Microstructure and storage properties of low V-containing Ti–Cr–V hydrogen storage alloys prepared by arc melting and suction casting

The microstructure and hydrogen storage properties of low V content （Ti0.46Cr0.54）100-xVx （x = 2.5-7.1, at%） and （TiyCr1-y）95V5 （y= 0.38-0.54） alloys were investigated. These alloys were prepared by arc melting and copper mould suction casting. The structures of as-cast （Ti0.46Cr0.54）100-xVx （x = 2.5, 5.0, and 7.1） alloy ingots evolve with V contents from pure Laves-（x = 2.5） to dual-phase TiCr2-BCC structures （5.0 and 7.1）, whereas the suction-cast （Ti0.46Cr0.54）100-xVx （x =2.5, 5.0, and 7.1） alloys only contain single BCC phase. The suction-cast alloy rod （Ti0.46Cr0.54）95V5, containing only 5.0 at% V is shown to possess the optimum hydrogen absorption capacity, with the maximum hydrogen content of 3.14 wt%. Furthermore, the hydrogen storage properties of the suction-cast low V alloys （TiyCr1-y）95V5 （y = 0.38-0.54） are sensitive to Ti/Cr ratios and only those alloys with Ti/Cr ratios close to the CN14 cluster [TiTCrs] have good hydrogen storage properties.

Postpartum Atypical Hemolytic Uremic Syndrome:an Unusual and Severe Complication Associated with Ig A Nephropathy

IGA nephropathy （IgAN） is one of the most commontypes of primary glomerulonephritis, which occursmore frequently in patients of reproductive age.Atypical hemolytic uremic syndrome （aHUS）without diarrhea is rare and has a poor prognosis. In theabsence of appropriate therapy, pregnancy-related aHUSis associated with high morbidity and mortality.

Life-threatening subclavian artery bleeding following percutaneous coronary intervention with stent implantation:A case report and review of literature

BACKGROUND Vascular complications of transradial percutaneous coronary intervention(PCI)are rare and usually occur at the access site below the elbow.Life-threatening vascular complications during transradial PCI therapy,such as vessel perforation and dissection in the brachiocephalic,subclavian,internal mammary,and thyrocervical arteries,are rarely reported.Subclavian artery bleeding is a potentially serious complication of vascular interventional procedures leading to tracheal obstruction,hemothorax,respiratory failure,hemorrhagic shock,and death if not diagnosed early and treated promptly.CASE SUMMARY A male patient with typical angina pectoris underwent coronary angiography and stent implantation.During the procedure,the patient felt pharyngeal pain and tightness,which we mistook for myocardial ischemia.After PCI,swelling in the right neck and supraclavicular area was observed.The patient experienced dyspnea,emergency endotracheal intubation was performed,and then a sudden drop in blood pressure was observed.Ultrasound and contrast-enhanced computed tomography scans demonstrated a cervical hematoma severely compressing the trachea due to subclavian artery bleeding.Brachiocephalic angiography revealed a vascular injury site at the root of the right subclavian artery at the intersection of the right common carotid artery.A covered stent was deployed to the right subclavian artery with successful sealing of the perforation,and a bare stent was implanted in the junction of the right common carotid and brachiocephalic arteries to prevent obstruction of blood flow to the brain.CONCLUSION Subclavian artery bleeding is a lifethreatening complication of PCI.Early prevention,rapid recognition,and prompt treatment may improve the prognosis.

Pheochromocytoma as a cause of repeated acute myocardial infarctions,heart failure,and transient erythrocytosis:A case report and review of the literature

BACKGROUND Pheochromocytoma is a rare catecholamines-secreting tumor arising from chromaffin cells in the adrenal medulla.It classically presents with paroxysmal hypertension,headaches,palpitations,sweating,and metabolic disorders.Atypical presentations such as acute myocardial infarction,heart failure,cardiomyopathy,stroke,and transient erythrocytosis have been infrequently documented.CASE SUMMARY We describe the case of a 72-year-old man diagnosed with pheochromocytoma presenting with non-ST segment elevation myocardial infarction,heart failure,and transient erythrocytosis with nonobstructed coronary arteries.This was his second heart attack.The patient was previously diagnosed with myocardial infarction,and an immense mass was found on the left adrenal gland 3 years prior.Based on clinical and laboratory findings,a diagnosis of pheochromocytoma was confirmed.His coronary angiogram showed nonobstructed coronary arteries except for a myocardial bridge in the left anterior descending branch.This was a form of type-2 myocardial infarction.The myocardial cell lesions were caused by sudden secretion of catecholamines by the pheochromocytoma.Even more atypically,his hemoglobin level was obviously elevated at admission,but after a few days of treatment with an alpha-adrenergic receptor blocker,it dropped to normal levels without additional treatment.CONCLUSION Pheochromocytoma may be a cause of acute myocardial infarction,heart failure,and transient erythrocytosis.

