Intermediates.

Understanding the dynamical evolution from metal ions to single atoms is of great importance to the rational development of synthesis strategies for single atom catalysts (SACs) against metal sintering during pyrolysis. Herein, an in situ observation is disclosed that the formation of SACs is ascertained as a two-step process. There is initially metal sintering into nanoparticles (NPs) (500-600 °C), followed by the conversion of NPs into metal single atoms (Fe, Co, Ni, Cu SAs) at higher temperature (700-800 °C). Theoretical calculations together with control experiments based on Cu unveil that the ion-to-NP conversion can arise from the carbon reduction, and NP-to-SA conversion being steered by generating more thermodynamically stable Cu-N4 configuration instead of Cu NPs. Based on the evidenced mechanism, a two-step pyrolysis strategy to access Cu SACs is developed, which exhibits excellent ORR performance.