The synergistic effect between Ni 3 N and Mo 5 N 6 , as well as porous morphology of the self-supporting catalyst Mo 5 N 6 /Ni 3 N/Ni/NF, lead to good catalytic activity and stability towards hydrogen evolution reaction (HER).
Rational design and synthesis of high-performance electrocatalysts for ethanol oxidation reaction (EOR) is crucial to large-scale commercialization of direct ethanol fuel cells, but it is still an incredible challenge. Herein, a unique Pd metallene/Ti3C2Tx MXene (Pdene/Ti3C2Tx)-supported electrocatalyst is constructed via an in-situ growth approach for high-efficiency EOR. The resulting Pdene/Ti3C2Tx catalyst achieves an ultrahigh mass activity of 7.47 A mgPd-1 under alkaline condition, as well as high tolerance to CO poisoning. In situ attenuated total reflection-infrared spectroscopy studies combined with density functional theory calculations reveal that the excellent EOR activity of Pdene/Ti3C2Tx catalyst is attributed to the unique and stable interfaces which reduce the reaction energy barrier of *CH3CO intermediate oxidation and facilitate oxidative removal of CO poisonous species by increasing the Pd-OH binding strength.
Abstract Metallic‐state 2D SnS 2 nanosheets with expanded lattice spacing and a defect‐rich structure were synthesized by the intercalation of Ni into the van der Waals gap of SnS 2 . The expanded lattice spacing efficiently enhanced the electrochemical performance of the SnS 2 for sodium‐ion batteries owing to the change electron state density and energy band structure. In operando synchrotron XRD and theoretical calculations were used to gain insight into the influence of foreign metal‐ion doping and its location. The optimized architecture obtained by in situ uniform growth of nanosheets on carbon fibers significantly enhanced the electrochemical performance. The inherent advantages of this architecture are shorter paths for ion insertion and extraction, larger contact area for more sodium diffusion pathways, and superior electrolyte penetration. Benefiting from the Ni intercalated SnS 2 bilayer, the internal adjustment of the electronic state and the enlarged interlayer spacing significantly enhanced the electron transport kinetics, which can be explained by the metallic‐state properties. The integrated electrode exhibited an initial high reversible capacity of 795 mAh g −1 at 0.1 A g −1 , with a stable capacity retention of 666 mAh g −1 after 100 cycles. Good rate capability was also exhibited with specific capacities of 691, 564, 437 mAh g −1 at current densities of 200, 500, and 1000 mA g −1 , respectively.
Abstract The carbon–carbon triple bond (–C≡C–) is an elementary constituent for the construction of conjugated molecular wires and carbon allotropes such as carbyne and graphyne. Here we describe a general approach to in situ synthesize –C≡C– bond on Cu(111) surface via homo-coupling of the trichloromethyl groups, enabling the fabrication of individual and arrays of poly( p -phenylene ethynylene) molecular wires. Scanning tunneling spectroscopy reveals a delocalized electronic state extending along these molecular wires, whose structure is unraveled by atomically resolved images of scanning tunneling microscopy and noncontact atomic force microscopy. Combined with density functional theory calculations, we identify the intermediates formed in the sequential dechlorination process, including surface-bound benzyl, carbene, and carbyne radicals. Our method overcomes the limitation of previous on-surface syntheses of –C≡C– incorporated systems, which require the precursors containing alkyne group; it therefore allows for a more flexible design and fabrication of molecular architectures with tailored properties.
Through systematic density-functional calculations, we found that Pd atoms in Au nanoclusters may only take (111) facets while leaving (001) facets with pure Au. This is promoted by the tendency that Pd prefers to form bonds with Au rather than Pd. The segregation from the (001) facet to the (111) facet appears to occur easily. The local activity of Pd is somewhat dependent on the size of cluster and on the site of substitution. The peculiar distribution pattern of the active constituent should strongly alter the chemical properties of bimetallic nanoclusters toward catalyzing reactions.
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