Two salts and seven copper(I/II) and silver(I) coordination polymers containing tetrazolyl ligands have been hydro(solvo)thermal synthesized by metal salts, NaN3 and various nitriles generated via [2 + 3] cycloaddition reactions of organonitriles and sodium azide. The study also shows that in some cases the azide can play a dual role in the in situ syntheses of metal tetrazole complexes, namely, starting material for tetrazole ligand and co-ligand in the tetrazole-based coordination complexes. Compounds and are simple salts of ammonium and sodium 5-methyltetrazolate. Compound has a 3-D framework with intersecting channel and unprecedented (4(9).6(6)) topology constructed from mixed-valent Cu8 clusters. Compounds and are isomorphous, and have 3-D organic-inorganic frameworks constructed by [M2(mtta)]+ (Hmtta = 5-methyltetrazole) ribbon and [M2(N3)]+ (M = Cu, Ag) layer two types of structural motifs, which contains an mu(4)-1,1,1,3 azide. Compound is a 3-D four-connected chiral complex with (4(2).8(4))(Cu)(4(2).8(2).10(2))(tta) topology. The structure of consists of 2-D three-connected layers that are linked by ligand-unsupported Ag(I)...Ag(I) interactions to form a 3-D supramolecular array. Compound shows a 3-D chiral framework containing tetrahedrally and linearly coordinated Ag(I) ions and mu3- and mu4-two types of 5-propyltetrazolate. Compound has a 2-D layered structure formed by linkage of [Ag(tetrazolyl)] ribbons via C-C and N-Ag bonds. Magnetic measurement confirmed that there are two Cu(II) ions and six Cu(I) ions per Cu8 unit consistent with a mixed-valent Cu(I,II) complex.

A novel facile approach has been developed to prepare graphene-like α-Co(OH) 2 two-dimensional ultrathin nanosheets. The layered hydrotalcite-like α-Co(OH) 2 aggregates were successfully exfoliated in formamide solution in a constant temperature oscillator. The influence of exfoliation on the thickness and surface structure of the Co(OH) 2 monolith was analyzed by scanning electron microscopy and transmission electron microscopy. After the exfoliation process, the electrochemical performances of the 2D α-Co(OH) 2 nanosheets were tested by cyclic voltammetry, galvanostatic discharge/charge, and electrochemical impedance spectroscopy. Impressively, the charge/discharge study shows that the exfoliated sample is capable of delivering a high spe- [a] Key

We performed Monte Carlo simulations to determine the roles of energetic factors and nanoscale effects in the surface segregation and chemical ordering patterns of Ag-Pd nanoalloy particles.Ag atoms significantly segregate onto the surface and preferentially occupy the low-coordinated sites, which significantly reduce the surface and strain energies of the nanoalloys. The segregation isotherms reveal that surface Ag composition is enhanced with increasing particle size or Ag concentration to circumvent the finite matter effects. Chemical ordering favored by attractive hetero-bonds can coexist and compete with surface segregation. Accordingly, small and Pd-rich nanoalloys display a continuous transition from Pd-core/ mixing-shell to mixingcore/ Ag-shell, where an ordered core is absent as a result of surface segregation and limited Ag supply. By contrast, large nanoalloys with equimolar or Ag-rich concentration exhibit the strong core ordering characteristics of bulk alloys. Particularly, surface patterns with partially alloyed facets and Ag-blocked vertices and edges are formed. This study also discussed the effects of isolating and blocking surface Pd active sites by Ag on the hydrogen evolution reaction and selective hydrogenation of acetylene.

We performed Monte Carlo simulations coupled with MAEAM potentials to study the surface segregation and chemical ordering patterns in Cu−Pt nanoalloy particles for a broad range of sizes, shapes, composition, and temperature. It was found that both the Cu segregation on the surface and the chemical ordering in the core are the general rules and usually compete with each other. Surface segregation of Cu is enhanced with increasing particle size or surface openness or global Cu composition. Despite their different morphologies, most of the types of ordered phases in the core region are the same as bulk alloys. Due to the modification or suppression effects of surface segregation, the degrees of chemical ordering shift to the Ptricher side and are more apparent in a large-sized particle. Particularly, at a narrow composition range, the multishell structures (onion-ring or multishell/maze-like core) form in (truncated) octahedrons, illustrating a subtle synergy between the segregated Cu {111} facets and the L1 1 ordering. The possibility and advantage of transformation from these multishell structures to Pt multilayer shell/single Cu-rich core ORR catalysts by selective etching of Cu were also discussed.

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