Controllable assembly of hollow interpenetrated zeolite imidazole framework nanocomposite for dopamine charge collection.

The synergistic armor-etching (SAE) approach was proposed using natural organic weak acid (tannic acid, i.e., TA) for the controllable assembly of hollow and interpenetrated HZIF-8@MWCNTs hybrid nanomaterial (ZIF-8, zeolitic imidazolate framework-8; MWCNTs, multi-walled carbon nanotubes), which exhibited highly ordered crystal structure and unique morphological characteristics. The SAE strategy not only can rapidly etch solid ZIF- material into a hollow structure (~ 10 min), but also form the TA shell (~ 33 nm) on its surface. Then, the HZIF-8@MWCNTs electrochemical sensor was constructed for selective and sensitive detection of the target molecule (dopamine, DA). A sequence of studies indicated that the fabricated TA coating was capable of promoting the spread of DA into the reactive centers of hollow MOF and MWCNTs, which exhibited outstanding electroanalytical characteristics through the synergistic effect. The DPV oxidation peak of DA was strongest at 50 mV vs. Ag/AgCl reference electrode. Under the optimal conditions, there are two linear dynamic ranges of current response of 0.01 ~ 10 and 10 ~ 550 µmol L- 1 with a detection limit of 0.003 µmol·L- 1 (S/N = 3). Simultaneously, the HZIF-8@MWCNTs electrochemical sensor could detect low levels of DA in real products. The recoveries of the actual sample tests were between 98.2% and 102%, and the relative standard deviation (R.S.D.) of all studies was less than 3.0%. The statistical analyses (F-test and t-test) were employed to demonstrate the accuracy of method developed. This work will enlighten researchers operating in the domain of MOFs composites, accelerating the advancement of electrochemical sensing on the basis of hollow MOFs materials.

Birth Tourism Is Associated with Fewer Neonatal Intensive Care Unit Admissions: A Healthy Migrant Effect?

OBJECTIVE: This work aimed to study perinatal, maternal, and neonatal characteristics of birth tourism (BT) mother-baby dyads and the rate of neonatal intensive care unit (NICU) admissions of BT infants. STUDY DESIGN: Retrospective study at a regional perinatal center comparing BT mother-baby dyads to all dyads. BT infants admitted to the NICU were compared with a randomly selected group of infants admitted to the NICU during the same time period. RESULTS: A total of 1,755 BT dyads were identified over 4 years. BT mothers were older (32 vs. 28 years, p < 0.0001), more likely to carry multiples (5.5 vs. 1.4%, p < 0.0001), deliver via cesarean section (40 vs. 34%, p < 0.0001), and require postpartum intensive care (0.6 vs. 0.1%, p < 0.0001). BT infants had significantly fewer NICU admissions 96 (5.5%) versus 3,213 (11.3%; p < 0.0001). There were no statistically significant differences in NICU course and outcome between BT and non-BT control infants. CONCLUSION: Birth tourism is associated with unique determinants of health. In our study, there were fewer NICU admissions, potentially explained by the healthy migrant effect. KEY POINTS: · Birthright citizenship attracts foreigners to give birth in the United States.. · BT is associated with unique social determinants of health.. · Fewer NICU admissions in our study are possibly explained by the healthy migrant effect..

Druggable negative allosteric site of P2X3 receptors.

Allosteric modulation provides exciting opportunities for drug discovery of enzymes, ion channels, and G protein-coupled receptors. As cation channels gated by extracellular ATP, P2X receptors have attracted wide attention as new drug targets. Although small molecules targeting P2X receptors have entered into clinical trials for rheumatoid arthritis, cough, and pain, negative allosteric modulation of these receptors remains largely unexplored. Here, combining X-ray crystallography, computational modeling, and functional studies of channel mutants, we identified a negative allosteric site on P2X3 receptors, fostered by the left flipper (LF), lower body (LB), and dorsal fin (DF) domains. Using two structurally analogous subtype-specific allosteric inhibitors of P2X3, AF-353 and AF-219, the latter being a drug candidate under phase II clinical trials for refractory chronic cough and idiopathic pulmonary fibrosis, we defined the molecular interactions between the drugs and receptors and the mechanism by which allosteric changes in the LF, DF, and LB domains modulate ATP activation of P2X3. Our detailed characterization of this druggable allosteric site should inspire new strategies to develop P2X3-specific allosteric modulators for clinical use.

