Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Poly(lactic acid)/Poly(butylene adipate-co-terephthalate)films with simultaneous high oxygen barrier and fast degradation properties

Although poly(lactic acid)(PLA)is a good environmentally-friendly bio-degradable polymer which is used to substitute traditional petrochemical-based polymer packaging films,the barrier properties of PLA films are still insufficient for high-barrier packaging applications.In this study,oxygen scavenger hydroxyl-terminated polybutadiene(HTPB)and cobalt salt catalyst were incorporated into the PLA/poly(butylene adipate-co-terephthalate)(PLA/PBAT),followed by melting extrusion and three-layer co-extrusion blown film process to prepare the composite films.The oxygen permeability coefficient of the composite film combined with 6 wt%oxygen scavenger and 0.4 wt%catalyst was decreased significantly from 377.00 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1) to 0.98 cc·mil·m^(-2)·day^(-1)·0.1 MPa^(-1),showing a remarkable enhancement of 384.69 times compared with the PLA/PBAT composite film.Meanwhile,the degradation behavior of the composite film was also accelerated,exhibiting a mass loss of nearly 60%of the original mass after seven days of degradation in an alkaline environment,whereas PLA/PBAT composite film only showed a mass loss of 32%.This work has successfully prepared PLA/PBAT composite films with simultaneously improved oxygen barrier property and degradation behavior,which has great potential for high-demanding green chemistry packaging industries,including food,agricultural,and military packaging.

Boosting Oxygen Evolution Reaction Performance on NiFe‑Based Catalysts Through d‑Orbital Hybridization

Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

Overview of in-situ oxygen production technologies for lunar resources

The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources.Oxygen,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic oxides.This oxygen and metal extraction can be achieved using existing metallurgical techniques.Furthermore,the ample reserves of water ice on the Moon offer another means for oxygen production.This paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental conditions.It delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar regolith.The two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the Moon.Considering the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the Moon.This review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.

Ru⁃doped Co_(3)O_(4)/reduced graphene oxide:Preparation and electrocatalytic oxygen evolution property

Binary composites(ZIF-67/rGO)were synthesized by one-step precipitation method using cobalt nitrate hexahydrate as metal source,2-methylimidazole as organic ligand,and reduced graphene oxide(rGO)as carbon carrier.Then Ru3+was introduced for ion exchange,and the porous Ru-doped Co_(3)O_(4)/rGO(Ru-Co_(3)O_(4)/rGO)composite electrocatalyst was prepared by annealing.The phase structure,morphology,and valence state of the catalyst were analyzed by X-ray powder diffraction(XRD),scanning electron microscope(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).In 1 mol·L^(-1)KOH,the oxygen evolution reaction(OER)performance of the catalyst was measured by linear sweep voltammetry,cyclic voltammetry,and chronoamperometry.The results show that the combination of Ru doping and rGO provides a fast channel for collaborative electron transfer.At the same time,rGO as a carbon carrier can improve the electrical conductivity of Ru-Co_(3)O_(4)particles,and the uniformly dispersed nanoparticles enable the reactants to diffuse freely on the catalyst.The results showed that the electrochemical performance of Ru-Co_(3)O_(4)/rGO was much better than that of Co_(3)O_(4)/rGO,and the overpotential of Ru-Co_(3)O_(4)/rGO was 363.5 mV at the current density of 50 mA·cm^(-2).

