Ti3O MOenes: Quantum Spin Hall Effect and Promising Semiconductors for Light-Harvesting.

The continuous pursuit of novel two-dimensional (2D) materials with intriguing properties has been a driving force in advancing various scientific and technological frontiers. Here, based on a wide range of first-principles calculations, we predicted the existence of a novel family of 2D transition-metal oxides, the Ti3O MOenes (MXene-like 2D transition oxides), and determined its distinctive electronic and topological properties. A pair of 2D antiferromagnetic (AFM) Dirac points precisely located at the Fermi level in the absence of spin-orbit coupling (SOC) is observed in the 1T-Ti3O monolayer. Moreover, upon halogenation on a bare monolayer, 1T-Ti3OCl3 and 1T-Ti3OBr3 monolayers display the quantum spin Hall (QSH) effect with nontrivial helical edge states within the gapless bulk states. Specifically, single layer 1T-Ti3OF3 behaves as an indirect semiconductor with a gap of 0.81 eV, exhibiting a strong light-harvesting capability. The indirect-gap feature can be switched to a direct one by only exerting a small tensile strain of 1.5%. These findings broaden emerging phenomena in a rich family of MOenes, suggesting a novel platform for the development of next-generation nanodevices.

Exciton-Driven and Layer-Independent Linear and Nonlinear Optical Properties in NbOCl2.

We investigate the electronic structure and linear and nonlinear [second-harmonic generation (SHG)] spectra of the NbOCl2 monolayer, bilayer, and bulk by using a real-time first-principles approach based on many-body theory. First, the interlayer couplings between NbOCl2 layers are very weak, due to the relatively large interlayer distance, saturation of the p orbital of Cl atoms, and high degree of localization of charge density around the Nb atom for both the lowest conduction band and the highest valence band. Second, the quasiparticle gaps and exciton binding energy for the three systems show layer-dependent features and decrease with an increase in layer thickness. Most importantly, the linear and SHG spectra of the NbOCl2 monolayer, bilayer, and bulk are dominated by strong excitonic resonances and exhibit layer-independent features due to the weak interlayer couplings. Our findings demonstrate that excitonic effects should be included in studying the optical properties of not only two-dimensional materials but also layered bulk materials with weak interlayer couplings.

Extending the Charge Carrier Recombination Lifetime by Octahedral Rotations in Ruddlesden-Popper Ba3Zr2S7 Perovskites.

Intentional distortions of [BX6] octahedra within perovskite structures have been recognized as a potent strategy for precise band gap adjustments and optimization of their photovoltaic properties, yet information regarding charge carrier dynamics linked to octahedral distortion under ambient conditions for chalcogenide perovskites remains limited. In this study, we utilize ab initio nonadiabatic molecular dynamics to explore the dynamics of photogenerated carriers in a representative two-dimensional Ba3Zr2S7 material in the Ruddlesden-Popper phase. The theoretical results highlight the influence of octahedral rotation on the materials' stability and carrier recombination lifetime of the system. Specifically, the octahedrally rotating P42/mnm phase exhibits a prolonged nonradiative carrier recombination lifetime attributed to the stabilized electron-phonon coupling. These findings offer valuable insights into the fundamental physical characteristics of imposed octahedral distortion and its potential for optimizing the optoelectronic performance of 2D Ruddlesden-Popper Ba-Zr-S chalcogenide materials.

Luteolin promotes neuronogenesis in hippocampus of chronic unpredictable mild stress rats and primary hippocampus of fetal rats.