Influence of the Insertion Method of Aryl-Extended Calix[4]pyrroles into Liposomal Membranes on Their Properties as Anion Carriers.

We disclose the results of our investigations on the influence that the insertion method of aryl-extended calix[4]pyrrole into liposomal membranes exerts on their properties as anion carriers. We use the standard HPTS assay to assess the transport properties of the carriers. We show that the post-insertion of the carrier, as DMSO solution, assigns better transport activities to the "two-wall" α,α-aryl-extended calix[4]pyrrole 1 compared to the "four-wall" α,α,α,α-counterpart 2. Notably, opposite results were obtained when the carriers were pre-inserted into the liposomal membranes. We assign this difference to an improved incorporation of carrier 2 into the membrane when delivered by the pre-insertion method. On the other hand, carrier 1 shows comparable levels of transport independently of the method used for its incorporation. Thus, an accurate comparison of the chloride transport activities featured by these two carriers demands their pre-incorporation in the liposomal membranes. In contrast, using the lucigenin assay with the pre-insertion method both carriers displayed similar transport efficiencies.

Genetic diversity and structure of tea plant in Qinba area in China by three types of molecular markers.

BACKGROUND: Qinba area has a long history of tea planting and is a northernmost region in China where Camellia sinensis L. is grown. In order to provide basic data for selection and optimization of molecular markers of tea plants. 118 markers, including 40 EST-SSR, 40 SRAP and 38 SCoT markers were used to evaluate the genetic diversity of 50 tea plant (Camellia sinensis.) samples collected from Qinb. tea germplasm, assess population structure. RESULTS: In this study, a total of 414 alleles were obtained using 38 pairs of SCoT primers, with an average of 10.89 alleles per primer. The percentage of polymorphic bands (PPB), polymorphism information content (PIC), resolving power (Rp), effective multiplex ratio (EMR), average band informativeness (Ibav), and marker index (MI) were 96.14%, 0.79, 6.71, 10.47, 0.58, and 6.07 respectively. 338 alleles were amplified via 40 pairs of SRAP (8.45 per primer), with PPB, PIC, Rp, EMR, Ibav, and MI values of 89.35%, 0.77, 5.11, 7.55, 0.61, and 4.61, respectively. Furthermore, 320 alleles have been detected using 40 EST-SSR primers (8.00 per primer), with PPB, PIC, Rp, EMR, Ibav, and MI values of 94.06%, 0.85, 4.48, 7.53, 0.56, and 4.22 respectively. These results indicated that SCoT markers had higher efficiency.Mantel test was used to analyze the genetic distance matrix generated by EST-SSRs, SRAPs and SCoTs. The results showed that the correlation between the genetic distance matrix based on EST-SSR and that based on SRAP was very small (r = 0.01), followed by SCoT and SRAP (r = 0.17), then by SCoT and EST-SSR (r = 0.19).The 50 tea samples were divided into two sub-populations using STRUCTURE, Neighbor-joining (NJ) method and principal component analyses (PCA). The results produced by STRUCTURE were completely consistent with the PCA analysis. Furthermore, there is no obvious relationship between the results produced using sub-populational and geographical data. CONCLUSION: Among the three types of markers, SCoT markers has many advantages in terms of NPB, PPB, Rp, EMR, and MI. Nevertheless, the values of PIC showed different trends, with the highest values generated with EST-SSR, followed by SCoT and SRAP. The average band informativeness showed similar trends. Correlation between genetic distances produced by three different molecular markers were very small, thus it is not recommended to use a single marker to evaluate genetic diversity and population structure. It is hence suggested that combining of different types of molecular markers should be used to evaluate the genetic diversity and population structure. It also seems crucial to screen out, for each type of molecular markers, core markers of Camellia sinensis. This study revealed that genes of exotic plant varieties have been constantly integrated into the gene pool of Qinba area tea. A low level of genetic diversity was observed; this is shown by an average coefficient of genetic similarity of 0.74.