Inhibitory effect of ferroptosis inhibitor toxicity induced by cobalt nanoparticles through reactive oxygen species

BACKGROUND:Soft tissue damage induced by cobalt nanoparticles is currently the most noticeable complication in patients with artificial joint prostheses.Therefore,an effective therapeutic strategy is needed to limit the toxicity of cobalt nanoparticles.OBJECTIVE:To investigate the protective effect of a ferroptosis inhibitor on cobalt nanoparticles-induced cytotoxicity.METHODS:To evaluate the detoxification effect of ferroptosis inhibitor on mouse fibroblasts(Balb/3T3),Balb/3T3 cells were treated with cobalt nanoparticles and ferroptosis inhibitor for 24 hours.The cell viabilities were measured by cell viability assay.Based on the results of the cell viability assay,the concentrations of cobalt nanoparticles and deferiprone were determined.The experiment was divided into four groups:the cobalt nanoparticles group(400μmol/L cobalt nanoparticles),the cobalt nanoparticles+deferiprone group(400μmol/L cobalt nanoparticles and 25μmol/L deferiprone),the deferiprone group(25μmol/L deferiprone),and the control group.The expressions of glutathione peroxidase 4 and solute carrier family 7 member 11 protein were examined by western blot assay.RESULTS AND CONCLUSION:(1)The cell viability assay results showed that as the exposure time or the drug concentration increased,cell viability decreased further,indicating that the cytotoxic effect of cobalt nanoparticles was time-and dose-dependent.Additionally,after 24 hours of exposure,cobalt nanoparticles significantly reduced cell viability and glutathione levels compared with the control group(P<0.05).At the same time,compared with the control group,there was an increase in reactive oxygen species production,intracellular iron levels,and the expression of inflammatory cytokines such as tumor necrosis factorα,interleukin-1β,and interleukin-6.After the addition of deferiprone,compared with the cobalt nanoparticles group,cell viability significantly improved,and reactive oxygen species production,intracellular iron levels,and the expression of inflammatory cytokines(tumor necrosis factorα,interleukin-1β,and interleukin-6)significantly decreased(P<0.05).This demonstrated that deferiprone had a protective effect on cells exposed to cobalt nanoparticles.(2)Western blot assay results showed that cobalt nanoparticles reduced the expression of glutathione peroxidase 4 and solute carrier family 7 member 11 protein(P<0.05),while deferiprone inhibited this effect(P<0.05).(3)The above findings verify that cobalt nanoparticles are highly cytotoxic and ferroptosis inhibitor deferiprone has a detoxification effect on cytotoxicity induced by cobalt nanoparticles.Ferroptosis plays an important role in the process by which cobalt nanoparticles induce cytotoxicity.The inhibitory effect of ferroptosis inhibitors on the toxicity of cobalt nanoparticles may provide valuable insights for further research into the mechanisms of cobalt nanoparticle toxicity and potential detoxification strategies.

De novo-design of highly exposed Co−N−C single-atom catalyst for oxygen reduction reaction

The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.

Current role of extracorporeal membrane oxygenation for the management of trauma patients:Indications and results

Extracorporeal membrane oxygenation(ECMO)has emerged as a vital circulatory life support measure for patients with critical cardiac or pulmonary conditions unresponsive to conventional therapies.ECMO allows blood to be extracted from a patient and introduced to a machine that oxygenates blood and removes carbon dioxide.This blood is then reintroduced into the patient’s circulatory system.This process makes ECMO essential for treating various medical conditions,both as a standalone therapy and as adjuvant therapy.Veno-venous(VV)ECMO primarily supports respiratory function and indicates respiratory distress.Simultaneously,veno-arterial(VA)ECMO provides hemodynamic and respiratory support and is suitable for cardiac-related complications.This study reviews recent literature to elucidate the evolving role of ECMO in trauma care,considering its procedural intricacies,indications,contraindications,and associated complications.Notably,the use of ECMO in trauma patients,particularly for acute respiratory distress syndrome and cardiogenic shock,has demonstrated promising outcomes despite challenges such as anticoagulation management and complications such as acute kidney injury,bleeding,thrombosis,and hemolysis.Some studies have shown that VV ECMO was associated with significantly higher survival rates than conventional mechanical ventilation,whereas other studies have reported that VA ECMO was associated with lower survival rates than VV ECMO.ECMO plays a critical role in managing trauma patients,particularly those with acute respiratory failure.Further research is necessary to explore the full potential of ECMO in trauma care.Clinicians should have a clear understanding of the indications and contraindications for the use of ECMO to maximize its benefits in treating trauma patients.