OBJECTIVE: To investigate the effects of luteolin on chronic unpredictable mild stress (CUMS)-induced depressive rats and corticosterone (CORT)-induced depressive primary hippocampal neurons, and to elucidate the mechanism behind the action. METHODS: The antidepressant mechanism of luteolin was studied by using CUMS rat model and primary hippocampal neurons in fetal rats. In vivo, novelty suppressed feeding, open-field and sucrose preference tests as well as Morris water maze were evaluated. The content of brain derived neurotrophic factor (BDNF), 5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA) in serum were detected by enzyme-linked immunosorbent assay. The mechanisms of luteolin were explored based on neurotrophin and hippocampal neurogenesis, and proliferation. Survival of the septo-temporal axis in hippocampus was assayed using the 5-bromo-2-deoxyuridine (BrdU), the expression of BDNF, neurotrophin-3 (NT-3), and nerve growth factor (NGF) in hippocampus dentate gyrus region were measured by Western-blotting. In vitro, BDNF, NT-3, tropomyosin receptor kinase B (TrkB), and phosphorylated cyclic adenosine monophosphate responsive element binding protein (p-CREB) were detected through the high content analysis (HCA) to investigate neurotrophin and apoptosis. RESULTS: Induction of CUMS in rats induced depressive symptoms, while luteolin significantly enhanced sucrose consumption, decreased feeding latency, increased locomotor activity, escape latency, distance of target quadrant and regulated the content of depressive-like biomarkers. Histology analysis revealed that luteolin increased the abundance of new born neurons that had been labeled with BrdU, BrdU + neuronal nuclear antigen, and BrdU + doublecortin in septo-temporal axis of S2 (mid-septal) and T3 (mid-temporal). Moreover, expression of BDNF, NT-3, and NGF increased significantly in the septo-temporal axis of S2 and T3. HCA showed increased expression of BDNF, NT-3, TrkB and p-CREB in primary hippocampal neurons. CONCLUSION: The results provided direct evidence that luteolin has an antidepressant effect and could effectively promote the regeneration of the septotemporal axis nerve and hippocampal neuronutrition, which suggested that the antidepressant effect of luteolin may be related to hippocampal neurogenesis.

Two-dimensional half-metals MSi2N4 (M = Al, Ga, In, Tl) with intrinsic p-type ferromagnetism and ultrawide bandgaps.

Intrinsic half-metallic nanomaterials with 100% spin polarization are highly demanded for next-generation spintronic devices. Here, by using first-principles calculations, we have designed a class of new two-dimensional (2D) p-type half-metals, MSi2N4 (M = Al, Ga, In and Tl), which show high mechanical, thermal and dynamic stabilities. MSi2N4 not only have ultrawide electronic bandgaps for spin-up channels in the range of 4.05 to 6.82 eV but also have large half-metallic gaps in the range of 0.75 to 1.47 eV, which are large enough to prevent the spin-flip transition. The calculated magnetic moment is 1 µB per cell, resulting from polarized N1-px/py orbitals. Moreover, MSi2N4 possess robust long-range ferromagnetic orderings with Curie temperatures in the range of 35-140 K, originating from the interplay of N1-M-N1 superexchange interactions. Furthermore, spin dependent electronic transport calculations reveal 100% spin polarization. Our results highlight new promising 2D ferromagnetic half-metals toward future spintronic applications.

Investigation of nonlinear optical properties in α-A2BB'O6 (A = Li, Na, K; B = Ti, Zr, Hf; B' = Se, Te) by first-principles calculations.

Nonlinear optical (NLO) crystals based on oxides typically have wide bandgaps and large laser damage thresholds (LDTs), which are important for generating high-power and continuous terahertz radiation. Recently, a new family of NLO materials α-A2BB'O6 including Li2TiTeO6 (LTTO) with a strong second harmonic generation (SHG) efficiency of 26 × KH2PO4 (KDP) and a large LDT of 550 MW cm-2 were reported. Herein, we systematically study the electronic structures and NLO properties of α-A2BB'O6 (A = Li, Na, K; B = Ti, Zr, Hf; B' = Se, Te) to explore the relationship between the structure and SHG coefficient. First, 15 members of the A2BB'O6 family are demonstrated to be highly stable and NLO materials, excluding K2TiTeO6, K2TiSeO6 and K2ZrSeO6. Then, the electronic band structure, dipole moment and distortion of BO6/B'O6 octahedrons, SHG coefficient and terahertz absorption spectrum are calculated comprehensively with the element variation of A-site, B-site and B'-site. Finally, the magnitude of the SHG coefficient is found to be directly proportional to the value of total dipole moment and distortion, and inversely proportional to the bandgap value. Most importantly, among the A2BB'O6 materials, K2HfSeO6 shows the smallest direct bandgap of 2.99 eV, the largest SHG coefficient d33 of about 5 × LTTO and low terahertz absorbance from 0.1 to 9 THz. Our results provide new NLO crystals that may have potential application in terahertz radiation sources and other nonlinear electronics.

