Bimetal Zeolitic Imidazolite Framework-Derived Iron‑, Cobalt- and Nitrogen-Codoped Carbon Nanopolyhedra Electrocatalyst for Efficient Oxygen Reduction

Replacing precious metal electrocatalysts with high-performance and low-cost nonprecious metal electrocatalysts (NPMCs) is crucial for the commercialization of fuel cell technologies. Herein, we present a novel and facile route for synthesis of iron-, cobalt-, and nitrogen-codoped carbon nanopolyhedra electrocatalysts (Fe,Co,N-CNP) by one-step pyrolysis of a new type of Fe/Co bimetal zeolitic imidazolate framework (Fe,Co-ZIF) crystals that were self-assembled by oxygen-free solvothermal reaction of Fe²⁺ and Co²⁺ with 2-methylimidazole. During the pyrolysis process, the Fe²⁺ ions in Fe,Co-ZIF not only effectively inhibit the aggregation of Co nanoparticles but also increase the specific surface area (SSA) and N content of the resultant electrocatalysts. The optimized Fe,Co,N-CNP(0.3) (Fe/Co molar ratio of 0.3 in Fe,Co-ZIF) electrocatalyst exhibited a highly promising activity for oxygen reduction reaction (ORR) with a positive half-wave potential (<i>E</i>_1/2) of 0.875 V (29 mV higher than that of the commercial Pt/C), excellent methanol tolerance, and electrochemical stability in the alkaline electrolyte. Also, Fe,Co,N-CNP(0.3) presents comparable ORR catalytic activity as Pt/C in the acidic electrolyte with <i>E</i>_1/2 of 0.764 V and superior methanol tolerance and electrochemical stability. The outstanding ORR performance of Fe,Co,N-CNP(0.3) is ascribed to the synergistic contribution of homogeneous Fe, Co, and N codoping structure, high SSA, and hierarchically porous structure for rapid mass transport. This novel and rational methodology for controlled synthesis of ZIFs-derived nitrogen-doped porous carbon nanopolyhedras offers new prospects in developing highly efficient NPMCs for ORR

Hydrothermal Synthesis of Highly Dispersed Co₃O₄ Nanoparticles on Biomass-Derived Nitrogen-Doped Hierarchically Porous Carbon Networks as an Efficient Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

Developing high-performance bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of vital importance in energy storage and conversion systems. Herein, we demonstrate a facile hydrothermal synthesis of highly dispersed Co₃O₄ nanoparticles (NPs) anchored on cattle-bone-derived nitrogen-doped hierarchically porous carbon (NHPC) networks as an efficient ORR/OER bifunctional electrocatalyst. The as-prepared Co₃O₄/NHPC exhibits a remarkable catalytic activity toward both ORR (outperforming the commercial Pt/C) and OER (comparable with the commercial RuO₂ catalyst) in alkaline electrolyte. The superior bifunctional catalytic activity can be ascribed to the large specific surface area (1070 m² g^–1), the well-defined hierarchically porous structure, and the high content of nitrogen doping (4.93 wt %), which synergistically contribute to the homogeneous dispersion of Co₃O₄ NPs and the enhanced mass transport capability. Moreover, the primary Zn–air battery using the Co₃O₄/NHPC cathode demonstrates a superior performance with an open-circuit potential of 1.39 V, a specific capacity of 795 mA h g_Zn^–1 (at 2 mA cm^–2), and a peak power density of 80 mW cm^–2. This work delivers a new insight into the design and synthesis of high-performance bifunctional nonprecious metal electrocatalysts for Zn–air battery and other electrochemical devices

Corona-Directed Nucleic Acid Delivery into Hepatic Stellate Cells for Liver Fibrosis Therapy

Strategies to modify nanoparticles with biological ligands for targeted drug delivery <i>in vivo</i> have been widely studied but met with limited clinical success. A possible reason is that, in the blood circulation, serum proteins could rapidly form a layer of protein “corona” on the vehicle surface, which might block the modified ligands and hamper their targeting functions. We speculate that strategies for drug delivery can be designed based upon elegant control of the corona formation on the vehicle surfaces. In this study, we demonstrate a retinol-conjugated polyetherimine (RcP) nanoparticle system that selectively recruited the retinol binding protein 4 (RBP) in its corona components. RBP was found to bind retinol, and direct the antisense oligonucleotide (ASO)-laden RcP carrier to hepatic stellate cells (HSC), which play essential roles in the progression of hepatic fibrosis. In both mouse fibrosis models, induced by carbon tetrachloride (CCl₄) and bile duct ligation (BDL), respectively, the ASO-laden RcP particles effectively suppressed the expression of type I collagen (collagen I), and consequently ameliorated hepatic fibrosis. Such findings suggest that this delivery system, designed to exploit the power of corona proteins, can serve as a promising tool for targeted delivery of therapeutic agents for the treatment of hepatic fibrosis

Mesopore- and Macropore-Dominant Nitrogen-Doped Hierarchically Porous Carbons for High-Energy and Ultrafast Supercapacitors in Non-Aqueous Electrolytes

Non-aqueous electrolytes (e.g., organic and ionic liquid electrolytes) can undergo high working voltage to improve the energy densities of supercapacitors. However, the large ion sizes, high viscosities, and low ionic conductivities of organic and ionic liquid electrolytes tend to cause the low specific capacitances, poor rate, and cycling performance of supercapacitors based on conventional micropore-dominant activated carbon electrodes, limiting their practical applications. Herein, we propose an effective strategy to simultaneously obtain high power and energy densities in non-aqueous electrolytes via using a cattle bone-derived porous carbon as an electrode material. Because of the unique co-activation of KOH and hydroxyapatite (HA) within the cattle bone, nitrogen-doped hierarchically porous carbon (referred to as NHPC–HA/KOH) is obtained and possesses a mesopore- and macropore-dominant porosity with an ultrahigh specific surface area (2203 m² g^–1) of meso- and macropores. The NHPC–HA/KOH electrodes exhibit superior performance with specific capacitances of 224 and 240 F g^–1 at 5 A g^–1 in 1.0 M TEABF₄/AN and neat EMIMBF₄ electrolyte, respectively. The symmetric supercapacitor using NHPC–HA/KOH electrodes can deliver integrated high energy and power properties (48.6 W h kg^–1 at 3.13 kW kg^–1 in 1.0 M TEABF₄/AN and 75 W h kg^–1 at 3.75 kW kg^–1 in neat EMIMBF₄), as well as superior cycling performance (over 89% of the initial capacitance after 10 000 cycles at 10 A g^–1)

Additional file 2 of MRI-assessed diaphragmatic function can predict frequent acute exacerbation of COPD: a prospective observational study based on telehealth-based monitoring system

Additional file 2. Correlation between diaphragm function and clinical parameters in the COPD grou