Improving the surface area of metal organic framework-derived porous carbon through constructing inner support by compatible graphene quantum dots

Efficient adsorption behavior of Fe-based ternary magnetic LDHs for naphthalene acetic acid: Role of Fe element

Naphthalene acetic acid (NAA) is an auxin plant growth regulator (PGR) and widely used to regulate the growth process of plants. As excessive NAA enter the environment, it damages the ecological environment and endangers human life and health. Layered bimetallic hydroxides (LDHs) are widely used for the adsorption of pollutants due to their large surface area and excellent structural properties. Based on the classical Fe3O4@MgAl-LDH material, Fe3O4@FeMgAl-LDHs were synthesized by adding different contents of Fe element to adsorb NAA in water. The morphology and properties of Fe3O4@FeMgAl-LDHs and the effect of Fe on adsorption efficiency were studied. The adsorption process and adsorption mechanism of NAA were analyzed. The results indicated that the content of Fe element will affect the adsorption effect of NAA by influencing the specific surface area and adsorption sites of Fe3O4@FeMgAl-LDHs. The maximum adsorption capacity for NAA can reach 330.1 mg/g when the proportion of Fe is 0.50. Exploring the adsorption mechanism, Fe3O4@FeMgAl-LDHs achieved efficient removal of NAA through hydrogen bonding, van der Waals forces, anion exchange, and electrostatic interactions. The adsorption efficiency of various PGRs were deeply explored. Fe3O4@FeMgAl-LDH (Fe-0.50) has good adsorption and regeneration ability for various PGRs. Therefore, by exploring the influence of different Fe ratios on the adsorption efficiency of the Fe3O4@FeMgAl-LDH, the adsorption performance of the material can be improved, making it have greater application advantages in wastewater treatment containing drugs.

Hierarchical-Porous Hollow Nitrogen-Doped Carbon-Supported Pt Alloy Catalysts with a Controllable Triheterointerface for Methanol Electrooxidation

Carbon-supported Pt-based catalysts are the most effective catalysts for direct methanol fuel cells (DMFCs). However, challenges such as high Pt loading, cost, and susceptibility to CO poisoning severely hinder the development of DMFCs. In this paper, CoFe2O4@polymer@ZIF-67 is prepared successfully through sequential solution polymerization and in situ growth with modified CoFe2O4 as the core. Subsequently, a hierarchical-porous hollow nitrogen-doped carbon-confined controllable triheterointerface catalyst, PtCoFe-CoFeOx@N-HHCS, was successfully prepared via a strategy involving high-temperature-induced phase migration and in situ chemical replacement. Under the optimal conditions, the mass activity of PtCoFe-CoFeOx@N-HHCS reached 1054 mA mgPt-1, which is 4.1 and 2.1 times higher than those of commercial Pt/C and commercial PtRu/C, respectively. The peak potential of the CO electrooxidation of the PtCoFe-CoFeOx@N-HHCS shifts negatively by 70 mV compared with commercial Pt/C. The high methanol oxidation performance is attributed to the highly dispersed triheterointerface, hierarchical-porous hollow structure, and nitrogen-doped ultrathin carbon layer. The highly dispersed triheterointerface of PtCoFe-CoFeOx@N-HHCS promotes the release of Pt and enhances the electron transfer rate through interfacial interaction, significantly improving the catalyst activity. The confinement effect of the nitrogen-doped ultrathin carbon layer prevents Pt dissolution and enhances the stability of the catalyst. The hierarchical-porous hollow structure provides rapid mass transfer channels for the methanol oxidation reaction, enhancing the reaction rate. The synergistic effect of multiple approaches endows PtCoFe-CoFeOx@N-HHCS with good methanol oxidation performance. This work provides important prospects for preparing highly active, stable, and low-loading Pt catalysts.

Boosting the Sustained Release Performance of Metronidazole and Ornidazole with MIL-53(Fe) Derived Spherical Porous Carbon

Metal-organic framework (MOF) derived spherical porous carbon (SPC) has potential application value in the field of adsorption and sustained release of nitroimidazole drugs. This work used MIL-53(Fe) as a precursor and prepared spherical 3-aminophenol-formaldehyde resin containing MIL-53(Fe) crystals using the advanced Stöber method, followed by the successful preparation of MIL-53(Fe) derived SPC (MSPC) with a structure containing both micropores and mesopores through high-temperature carbonization. The effects of the doping amount of MIL-53(Fe) on the sphericity and particle size of MSPC were investigated. The drug uptake capacity and sustained release performances of MSPC for metronidazole (MNZ) and ornidazole (ONZ) were assessed through batch tests, along with an investigation into the impact of varying pH levels on the sustained release performances. The experimental findings revealed that the drug loading of MNZ and ONZ onto MSPC achieved 111 and 120 mg/g, respectively, with a sustained release time of up to 24 h. The drug loading process adhered to the Langmuir isotherm adsorption model and conformed to the pseudo-second-order kinetics model, whereas the sustained release mechanism was consistent with the Korsmeyer-Peppas model. Furthermore, cytotoxicity and cyclic drug loading experiments indicated that MSPC exhibited good biocompatibility and stability. Therefore, this study provides new ideas for the development of SPC drug carriers.

