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Despite significant advances in the fabrication and applications of graphene-like materials, it remains a challenge to prepare single-layered metallic materials, which have great potential applications in physics, chemistry and material science. Here we report the fabrication of poly(vinylpyrrolidone)-supported single-layered rhodium nanosheets using a facile solvothermal method. Atomic force microscope shows that the thickness of a rhodium nanosheet is o4 Å. Electron diffraction and X-ray absorption spectroscopy measurements suggest that the rhodium nanosheets are composed of planar single-atom-layered sheets of rhodium. Density functional theory studies reveal that the single-layered Rh nanosheet involves a d-bonding framework, which stabilizes the single-layered structure together with the poly(vinylpyrrolidone) ligands. The poly(vinylpyrrolidone)-supported single-layered rhodium nanosheet represents a class of metallic two-dimensional structures that might inspire further fundamental advances in physics, chemistry and material science.

Despite 20 years of progress in synthesizing thiolated gold nanoclusters (Au NCs), the knowledge of their growth mechanism still lags behind. Herein the detailed process from reduction of Au(I)-thiolate complex precursors to the eventual evolution of and focusing to the atomically precise Au25 NCs was revealed for the first time by monitoring the time evolution of Au(I) precursor and Au NC intermediate species with ESI-MS. A two-stage, bottom-up formation and growth process was proposed: a fast stage of reduction-growth mechanism, followed by a slow stage of intercluster conversion and focusing. Balanced reactions of formation for each identified NC were suggested, backed by theoretical calculations of the thermodynamic driving force. This work advances one step further toward understanding the mechanism of formation and growth of thiolated Au NCs.

Breaking down is usually hard to do…︁ The direct conversion of lignin into alkanes and methanol was carried out in a two‐step process (hydogenolysis and hydrogenation) involving initial treatment of white birch wood sawdust with H2 in dioxane/water/phosphoric acid using Rh/C as the catalyst. The resulting monomers and dimers obtained by selective CO hydrogenolysis were then hydrogenated in near‐critical water employing Pd/C as the catalyst.

In coordination chemistry, catalytically active metal complexes in a zero- or low-valent state often adopt four-coordinate square-planar or tetrahedral geometry. By applying this principle, we have developed a stable Pt1 single-atom catalyst with a high Pt loading (close to 1 wt %) on phosphomolybdic acid(PMA)-modified active carbon. This was achieved by anchoring Pt on the four-fold hollow sites on PMA. Each Pt atom is stabilized by four oxygen atoms in a distorted square-planar geometry, with Pt slightly protruding from the oxygen planar surface. Pt is positively charged, absorbs hydrogen easily, and exhibits excellent performance in the hydrogenation of nitrobenzene and cyclohexanone. It is likely that the system described here can be extended to a number of stable SACs with superior catalytic activities.

This review provides a comprehensive overview of nickel based bimetallic catalysts for energy and environmental applications.

In this paper, NiRu, NiRh, and NiPd catalysts were synthesized and evaluated in the hydrogenolysis of lignin C− O bonds, which is proved to be superior over single-component catalysts. The optimized NiRu catalyst contains 85% Ni and 15% Ru, composed of Ni surface-enriched, Ru−Ni atomically mixed, ultrasmall nanoparticles. The Ni 85 Ru 15 catalyst showed high activity under low temperature (100 °C), low H 2 pressure (1 bar) in β-O-4 type C−O bond hydrogenolysis. It also exhibited significantly higher activity over Ni and Ru catalysts in the direct conversion of lignin into monomeric aromatic chemicals. Mechanistic investigation indicates that the synergistic effect of NiRu can be attributed to three factors: (1) increased fraction of surface atoms (compared with Ni), (2) enhanced H 2 and substrate activation (compared with Ni), and (3) inhibited benzene ring hydrogenation (compared with Ru). Similarly, NiRh and NiPd catalysts were more active and selective than their singlecomponent counterparts in the hydrogenolysis of lignin model compounds and real lignin.

We report a NaOH-mediated NaBH4 reduction method for the synthesis of mono-, bi-, and tri-thiolate-protected Au25 nanoclusters (NCs) with precise control of both the Au core and thiolate ligand surface. The key strategy is to use NaOH to tune the formation kinetics of Au NCs, i.e., reduce the reduction ability of NaBH4 and accelerate the etching ability of free thiolate ligands, leading to a well-balanced reversible reaction for rapid formation of thermodynamically favorable Au25 NCs. This protocol is facile, rapid (≤3 h), versatile (applicable for various thiolate ligands), and highly scalable (>1 g Au NCs). In addition, bi- and tri-thiolate-protected Au25 NCs with adjustable ratios of hetero-thiolate ligands were easily obtained. Such ligand precision in molecular ratios, spatial distribution and uniformity resulted in richly diverse surface landscapes on the Au NCs consisting of multiple functional groups such as carboxyl, amine, and hydroxy. Analysis based on NMR spectroscopy revealed that the hetero-ligands on the NCs are well distributed with no ligand segregation. The unprecedented synthesis of multi-thiolate-protected Au25 NCs may further promote the practical applications of functional metal NCs.