Prognostic factors for acute central retinal artery occlusion treated with hyperbaric oxygen:The Hong Kong study report number five

BACKGROUND Central retinal artery occlusion(CRAO)is a potentially blinding disease,and hyperbaric oxygen therapy(HBOT)is becoming increasingly popular with the support of scientific evidence.Despite the presence of various acute management measures,there is no clear evidence on the gold standard treatment for CRAO.AIM To identify factors and imaging parameters associated with good visual outcome,which guide ophthalmologists in the triage of CRAO patients for HBOT.METHODS Patients who suffered from CRAO and had a symptom onset≤6 h were recruited for a course of HBOT in a tertiary hospital after failing bedside treatment.Patient demographics,onset time,CRAO eye parameters,and past medical history were prospectively collected.Visual outcomes after HBOT were also analyzed.RESULTS A total of 26 patients were included;the female-to-male ratio was 1:1.6,and the mean age was 67.5 years±13.3 years(range 44–89 years).The mean duration of follow-up and mean visual acuity(VA)improvement were 10.0 mo±5.3 mo and 0.48 logarithm of minimal angle of resolution(logMAR)±0.57 logMAR(approx-imately 9 letters in ETDRS)(P=0.0001,Z=-3.67),respectively.The 1 mm zone of central macular thickness(CMT)on optical coherence tomography was not associated with VA changes(P=0.119);however,the 1-to-3 mm circular rim of CMT was fairly associated(P=0.02,Spearman's coefficient=0.45).Complete retinal perfusion time during fundus fluorescein angiography(FFA)was mode-rately associated(P=0.01,Spearman's coefficient=0.58)with visual outcome.

Disruption of Energy Metabolism and Reactive Oxygen Species Homeostasis in Honglian Type-Cytoplasmic Male Sterility(HL-CMS)Rice Pollen

Honglian type-cytoplasmic male sterility(HL-CMS)is caused by the inter-communication between the nucleus and mitochondria.However,the mechanisms by which sterility genes regulate metabolic alterations and changes in mitochondrial morphology in the pollen of HL-CMS remain unclear.In this study,we compared the morphological differences between the pollen of the male sterile line YA and the near-isogenic line NIL-Rf6 using hematoxylin-eosin staining and 4ʹ,6-diamidino-2-phenylindole(DAPI)staining.HL-CMS is characterized by gametophytic sterility,where the aborted pollen grains are empty,and the tapetal layer remains intact.Transmission electron microscopy was employed to observe mitochondrial morphological changes at the microspore stage,revealing significant mitochondrial alterations,characterized by the formation of'large spherical mitochondria',occurred at the binucleate stage in the YA line.Additionally,metabolomics analysis revealed decreased levels of metabolites associated with the carbohydrate and flavonoid pathways.Notably,the decrease in flavonoids was found to contribute to an elevation in reactive oxygen species(ROS)levels.Therefore,we propose a model in which rice fertility is modulated by the levels of pollen carbohydrates and flavonoid metabolites,with impaired mitochondrial energy production and reduced flavonoid biosynthesis as the main causes of ROS accumulation and pollen abortion in rice.

Hyperbaric oxygen therapy in the treatment of severe gastric laceration with active bleeding: A case report

