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Atomically dispersed metal catalysts maximize atom e ciency and display unique catalytic properties compared to regular metal nanoparticles. However, achieving high reactivity while still preserving high stability at high loadings remains as a grand challenge. Here we solve the challenge by synergizing strong metal-support interactions and spatial con nement, which enable to fabricate highly loaded (3.1 wt%), active and stable atomic Ni and dense atomic Cu grippers (8.1 wt%) on a graphitic C 3 N 4 support.For semi-hydrogenation of acetylene in excess of ethylene, the fabricated catalyst shows 11 times higher activity than the atomic Ni alone, high ethylene selectivity (90%), and high stability against both sintering and coke formation for 350 h. Comprehensive microscopic and spectroscopic characterization and theoretical calculations reveal the active site of the bridging Ni con ned in two hydroxylated Cu grippers, whose structure changes dynamically by breaking interfacial Ni-support bonds upon reactant adsorption and making these bonds upon product desorption. Such a dynamic effect confers high activity/selectivity and high stability, providing an avenue to rational design of e cient, stable, highly loaded, yet atomically dispersed catalysts.

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The development of highly efficient metal-free carbon electrocatalysts for the oxygen reduction reaction (ORR) is one very promising strategy for the exploitation and commercialization of renewable and clean energy,but this still remains as ignificant challenge.H erein, we demonstrate afacile approach to prepare three-dimensional (3D) N-doped carbon with as p 3 /sp 2 carbon interface derived from ionic liquids via as imple pyrolysis process.T he tunable hybrid sp 3 and sp 2 carbon composition and pore structures stem from the transformation of ionic liquids to polymerizedo rganics and introduction of aC om etal salt. Through tuning both composition and pores,t he 3D N-doped nanocarbon with ah igh sp 3 /sp 2 carbon ratio on the surface exhibits as uperior electrocatalytic performance for the ORR compared to that of the commercial Pt/C in Zn-air batteries.D ensity functional theory calculations suggest that the improved ORR performance can be ascribed to the existence of Ndopants at the sp 3 / sp 2 carbon interface,w hichc an lower the theoretical overpotential of the ORR.

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Flaviviruses have evolved complex mechanisms to evade the mammalian host immune systems including the RIG-I (retinoic acid-inducible gene I) like receptor (RLR) signaling. Zika virus (ZIKV) is a re-emerging flavivirus that is associated with severe neonatal microcephaly and adult Guillain-Barre syndrome. However, the molecular mechanisms underlying ZIKV pathogenesis remain poorly defined. Here we report that ZIKV non-structural protein 4A (NS4A) impairs the RLR-mitochondrial antiviral-signaling protein (MAVS) interaction and subsequent induction of antiviral immune responses. In human trophoblasts, both RIG-I and melanoma differentiation-associated protein 5 (MDA5) contribute to type I interferon (IFN) induction and control ZIKV replication. Type I IFN induction by ZIKV is almost completely abolished in MAVS-/- cells. NS4A represses RLR-, but not Toll-like receptor-mediated immune responses. NS4A specifically binds the N-terminal caspase activation and recruitment domain (CARD) of MAVS and thus blocks its accessibility by RLRs. Our study provides in-depth understanding of the molecular mechanisms of immune evasion by ZIKV and its pathogenesis.

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