Ultrastrong Polyoxyzole Nanofiber Membranes for Dendrite-Proof and Heat-Resistant Battery Separators.

Polymeric nanomaterials emerge as key building blocks for engineering materials in a variety of applications. In particular, the high modulus polymeric nanofibers are suitable to prepare flexible yet strong membrane separators to prevent the growth and penetration of lithium dendrites for safe and reliable high energy lithium metal-based batteries. High ionic conductance, scalability, and low cost are other required attributes of the separator important for practical implementations. Available materials so far are difficult to comply with such stringent criteria. Here, we demonstrate a high-yield exfoliation of ultrastrong poly(p-phenylene benzobisoxazole) nanofibers from the Zylon microfibers. A highly scalable blade casting process is used to assemble these nanofibers into nanoporous membranes. These membranes possess ultimate strengths of 525 MPa, Young's moduli of 20 GPa, thermal stability up to 600 °C, and impressively low ionic resistance, enabling their use as dendrite-suppressing membrane separators in electrochemical cells. With such high-performance separators, reliable lithium-metal based batteries operated at 150 °C are also demonstrated. Those polyoxyzole nanofibers would enrich the existing library of strong nanomaterials and serve as a promising material for large-scale and cost-effective safe energy storage.

An asymmetric approach to bicyclo[2.2.1]heptane-1-carboxylates via a formal [4 + 2] cycloaddition reaction enabled by organocatalysis.

An organocatalytic formal [4 + 2] cycloaddition reaction has been realized that permits rapid access to a wide range of bicyclo[2.2.1]heptane-1-carboxylates in a highly enantioselective manner from simple starting materials under mild and operationally simple conditions.

Asymmetric total synthesis of hedyosumin E aglycon, 7,10-epoxyhedyosminolide and ent-zedolactone A.

The asymmetric total syntheses of hedyosumin E aglycon, 7,10-epoxyhedyosminolide and ent-zedolactone A were realized, with the first two being achieved for the first time.

[Correlation between electrocardiogram, myocardial biomarkers and left ventricular dysfunction in acute anterior ST segment elevation myocardial infarction].

OBJECTIVE: To analyze the correlation between ST segment elevation, Q wave and peak biomarkers with left ventricular dysfunction in patients with acute anterior ST elevation myocardial infarction (STEMI). METHODS: A total of 138 consecutive inpatients with acute anterior STEMI, left anterior descending branch as the convict vessel, from January 2009 to January 2012 in our hospital were enrolled in this study. They were divided into reperfusion (n = 92) and non-reperfusion group(n = 46). Clinical data, electrocardiogram, peak biomarkers, type B natriuretic peptide (BNP) were collected by physicians and the patients were followed up three months. RESULTS: The sum of the ST segments elevation, Q waves and Q wave leads in anterior STEMI were positive correlation with the Killip grades, myocardium biomarkers, BNP and left ventricle end diastolic diameters (LVEDD) [γ, 0.52-0.75, P < 0.01], while negative correlation with left ventricle ejection fraction (LVEF) [γ, -0.63--0.95, P < 0.01]. The sum of R wave altitude was negative correlation with myocardium biomarkers, BNP and LVEDD in three months after the onset of STEMI [γ, -0.48--0.79, P < 0.01], while positive correlation with LVEF [γ, 0.73-0.82, P < 0.01]. BNP, one of the best markers of left heart dysfunction, was found to be strongly negative correlation with LVEF in acute stage and three months after the onset of STEMI [γ , -0.92, -0.80, P < 0.01]. CONCLUSION: There are close correlations between electrocardiogram, myocardial biomarkers and left ventricular dysfunction in acute anterior ST segment elevation myocardial infarction, which may be strong predictors for the short-term prognosis.

Portable electrochemical sensor for adrenaline detection using CoNi-MOF-based CS-PAM hydrogel.