BACKGROUND Endoscopic therapy is the primary approach for treating Mallory-Weiss syndro-me,particularly under conditions of mucosal protection and gastric acid suppre-ssion.However,for a subset of patients who cannot undergo endoscopic interven-tion or for whom such treatment proves ineffective,alternative measures like arterial embolization or surgical intervention may be required.While hyperbaric oxygen therapy(HBOT)has been applied across a range of medical conditions,its application in managing hemorrhage due to gastric tears remains undocumented.CASE SUMMARY A 52-year-old patient was admitted with symptoms of hematemesis and melena,and an endoscopy revealed a gastric fundus tear approximately 4 cm×5 cm in size.The lesion was considered unsuitable for endoscopic repair by the attending endoscopist.Despite conservative measures,including fasting and acid sup-pression,the patient experienced persistent bleeding and a substantial decrease in hemoglobin levels relative to admission values.Following a multidisciplinary consultation,HBOT was initiated,resulting in the cessation of bleeding and rapid wound healing.CONCLUSION For patients with gastric tears presenting with active hemorrhage,HBOT might offer an effective alternative when conventional endoscopic therapies are not viable or have been unsuccessful.

Assessing the impact of climate change on dissolved oxygen using a flow field ecosystem model that takes into account the anaerobic and aerobic environment of bottom sediments

This study examines the potential impacts o climate change on Lake Biwa,Japan’s largest freshwate lake,with a focus on temperature,wind speed,and pre cipitation variations.Leveraging data from the IPCC Sixth Assessment Report,including CCP scenarios,projecting a significant temperature rise of 3.3–5.7℃in the case o very high GHG emission power,the research investigates how these shifts may influence dissolved oxygen levels in Lake Biwa.Through a one-dimensional model incorporat ing sediment redox reactions,various scenarios where ai temperature and wind speed are changed are simulated.I is revealed that a 5℃increase in air temperature leads to decreasing 1-2 mg/L of dissolved oxygen concentrations from the surface layer to the bottom layer,while a decrease in air temperature tends to elevate 1–3 mg/L of oxygen lev els.Moreover,doubling wind speed enhances surface laye oxygen but diminishes it in deeper layers due to increased mixing.Seasonal variations in wind effects are noted with significant surface layer oxygen increases from 0.4to 0.8 mg/L during summer to autumn,increases from 0.4 to 0.8 mg/L in autumn to winter due to intensified vertica mixing.This phenomenon impacts the lake’s oxygen cycle year-round.In contrast,precipitation changes show limited impact on oxygen levels,suggesting minor influence com pared to other meteorological factors.The study suggests the necessity of comprehensive three-dimensional models that account for lake-specific and geographical factors fo accurate predictions of future water conditions.A holistic approach integrating nutrient levels,water temperature,and river inflow is deemed essential for sustainable management of Lake Biwa’s water resources,particularly in addressing precipitation variations.

Taming of trinitromethyl-oxadiazole to access high density and high oxygen balance via a dual modulation strategy

Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.

Extracorporeal membrane oxygenation combined with intra-aortic balloon counterpulsation for pheochromocytoma:A case report

BACKGROUND Pheochromocytoma(PHEO)is a type of tumor that originates from chromaffin cells in the adrenal medulla and is classified as an adrenal paraganglioma.PHEOs can secrete catecholamines,leading to a variety of symptoms.Accurate diagnosis and appropriate treatment selection are crucial for favorable outcomes in these cases.CASE SUMMARY The patient presented with unexplained chest tightness,palpitations,and pink sputum.Upon examination and analysis of laboratory results,a diagnosis of adrenal PHEO was established.The PHEO secreted high levels of catecholamines,causing sudden fluctuations in blood pressure and heart rate,leading to extre-mely unstable hemodynamics.Treatment with extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation helped stabilize the patient’s vital signs,allowing for timely surgical intervention.CONCLUSION The combination of extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation can enhance tissue perfusion,thus providing a solid foundation for the accurate diagnosis and effective surgical treatment of PHEO.