Application value of different language assessment tools in language development assessment of 12-month-old high-risk infants / 中国儿童保健杂志

【Objective】 To explore the application value of different language assessment tools in the assessment of language development of 12-month-old high-risk infants, and to screen out simple and valid language assessment tools. 【Methods】 A total of 217 11- to 13-month-old high-risk infants who were followed up at the outpatient service for high-risk infants at the child health clinic of Guiyang Maternal and Child Health Hospital from March 2022 to May 2023 were selected as the study subjects. Their language was evaluated by Early Language Milestone Scale (ELMS), Putonghua Communicative Development Inventory (PCDI) and Ages and Stages Questionnaire-Third Edition (ASQ-3). With Gesell as the gold standard for the assessment of language, the area under receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy, positive predictive value, negative predictive value, Youden index and Kappa value of the three tools were calculated. Spearman correlation analysis was used to analyze the correlation between the different language assessment scales. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was used to evaluate the three tools. 【Results】 1)Among 217 high-risk infants, 78 preterm infants was the most (35.94%). The rate of delayed language development detected by Gesell, ELMS, PCDI-comprehension, PCDI-expression, ASQ-3 were 5.5%, 7.8%, 36.4%, 30.0% and 11.5%, respectively. 2)ASQ-3 had the strongest correlation with Gesell language region (rs=0.607, P<0.01) and it had the most AUC (AUC=0.812, P<0.05). The consistency between ASQ-3 and Gesell was moderate (Kappa=0.56, P<0.01). ASQ-3 had the highest sensitivity(91.7%), accuracy(93.1%), negative predictive value(99.5%) and Youden index(0.85), and ELMS had the highest specificity(94.6%). 3) Comprehensive evaluation of three tools by the TOPSIS indicated that ASQ-3 was the best, followed by ELMS and PCDI-comprehension was the worse. 【Conclusion】 Among the three assessment tools, ASQ-3 has the highest value in assessing the language development of 11- to 13-month-old high risk infants, and it may be necessary to expand the age range and establish a national norm of ELMS and PCDI in the future.

Effect of dementia on postoperative complications in older patients with hip fractures / 中国组织工程研究

BACKGROUND:The number of hip fracture patients with dementia is increasing with an aging population,posing challenges for surgical treatment. OBJECTIVE:To determine the effect of dementia on postoperative complications in older patients with hip fractures. METHODS:Patients aged over 60 years old with hip fractures from 2000 to 2019 at Chinese PLA General Hospital were included.Dementia patients with a preexisting diagnosis of dementia at admission were identified.Each dementia patient was matched,for age±5 years,gender,and fracture type with 10 non-dementia patients.The differences in postoperative complications were compared between the two groups,including pneumonia,respiratory failure,gastrointestinal bleeding,urinary tract infection,surgical site infection,deep venous thrombosis,pulmonary embolism,angina pectoris,arrhythmia,heart failure,myocardial infarction,stroke,and death.The impact of dementia on major complications was evaluated using multivariate conditional logistic regression. RESULTS AND CONCLUSION:A total of 2 887 patients were included,of whom 125(4.3%)were dementia patients and matched with 1 243 non-dementia patients.The average age of dementia patients was(80.6±7.4)years;64.8%were female;53.6%were intertrochanteric fractures,and 46.4%were femoral neck fractures.Major complications occurred in 25(20.0%)patients with dementia and 123(9.9%)patients without dementia(P<0.01).The risk of major complications was 200.0 per 1 000 persons(95%CI,139.3-278.6)in dementia patients and 99.0 per 1 000 persons(95%CI,83.6-116.9)in non-dementia patients.Multivariate conditional logistic regression showed that a 2-fold risk of major postoperative complications after hip fracture surgery was found in dementia patients than in those without dementia(adjusted OR,2.11;95%CI,1.08-4.10).The results show that dementia is an independent risk factor for postoperative complications in elderly patients with hip fractures.Appropriate preoperative risk assessment and corresponding preventive and therapeutic measures should be given to this vulnerable population to mitigate postoperative complications.

Progress in mechanism of complement system involved in pathological pain / 中国病理生理杂志

The complement system comprises intrinsic complement components,complement regulatory pro-teins,and complement receptors.Complement activation plays a role in promoting the sensitization of peripheral pain re-ceptors,enhancing immune cell activity,and participating in the regulation of axon regeneration after nerve injury.The in-teraction of the complement system contributes to the development and maintenance of pathological pain,affecting the dor-sal root ganglion neurons,spinal dorsal horn,and brain.Consequently,targeting the complement system holds promise as a therapeutic approach for neuropathic pain treatment.This paper reviews the progress in understanding the functions of the complement system and its implications in pathological pain,offering valuable insights for the future development of targeted drug therapies.