The development of a portable smartphone-based electrochemical sensor for analyzing adrenaline levels in real samples can make a great contribution to the research community worldwide. In order to achieve this goal, the key challenge is to build sensing interfaces with excellent electrocatalytic properties. In this work, microspherical bimetallic metal-organic frameworks (CoNi-MOF) consisting of nanoclusters were first synthesized using a hydrothermal method. On this basis, the catalytic activity of pure chitosan-polyacrylamide hydrogel (CS-PAM) was modulated by adding different amounts of CoNi-MOF during the in-situ synthesis of CS-PAM. Finally, a portable electrochemical detection system based on CS-PAM was established for the detection of adrenaline. A series of resulting composite hydrogels with a large specific surface area, abundant active sites, and unique network structure facilitate the enrichment and catalysis of adrenaline molecules. Under optimal conditions, the analytical platform constructed by using CoNi-MOF-based CS-PAM has the advantages of a wide detection range (0.5-10 and 10-2500 µM), a low detection limit (0.167 µM), and high sensitivity (0.182 and 0.133 µA·µM·cm-2). In addition, the sensor maintains selective detection of the target in the presence of many different types of interferences, and the current response is not significantly reduced even after 60 cycles of testing. We strongly believe that the designed smart portable sensing can realize the accurate determination of adrenaline in complex systems, and this study can provide new ideas for the research of MOFs-based hydrogels in electrochemical analysis.

Self-Assembly Dual Active Site Nanocomposite Anode Ce0.6Mn0.3Fe0.1O2-δ/NiFe/MnOx for Electrooxidative Dehydrogenation of Ethane to Ethylene.

As the demand for ethylene grows continuously in industry, conversion of ethane to ethylene has become more and more important; however, it still faces fundamental challenges of low ethane conversion, low ethylene selectivity, overoxidation, and instability of catalysts. Electrooxidative dehydrogenation of ethane (EODHE) in a solid oxide electrolysis cell (SOEC) is an alternative process. Here, a multiphase oxide Ce0.6Mn0.3Fe0.1O2-δ-NiFe-MnOx has been fabricated by a self-assembly process and utilized as the SOEC anode material for EODHE. The highest ethane conversions reached 52.23% with 94.11% ethylene selectivity at the anode side and CO with 10.9 mL min-1 cm-2 at the cathode side, at 1.8 V at 700 °C. The remarkable electrooxidative performance of CMF-NiFe-MnOx is ascribed to the NiFe alloy and MnOx nanoparticles and improvement of the concentration of oxygen vacancies within the fluorite substrate, generating dual active sites for C2H6 adsorption, dehydrogenation, and selective transformation of hydrogen without overoxidizing the ethylene generated. Such a tailored strategy achieves no significant degradation observed after 120 h of operation and constitutes a promising basis for EODHE.

Compound Chinese medicine (F1) improves spleen deficiency diarrhea by protecting the intestinal mucosa and regulating the intestinal flora.

Compound Chinese medicine (F1) is a traditional prescription in Chinese medicine that is commonly used to treat spleen deficiency diarrhea (SDD). It has demonstrated remarkable effectiveness in clinical practice. However, the precise mechanism by which it exerts its antidiarrheal effect is still unclear. This study aimed at investigating the antidiarrheal efficacy and mechanism of F1 on senna-induced secretory diarrhea (SDD). Senna was utilized to induce the development of a mouse model of senna-induced secretory diarrhea (SDD) in order to observe the rate of diarrhea, diarrhea index, blood biochemistry, and histopathological changes in the small intestine. Additionally, the levels of sodium and hydrogen exchange protein 3 (NHE3) and short-chain fatty acids (SCFAs) were determined using enzyme-linked immunosorbent assay (ELISA). The impact of F1 on the senna-induced SDD mouse models was evaluated by monitoring changes in the gut microbiota through 16S rRNA (V3-V4) sequencing. The results demonstrated that F1, a traditional Chinese medicine, effectively increased the body weight of SDD mice and reduced the incidence of diarrhea and diarrhea index. Additionally, F1 restored liver and kidney function, reduced the infiltration of inflammatory cells in intestinal tissue, and promoted the growth of intestinal villi. Furthermore, F1 was found to enhance the expression of NHE3 and SCFAs. It also increased the abundance of Firmicutes and Lactobacillus species, while decreasing the abundance of Proteobacteria and Shigella.

