Electrospinning-derived transition metal/carbon nanofiber composites as electrocatalysts for Zn-air batteries.

The sluggish kinetics of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) significantly impede the broader implementation of Zn-air batteries (ZABs), underscoring the necessity for advanced high-efficiency materials to catalyze these electrochemical processes. Recent advancements have highlighted the potential of transition metal/carbon nanofiber (TM/CNF) composite materials, synthesized via electrospinning technology, due to their expansive surface area, profusion of active sites, and elevated catalytic efficacy. This review comprehensively examines the structural characteristics of TM/CNFs, with a particular emphasis on the pivotal role of electrospinning technology in fabricating diverse structural configurations. Additionally, it delves into the mechanistic underpinnings of various strategies aimed at augmenting the catalytic activity of TM/CNFs. A meticulous discourse is also presented on the application scope of TM/CNFs in the realm of electrocatalysis, with a special focus on their impact on the performance of assembled ZABs. Lastly, this review encapsulates the challenges and future prospects in the development of TM/CNF composite materials via electrospinning, aiming to provide an exhaustive understanding of the current state of research in this domain and to foster further advancements in the commercialization of ZABs.

Structural and compositional analysis of MOF-derived carbon nanomaterials for the oxygen reduction reaction.

The development of low-cost and efficient cathode catalysts is crucial for the advancement of fuel cells, as the oxygen reduction reaction (ORR) on the cathode is constrained by expensive commercial Pt/C catalysts and a significant energy barrier. Metal-organic frameworks (MOFs) are considered excellent precursors for synthesizing carbon nanomaterials due to their simple synthesis, rich structure and composition. MOF-derived carbon nanomaterials (MDCNM) inherit the morphology of their precursors at low dimensional scales, providing abundant edge defects, larger specific surface area, and excellent electron transport paths. Furthermore, the rich composition of MOFs enables the carbon nanomaterials derived from them to exhibit various physicochemical properties, including stronger electron gaining ability, oxygen affinity, and a higher degree of graphitization, resulting in excellent ORR activity. However, a more detailed analysis is necessary to understand the advantages and mechanisms of MDCNM in the field of the ORR. This review classifies and summarizes the structure and different chemical compositions of MDCNM in low dimensions, and provides an in-depth analysis of the reasons for their improved ORR activity. Additionally, the recent practical applications of MDCNM as cathode material in fuel cells are introduced and analyzed in detail, with a focus on the enhanced electrochemical performance.

Recent advances and promise of MXene-based composites as electrode materials for sodium-ion and potassium-ion batteries.

With the increasing demand for sustainable energy and concerns about the scarcity of lithium resources, sodium and potassium ion batteries have emerged as promising alternative energy storage technologies. MXene, as a novel two-dimensional material, possesses exceptional electrical conductivity, high surface area, and tunable structural features that make it an ideal candidate for high-performance electrode materials. However, its limited theoretical capacity hinders its widespread application. To overcome this limitation, MXene has been combined with other materials through synergistic effects between different components to enhance the overall electrochemical performance and expand its application in sodium/potassium ion batteries. Recently, substantial advancements have been realized in the exploration of MXene-based composites as energy storage materials, encompassing their synthesis, design, and the comprehension of charge storage mechanisms. This paper aims to propose a comprehensive summary of the latest developments in MXene-based composites as electrode materials for sodium ion batteries and potassium ion batteries, with a particular emphasis on the enhanced physicochemical properties resulting from composite formation. Moreover, the challenges faced by MXene materials in sodium ion batteries and potassium ion batteries are thoroughly discussed, and future research directions to further advance this field are proposed.

Use of small pulmonary vascular alterations to identify different types of pulmonary hypertension: a quantitative computed tomography analysis.

BACKGROUND: The morphological alterations of small pulmonary vessels measured by computed tomography (CT) is increasingly used in evaluation of suspected pulmonary hypertension (PH). OBJECTIVE: To investigate the significance alterations of quantitative assessment of small pulmonary vessels on chest CT in distinguishing different types of PH and their severity. METHODS: We retrospectively analyzed a dataset of 120 healthy controls (HCs) and 91 PH patients, including 34 patients with connective tissue diseases-related PH (CTD-PH), 26 patients with idiopathic pulmonary arterial hypertension (iPAH), and 31 patients with chronic obstructive pulmonary disease-related PH (COPD-PH). The CTD-PH patients were divided into mild to moderate PH (CTD-LM-PH) group (n = 17) and severe PH (CTD-S-PH) group (n = 17). A total of 53 CTD patients without PH (CTD-nPH) were enrolled for comparison with the CTD-PH. We measured the cross-sectional area of small pulmonary vessels < 5 mm2 (%CSA <5) and between 5-10 mm2 (%CSA5-10) as a percentage of total lung area among the populations included above and compared %CSA in different types of PH groups and HCs group. The mean pulmonary arterial pressure (mPAP) was measured by right heart catheterization. RESULTS: The %CSA5-10 of COPD-PH, CTD-PH, and iPAH patients increased (0.21±0.09, 0.49±0.20 and 0.61±0.20, p < 0.02) sequentially, while the %CSA <5 of CTD-PH, iPAH, and COPD-PH patients decreased (0.79±0.65, 0.65±0.38 and 0.52±0.27, p < 0.05) sequentially. The %CSA5-10 was significantly higher in CTD-S-PH patients than CTD-LM-PH patients and CTD-nPH patients (0.51±0.21, 0.31±0.15 and 0.28±0.12, p < 0.01). The %CSA5-10 was positively correlated with mPAP in the CTD-PH group. CONCLUSIONS: The quantitative parameters %CSA <5 and %CSA5-10 assessed by chest CT are useful for distinguishing different types of PH. In addition, the %CSA5-10 can provide information for identification of CTD-PH severity.