The growth and thermal stability of Au clusters on a partially-reduced rutile TiO2 （110）-1 × 1 surface were investigated by high-resolution photoelectron spectroscopy using synchrotron- radiation-light. The val...The growth and thermal stability of Au clusters on a partially-reduced rutile TiO2 （110）-1 × 1 surface were investigated by high-resolution photoelectron spectroscopy using synchrotron- radiation-light. The valence-band photoelectron spectroscopy results demonstrate that the Ti^3＋3d feature attenuates quickly with the initial deposition of Au clusters, implying that Au clusters nucleate at the oxygen vacancy sites. The Au4f core-level photoelectron spectroscopy results directly prove the existence of charge transfer from oxygen vacancies to Au clusters. The thermal stability of Au clusters on the partially-reduced and stoichiometric TiO2（110） surfaces was also comparatively investigated by the annealing experiments. With the same film thickness, Au clusters are more thermally stable on the partially-reduced TiO2（110） surface than on the stoichiometric TiO2（110） surface. Meanwhile, large Au nanoparticles are more thermally stable than fine Au nanoparticles.展开更多
Well-defined gold nanoclusters with average size less than 2 nm have emerged as a new and novel catalyst. The gold nanocluster loaded on the oxide surface usually aggregates to larger particles at high temperature （...Well-defined gold nanoclusters with average size less than 2 nm have emerged as a new and novel catalyst. The gold nanocluster loaded on the oxide surface usually aggregates to larger particles at high temperature （〉 300℃）, which is caused by the removal of the surface ligands. We herein pre-sent a novel method to prepare Au25cluster catalyst （-1.3 nm） with high thermal stability （up to 400℃）. Au25@Si02 is synthesized via a co-hydrolyzing reaction of Au2s[SC3H6Si（OCH3）3118 and tet-raethyl orthosilicate, and then it is treated at different temperature （e.g., 200, 300, 400℃） in air to remove the organic ligands. Au25@SiO2 is well characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and diffuse reflectance UV-vis spectroscopy. Further, the Au2s@SiO2 catalysts are investigated in the hydrogenation ofp-nitrophenol into p-aminophenol.展开更多
With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new cluste...With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new clusters, the aluminum core-frame acts as a super-atom with n vertexes and 2n A1-A1 edges, which allow to adsorb n hydrogen atoms at the top-site and 2n at the bridge-site. Using Al12H36 as the basic unit, stable chain structures, （Al12H36）m, have been constructed following the same connection mechanism as for （A1H3）n linear polymeric structures. Apart from high hydrogen percentage per molecule, calculations have shown that these new clusters possess large heat of formation values and their combustion heat is about 4.8 times of the methane, making them a promising high energy density material.展开更多
Polymer‐stabilized Au nano clusters （NCs） with mean diameters of 2–10 nm exhibit unique catalytic properties. Several studies have shown that the key factors affecting the catalytic activity of poly‐mer‐stabiliz...Polymer‐stabilized Au nano clusters （NCs） with mean diameters of 2–10 nm exhibit unique catalytic properties. Several studies have shown that the key factors affecting the catalytic activity of poly‐mer‐stabilized Au NCs are control of the Au NC size, appropriate selection of polymers and optimi‐zation of the reaction conditions. This is because polymer‐stabilized Au NCs exhibit a clear size effect in several catalytic reactions, and the catalytic activity differs with the type of polymer used and the reaction conditions. In order to elucidate the reason underlying the catalytic activity of the polymer‐stabilized Au NCs, much attention is being devoted to the interplay of theoretical calcula‐tions and experiments in catalysis by polymer stabilized Au NCs. The present article mainly summa‐rizes our progress in understanding this interplay in polymer‐stabilized Au NC catalysis.展开更多
Protein protected gold nanoclusters have outstanding physical and chemical properties that make them excellent scaffolds for the construction of novel chemical and biological probes. In this study, a simple one-pot sy...Protein protected gold nanoclusters have outstanding physical and chemical properties that make them excellent scaffolds for the construction of novel chemical and biological probes. In this study, a simple one-pot synthesis method was proposed for the preparation of fluorescent probes based on ovalbumin-stabilized gold nanoclusters. This strategy allowed the generation of water-soluble gold nanoclusters within 5 min. The as-prepared fluorescent probe exhibited a red fluorescence emission at 625 nm, and good thermostability. The fluorescent probe was applied to measure glucose concentrations based on the hydrogen peroxide-induced fluorescence quenching principle, and showed favorable biocompatibility, high sensitivity and good selectivity. As a result of the advantageous properties and performance of this fluorescent probe, the present assay allowed for the selective determination of glucose in the range of 5.0×10-6 to 10.0×10-3 mol/L with a detection limit of 1.0×10?6 mol/L. Moreover, the glucose content in urinary samples was analyzed using the constructed fluorescent probe: this indicated the potential of the fluorescent gold nanoclusters for applications in biological and clinical diagnosis and therapy.展开更多