Modulated noble metal/2D MOF heterostructures for improved hydrogen storage of MgH_(2)

The conjugation of external species with twodimensional(2D)materials has broad application prospects.In this study,we have explored the potential of noble metal/2D MOF heterostructures in hydrogen storage.Specifically,the MgH_(2)-Ni-MOF@Pd system has shown remarkable hydrogen desorption/sorption performances,starting to liberate hydrogen at 1810C,which is 2300C lower than that of pristine MgH2.Under the catalytic effect of Ni-MOF@Pd,the dehydrogenation apparent activation energy of MgH2 is noticeably decreased from(133.5±17.5)to(34.58±1.87)kJ·moL^(-1),and the hydrogenation apparent activation energy is reduced from(70.41±7.43)to(25.78±4.64)kJ·moL^(-1),which is lowered by 63.4%.The fully-dehydrogenated MgH2-NiMOF@Pd composite rapidly uptakes hydrogen,with 2.62wt%at 100℃and 6.06 wt%at 150℃within 300 s,respectively.The mechanism analysis of MgH2 catalyzed by Ni-MOF@Pd has revealed that the transformation of Mg_2Ni and Mg_2NiH_4 could act as a"hydrogen pump",providing numerous channels for fast diffusion and transport of hydrogen atoms.Moreover,in the dehydrogenation process,the element Pd reacts with MgH_(2)to form the MgPd alloy phase,which makes MgH_(2)take precedence to decompose through the Mg-Pd alloy rather than self-decomposition,further reducing thermal stability and improving de/hydrogenation kinetics.The synergistic effect of Mg-Pd,Mg_2Ni,and the special ultra-thin 2D sheet structure of the additive is the main reason for the good hydrogen storage property of MgH_(2)-Ni-MOF@Pd.Our findings provide inspiration for designing efficient multifunctional additives with unique morphologies to optimize the hydrogen desorption/sorption behaviors of hydrogen storage materials.

Enhanced hydrogen evolution performance by 3D ordered macroporous Ru-CoP@NC electrocatalysts

Electrocatalytic water splitting coupled with sustainable energies is identified as an environmentally friendly and renewable strategy to generate high-quality hydrogen for the fuel cells.However,the main challenge is to develop high performance,low cost and chemically stable electrocatalysts to decline the energy barriers and enhance the sluggish kinetics of hydrogen evolution reaction(HER).Herein,a three-dimensional hierarchically ordered macroporous Ru-CoP@NC electrocatalyst(3DOM Ru-CoP@NC)derived from ordered macro-microporous metal-organic frameworks has been prepared using the precursor@template and double-solvent methods.The prepared 3DOM Ru-CoP@NC catalyst exhibits an overpotential of 15 mV(j=10 mA·cm^(-2))and a reaction Tafel slope of 38 mV·dec^(-1)in alkaline electrolyte,which are superior to commercial Pt@C catalyst.Additionally,the overpotential and reaction Tafel slope of this catalyst in acidic media are 45 mV and 50 mV·dec^(-1),respectively.The outstanding HER activities of 3DOM Ru-CoP@NC catalysts are ascribed to the 3D highly interconnectedreticular nanospaces that can increase effective reaction active sites.The N dope d carbon framework improves the electronic properties and conductivity.Moreover,the strong interaction of Ru and CoP nanoparticles also boosts the HER process.These results indicate that 3DOM Ru-CoP@NC catalysts with high catalytic activities have a broad application prospect in the future.

Optimizing hydrogen ad/desorption of Mg-based hydrides for energy-storage applications

Hydrogen energy is expected to be an“ideal fuel”in the era of decarbonization.The discovery,de-velopment,and modification of high-performance hydrogen storage materials are the keys to the fu-ture development of solid-state hydrogen storage and hydrogen energy utilization.Magnesium hydride(MgH_(2)),with its high hydrogen storage capacity,abundant natural reserves,and environmental friend-liness,has been extensively researched.Herein,we briefly summarize the typical structure and hy-drogenation/dehydrogenation reaction mechanism of MgH_(2)and provide a comprehensive overview of strategies to effectively tune the thermodynamics and kinetics of Mg-based materials,such as alloy-ing,nanosizing,the introduction of additives,and composite modification.With substantial efforts,great achievements have been achieved,such as lower absorption/desorption temperatures and better cy-cling stability.Nonetheless,some pivotal issues remain to be addressed,such as unfavorable hydro-genation/dehydrogenation factors,harsh conditions,slow kinetics,incomplete dehydrogenation,low hy-drogen purity,expensive catalysts,and a lack of valid exploration of mechanisms in the hydrogena-tion/dehydrogenation process.Lastly,some future development prospects of MgH_(2)in energy-efficient conversion and storage have been presented,including advanced manufacturing ways,stabilization of nanostructures,the introduction of additives combined with structural modification,and utilization of advanced characterization techniques.

Progress in improving thermodynamics and kinetics of new hydrogen storage materials

Hydrogen storage material has been much developed recently because of its potential for proton exchange membrane （PEM） fuel cell applications. A successful solid-state reversible storage material should meet the requirements of high storage capacity, suitable thermodynamic properties, and fast adsorption and desorption kinetics. Complex hydrides, including boron hydride and alanate, ammonia borane, metal organic frameworks （MOFs）, covalent organic frameworks （COFs） and zeolitic imidazolate frameworks （ZIFs）, are remarkable hydrogen storage materials because of their advantages of high energy density and safety. This feature article focuses mainly on the thermodynamics and kinetics of these hydrogen storage materials in the past few years.

Substitution effects on the hydrogen storage behavior of AB2 alloys by first principles

The hydrogen storage behavior of the TiCr2 and ZrCr2 alloys substituted with the third components （Zr, V, Fe, Ni） have been studied using first-principles calculations. The change of the hydrogen absorption energies caused by metal doping is arising from the charge transfer among the doped alloys interior. Zr and V atoms devoted abundant electrons, leading to a great enhancement of the H absorption energy, while Fe and Ni atoms always accepted electrons, yielding a remarkable decrease of the H absorption energy. The hydrogen diffusion energy barrier is closely correlated with the geometry effect rather than the electronic structure.