Metabonomic study of blood of mice with high-voltage electrical injury / 局解手术学杂志

Objective To explore the changes of metabonomics in blood of mice after high-voltage electric shock,then screen out the significantly changed differential metabolites and metabolic pathways.Methods The head of C57BL/6J mice was subjected to high-voltage electric shock(electric shock group)or exposed to acoustic and optical stimulation of high-voltage electric(control group),then the whole blood from mice were collected to separate serum.The dual platform combined metabonomic analysis based on gas chromatography-mass spectrometer(GC-MS)and liquid chromatography-mass spectrometer(LC-MS)was performed and orthogonal partial least squares discriminant analysis(OPLS-DA)was used to screen the differential metabolites and related metabolic pathways.Results A total of 415 differential metabolites were screened out in metabonomics in blood of mice after high-voltage electric shock,including 187 up-regulated and 228 down-regulated metabolites.These differentially metabolites were significantly enriched in metabolic pathways including central carbon metabolism in cancer,glucagon signaling pathway,etc.Conclusion By establishing the model of high-voltage electrical injury on experimental mice,this study reveals the significant change of metabolite content and metabolic pathway in blood by high-voltage electrical injury.Which provides a basis for the damage of blood metabolic activity by high-voltage electrical injury,and suggests the potential harm of high-voltage electrical injury to blood metabolic activity in the whole body.

Research on Procurement Budget Management Countermeasures from the Perspective of Public Hospital Operation Management / 中国卫生经济

Aiming at the background of budget management reform in public hospitals and the problems existing in the implemen-tation process,it discusses how to strengthen procurement budget management from the perspective of operation management,im-prove the efficiency and effect of budget funds,reduce costs and increase efficiency,prevent risks,and promote high-quality development.It is suggested that efforts should be made to connect procurement budget management with the top-level design of public hospital development,explore the coordination between fund budget and project process management,unify rigid budget constraints with dynamic adjustment,and establish a multi-dimensional,whole-process procurement budget performance evaluation system.

Effects of Regulation of SHH/Gli1 Signaling Pathway by Baishile Capsules on Hippocampal Neurogenesis Depression Model Rats / 中国中医药信息杂志

Objective To explore the effects and mechanism of Baishile Capsules regulating SHH/Gli1 signaling pathway on hippocampal neurogenesis of depression model rats.Methods Totally 32 SD rats were randomly divided into control group,model group,fluoxetine(5.4 mg/kg)group and Baishile Capsules(2.88 g/kg)group,with 8 rats in each group.A depression rat model was established using chronic unpredictable mild stress and single cage feeding method.The model was established and administered simultaneously for 21 consecutive days.Depression-like behavior in rats were evaluated by sucrose preference experiment and open field experiment,ELISA was used to detect brain derived neurotrophic factor(BDNF)contents in rat serum and hippocampal tissue,the number of BrdU,BrdU/DCX,BrdU/NeuN positive cells in dentate gyrus of the hippocampus was observed by immunofluorescence,immunofluorescence and Western blot were used to detect the fluorescence intensity and protein expression of SHH,Gli1,Smo,Ptch in hippocampal tissue.Results Compared with the control group,the degree of sucrose preference significantly decreased in the model group(P<0.01),the number of horizontal and vertical movements significantly decreased(P<0.01),the contents of BDNF in serum and hippocampal tissue significantly decreased(P<0.05),the number of BrdU,BrdU/DCX,BrdU/NeuN positive cells in dentate gyrus of the hippocampus significantly decreased(P<0.01),and the fluorescence intensity and protein expression of SHH,Gli1,Smo,Ptch in hippocampal tissue significantly decreased(P<0.01,P<0.05).Compared with the model group,the degree of sucrose preference and the number of horizontal and vertical movements in fluoxetine group and Baishile Capsule group increased significantly(P<0.05,P<0.01),the contents of BDNF in serum and hippocampal tissue significantly increased(P<0.05,P<0.01),and the number of BrdU,BrdU/DCX,BrdU/NeuN positive cells in dentate gyrus of the hippocampus significantly increased(P<0.01,P<0.05),the fluorescence intensity and protein expressions of SHH,Gli1,Smo,Ptch in hippocampal tissue significantly increased(P<0.01,P<0.05).Conclusion Baishile Capsule can promote the hippocampus neurogenesis in depression model rats by regulating SHH/Gli1 signaling pathway,and play an antidepressant role.

