Latest ArticlesTo find potential zeolitic imidazolate frameworks (ZIFs) for CO2 capture from flue gas, we built 169, 898 ZIF models from 84, 949 hypothetical zeolite networks. By calculating their lattice energies, accessible volumes to CO2, the isosteric adsorption heat (Qst) of H2O, Henry's constant ratio (SKH) of CO2/N2, percent regenerability (R%), CO2 working capacity (ΔNCO2), CO2/N2 adsorption selectivity (SCO2/N2) and adsorbent performance score (APS), we identified 49 hydrophobic ZIF structures that might outplay already-realised ZIFs built from the same imidazolate linkers for CO2 capture from flue gas.
Efficient catalytic system with low energy consumption exhibits increasing importance due to the upcoming energy crisis. Given this situation, it should be an admirable strategy for reducing energy input by effectively utilizing incident solar energy as a heat source during catalytic reactions. Herein, aza-fused π-conjugated microporous polymer (aza-CMP) with broad light absorption and high photothermal conversion efficiency was synthesized and utilized as a support for bimetallic AuPd nanocatalysts in light-driven benzyl alcohol oxidation. The AuPd nanoparticles anchored on aza-CMP (aza-CMP/AuxPdy) exhibited excellent catalytic performance for benzyl alcohol oxidation under 50 mW/cm2 light irradiation. The improved catalytic performance by the aza-CMP/AuxPdy is attributed to the unique photothermal effect induced by aza-CMP, which can promote the catalytic benzyl alcohol oxidation occurring at AuPd. This work presents a novel approach to effectively utilize solar energy for conventional catalytic reactions through photothermal effect.
Direct conversion of methane (CH4) to methanol (DMTM) is a promising, but very challenging process for the utilization of abundant CH4 as a low carbon resource. In this context, Cu loaded zeolites, mordenite (MOR) in particular, were recognized as the most effective system to perform DMTM. In this work, different Cu salts were used to exchange with MOR, by which the effect of counter ions on the catalytic performance towards DMTM was investigated. The prepared catalysts were characterized and evaluated systematically. It was found that the counter ions affected the speciation of Cu sites, probably due to their capability in extraction of protons from MOR and the influence on the hydrolysis state of the Cu2+ in aqueous solution. These behaviors adjusted the association between Cu2+ and the exchangeable protons in MOR. As a result, varied DMTM performance was observed. Among the used Cu salts, Cu(CH3COO)2 exchanged MOR showed the highest performance, achieving stable CH3OH yield of 117±28 μmol/g in 5 consecutive cycles, these values are among the highest for Cu loaded MOR zeolites in open publications.
Design and development of iron porphyrin-based artificial enzymes system have been attracting a lot of attention. Herein, without any toxic reductant and harsh processing, we present a facile one-pot method to fabricate bifunctional catalytic nanocomposites consisting of graphene and hemin by using vitamin C as a mild reduction reagent. The presence of graphene helps the formation of a high degree of highly active and stable hemin on the graphene surface in a monomeric form through their π-π stacking interaction. As a result, such nanocomposites possess a superior adsorption capacity and intrinsic peroxidase-like catalytic activity. Moreover, by the combination of their dye adsorption ability, RGOhemin nanocomposites can serve as a suitable candidate for efficient capture and removal of dyes via a synergistic effect. Our findings may pave the way to apply graphene-supported artificial enzymes in a variety of fields, such as environmental chemistry, bionics, medicine, and biotechnology
With the rapid growth in electronic device performance, there has been an increasing demand for thermally conductive polymer composites to handle the thermal management issue, thus contributing to the great importance to develop the graphene framework, which is evaluated as the most promising reinforcements for enhancing the thermal conductivity of polymer. Vacuum filtration is a common method to fabricate graphene framework, whereas, it is available to prepare a framework with centimeter-scale thickness by filtrating the graphene-water dispersion, due to the fact of sample cracking caused by the mismatch of surface tension between graphene and water. In this work, a surfactantassisted strategy was proposed by adjusting the surface tension of the water close to that of graphene first, then performing a conventional filtration process, to fabricate graphene framework. As a result, a thick graphene framework (thickness: 3 cm) was successfully prepared, and after embedding into epoxy, the framework endows the composite (13.6 wt%) with a high in-plane thermal conductivities of 12.4 W/mK, which is equivalent to ≈64 times higher than that of neat epoxy. Our method is simple and compatible with the conventional filtration process, suggesting great potential for the mass-production of graphene framework to meet the practical application requirements.
Fabrication of biocompatible core-shell microcapsules in a controllable and scalable manner remains an important but challenging task. Here, we develop a one-step microfluidic approach for the highthroughput production of biocompatible microcapsules, which utilizes single emulsions as templates and controls the precipitation of biocompatible polymer at the water/oil interface. The facile method enables the loading of various oils in the core and the enhancement of polymer shell strength by polyelectrolyte coating. The resulting microcapsules have the advantages of controllability, scalability, biocompatibility, high encapsulation efficiency and high loading capacity. The core-shell microcapsules are ideal delivery vehicles for programmable active release and various controlled release mechanisms are demonstrated, including burst release by vigorous shaking, pH-triggered release for targeted intestinal release and sustained release of perfume over a long period of time. The utility of our technique paves the way for practical applications of core-shell microcapsules.
We describe a simple method to prepare magnetic responsive polydivinylbenzene (PDVB) nanofiber composites by precipitated cationic living polymerization in the present of oleic acid capped Fe3O4 nanoparticles (NPs). The Fe3O4 NPs are encapsulated with the PDVB forming dendrites, from which thin nanofibers are grown in the tip-growth mode. The thin nanofibers are interwoven with the thick nanofibers forming robust composite network. The composites are magnetic responsive and highly efficient to gel almost all chemicals. Separation of the gelled chemicals from water becomes easier with a magnet. The performance is promising for magnetic collection of chemical spills.
The development of polymeric optical materials with a higher refractive index, transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses, image sensors, and organic light-emitting diodes. Most acrylates have a low refractive index (around 1.50) which does not meet the high performance requirements of advanced optical materials. In this research, three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers. All of the polymers reveal good optical properties including high transparency (≥90%) in the visible spectrum region and high refractive index values (1.6363) at 550 nm. Moreover, nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography. These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.
CO2-controlled assembly of conjugated polymer and boron nitride (BN) was fabricated via electrostatic and hydrophobic interactions between the BN fiber and conjugated polymer of PFBT containing fluorene units and 2, 1, 3-benzothiadiazole units. CO2, an effective and green stimulus for regulating the assembly of PFBT and BN fibers, leads to an obvious fluorescence variation. Moreover, PFBT enables the assembly with the signal amplification and light-harvesting properties. This work provides a new triggering method to construct intelligent conjugated polymer-based platform, and offers fluorescence monitoring strategy for carbon dioxide capture.
Graphene oxide (GO) is widely used in the construction and application of various 2D membrane-based materials due to its unique colloidal structure. Herein, we demonstrate that micrometer-sized particles can make up freestanding membranes enabled by the extraordinary amphiphilic and polymer-like properties of graphene oxide through freeze casting. The 2D macromolecule, GO could well wrap the particles for better uniformity and stability in either dispersion or membrane. Importantly, freeze casting plays an important role in avoiding the severe aggregation of micrometer-sized particles in the solventremoving process. After reduction, the membrane exhibits good electrical conductivity while maintaining its integral structure, which can be directly used as a freestanding binder-free electrode. This work provides a universal approach to fabricate freestanding membranes with various micrometersized materials for energy storage.