Enzyme-mimicking capacities of carbon-dots nanozymes: Properties, catalytic mechanism, and applications – A review

Enzyme-mimicking capacities of carbon-dots nanozymes: Properties, catalytic mechanism, and applications - A review.

Metal nanoparticle/metal–organic framework (MNP/MOF) composites are newly emerging functional hybrid nanomaterials. The MNP/MOF composites formed by encapsulating or loading functional MNPs in or onto MOFs show intriguing synergistic effects when applied in various sensing applications. Owing to the synergy between the properties of MNPs and MOFs, MNP/MOF composite-based sensors exhibit significantly enhanced sensing performance in terms of sensitivity, stability, and selectivity. To date, a large number of MNP/MOF composite-based sensors have been reported and this interdisciplinary research field is rapidly expanding. In this review, we focus on the significant progress in the development of MNP/MOF composites for sensing applications. Various synthesis strategies for preparing MNP/MOF composites are introduced and the interactions between the MNPs and MOFs that contribute synergistically to improving sensing performance are comprehensively reviewed.

Recent advances in sensing applications of metal nanoparticle/metal–organic framework composites

The booming of global environmental awareness has driven the scientific community to search for alternative sustainable approaches. This is accentuated in the 13th sustainable development goal (SDG13), climate action, where urgent efforts are salient in combating the drastic effects of climate change. Membrane separation is one of the indispensable gas purification technologies that effectively reduces the carbon footprint and is energy-efficient for large-scale integration. Metal-organic frameworks (MOFs) are recognized as promising fillers embedded in mixed matrix membranes (MMMs) to enhance gas separation performance. Tremendous research studies on MOFs-based MMMs have been conducted. Herein, this review offers a critical summary of the MOFs-based MMMs developed in the past 3 years. The basic models to estimate gas transport, preparation methods, and challenges in developing MMMs are discussed. Subsequently, the application and separation performance of a variety of MOFs-based MMMs including those of advanced MOFs materials are summarized. To accommodate industrial needs and resolve commercialization hurdles, the latest exploration of MOF materials for a harsh operating condition is emphasized. Along with the contemplation on the outlook, future perspective, and opportunities of MMMs, it is anticipated that this review will serve as a stepping stone for the coming MMMs research on sustainable and benign environmental application.

Metal-Organic Frameworks (MOFs)-Based Mixed Matrix Membranes (MMMs) for Gas Separation: A Review on Advanced Materials in Harsh Environmental Applications.

Membrane-based separations have garnered considerable attention owing to their high energy efficiency, low capital cost, small carbon footprint, and continuous operation mode. As a class of highly porous crystalline materials with well-defined pore systems and rich chemical functionalities, metal-organic frameworks (MOFs) have demonstrated great potential as promising membrane materials over the past few years. Different types of MOF-based membranes, including polycrystalline membranes, mixed matrix membranes (MMMs), and nanosheet-based membranes, have been developed for diversified applications with remarkable separation performances. In this comprehensive review, we first discuss the general classification of membranes and outline the historical development of MOF-based membranes. Subsequently, particular attention is devoted to design strategies for MOF-based membranes, along with detailed discussions on the latest advances on these membranes for various gas and liquid separation processes. Finally, challenges and future opportunities for the industrial implementation of these membranes are identified and outlined with the intent of providing insightful guidance on the design and fabrication of high-performance membranes in the future.

Advances in metal-organic framework-based membranes.

In this work, zeolitic imidazolate frameworks (ZIF-8) and carboxylated carbon nanotubes (CNTs) were compounded to prepare a kebab-like one-dimensional linear composite, ZIF-8@CNTs. The mixed-matrix membrane (MMM) for separating carbon dioxide is prepared by embedding it into the polymer matrix Pebax-1657. The results indicated the successful synthesis of the ZIF-8@CNT composite. The combination of ZIF-8 and carboxylated CNTs avoided the aggregation of ZIF-8 in the polymer, increased the free volume of the MMM, and enhanced the CO2 adsorption performance and CO2/N2 separation performance. In addition, the interaction between CNTs and ZIF-8 provided a fast transport channel for CO2 molecules and improved the mechanical properties of the MMM. The 5 wt % ZIF-8@CNT MMM showed the best separation performance with a CO2 permeability of 225.5 Barrer and a CO2/N2 selectivity of 48.9, which exceeded the Robeson upper limit in 2008. The combination of high permeability and selectivity made Pebax/ZIF-8@CNT MMMs promising for industrial CO2 separation applications.