Advancements and Challenges in the Application of Metal-Organic Framework (MOF) Nanocomposites for Tumor Diagnosis and Treatment

Nanoscale metal-organic frameworks (MOFs) offer high biocompatibility, nanomaterial permeability, substantial specific surface area, and well-defined pores. These properties make MOFs valuable in biomedical applications, including biological targeting and drug delivery. They also play a critical role in tumor diagnosis and treatment, including tumor cell targeting, identification, imaging, and therapeutic methods such as drug delivery, photothermal effects, photodynamic therapy, and immunogenic cell death. The diversity of MOFs with different metal centers, organics, and surface modifications underscores their multifaceted contributions to tumor research and treatment. This review is a summary of these roles and mechanisms. The final section of this review summarizes the current state of the field and discusses prospects that may bring MOFs closer to pharmaceutical applications.

MIL-53(Al) assisted in upcycling plastic bottle waste into nitrogen-doped hierarchical porous carbon for high-performance supercapacitors

Disposable aluminum cans and plastic bottles are common wastes found in modern societies. This article shows that they can be upcycled into functional materials, such as metal-organic frameworks and hierarchical porous carbon nanomaterials for high-value applications. Through a solvothermal method, used poly(ethylene terephthalate) bottles and aluminum cans are converted into MIL-53(Al). Subsequently, the as-prepared MIL-53(Al) can be further carbonized into a nitrogen-doped (4.52 at%) hierarchical porous carbon framework. With an optical amount of urea present during the carbonization process, the carbon nanomaterial of a high specific surface area of 1324 m2 g-1 with well-defined porosity can be achieved. These features allow the nitrogen-doped hierarchical porous carbon to perform impressively as the working electrode of supercapacitors, delivering a high specific capacitance of 355 F g-1 at 0.5 A g-1 in a three-electrode cell and exhibiting a high energy density of 20.1 Wh kg-1 at a power density of 225 W kg-1, while simultaneously maintaining 88.2% capacitance retention over 10,000 cycles in two-electrode system. This work demonstrates the possibility of upcycling wastes to obtain carbon-based high-performance supercapacitors.

Construction and Application of Multipurpose metal-organic frameworks -based Hydrogen Sulfide Probe

Hydrogen sulfide (H2S) is a toxic gas derived from the sulfur industry and trace H2S in the environment can cause serious ecological damage while inhalation can cause serious damage and lead to disease. Therefore, the real-time and accurate detection of trace sulfur ions is of great significance for environmental protection and early disease detection. Considering the shortcoming of current H2S probes in terms of stability and sensitivity, the development of novel probes is necessary. Herein, a novel metal-organic frameworks (MOF)-based material, UiO-66-NH2@BDC, was designed and prepared for the visual detection of H2S with rapid response (< 6 s) and low detection limit of S2- (0.13 µM) by hydrogen bonding. Based on its good optical performance, the UiO-66-NH2@BDC probe can detect S2- in various water environments. More importantly, UiO-66-NH2@BDC probe realize imaging S2- in cells and live zebrafish.

Coordination Engineering of Defective Cobalt-Nitrogen-Carbon Electrocatalysts with Graphene Quantum Dots for Boosting Oxygen Reduction Reaction

Developing efficient and robust metal-nitrogen-carbon electrocatalysts for oxygen reduction reaction (ORR) is of great significance for the application of hydrogen-oxygen fuel cells and metal-air batteries. Herein, a coordination engineering strategy is developed to improve the ORR kinetics and stability of cobalt-nitrogen-carbon (Co-N-C) electrocatalysts by grafting the oxygen-rich graphene quantum dots (GQDs) onto the zeolite imidazole frameworks (ZIFs) precursors. The optimized oxygen-rich GQDs-functionalized Co-N-C (G-CoNOC) electrocatalyst demonstrates an increased mass activity, nearly two times higher than that of pristine defective Co-N-C electrocatalyst, and retains a stability of 90.0% after 200 h, even superior to the commercial Pt/C. Comprehensive investigations demonstrate that the GQDs coordination can not only decrease carbon defects of Co-N-C electrocatalysts, improving the electron transfer efficiency and resistance to the destructive free radicals from H₂ O₂ , but also optimize the electronic structure of atomic Co active site to achieve a desired adsorption energy of OOH^- , leading to enhanced ORR kinetics and stability by promoting further H₂ O₂ reduction, as confirmed by theoretical calculations and experimental results. Such a coordination engineering strategy provides a new perspective for the development of highly active noble-metal-free electrocatalysts for ORR.