NE activates Nrf2/HO⁃1 signaling pathway to regulate oxidative stress in human endometrial epithelial cells / 安徽医科大学学报

Objective @#To investigate whether norepinephrine (NE) regulates the oxidative stress in human endometrial epithelial cells (hEECs) by activating nuclear factor E2⁃related factor 2(Nrf2)/ heme oxygenase ⁃1(HO⁃1) signal pathway.@*Methods @#C ultured hEECs were used. The expression of α and β adrenergic receptors was detected by reverse transcription⁃polymerase chain reaction (RT⁃PCR) . Cell counting kit ⁃8(CCK⁃8) assay was applied to test the effect of NE on cell viability , then the cells were divided into C ontrol group and NE treatment group , and the appropriate concentrations were chosen. The expression of tight j unction proteins Occludin and zona occludens-1 (ZO⁃1) , apoptosis⁃related proteins apoptosis⁃related protein B ⁃cell lymphoma⁃2 protein(Bcl ⁃2) and Bcl ⁃2 associated X protein(Bax) , antioxidant proteins Nrf2 and HO⁃1 were examined by Western blot. The apoptosis was detected by flow cytometry. The malonaldehyde (MDA) and superoxide dismutase(SOD) in the cell culture medium were detected by enzyme⁃linked immunosorbent assays kit ( ELISA) .@*Results @#The mRNA expression of α1 a ,α1 b , α2 a , α2 b , α2 c , β1 , β3 was detected in the hEECs. After the NE treatment , no significant change in cell viability was ob served in low concentration (5 μmol/L and 10 μmol/L) groups , while 15 μmol/L and 20 μmol/L NE treatments for 6 h or 24 h promoted the cell viability significantly. The expression of ZO⁃1 and Occludin increased significantly in 15 μmol/L group after 24 h treatment , the expression of ZO⁃1 decreased in 6 h treatment group , significant down regulation was ob served after 15 μmol/L NE application , the expression of Occludin increased in 6 h group. The cell apoptosis increased compared with the control group after NE stimulation , espeserved after 24 h treatment. The ration of Bcl ⁃2/Bax > 1 . The expression of Nrf2 and HO⁃1 was elevated by NE. There was no obvious change in MDA level while significant elevation in SOD was detected in cell culture medium.@*Conclusion@#Nrf2/H0-1 signal is activated after application of NE to the hEECs, which may responsible for the upregulation of SOD, antioxidant and anti-apoptotic effect in the hEECs.

Aortic stenosis of fetus caused by chimeric Y-chromosome isobaric double-adherent granules:A case report and literature review / 吉林大学学报(医学版)

Objective:To confirm the potential etiological factors of congenital aortic stenosis(AS)by genetic analysis on prenatal diagnostic results of the fetus with AS.Methods:Amniocentesis for chromosomal G-band karyotyping combinated with single nucleotide polymorphism array(SNP-array)analysis was conducted on the amniotic fluid collected from a 25-week pregnant woman diagnosed as"fetus AS";chromosome karyotyping was also performed on the peripheral blood of the fetal parents.Results:The fetal karyotype analysis showed a chimeric Y-chromosome isobaric double-adherent granules.The SNP-array analysis results revealed a 11.2 Mb duplication in the Yp11.31q11.21 region and a 14.8 Mb deletion in the Yq11.21q11.23 region.Both the parents presented a normal karyotype,suggesting it was a newfound mutation.After extensive genetic counseling,the pregnant woman and her family chose to terminate the pregnancy locally.Conclusion:The chromosomal karyotype of the chimeric Y-chromosome isobaric double-adherent granules may be a contributing factor to the AS phenotype in the male fetus.The combined use of chromosomal karyotyping and SNP-array analysis on the amniotic cells is instrumental in the early diagnosis of the disease.

