Rare Metals最新文献

The rational design of a specific co-drug delivery platform that can address the unavoidable resistance, toxic side effects and low targeting efficiency of traditional cancer treatments is of great meaningful. Herein, Zn-based MOF-zeolitic imidazole framework-90 (ZIF-90) was selected as the drug delivery carrier, with the cancer therapeutic drug mercaptopurine (6-MP) and glucose oxidase (GOD) as the drug models, hyaluronic acid (HA) was used for protection and targeted delivery, which designed and fabricated an intelligent drug delivery platform (6-MP@ZIF-90@GOD@HA). This platform aims to reduce the toxic side effects of 6-MP and enhance its efficacy while improving the targeting ability of GOD, thereby further enhancing the treatment outcome. Notably, results from both in vitro and in vivo experiments demonstrate that the targeted synergistic chemo/reactive oxygen species (ROS)-mediated/starvation therapy inhibited the cancer cell growth while reducing the chemotherapy toxicity, which provides new possibilities for the development of more precise and effective treatment strategies.

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The high operating temperatures and slow kinetics limit the application of MgH₂-based hydrogen storage materials. Here, a composite of Ni₃ZnC_0.7/carbon nanotubes loaded onto a melamine sponge-derived carbon (MS) skeleton is prepared and loaded onto MgH₂. During dehydrogenation, Ni₃ZnC_0.7 reacts with MgH₂ and in situ changes to Mg₂Ni/Zn. The transformation of Mg₂Ni/Mg₂NiH₄ serves as a “hydrogen pump”, providing diffusion channels for hydrogen atoms and molecules to promote the de-/hydrogenation processes. Moreover, Zn/MgZn₂ provides the catalytic sites for the transformation of Mg/MgH₂. The length of the Mg–H bond is elongated from 1.72 to 1.995 Å, and the dissociation energy barrier of MgH₂ is reduced from 1.55 to 0.49 eV. As a result, MgH₂ with 2.5 wt% MS@Ni₃ZnC_0.7 can absorb 5.18 wt% H₂ at 423 K within 200 s, and its initial dehydrogenation temperature is reduced to 585 K. After 20 cycles, the dehydrogenation capacity retention is determined to be 94.6%. This work demonstrates an efficient non-stoichiometric metal carbide catalyst for MgH₂.

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Tumor microenvironment-responsive drug self-delivery systems utilize tumor microenvironment-responsive chemical bonds to link anti-tumor drugs, exploiting the hydrophilic and hydrophobic properties of different drugs to form amphiphilic prodrug molecules with self-assembly characteristics. Upon stimulation by specific factors in the tumor microenvironment, these amphiphilic prodrug molecules can release drugs at precise sites within the tumor. These strategies significantly increase the drug concentration at the tumor site while effectively reducing the damage of anti-cancer drugs to normal tissues. Owing to the advanced delivery strategies such as synergistic administration and controlled drug release, tumor microenvironment-responsive drug self-delivery systems hold great potential for treating malignant tumors with multidrug resistance (MDR). At the same time, the stimulus-reactivity of metal complexes provides an important opportunity to design site-specific prodrugs that can maximize therapeutic efficacy while minimizing adverse side effects of metal drugs. This innovative drug design complements the tumor microenvironment-responsive self-delivery system, providing more feasible therapeutic strategies and possibilities in the field of cancer therapy and drug delivery. This work provides a comprehensive review of recent advancements in drug self-delivery systems, offering insights into their potential applications in cancer therapy and MDR reversal.

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Retaining satisfactory electrocatalytic performance under high current density plays a crucial role in industrial water splitting but is still limited to the enormous energy loss because of insufficient exposure of active sites caused by the blocked mass/charge transportation at this condition. Herein, we present a freestanding lamellar nanoporous Ni–Co–Mn alloy electrode (Lnp-NCM) designed by a refined variant of the “dealloying-coarsening-dealloying” protocol for highly efficient bifunctional electrocatalyst, where large porous channels distribute on the surface and small porous channels at the interlayer. With its 3D lamellar architecture regulating, the electrocatalytic properties of the electrodes with different distances between lamellas are compared, and faster energy conversion kinetics is achieved with efficient bubble transport channels and abundant electroactive sites. Note that the optimized sample (Lnp-NCM4) is expected to be a potential bifunctional electrocatalyst with low overpotentials of 258 and 439 mV at high current densities of 1000 and 900 mA·cm⁻² for hydrogen and oxygen evolution reactions (HER and OER), respectively. During overall water splitting in a two-electrode cell with Lnp-NCM4 as cathode and anode, it only needs an ultralow cell voltage of 1.75 V to produce 100 mA·cm⁻² with remarkable long-term stability over 50 h. This study on lamellar nanoporous electrode design approaches industrial water splitting requirements and paves a way for developing other catalytic systems.

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Two-dimensional (2D) metal oxides (2DMOs), such as MoO₂, have made impressive strides in recent years, and their applicability in a number of fields such as electronic devices, optoelectronic devices and lasers has been demonstrated. However, 2DMOs present challenges in their synthesis using conventional methods due to their non-van der Waals nature. We report that KCl acts as a flux to prepare large-area 2DMOs with sub-millimeter scale. We systematically investigate the effects of temperature, homogeneous time and cooling rate on the products in the flux method, demonstrating that in this reaction a saturated homogenous solution is obtained upon the melting of the salt and precursor. Afterward, the cooling rate was adjusted to regulate the thickness of the target crystals, leading to the precipitation of 2D non-layered material from the supersaturated solution; by applying this method, the highly crystalline non-layered 2D MoO₂ flakes with so far the largest lateral size of up to sub-millimeter scale (~ 464 μm) were yielded. Electrical studies have revealed that the 2D MoO₂ features metallic properties, with an excellent sheet resistance as low as 99 Ω·square⁻¹ at room temperature, and exhibits a property of charge density wave in the measurement of resistivity as a function of temperature.