Strong synergy between physical and chemical properties:Insight into optimization of atomically dispersed oxygen reduction catalysts

Atomically dispersed catalysts exhibit significant influence on facilitating the sluggish oxygen reduction reaction(ORR)kinetics with high atom economy,owing to remarkable attributes including nearly 100%atomic utilization and exceptional catalytic functionality.Furthermore,accurately controlling atomic physical properties including spin,charge,orbital,and lattice degrees of atomically dispersed catalysts can realize the optimized chemical properties including maximum atom utilization efficiency,homogenous active centers,and satisfactory catalytic performance,but remains elusive.Here,through physical and chemical insight,we review and systematically summarize the strategies to optimize atomically dispersed ORR catalysts including adjusting the atomic coordination environment,adjacent electronic orbital and site density,and the choice of dual-atom sites.Then the emphasis is on the fundamental understanding of the correlation between the physical property and the catalytic behavior for atomically dispersed catalysts.Finally,an overview of the existing challenges and prospects to illustrate the current obstacles and potential opportunities for the advancement of atomically dispersed catalysts in the realm of electrocatalytic reactions is offered.

Hybrid model for BOF oxygen blowing time prediction based on oxygen balance mechanism and deep neural network

The amount of oxygen blown into the converter is one of the key parameters for the control of the converter blowing process,which directly affects the tap-to-tap time of converter. In this study, a hybrid model based on oxygen balance mechanism (OBM) and deep neural network (DNN) was established for predicting oxygen blowing time in converter. A three-step method was utilized in the hybrid model. First, the oxygen consumption volume was predicted by the OBM model and DNN model, respectively. Second, a more accurate oxygen consumption volume was obtained by integrating the OBM model and DNN model. Finally, the converter oxygen blowing time was calculated according to the oxygen consumption volume and the oxygen supply intensity of each heat. The proposed hybrid model was verified using the actual data collected from an integrated steel plant in China, and compared with multiple linear regression model, OBM model, and neural network model including extreme learning machine, back propagation neural network, and DNN. The test results indicate that the hybrid model with a network structure of 3 hidden layer layers, 32-16-8 neurons per hidden layer, and 0.1 learning rate has the best prediction accuracy and stronger generalization ability compared with other models. The predicted hit ratio of oxygen consumption volume within the error±300 m^(3)is 96.67%;determination coefficient (R^(2)) and root mean square error (RMSE) are0.6984 and 150.03 m^(3), respectively. The oxygen blow time prediction hit ratio within the error±0.6 min is 89.50%;R2and RMSE are0.9486 and 0.3592 min, respectively. As a result, the proposed model can effectively predict the oxygen consumption volume and oxygen blowing time in the converter.

Boric Acid-Assisted Pyrolysis for High-Loading Single-Atom Catalysts to Boost Oxygen Reduction Reaction in Zn-Air Batteries

The emerging of single-atom catalysts(SACs)offers a great opportunity for the development of advanced energy storage and conversion devices due to their excellent activity and durability,but the actual mass production of high-loading SACs is still challenging.Herein,a facile and green boron acid(H_(3)BO_(3))-assisted pyrolysis strategy is put forward to synthesize SACs by only using chitosan,cobalt salt and H_(3)BO_(3)as precursor,and the effect of H_(3)BO_(3)is deeply investigated.The results show that molten boron oxide derived from H_(3)BO_(3)as ideal high-temperature carbonization media and blocking media play important role in the synthesis process.As a result,the acquired Co/N/B tri-doped porous carbon framework(Co-N-B-C)not only presents hierarchical porous structure,large specific surface area and abundant carbon edges but also possesses high-loading single Co atom(4.2 wt.%),thus giving rise to outstanding oxygen catalytic performance.When employed as a catalyst for air cathode in Zn-air batteries,the resultant Co-N-B-C catalyst shows remarkable power density and long-term stability.Clearly,our work gains deep insight into the role of H_(3)BO_(3)and provides a new avenue to synthesis of high-performance SACs.