Associations between education levels and prevalence of depressive symptoms: NHANES (2005-2018).

PURPOSE: Our study investigated the relationships between the prevalence of depressive symptoms and education levels in those aged ≥20 years. METHODS: A total of 34,102 participants from the National Health and Nutrition Examination Surveys 2005-2018 were involved in our cross-sectional study. The relations of depressive symptoms (as outcome variable) and education levels (as an independent variable) were analyzed using multivariable logistic regression models in the main analyzes. Sensitivity analyzes, including a multiple sensitivity analysis, were also performed. RESULT: The education levels were negatively associated with depressive symptoms after adjusting related covariates. Compared with the reference group of individuals with less than 9th grade, people with college graduate or above had an adjusted odds ratio (OR) of 0.464 (95% CI 0.361, 0.595, P < 0.0001). On the other hand, the statistically significant negative association disappeared among Mexican Americans, other races, separated, and high family poverty income ratio group. These results remained stable under a wide range of sensitivity analyzes. CONCLUSION: Our study indicated the elevated education levels correlated with the decreased prevalence of depressive symptoms, and race, marital status, and family economic factors played a critical role in the relationship. This report reminds us to pay close attention to the further study of factors that affected the association between depressive symptoms and education levels. LIMITATIONS: The cross-sectional study leaves problems about the direction of causality unclear.

Improvement of Aerosol Filtering Performance of PLLA/PAN Composite Fiber with Gradient Structure.

Since commercial non-woven air filtering materials have unstable filtering efficiency and poor moisture permeability for the abundant condensed aerosol particles in the highly humid atmospheric environment, the PLLA/PAN composite fiber material with a hydrophobic and hydrophilic gradient structure is designed and prepared by using electrode sputtering electro spinning technology. By characterizing and testing the filtrating effect of SEM, XRD, FTIR, wettability, mechanical property, N2 adsorption isotherm, and BET surface area, NaCl aerosol of PLLA fiber, PAN fiber, and PLLA/PAN composite fiber membranes, the study found that the electrode sputtering electrospinning is fine, the fiber mesh is dense, and fiber distribution is uniform when the diameter of the PAN fiber is 140-300 nm, and the PLLA fiber is 700-850 nm. In this case, PLLA/PAN composite fiber materials gather the hydrophobicity of PLLA fiber and the hydrophilicity of PAN fiber; its electrostatic effect is stable, its physical capturing performance is excellent, it can realize the step filtration of gas-solid liquid multiphase flow to avoid the rapid increase of air resistance in a high-humidity environment, and the filtrating efficiency η of NaCl aerosol particles with 0.3 µm reaches 99.98%, and the quality factor QF 0.0968 Pa-1. The manufacturing of PLLA/PAN composite fiber material provides a new method for designing and developing high-performance air filtration materials and a new technical means for the large-scale production of high-performance, high-stability, and low-cost polylactic acid nanofiber composites.

Ti/Ni co-doped perovskite cathode with excellent catalytic activity and CO2 chemisorption ability via nanocatalysts exsolution for solid oxide electrolysis cell.

Carbon dioxide (CO2) gas is the main cause of global warming and has a significant effect on both climate change and human health. In this study, Ni/Ti co-doped Sr1.95Fe1.2Ni0.1Ti0.2Mo0.5O6-δ (SFNTM) double perovskite oxides were prepared and used as solid oxide electrolysis cell (SOEC) cathode materials for effective CO2 reduction. Ti-doping enhances the structural stability of the cathode material and increases the oxygen vacancy concentration. After treatment in 10% H2/Ar at 800°C, Ni nanoparticles were exsolved in situ on the SFNTM surface (Ni@SFNTM), thereby improving its chemisorption and activation capacity for CO2. Modified by the Ti-doping and the in situ exsolved Ni nanoparticles, the single cell with Ni@SFNMT cathode exhibits improved catalytic activity for CO2 reduction, exhibiting a current density of 2.54 A cm-2 at 1.8 V and 800°C. Furthermore, the single cell shows excellent stability after 100 h at 1.4 V, indicating that Ni/Ti co-doping is an effective strategy for designing novel cathode material with high electrochemical performance for SOEC.