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In recent years, researchers have increasingly focused on aqueous rechargeable Zn-ion batteries (AZIBs) as a cost-effective and safe alternative to lithium-ion batteries for energy storage. Nevertheless, the limited reversibility of the Zn anode and the low coulombic efficiency of the electroplating process limit the application of AZIBs. In this work, pyrrole is employed as a cost-effective electrolyte additive for stabilizing the Zn anode for the first time. By altering the coordination environment of Zn (H₂O)₆²⁺, chemical and hydrogen evolution corrosion was reduced, and a molecular interface layer was in-situ constructed on the surface of the metal Zn anode, thus effectively inhibiting the corrosion of Zn anode and the growth of dendrites. In addition, the molecular interface layer based on pyrrole can effectively regulate the uniform deposition of Zn ions and limit the 2D diffusion of Zn ions. Therefore, the electrochemical performance of the metal Zn anode is greatly improved in the pyrrole-based electrolyte. At the current density of 1 mA·cm⁻², the stable cycle can exceed 1200 h, and the average Coulomb efficiency is as high as 99%. Moreover, the full battery can have more than 400 stable cycles with a reversible capacity 247.9 mAh·g⁻¹ at a current density 0.5 A·g⁻¹ when assembled with V₂O₅ cathodes. This work provides a simple and feasible strategy for realizing the high performance of aqueous Zn-ion batteries.

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Iron overload has been evidenced to contribute to obesity-associated metabolic disorders, including insulin resistance. Strategies to reduce iron levels might help manage the metabolic complications associated with obesity. Here, it is demonstrated that the specific accumulation of oleic acid-modified polyoxovanadates (OPOVs) in adipose tissue leads to the reduction of iron concentrations in adipocytes in mice fed with a high-fat diet (HFD). Conjugation of oleic acids to polyoxovanadates enables tissue-specific depletion of iron from white adipose tissue (WAT) by OPOVs, protecting mice from HFD-induced obesity and obesity-associated metabolic deteriorations. Glucose tolerance and insulin sensitivity are improved in OPOV-treated mice, which demonstrates that the OPOV-induced iron depletion can reverse the metabolic degeneration caused by HFD-induced obesity. Furthermore, a decrease in expression of the marker genes of iron overload suggests the participation of OPOVs in maintaining iron homeostasis and a potential medical application of vanadium clusters in targeting the iron overload caused by obesity. These findings underscore the potential of vanadate-based clusters tailored to address the complex interplay between iron metabolism and metabolic health.

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To alleviate the crisis of energy shortages, the scalable fabrication of highly efficient electrocatalysts is highly sought after for metal–air batteries and pH-universal overall water splitting. Hereby, an in situ construction to achieve Co@Ir nanoparticles in N-doped carbon nanotubes has been explored, which were directly fabricated by the pyrolysis and galvanic replacement. The interface engineering of Co@Ir core–shell structures could enhance interfacial and synergistic effects, achieving the tailorable electrocatalytic activities for oxygen reduction reaction, oxygen evolution reaction and hydrogen evolution reaction. Co@Ir-NT demonstrates the outstanding stability for overall water splitting under pH-universal conditions. Co@Ir-NT-based r-ZABs display a high power density of 295.1 mW·cm⁻² and a ultralong cycle stability over 2000 continuous charge–discharge cycles, and Co@Ir-NT-based F-ZABs maintain the similar performance at different bending angles, suggesting its promising potential in the application of wearable electronics. The corresponding theoretical calculations also indicate that Co@Ir core–shell structure could improve the adsorption capacity and facilitate the breakage of O–O band. Hence, this work might be helpful for developing multifunctional catalysts for metal–air batteries and water splitting under pH-universal conditions.

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The inherent electrocatalytic potential of transition metal phosphides (TMPs) for oxygen evolution is influenced by the reduced efficiency of electron transfer resulting from the interaction between electronegative phosphorus atoms and transition metals. Here, we introduce Fe into Ni₂P nanocrystals by thermal injection synthesis method, and anchor them on nickel foam (NF) by facile spraying to prepare self-supporting oxygen evolution reaction (OER) electrocatalyst. Promisingly, the optimized electrode of Ni₂P-Fe-2/NF demonstrates low overpotentials of 212 mV with 10 mA·cm⁻² and a 0.9% decay within 300 h test of 50 mA·cm⁻². Notably, when electrode size was expanded to 600 cm² and applied to a larger electrolyzer, its 9 h decay rate at 6 A current was only 1.69%. Characterization results show that Fe doped NiOOH is generated during OER reaction as actual catalyst. Results from density functional theory (DFT) computations suggest that Fe doping shifts NiOOH d-band center to Fermi level, lowering critical *OOH intermediates formation energy barrier during the OER reaction. These findings inform the large-scale industrial application of TMPs as robust electrocatalysts.

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