The development of highly efficient and cost-effective hydrogen evolution reaction (HER) catalysts is highly desirable to efficiently promote the HER process, especially under alkaline condition. Herein, a polyoxometalates-organic-complex-induced carbonization method is developed to construct MoO2 /Mo3 P/Mo2 C triple-interface heterojunction encapsulated into nitrogen-doped carbon with urchin-like structure using ammonium phosphomolybdate and dopamine. Furthermore, the mass ratio of dopamine and ammonium phosphomolybdate is found critical for the successful formation of such triple-interface heterojunction. Theoretical calculation results demonstrate that such triple-interface heterojunctions possess thermodynamically favorable water dissociation Gibbs free energy (ΔGH2O ) of -1.28 eV and hydrogen adsorption Gibbs free energy (ΔGH* ) of -0.41 eV due to the synergistic effect of Mo2 C and Mo3 P as water dissociation site and H* adsorption/desorption sites during the HER process in comparison to the corresponding single components. Notably, the optimal heterostructures exhibit the highest HER activity with the low overpotential of 69 mV at the current density of 10 mA cm-2 and a small Tafel slope of 60.4 mV dec-1 as well as good long-term stability for 125 h. Such remarkable results have been theoretically and experimentally proven to be due to the synergistic effect between the unique heterostructures and the encapsulated nitrogen-doped carbon.
Molnupiravir (MPV) is a widely used oral anti-COVID-19 drug. Owing to the rotatable bonds and the large number of acceptors and donors of hydrogen bonds in the molecular structure of MPV, three pure polymorphs (forms I, II, and III) and four solvates (ethanol, isopropanol, isobutanol, and tetrahydrofuran) of MPV (MPV-EtOH, MPV-IPA, MPV-IBA, and MPV-THF) were obtained. Importantly, the crystal structures of form I and the four solvates were successfully determined by single-crystal X-ray diffraction for the first time. Interestingly, all solvates are isostructural and have very similar unit cell parameters. Meanwhile, the solvent molecules in their structures are all in the voids surrounded by MPV molecules, forming a channel structure that facilitates desolvation. The formation mechanism of the solvates was also investigated based on the molecular electrostatic potential and hydrogen-bond energy of possible synthons. Moreover, a detailed stability study of MPV was conducted by using thermal analysis and dynamic vapor sorption. Finally, the phase transformations of the different solid forms were summarized. Our study provides a comprehensive understanding of the crystal landscape of the MPV.
Cyclable lithium batteries with a lithium metal anode are of great interest for future mobile and stationary applications due to their high potential energy density. To suppress lithium dendrite formation and growth, solid electrolytes (all‐solid‐state‐batteries) are an alternative for liquid electrolytes. Compared with all other solid electrolytes, the ceramic lithium garnet solid electrolyte Li 7 La 3 Zr 2 O 12 (LLZO) features a high thermal, electrochemical, and chemical stability. Due to its nonflammable nature, it is beneficial for battery cell safety. Despite major research efforts, an industrially applicable process route to produce the ceramic solid electrolyte has not been identified yet. Herein, film fabrication at room temperature of Al 0.2 Li 6.025 La 3 Zr 1.625 Ta 0.375 O 12 (ALLZTO) via powder aerosol deposition (PAD) on a scalable apparatus is investigated. In addition to the description of synthesis and process conditions regarding industrial scalability, the sprayed 30 μm‐thick PAD films are examined optically and electrochemically in half cells and symmetrical cells with lithium metal electrodes. By categorizing the process data and the electrochemical results compared with common reported production methods, a statement about the suitability for the industrial production of ceramic solid electrolytes using PAD is provided.
Abstract Type‐I photosensitizers have shown advantages in addressing the shortcomings of traditional oxygen‐dependent type‐II photosensitizers for the photodynamic therapy (PDT) of hypoxic tumors. However, developing type‐I photosensitizers is yet a huge challenge because the type‐II energy transfer process is much faster than the type‐I electron transfer process. Herein, from the fundamental point of view, an effective approach is proposed to improve the electron transfer efficiency of the photosensitizer by lowering the internal reorganization energy and exciton binding energy via self‐assembly‐induced exciton delocalization. An example proof is presented by the design of a perylene diimide (PDI)‐based photosensitizer (PDIMp) that can generate singlet oxygen ( 1 O 2 ) via a type‐II energy transfer process in the monomeric state, but induce the generation of superoxide anion (O 2 ˙ˉ) via a type‐I electron transfer process in the aggregated state. Significantly, with the addition ofcucurbit[6]uril (CB[6]), the self‐assembled PDIMp can convert back to the monomeric state via host–guest complexation and consequently recover the generation of 1 O 2 . The biological evaluations reveal that supramolecular nanoparticles (PDIMp‐NPs) derived from PDIMp show superior phototherapeutic performance via synergistic type‐I PDT and mild photothermal therapy (PTT) against cancer under either normoxia or hypoxia conditions.
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