Regulating Solvation Structures Enabled by the Mesoporous Material MCM-41 for Rechargeable Lithium Metal Batteries.

For developing the reversible lithium metal anode, constructing an ideal solid electrolyte interphase (SEI) by regulating the Li+ solvation structure is a powerful way to overcome the major obstacles of lithium dendrite and limited Coulombic efficiency (CE). Herein, spherical mesoporous molecular sieve MCM-41 nanoparticles are coated on a commercial PP separator and used to regulate the Li+ solvation structure for lithium metal batteries (LMBs). The regulated solvation structure exhibits an agminated state with more contact ion pairs (CIPs) and ionic aggregates (AGGs), which successfully construct a homogeneous inorganic-rich SEI in the lithium anode. Meanwhile, the regulated solvation structure weakens the interaction between the solvents and Li+, resulting in low Li+ desolvation energy and uniform Li deposition. Thus, a high CE (∼96.76%), dendrite-free Li anode, and stable Li plating/stripping cycling for approximately 1000 h are achieved in the regulated carbonate-based electrolyte without any additives. Therefore, regulating the Li+ solvation structure in the electrolyte by employing a mesoporous material is a forceful way to construct an ideal SEI and harness lithium metal.

Study on population structure of kiwifruit and GWAS for hairiness character.

BACKGROUND: A total of 74,936 SNPs were employed to carry out population structure and genome-wide association studies and post-GWAS for hairiness character of the fifty-six samples including thirty-six Actinidia chinensis var. deliciosa, eighteen A. chinensis var. chinensis, and two A. polygama in the light of morphological observations. RESULTS: The percentage of heterozygous sites of A. chinensis var. deliciosa is higher than that of A. chinensis var. chinensis, which could be one of the reasons for A. chinensis var. deliciosa high disease resistance. Fifty-six samples were divided into two subgroups, in which the genetic distance, ranged from 0.17 to 0.99, according to their genetic divergence. Analysis of molecular variance shows that the frequency of genetic variations within the population is 83.53% and 16.47% between populations. Fst between the two populations is 0.14, and Nm is 1.60. Set at α ≤ 0.05, a total of 327 SNPs and 260 haplotypes were related to the hairiness character. A total of 246 proteins were annotated using GO and KEGG analyses, which indicated the membrane-related genes and stress-resistant metabolic pathways are related to the hairiness character of leaves, stems, and peels of kiwifruit. Protein interaction analysis showed that DNA-directed RNA polymerase was an important node protein that interacted with many proteins. CONCLUSIONS: The genetic basic in the fifty-six genotypes was rich. The results of clustering and morphological observations are not completely consistent, indicating the hairiness character play an important role in the classification of kiwifruit, in which two A. polygama were clustered together with those of A. chinensis var. chinensis. Phylogeny and haplotype analysis showed that the evolution of A. chinensis var. chinensis is later than that of A. chinensis var. deliciosa in A. chinesis. The loss of hairiness character on leaves, stems and peels of A. chinensis var. chinensis compare with A. chinensis var. deliciosa, which is also the result of its poor resistance.

Enhancing Polysulfide Confinement and Electrochemical Kinetics by Amorphous Cobalt Phosphide for Highly Efficient Lithium-Sulfur Batteries.