A defective iron-based perovskite cathode for high-performance IT-SOFCs:Tailoring the oxygen vacancies using Nb/Ta co-doping

The sluggish kinetics of the electrochemical oxygen reduction reaction(ORR)in intermediatetemperature solid oxide fuel cells(IT-SOFCs)greatly limits the overall cell performance.In this study,an efficient and durable cathode material for IT-SOFCs is designed based on density functional theory(DFT)calculations by co-doping with Nb and Ta the B-site of the SrFeO_(3-δ)perovskite oxide.The DFT calculations suggest that Nb/Ta co-doping can regulate the energy band of the parent SrFeO_(3-δ)and help electron transfer.In symmetrical cells,such cathode with a SrFe_(0.8)Nb_(0.1)Ta_(0.1)O_(3-δ)(SFNT)detailed formula achieves a low cathode polarization resistance of 0.147Ωcm^(2) at 650℃.Electron spin resonance(ESR)and X-ray photoelectron spectroscopy(XPS)analysis confirm that the co-doping of Nb/Ta in SrFeO_(3-δ)B-site increases the balanced concentration of oxygen vacancies,enhancing the electrochemical performance when compared to 20 mol%Nb single-doped perovskite oxide.The cathode button cell with NiSDC|SDC|SFNT configuration achieves an outstanding peak power density of 1.3 W cm^(-2)at 650℃.Moreover,the button cell shows durability for 110 h under 0.65 V at 600℃ using wet H_(2) as fuel.

Excess Activity Tuned by Distorted Tetrahedron in CoMoO_(4) for Oxygen Evolution

Oxygen vacancies enable modulating surface reconstruction of transition metal oxides containing metal-oxygen polyhedrons into metallic oxyhydroxide for oxygen evolution reaction(OER),while revealing reconstructing mechanism is stuck by the requirement to precisely control exact sites of these vacancies.Herein,oxygen vacancies are localized only within MoO_(4)tetrahedrons rather than CoO_(6)octahedrons in CoMoO_(4)catalyst,guaranteeing coherent reconstruction of CoO_(6)octahedrons into pure CoOOH with tunable activities for OER.Meanwhile,distorted tetrahedron accelerates the dissolution of Mo atoms into alkaline electrolyte,triggering spontaneous transition of partial CoMoO_(4)into Co(OH)_(2).CoO_(6)octahedrons in both CoMoO_(4)and Co(OH)_(2)can transform pure CoOOH completely at lower potential,resulting in excess intrinsic activity whose summit is identified by overpotential at 10 mA cm^(-2)with 22.9%reduction and Tafel slope with 65.3%reduction.Well-defined manipulation over the distorted polyhedrons offers one versatile knob to precisely modulate electronic structure of oxide catalysts with outstanding OER performance.

Co/CoO heterojunction rich in oxygen vacancies introduced by O_(2) plasma embedded in mesoporous walls of carbon nanoboxes covered with carbon nanotubes for rechargeable zinc-air battery

Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well designed through zeolite-imidazole framework(ZIF-67)carbonization,chemical vapor deposition,and O_(2) plasma treatment.As a result,the threedimensional NHCNBs coupled with NCNTs and unique heterojunction with rich oxygen vacancies reduce the charge transport resistance and accelerate the catalytic reaction rate of the P-Co/CoOV@NHCNB@NCNT,and they display exceedingly good electrocatalytic performance for oxygen reduction reaction(ORR,halfwave potential[EORR,1/2=0.855 V vs.reversible hydrogen electrode])and oxygen evolution reaction(OER,overpotential(η_(OER,10)=377mV@10mA cm^(−2)),which exceeds that of the commercial Pt/C+RuO_(2) and most of the formerly reported electrocatalysts.Impressively,both the aqueous and flexible foldable all-solid-state rechargeable zinc-air batteries(ZABs)assembled with the P-Co/CoOV@NHCNB@NCNT catalyst reveal a large maximum power density and outstanding long-term cycling stability.First-principles density functional theory calculations show that the formation of heterojunctions and oxygen vacancies enhances conductivity,reduces reaction energy barriers,and accelerates reaction kinetics rates.This work opens up a new avenue for the facile construction of highly active,structurally stable,and cost-effective bifunctional catalysts for ZABs.