Clinical effect of esmolol combined with atorvastatin in the treatment of severe sepsis complicated with cardiac insufficiency / 重庆医学

Objective To investigate the clinical efficacy of esmolol combined with atorvastatin on se-vere sepsis complicated with cardiac insufficiency.Methods This study was a prospective,double-blind,ran-domized controlled clinical trial.A total of 153 patients with severe sepsis complicated with cardiac insufficien-cy admitted to this hospital from January 2021 to December 2022 were selected and divided into groups A,B,and C by random number table method,with 51 cases in each.Patients in group A were given routine symp-tomatic supportive treatment after admission.On this basis,patients in group B and group C were given esmo-lol,esmolol+atorvastatin,respectively.The hemodynamic indexes,serological indexes and clinical prognosis of the three groups before and after intervention were compared.Results There was no significant difference in baseline data,and hemodynamic and serological indexes of three groups before intervention(P＞0.05).Compared with before intervention,after five days of intervention,heart rate,systemic vascular resistance in-dex(SVRI),blood levels of creatine kinase-MB(CK-MB),cardiac troponin Ⅰ(cTn Ⅰ),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)and high sensitive C-reactive protein(hs-CRP)in three groups were de-creased,while the values of cardiac index(CI)were increased,and the differences were statistically significant(P＜0.05).After five days of intervention,the heart rate,SVRI,blood levels of CK-MB,cTn Ⅰ,TNF-α,IL-6,and hs-CRP in group C were lower than those in group A and group B,and the levels in group B were lower than those in group A;the value of CI in group C was higher than that in group A and group B,and group B was higher than that in group A,the differences were statistically significant(P＜0.05).After intervention,the length of stay in intensive care unit(ICU)in group C was the shortest,and that in group B was shorter than that in group A,the difference was statistically significant(P＜0.05).There was no significant difference in 28 d mortality among the three groups(P＞0.05).Conclusion Esmolol combined with atorvastatin can signif-icantly inhibit the inflammatory response in patients with severe sepsis complicated with cardiac insufficiency,relieve myocardial injury and promote rehabilitation,and the therapeutic effect is better than esmolol alone.

Exploration of the origin of the excellent charge-carrier dynamics in Ruddlesden-Popper oxysulfide perovskite Y2Ti2O5S2.

Although the efficient separation of electron-hole (e-h) pairs is one of the most sought-after electronic characteristics of materials, due to thermally induced atomic motion and other factors, they do not remain separated during the carrier transport process, potentially leading to rapid carrier recombination. Here, we utilized real-time time-dependent density functional theory in combination with nonadiabatic molecular dynamics (NAMD) to explore the separated dynamic transport path within Ruddlesden-Popper oxysulfide perovskite Y2Ti2O5S2 caused by the dielectric layer and phonon frequency difference. The underlying origin of the efficient overall water splitting in Y2Ti2O5S2 is systematically explored. We report the existence of the bi-directional e-h separate-path transport, in which, the electrons transport in the Ti2O5 layer and the holes diffuse in the rock-salt layer. This is in contrast to the conventional e-h separated distribution with a crowded transport channel, as observed in SrTiO3 and hybrid perovskites. Such a unique feature finally results in a long carrier lifetime of 321 ns, larger than that in the SrTiO3 perovskite (160 ns) with only one carrier transport channel. This work provides insights into the carrier transport in lead-free perovskites and yields a novel design strategy for next-generation functionalized optoelectronic devices.

Synthesis of MnOOH and its application in a supporting hexagonal Pd/C catalyst for the oxygen reduction reaction.

With the expansion of global energy problems and the deepening of research on oxygen reduction reaction (ORR) in alkaline media, the development of low cost and high electrocatalytic performance catalysts has become a research hotspot. In this study, a hexagonal Pd-C-MnOOH composite catalyst was prepared by using the triblock copolymer P123 as the reducing agent and protective agent, sucrose as the carbon source and self-made MnOOH as the carrier under hydrothermal conditions. When the Pd load is 20% and the C/MnOOH ratio is 1 : 1, the 20% Pd-C-MnOOH-1 : 1 catalyst obtained by the one-step method has the highest ORR activity and stability in the alkaline system. At 1600 rpm, the limiting diffusion current density and half-wave potential of the 20% Pd-C-MnOOH-1 : 1 electrocatalyst are -4.78 mA cm-2 and 0.84 V, respectively, which are better than those of the commercial 20%Pd/C catalyst. According to the Koutecky-Levich (K-L) equation and the linear fitting results, the electron transfer number of the 20%Pd-C-MnOOH-1 : 1 electrocatalyst for the oxygen reduction reaction is 3.8, which is similar to that of a 4-electron process. After 1000 cycles, the limiting diffusion current density of the 20%Pd-C-MnOOH-1 : 1 catalyst is -4.61 mA cm-2, which only decreases by 3.7%, indicating that the 20%Pd-C-MnOOH-1 : 1 catalyst has good stability. The reason for the improvement of the ORR performance of the Pd-C-MnOOH composite catalyst is the improvement of the conductivity of the carbon layer formed by original carbonization, the regular hexagonal highly active Pd particles and the synergistic catalytic effect between Pd and MnOOH. The method of introducing triblock copolymers in the synthesis of oxides and metal-oxide composite catalysts is expected to be extended to other electrocatalysis fields.

