4 research outputs found

    Bridging the g‑C<sub>3</sub>N<sub>4</sub> Interlayers for Enhanced Photocatalysis

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    Graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) has been widely investigated and applied in photocatalysis and catalysis, but its performance is still unsatisfactory. Here, we demonstrated that K-doped g-C<sub>3</sub>N<sub>4</sub> with a unique electronic structure possessed highly enhanced visible-light photocatalytic performance for NO removal, which was superior to Na-doped g-C<sub>3</sub>N<sub>4</sub>. DFT calculations revealed that K or Na doping can narrow the bandgap of g-C<sub>3</sub>N<sub>4</sub>. K atoms, intercalated into the g-C<sub>3</sub>N<sub>4</sub> interlayer via bridging the layers, could decrease the electronic localization and extend the π conjugated system, whereas Na atoms tended to be doped into the CN planes and increased the in-planar electron density. On the basis of theoretical calculation results, we synthesized K-doped g-C<sub>3</sub>N<sub>4</sub> and Na-doped g-C<sub>3</sub>N<sub>4</sub> by a facile thermal polymerization method. Consistent with the theoretical prediction, it was found that K was intercalated into the space between the g-C<sub>3</sub>N<sub>4</sub> layers. The K-intercalated g-C<sub>3</sub>N<sub>4</sub> sample showed increased visible-light absorption, efficient separation of charge carriers, and strong oxidation capability, benefiting from the narrowed band gap, extended π conjugated systems, and positive-shifted valence band position, respectively. Despite that the Na-doped g-C<sub>3</sub>N<sub>4</sub> exhibited narrowed bandgap, the high recombination rate of carriers resulted in the reduced photocatalytic performance. Our discovery provides a promising route to manipulate the photocatalytic activity simply by introducing K atoms in the interlayer and gains a deep understanding of doping chemistry with congeners. The present work could provide new insights into the mechanistic understanding and the design of electronically optimized layered photocatalysts for enhanced solar energy conversion

    Optimizing Electrolyte Physiochemical Properties toward 2.8 V Aqueous Supercapacitor

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    Achieving a wide potential window of aqueous supercapacitor has been one of the key research interests to address its poor energy density. However, in this process, water decomposition becomes an increasingly significant issue that has to be tackled in order to attain a reliable aqueous supercapacitor. In order to avoid possible water decomposition at a wide potential, benign interaction between electrolyte and electrode during the cell operation has to be considered. In this work, a water-in-bisalt electrolyte consisting of 21 M lithium bis­(trifluoromethane)­sulfonamide and 1 M lithium sulfate was proposed. To complement the electrolyte, Li<sup>+</sup> inserted MnO<sub>2</sub> and carbon were selected as electrode materials due to their low oxygen evolution reaction/hydrogen evolution reaction activities. The resultant aqueous supercapacitor was able to operate at 2.8 V which, to the best of our knowledge, is one of the widest potential windows reported for an aqueous supercapacitor system. The cell was able to deliver an energy density of 55.7 Wh kg<sup>–1</sup> at power density of 1 kW kg<sup>–1</sup>, while attaining a good cyclic stability of 84.6% retention after 10000 cycles at a current density of 30 A g<sup>–1</sup>. Such a strategy may be effective in the design of wide potential aqueous supercapacitors, which is crucial toward future supercapacitor development

    Table1_Identification of a novel ANK1 gene variant c.1504-9G>A and its mechanism of intron retention in hereditary spherocytosis.DOCX

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    Objective: The objective of this study was to pinpoint pathogenic genes and assess the mutagenic pathogenicity in two pediatric patients with hereditary spherocytosis.Methods: We utilized whole-exome sequencing (WES) for individual analysis (case 1) and family-based trio analysis (case 2). The significance of the intronic mutation was validated through a Minigene splicing assay and supported by subsequent in vitro experiments.Results: Both probands received a diagnosis of hereditary spherocytosis. WES identified a novel ANK1 c.1504-9G>A mutation in both patients, causing the retention of seven nucleotides at the 5′ end of intron 13, as substantiated by the Minigene assay. This variant results in a premature stop codon and the production of a truncated protein. In vitro studies indicated a reduced expression of the ANK1 gene.Conclusion: The novel ANK1 c.1504-9G>A variant is established as the causative factor for hereditary spherocytosis, with the c.1504-9G site functioning as a splicing receptor.</p

    In Situ Construction of g‑C<sub>3</sub>N<sub>4</sub>/g‑C<sub>3</sub>N<sub>4</sub> Metal-Free Heterojunction for Enhanced Visible-Light Photocatalysis

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    The photocatalytic performance of the star photocatalyst g-C<sub>3</sub>N<sub>4</sub> was restricted by the low efficiency because of the fast charge recombination. The present work developed a facile in situ method to construct g-C<sub>3</sub>N<sub>4</sub>/g-C<sub>3</sub>N<sub>4</sub> metal-free isotype heterojunction with molecular composite precursors with the aim to greatly promote the charge separation. Considering the fact that g-C<sub>3</sub>N<sub>4</sub> samples prepared from urea and thiourea separately have different band structure, the molecular composite precursors of urea and thiourea were treated simultaneously under the same thermal conditions, in situ creating a novel layered g-C<sub>3</sub>N<sub>4</sub>/g-C<sub>3</sub>N<sub>4</sub> metal-free heterojunction (g-g CN heterojunction). This synthesis method is facile, economic, and environmentally benign using easily available earth-abundant green precursors. The confirmation of isotype g-g CN heterojunction was based on XRD, HRTEM, valence band XPS, ns-level PL, photocurrent, and EIS measurement. Upon visible-light irradiation, the photogenerated electrons transfer from g-C<sub>3</sub>N<sub>4</sub> (thiourea) to g-C<sub>3</sub>N<sub>4</sub> (urea) driven by the conduction band offset of 0.10 eV, whereas the photogenerated holes transfer from g-C<sub>3</sub>N<sub>4</sub> (urea) to g-C<sub>3</sub>N<sub>4</sub> (thiourea) driven by the valence band offset of 0.40 eV. The potential difference between the two g-C<sub>3</sub>N<sub>4</sub> components in the heterojunction is the main driving force for efficient charge separation and transfer. For the removal of NO in air, the g-g CN heterojunction exhibited significantly enhanced visible light photocatalytic activity over g-C<sub>3</sub>N<sub>4</sub> alone and physical mixture of g-C<sub>3</sub>N<sub>4</sub> samples. The enhanced photocatalytic performance of g-g CN isotype heterojunction can be directly ascribed to efficient charge separation and transfer across the heterojunction interface as well as prolonged lifetime of charge carriers. This work demonstrated that rational design and construction of isotype heterojunction could open up a new avenue for the development of new efficient visible-light photocatalysts
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