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  • Vind Reed posted an update 1 year, 3 months ago

    Powerful separation capability was demonstrated with glycan profiling of cancerous and normal cells, which revealed that cancerous cells exhibited characteristic N-glycans. Because DMSNs with tunable particle size and mesopores can be controllably prepared, DMSNs hold great potential to be a new record toward the ultimate generation of packing materials for ultraefficient liquid chromatographic separation.Carbon dioxide (CO2) is not only a greenhouse gas and a common waste product but also an inexpensive, readily available, and renewable carbon resource. It is an important one-carbon (C1) building block in organic synthesis for the construction of valuable compounds. However, its utilization is challenging owing to its thermodynamic stability and kinetic inertness. Although significant progress has been achieved, many limitations remain in this field with regard to the substrate scope, reaction system, and activation strategies.Since 2015, our group has focused on CO2 utilization in organic synthesis. We are also interested in the vast possibilities of radical chemistry, although the high reactivity of radicals presents challenges in controlling selectivity. We hope to develop highly useful CO2 transformations involving radicals by achieving a balance of reactivity and selectivity under mild reaction conditions. Over the past 6 years, we along with other experts have disclosed radical-type carboxylative cyclizh CO2 via generation of a CO2 or alkene radical anion. On the basis of this novel CTC, the visible-light-driven organocatalytic hydrocarboxylation of alkenes with CO2 has also been realized using a Hantzsch ester as an effective reductant.Conversion from CO2 to C2H4 is important for the development of energy and the environment, but the high energy barrier of hydrogenation of the *CO intermediate and C-C coupling step tend to result in C1 compounds as the main product and thus restrict the generation of C2H4. Here, we report a metal-organic framework (denoted as PcCu-Cu-O), composed of 2,3,9,10,16,17,23,24-octahydroxyphthalo-cyaninato)copper(II) (PcCu-(OH)8) ligands and the square-planar CuO4 nodes, as the electrocatalyst for CO2 to C2H4. Compared with the discrete molecular copper-phthalocyanine (Faradaic efficiency (FE) of C2H4 = 25%), PcCu-Cu-O exhibits much higher performance for electrocatalytic reduction of CO2 to C2H4 with a FE of 50(1)% and a current density of 7.3 mA cm-2 at the potential of -1.2 V vs RHE in 0.1 M KHCO3 solution, representing the best performance reported to date. In-situ infrared spectroscopy and control experiments suggested that the enhanced electrochemical performance may be ascribed to the synergistic effect between the CuPc unit and the CuO4 unit, namely the CO on the CO-producing site (CuO4 site) can efficiently migrate and dimerize with the *CO intermediate adsorbed on the C2H4-producing site (CuPc), giving a lower C-C dimerization energy barrier.The human tissues most sensitive to electrical activity such as neural and muscle tissues are relatively soft, and yet traditional conductive materials used to interface with them are typically stiffer by many orders of magnitude. Overcoming this mismatch, by creating both very soft and electroactive materials, is a major challenge in bioelectronics and biomaterials science. One strategy is to imbue soft materials, such as hydrogels, with electroactive properties by adding small amounts of highly conductive nanomaterials. However, electroactive hydrogels reported to date have required relatively large volume fractions (>1%) of added nanomaterial, have shown only modest electroactivity, and have not been processable via additive manufacturing to create 3D architectures. Here, we describe the development and characterization of improved biocompatible photo-cross-linkable soft hybrid electroactive hydrogels based on gelatin methacryloyol (GelMA) and large area graphene oxide (GO) flakes, which resolve each of thition also enhanced the rheological properties of the GelMA composites, thus facilitating 3D extrusion printing. GelMA/GO enhanced filament formation as well as improved printability and the shape fidelity/integrity of 3D printed structures compared with GelMA alone. Additionally, the GelMA/GO 3D printed structures presented a higher electroactive behavior than nonprinted samples containing the same GelMA/GO amount, which can be attributed to the higher electroactive surface area of 3D printed structures. These findings provide new rational choices of electroactive hydrogel (EAH) compositions with broad potential applications in bioelectronics, tissue engineering, and drug delivery.In this study, we have taken advantage of a pulsed CO2 electroreduction reaction (CO2RR) approach to tune the product distribution at industrially relevant current densities in a gas-fed flow cell. We compared the CO2RR selectivity of Cu catalysts subjected to either potentiostatic conditions (fixed applied potential of -0.7 VRHE) or pulsed electrolysis conditions (1 s pulses at oxidative potentials ranging from Ean = 0.6 to 1.5 VRHE, followed by 1 s pulses at -0.7 VRHE) and identified the main parameters responsible for the enhanced product selectivity observed in the latter case. selleckchem Herein, two distinct regimes were observed (i) for Ean = 0.9 VRHE we obtained 10% enhanced C2 product selectivity (FEC2H4 = 43.6% and FEC2H5OH = 19.8%) in comparison to the potentiostatic CO2RR at -0.7 VRHE (FEC2H4 = 40.9% and FEC2H5OH = 11%), (ii) while for Ean = 1.2 VRHE, high CH4 selectivity (FECH4 = 48.3% vs 0.1% at constant -0.7 VRHE) was observed. Operando spectroscopy (XAS, SERS) and ex situ microscopy (SEM and TEM) measurements revealed that these differences in catalyst selectivity can be ascribed to structural modifications and local pH effects. The morphological reconstruction of the catalyst observed after pulsed electrolysis with Ean = 0.9 VRHE, including the presence of highly defective interfaces and grain boundaries, was found to play a key role in the enhancement of the C2 product formation. In turn, pulsed electrolysis with Ean = 1.2 VRHE caused the consumption of OH- species near the catalyst surface, leading to an OH-poor environment favorable for CH4 production.