Theoretical Dissection of Cation-Deficient Layered Ruddlesden-Popper Oxysulfide Perovskites with a High-Efficiency Carrier Transport Channel.

The search for lead-free perovskite materials has triggered intensive interest. Here, we study the electronic structures and optical properties of cation-deficient Ruddlesden-Popper oxysulfide perovskites Ln2Ti2O5S2 (Ln = Sc, Y, or La), with a tunable band gap of 1.45-2.1 eV and a small exciton binding energy of ∼0.1 eV, among which Y2Ti2O5S2 has been synthesized experimentally. Sc2Ti2O5S2 possesses the largest light absorbance in the visible region. We further rationalize the light absorption via the transition dipole moment and suggest potential applications of Sc2Ti2O5S2 in solar cells and Y2Ti2O5S2 and La2Ti2O5S2 in water splitting. In addition, this family exhibits small effective masses within the x-y plane and large ones along the z direction. Most importantly, electron gas-like carrier behaviors are observed within the Ti-O bond region, offering a diffusion channel for electron transport. These findings greatly advance our understanding of lead-free perovskites and offer a novel material platform for future optoelectronic devices.

A novel phase of superionic conductor ß'-Na3PS4 with a large band gap and a low migration barrier.

Na3PS4 crystals with high ionic conductivity are promising solid-state electrolytes. Here, a novel phase of Na3PS4 (ß'-NPS) crystallizing in a cubic lattice with a space group of P4̄3m was systematically investigated using first-principles calculations. First of all, ß'-NPS is determined to be thermodynamically, dynamically and mechanically stable. The phase transition from tetragonal Na3PS4(α-NPS) to a cubic ß'-NPS system occurs at approximately 480 K, suggesting high feasibility of experimental access. Moreover, the ß'-NPS is an insulator with a large band gap of 4.05 eV and a low migration energy barrier of 0.10 eV for an interstitial Na ion. Significantly, a novel Na ion diffusion mechanism, that is, interstitial diffusion, is proposed, in contrast to traditional vacancy diffusion or kick-off diffusion as observed in most solid electrolytes. This work proposes ß'-NPS as a promising superionic conductor for sodium ion batteries and provides theoretical guidance towards designing future ideal solid-state electrolytes.

Highly lithiophilic and structurally stable Cu-Zn alloy skeleton for high-performance Li-rich ternary anodes.

Lithium (Li)-rich ternary alloy, comprising a multi-alloy phase as the built-in three-dimensional (3D) framework and a Li metal phase as a reversible Li reservoir, is a promising high-energy-density anode for rechargeable Li metal batteries. The introduction of metal/metalloid components to the alloy can effectively regulate Li deposition and maintain the dimensional integrity of the Li anode. Herein, the lithium-copper-zinc (Li-Cu-Zn) ternary alloy, as a new type of alloy anode, is synthesized via a facile thermal melting method. The fully delithiated 3D scaffold comprised two Cu-Zn alloy phases named CuZn and CuZn5. These alloy phases exhibit higher lithiophilicity and structural stability than Li-Zn and Li-Cu alloys. Moreover, the CuZn phase is electrochemically inert, ensuring the geometric stability of the anode, while the CuZn5 phase can readily undergo alloying reaction with Li to form the LiZn phase, thereby facilitating uniform Li nucleation and deposition. The hybridized multiphase alloy structure and specific energy storage mechanism of the Cu-Zn based alloy scaffold in the ternary alloy anode facilitate dendrite-free Li deposition and prolonged cycle lifetime. The Li metal full battery based on lithium iron phosphate (LiFePO4) cathode exhibits high cycling stability with high-capacity retention of 95.4% after 1000 cycles at 1C.