Crystalline high-entropy ceramics (CHC), a new class of solids that contain five or more elemental species, have attracted increasing interest because of their unique structure and potential applications. Up to now, only a couple of CHCs (e.g., high-entropy metal oxides and diborides) have been successfully synthesized. Here, a new strategy for preparing high-entropy metal nitride (HEMN-1) is proposed via a soft urea method assisted by mechanochemical synthesis. The as-prepared HEMN-1 possesses five highly dispersed metal components, including V, Cr, Nb, Mo, Zr, and simultaneously exhibits an interesting cubic crystal structure of metal nitrides. By taking advantage of these unique features, HEMN-1 can function as a promising candidate for supercapacitor applications. A specific capacitance of 78 F g is achieved at a scan rate of 100 mV s in 1 m KOH. In addition, such a facile synthetic strategy can be further extended to the fabrication of other types of HEMNs, paving the way for the synthesis of HEMNs with attractive properties for task-specific applications.
An in situ coupling approach is developed to create a new highly efficient and durable cobalt-based electrocatalyst for the oxygen evolution reaction (OER). Using a novel cyclotetramerization, a task-specific bimetallic phthalocyanine-based nanoporous organic framework is successfully built as a precursor for the carbonization synthesis of a nonprecious OER electrocatalyst. The resultant material exhibits an excellent OER activity with a low overpotential of 280 mV at a current density of 10 mA cm and high durability in an alkaline medium. This impressive result ranks among the best from known Co-based OER catalysts under the same conditions. The simultaneous installation of multiple diverse cobalt-based active sites, including FeCo alloys and Co N nanoparticles, plays a critical role in achieving this promising OER performance. This innovative approach not only enables high-performance OER activity to be achieved but simultaneously provides a means to control the surface features, thereby tuning the catalytic property of the material.
Optical resolution photoacoustic microscopy (ORPAM) represents one of the fastest evolving optical microscopic techniques. However, due to the bulky size and complicated system configuration of conventional ORPAM, it is largely limited to small animal experiments. In this Letter, we present the design and evaluation of a portable ORPAM with a high spatiotemporal resolution and a large field of view. In this system, we utilize a rotatory scanning mechanism instead of the conventional raster scanning to achieve translationless imaging of the probe/samples, making it accessible to the human oral lip and tongue. After phantom evaluation, we applied this system to monitor longitudinal neo-angiogenesis of tumor growth and, for the first time, to the best of our knowledge, image the oral vascular network of humans to show its potential in clinical detection of early-stage oral cancer.
Optical resolution photoacoustic microscopy (ORPAM), benefiting from rich optical contrast, scalable acoustic resolution, and deep penetration depth, is of great importance for the fields of biology and medicine. However, limited by the size and performance of reported optical/acoustic scanners, existing portable/handheld ORPAMs are bulky and heavy, and suffer from low imaging quality/speed. Here, we present an ultracompact ORPAM probe, which is miniature and light, and has high imaging quality. The probe only weighs 20 grams and has an outer size of 22 mm×30 mm×13 mm, a high lateral resolution of 3.8 μm, and an effective imaging domain of 2 mm×2 mm. To show its advantages over existing ORPAMs, we apply this probe to image vasculatures of internal organs in a rat abdominal cavity and inspect the entire human oral cavity.
Thiazolothiazole-linked porous organic polymers have been synthesized from a facile catalyst-free condensation reaction between aldehydes and dithiooxamide under solvothermal conditions. The resultant porous frameworks exhibit a highly selective uptake of CO2 over N2 under ambient conditions.
Controlled synthesis of efficient CO 2 adsorbents with high porosities and CO 2 binding affinities remains a challenge. Herein, we report the use of a substituent effect to develop a novel family of porous organic polymers for enhanced carbon capture. Based on the in silico-aided design strategy, the task-specific polymeric adsorbent derived from a 2,6-carbazole-substituted pyridinic scaffold exhibits a superior uptake of CO 2 , which reaches as high as 5.76 mmol g −1 at 273 K and 1 bar and ranks among the best by porous polymeric CO 2 adsorbents. This approach not only enables us to achieve a very high CO 2 capture for porous polymers but also provides tunable control of polymeric architectures and, in turn, their properties.
A novel solid-state synthetic approach has been developed for the generation of conjugated nanoporous polymer networks. Using mechanochemical-assisted oxidative coupling polymerization, we demonstrated a rapid and solvent-free synthesis of conjugated polycarbazoles with high porosities and promising CO 2 storage abilities. This innovative approach constitutes a new direction for the development of novel nanoporous polymer frameworks through sustainable solid-state assembly pathways, and may open up new possibilities for the rational design and synthesis of nanoporous materials for carbon capture.
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