Pebax Mixed-Matrix Membrane with Highly Dispersed ZIF-8@CNTs to Enhance CO2/N2 Separation.

Au/N-Doped Carbon Dot Nanozymes as Light-Controlled Anti- and Pro-Oxidants

Metal nanozymes hold promise for chemical and biological applications, and their implementation relies on high catalytic efficiency and stability. Using the metal-organic framework as an ideal carrier for well-dispersed ultra-small metal nanoparticles (NPs) is beneficial for improving the catalytic efficiency of nanozymes. In this study, a zirconium-based metal organic framework (UiO-66) with good chemical stability and high porosity was synthesized and used to construct Pt/UiO-66 nanocomposites. The percentage of Pt in UiO-66 can be tuned easily by adjusting the feeding amount of PtCl4 2-. Because of the confinement effect of mesopores, the Pt particles with an average diameter of 3.8 nm are formed and dispersed throughout the pores of the UiO-66 particle. The Pt/UiO-66 composites show efficient oxidase- and peroxidase-like activity. Both the oxidase- and peroxidase-like activities are dependent on the Pt percentage. Pt/UiO-66-6% exhibits enhanced peroxidase-like activity, ∼3.9 times higher than that of commercial Pt/C with 10 wt % Pt. We propose that the construction of Pt/UiO-66 increased the utilization efficiency and stability of Pt NPs and provided more active sites for catalytic reactions. Using the peroxidase-like activity of Pt/UiO-66, a colorimetric method that can be used for actual blood glucose detection was developed for the specific detection of glucose with a limit of detection of 0.033 mM.

Pt Nanoparticles Confined by Zirconium Metal–Organic Frameworks with Enhanced Enzyme-like Activity for Glucose Detection

The invention provides a method for preparing a patterned Co3O4 nanomaterial on a foamed nickel substrate The method comprises the following steps: S1, putting a foamed nickel net into a centrifuge tube, sequentially soaking with anhydrous ethanol and a hydrochloric acid solution, washing, and drying to obtain a treated nickel net; S2, mixing urea with deionized water to obtain a solution A, heating a cobalt salt, adding the heated cobalt salt into the solution A to obtain a solution B, performing vacuum treatment on the solution B, and allowing water in the solution B to form gathered microbubbles in the vacuum environment to rise, uniformly dissolving the cobalt salt in the solution B to obtain a solution C, and finally adding a catalyst into the solution C to obtain a solution D; and S3, adjusting the pH value of the solution D, transferring the solution D into a high-pressure reaction kettle, adding the treated nickel net, carrying out a stepped constant-temperature reaction, washing, and drying to obtain the Co3O4 nanomaterial

Method for preparing patterned Co3O4 nanomaterial on foamed nickel substrate

The invention discloses a method for synthesizing a spinel type CuCo2O4 high-performance electrode material growing on a carbon cloth substrate. The method comprises the steps of performing surface wet modification on a hydrophilic carbon cloth, then dissolving Cu (NO3) 2.3 H2O and Co (NO3) 2.6 H2O into a mixed solution of deionized water and ethanol in different proportions; adding urea and ammonium fluoride, putting the modified carbon cloth, carrying out soaking treatment by adopting a water/ethanol (3: 2v/v) solution of 8wt% CaCl2 as a soaking solution after the reaction is finished, calcining the obtained sample, and naturally cooling to obtain the CuCo2O4 nano/carbon cloth. The high-performance electrode material prepared by the method provided by the invention highly combines the excellent properties of the carbon cloth and the nano material CuCo2O4 and has the advantages of corrosion resistance, high temperature resistance, low cost, no environmental pollution, stable chemicalproperties, high conductivity at room temperature, good oxidation reduction invertibility, high charge storage capacity, etc., the used raw materials are cheap and are easy to obtain, and the preparation method is simple and controllable and is suitable for the large-scale production.

Yuping Tong

Papers

Pebax Mixed-Matrix Membrane with Highly Dispersed ZIF-8@CNTs to Enhance CO2/N2 Separation.

Au/N-Doped Carbon Dot Nanozymes as Light-Controlled Anti- and Pro-Oxidants

Pt Nanoparticles Confined by Zirconium Metal–Organic Frameworks with Enhanced Enzyme-like Activity for Glucose Detection

Method for preparing patterned Co3O4 nanomaterial on foamed nickel substrate

Method for synthesizing spinel type CuCo2O4 high-performance electrode material growing on carbon cloth substrate