The application of lithium-sulfur (Li-S) batteries is severely hampered by the shuttle effect and sluggish redox kinetics. Herein, amorphous cobalt phosphide grown on a reduced graphene oxide-multiwalled carbon nanotube (rGO-CNT-CoP(A)) is designed as the sulfur host to conquer the above bottlenecks. The differences between amorphous cobalt phosphide (CoP) and crystalline CoP on the surface adsorption as well as conversion of lithium polysulfides (LiPSs) are investigated by systematical experiments and density-functional theory (DFT) calculations. Specifically, the amorphous CoP not only strengthens the chemical adsorption to LiPSs but also greatly accelerates liquid-phase conversions of LiPSs as well as the nucleation and growth of Li2S. DFT calculation reveals that the amorphous CoP possesses higher binding energies and lower diffusion energy barriers for LiPSs. In addition, the amorphous CoP features reduced energy gap and the increased electronic concentrations of adsorbed LiPSs near Fermi level. These characteristics contribute to the enhanced chemisorption ability and the accelerated redox kinetics. Simultaneously, the prepared S/rGO-CNT-CoP(A) electrode delivers an impressive initial capacity of 872 mAh g-1 at 2 C and 617 mAh g-1 can be obtained after 200 cycles, exhibiting excellent cycling stability. Especially, it achieves outstanding electrochemical performance even under high sulfur loading (5.3 mg cm-2) and lean electrolyte (E/S = 7 µLE mg-1S) conditions. This work exploits the application potential for amorphous materials and contributes to the development of highly efficient Li-S batteries.

Enhanced Electrochemical Performance of the Fe-Based Layered Perovskite Oxygen Electrode for Reversible Solid Oxide Cells.

Reversible solid oxide cells (RSOCs) present a conceivable potential for addressing energy storage and conversion issues through realizing efficient cycles between fuels and electricity based on the reversible operation of the fuel cell (FC) mode and electrolysis cell (EC) mode. Reliable electrode materials with high electrochemical catalytic activity and sufficient durability are imperatively desired to stretch the talents of RSOCs. Herein, oxygen vacancy engineering is successfully implemented on the Fe-based layered perovskite by introducing Zr4+, which is demonstrated to greatly improve the pristine intrinsic performance, and a novel efficient and durable oxygen electrode material is synthesized. The substitution of Zr at the Fe site of PrBaFe2O5+δ (PBF) enables enlarging the lattice free volume and generating more oxygen vacancies. Simultaneously, the target material delivers more rapid oxygen surface exchange coefficients and bulk diffusion coefficients. The performance of both the FC mode and EC mode is greatly enhanced, exhibiting an FC peak power density (PPD) of 1.26 W cm-2 and an electrolysis current density of 2.21 A cm-2 of single button cells at 700 °C, respectively. The reversible operation is carried out for 70 h under representative conditions, that is, in air and 50% H2O + 50% H2 fuel. Eventually, the optimized material (PBFZr), mixed with Gd0.1Ce0.9O2, is applied as the composite oxygen electrode for the reversible tubular cell and presents excellent performance, achieving 4W and 5.8 A at 750 °C and the corresponding PPDs of 140 and 200 mW cm-2 at 700 and 750 °C, respectively. The enhanced performance verifies that PBFZr is a promising oxygen electrode material for the tubular RSOCs.

Pr-Doping Motivating the Phase Transformation of the BaFeO3-δ Perovskite as a High-Performance Solid Oxide Fuel Cell Cathode.

Intermediate temperature solid oxide fuel cells (IT-SOFCs) have been extensively studied due to high efficiency, cleanliness, and fuel flexibility. To develop highly active and stable IT-SOFCs for the practical application, preparing an efficient cathode is necessary to address the challenges such as poor catalytic activity and CO2 poisoning. Herein, an efficient optimized strategy for designing a high-performance cathode is demonstrated. By motivating the phase transformation of BaFeO3-δ perovskites, achieved by doping Pr at the B site, remarkably enhanced electrochemical activity and CO2 resistance are thus achieved. The appropriate content of Pr substitution at Fe sites increases the oxygen vacancy concentration of the material, promotes the reaction on the oxygen electrode, and shows excellent electrochemical performance and efficient catalytic activity. The improved reaction kinetics of the BaFe0.95Pr0.05O3-δ (BFP05) cathode is also reflected by a lower electrochemical impedance value (0.061 Ω·cm2 at 750 °C) and activation energy, which is attributed to high surface oxygen exchange and chemical bulk diffusion. The single cells with the BFP05 cathode achieve a peak power density of 798.7 mW·cm-2 at 750 °C and a stability over 50 h with no observed performance degradation in CO2-containing gas. In conclusion, these results represent a promising optimized strategy in developing electrode materials of IT-SOFCs.