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  1. Abstract

    The electrocatalytic hydrogen evolution reaction (HER) is one of the most studied and promising processes for hydrogen fuel generation. Single-atom catalysts have been shown to exhibit ultra-high HER catalytic activity, but the harsh preparation conditions and the low single-atom loading hinder their practical applications. Furthermore, promoting hydrogen evolution reaction kinetics, especially in alkaline electrolytes, remains as an important challenge. Herein, Pt/C60catalysts with high-loading, high-dispersion single-atomic platinum anchored on C60are achieved through a room-temperature synthetic strategy. Pt/C60-2 exhibits high HER catalytic performance with a low overpotential (η10) of 25 mV at 10 mA cm−2. Density functional theory calculations reveal that the Pt-C60polymeric structures in Pt/C60-2 favors water adsorption, and the shell-like charge redistribution around the Pt-bonding region induced by the curved surfaces of two adjacent C60facilitates the desorption of hydrogen, thus favoring fast reaction kinetics for hydrogen evolution.

     
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    Free, publicly-accessible full text available December 1, 2024
  2. Free, publicly-accessible full text available November 22, 2024
  3. Abstract

    Actinide diatomic molecules are ideal models to study elusive actinide multiple bonds, but most of these diatomic molecules have so far only been studied in solid inert gas matrices. Herein, we report a charged U≡N diatomic species captured in fullerene cages and stabilized by the U-fullerene coordination interaction. Two diatomic clusterfullerenes, viz. UN@Cs(6)-C82and UN@C2(5)-C82, were successfully synthesized and characterized. Crystallographic analysis reveals U-N bond lengths of 1.760(7) and 1.760(20) Å in UN@Cs(6)-C82and UN@C2(5)-C82. Moreover, U≡N was found to be immobilized and coordinated to the fullerene cages at 100 K but it rotates inside the cage at 273 K. Quantum-chemical calculations show a (UN)2+@(C82)2−electronic structure with formal +5 oxidation state (f1) of U and unambiguously demonstrate the presence of a U≡N bond in the clusterfullerenes. This study constitutes an approach to stabilize fundamentally important actinide multiply bonded species.

     
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  4. Free, publicly-accessible full text available February 28, 2024
  5. Considerable efforts are being made to find cheaper and more efficient alternatives to the currently commercially available catalysts based on precious metals for the Hydrogen Evolution Reaction (HER). In this context, fullerenes have started to gain attention due to their suitable electronic properties and relatively easy functionalization. We found that the covalent functionalization of C 60 , C 70 and Sc 3 N@ I h C 80 with diazonium salts endows the fullerene cages with ultra-active charge polarization centers, which are located near the carbon-diazonium bond and improve the efficiency towards the molecular generation of hydrogen. To support our findings, Electrochemical Impedance Spectroscopy (EIS), double layer capacitance ( C dl ) and Mott–Schottky approximation were performed. Among all the functionalized fullerenes, DPySc 3 N@ I h C 80 exhibited a very low onset potential (−0.025 V vs. RHE) value, which is due to the influence of the inner cluster on the extra improvement of the electronic density states of the catalytic sites. For the first time, the covalent assembly of fullerenes and diazonium groups was used as an electron polarization strategy to build superior molecular HER catalytic systems. 
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  6. null (Ed.)
    Abstract The nature of the actinide-actinide bonds is of fundamental importance to understand the electronic structure of the 5 f elements. It has attracted considerable theoretical attention, but little is known experimentally as the synthesis of these chemical bonds remains extremely challenging. Herein, we report a strong covalent Th-Th bond formed between two rarely accessible Th 3+ ions, stabilized inside a fullerene cage nanocontainer as Th 2 @ I h (7)-C 80 . This compound is synthesized using the arc-discharge method and fully characterized using several techniques. The single-crystal X-Ray diffraction analysis determines that the two Th atoms are separated by 3.816 Å. Both experimental and quantum-chemical results show that the two Th atoms have formal charges of +3 and confirm the presence of a strong covalent Th-Th bond inside I h (7)-C 80 . Moreover, density functional theory and ab initio multireference calculations suggest that the overlap between the 7 s /6 d hybrid thorium orbitals is so large that the bond still exists at Th-Th separations larger than 6 Å. This work demonstrates the authenticity of covalent actinide metal-metal bonds in a stable compound and deepens our fundamental understanding of f element metal bonds. 
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