We have developed an effective method to exfoliate and disintegrate multi-walled carbon nanotubes and graphite flakes. With this technique, high yield production of luminescent graphene quantum dots with high quantum yield and low oxidization can be achieved.

Tackling global climate change and the energy crisis requires novel approaches in clean energy generation and efficient manufacturing. [1] Hydrogen (H 2 ) is one of the most popular clean energy sources, providing the highest energy outputThe hydrogen evolution reaction (HER) is an emerging key technology to provide clean, renewable energy. Current state-of-the-art catalysts still rely on expensive and rare noble metals, however, the relatively cheap and abundant transition metal dichalcogenides (TMDs) have emerged as exceptionally promising alternatives. Early studies in developing TMD-based catalysts laid the groundwork in understanding the fundamental catalytically active sites of different TMD phases, enabling a toolbox of physical, chemical, and electronic engineering strategies to improve the HER catalytic activity of TMDs. This report focuses on recent progress in improving the catalytic properties of TMDs toward highly efficient production of H 2 . Combining theoretical and experimental considerations, a summary of the progress to date is provided and a pathway forward for viable hydrogen evolution from TMD driven catalysis is concluded.

ABSTRACT. Catalytically-driven electrochemical hydrogen evolution reaction (HER) of monolayered molybdenum sulfide (MoS 2 ) is usually highly supressed by the scarcity of edges and low electrical conductivity. Here, we show how the catalytic performance of MoS 2 monolayers can be improved dramatically by catalyst size reduction and surface sulphur (S)

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Polyoxometalate-based metal-organic frameworks (POMOFs) as one type of extended structures that simultaneously possessing the virtues of polyoxometalates (POMs) and metal-organic frameworks (MOFs), have been attracting immense attentions not only because...

Seven lanthanide coordination polymers (CPs), [Ln2(azdc)3(DMA)2]n·2n(DMA) (Ln = Sm(III) for 1, Eu(III) for 2, Gd(III) for 3, Tb(III) for 4, Dy(III) for 5, Ho(III) for 6, Er(III) for 7; H2azdc = 4,4'-azobenzoic acid, DMA = N,N-dimethylacetamide), have been successfully prepared with high yields via solvothermal methods and further studied by elemental analyses (EA), powder X-ray diffraction (PXRD), UV-vis spectra, photoluminescent spectra, thermogravimetric analyses (TGA), variable-temperature in situ PXRD analyses, and single-crystal X-ray diffraction. CPs 1-7 all consist of unique 1D lanthanide-carboxylate building units [Ln2(CO2)6]n constructed from the adjacent Ln(III) cations and carboxyl groups of the H2azdc ligands, which can further generate 3D frameworks with "fsy"-type topological structures via the link of azdc(2-). Furthermore, variable-temperature magnetic susceptibility measurements of 1-7 have been investigated. The results indicate that unusual ferromagnetic coupling between adjacent Gd(III) cations exists in 3, which is rarely reported in the Gd(III) complexes only bridged by μ1,3-COO groups. Meanwhile, the magnetic study reveals that 3 displays cryogenic magnetic refrigeration property, whereas 5 shows magnetic dynamics at low temperature.

Molybdenum disulfide (MoS 2) has a theoretical catalytic activity comparable to Pt but in practice is a poor catalyst in bulk form due to the scarcity of metal edge sites and low electrical conductivity. Recent developments on MoS 2 monolayers (MLs) are more encouraging in developing cheap and efficient catalysts, but the majority metal atoms are on the basal plane are catalytically inactive. The rapid recombination of the electron-hole pairs and electronic band structure of the most stable 2H-MoS 2 MLs are also unsuitable for efficient photocatalysis, especially for solar-driven water splitting. Here, we show that reducing the lateral size and creating sulphur (S) vacancies of MoS 2 MLs not only increases dramatically the density of catalytically active sites, but also adjusts the band structure to become highly suitable for solar-driven catalysis. Besides, this preparation efficiently avoids fast charge recombination associated with MoS 2 , improves light harvesting, and gives a newly formed metallic state to transfer electrons for photocatalytic reactions. By way of example, we have demonstrated remarkable photocatalytic degradation of methylene blue (MB) and methylene orange (MO) dye using the S-depleted Mo-S nanocrystals (NCs, 2-25 nm). The NCs are also promising to efficiently generate hydrogen (H 2) from water with sacrificial reagents and solar light irradiation. Our study shows how careful design and modification of materials can result in highly efficient photocatalysts, which give considerable opportunities of the transition metal dichalcogenides (TMDs) beyond just MoS 2 to develop highly efficient and economic catalysts.

SummaryThe precisionFDA Truth Challenge V2 aimed to assess the state-of-the-art of variant calling in difficult-to-map regions and the Major Histocompatibility Complex (MHC). Starting with FASTQ files, 20 challenge participants applied their variant calling pipelines and submitted 64 variant callsets for one or more sequencing technologies (~35X Illumina, ~35X PacBio HiFi, and ~50X Oxford Nanopore Technologies). Submissions were evaluated following best practices for benchmarking small variants with the new GIAB benchmark sets and genome stratifications. Challenge submissions included a number of innovative methods for all three technologies, with graph-based and machine-learning methods scoring best for short-read and long-read datasets, respectively. New methods out-performed the 2016 Truth Challenge winners, and new machine-learning approaches combining multiple sequencing technologies performed particularly well. Recent developments in sequencing and variant calling have enabled benchmarking variants in challenging genomic regions, paving the way for the identification of previously unknown clinically relevant variants.