While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique...While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way展开更多
In this work, we fabricated the poly（N-vinyl-2-pyrrolidone） （PVP）-stabilized ruthenium（0） nanoclusters by reduction of RuC13 using different reducing agents, and studied their catalytic activity in hydrogen gene...In this work, we fabricated the poly（N-vinyl-2-pyrrolidone） （PVP）-stabilized ruthenium（0） nanoclusters by reduction of RuC13 using different reducing agents, and studied their catalytic activity in hydrogen generation from the decomposition of formic acid. It was demonstrated that N-vinyl-2-pyrrolidone （NVP）, which is a monomer of PVP, could promote the reaction by coordination with Ru nanoparticles. The Ru nanoparticles catalyst reduced by sodium borohydride （NaBH4） exhibited highest catalytic activity for the decomposition of formic acid into H2 and CO2. The turnover of numenber （TOF） value could reach 26113 h-1 at 80 ℃. We believe that the effective catalysts have potential of application in hydrogen storage by formic acid.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20773113 and No.20803072）, the Hundred Talent Program of Chinese Academy of Sciences, the MOE Program for Changjiang Scholars and Innovative Research Team （No.IRT0756）, and the MPG-CAS Partner-group Program.
文摘The growth and thermal stability of Au clusters on a partially-reduced rutile TiO2 （110）-1 × 1 surface were investigated by high-resolution photoelectron spectroscopy using synchrotron- radiation-light. The valence-band photoelectron spectroscopy results demonstrate that the Ti^3＋3d feature attenuates quickly with the initial deposition of Au clusters, implying that Au clusters nucleate at the oxygen vacancy sites. The Au4f core-level photoelectron spectroscopy results directly prove the existence of charge transfer from oxygen vacancies to Au clusters. The thermal stability of Au clusters on the partially-reduced and stoichiometric TiO2（110） surfaces was also comparatively investigated by the annealing experiments. With the same film thickness, Au clusters are more thermally stable on the partially-reduced TiO2（110） surface than on the stoichiometric TiO2（110） surface. Meanwhile, large Au nanoparticles are more thermally stable than fine Au nanoparticles.
基金supported by the National Natural Science Foundation of China (21273231, 21422308)Dalian Excellent Youth Foundation (2014J11JH126) (FW)the Starting Funds of “Thousand Youth Talents Plan” (GL)~~
文摘Well-defined gold nanoclusters with average size less than 2 nm have emerged as a new and novel catalyst. The gold nanocluster loaded on the oxide surface usually aggregates to larger particles at high temperature （〉 300℃）, which is caused by the removal of the surface ligands. We herein pre-sent a novel method to prepare Au25cluster catalyst （-1.3 nm） with high thermal stability （up to 400℃）. Au25@Si02 is synthesized via a co-hydrolyzing reaction of Au2s[SC3H6Si（OCH3）3118 and tet-raethyl orthosilicate, and then it is treated at different temperature （e.g., 200, 300, 400℃） in air to remove the organic ligands. Au25@SiO2 is well characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and diffuse reflectance UV-vis spectroscopy. Further, the Au2s@SiO2 catalysts are investigated in the hydrogenation ofp-nitrophenol into p-aminophenol.
基金This work was supported by the Swedish Research Council, Swedish National Infrastructure for Computing, the National Natural Science Foundation of China （No.10534010 and No.20925311）, the Funda-mental Research Funds for the Central Universities （No.201103255）, and the China Scholarship Council.
文摘With the concept of super-atom, first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters, AlnHn＋2. In the new clusters, the aluminum core-frame acts as a super-atom with n vertexes and 2n A1-A1 edges, which allow to adsorb n hydrogen atoms at the top-site and 2n at the bridge-site. Using Al12H36 as the basic unit, stable chain structures, （Al12H36）m, have been constructed following the same connection mechanism as for （A1H3）n linear polymeric structures. Apart from high hydrogen percentage per molecule, calculations have shown that these new clusters possess large heat of formation values and their combustion heat is about 4.8 times of the methane, making them a promising high energy density material.
基金supported by Japan Science and Technology Agency (JST)Advanced Low Carbon Technology Research and Development Program (ALCA)Core Research for Evolutional Science and Technology (CREST)
文摘Polymer‐stabilized Au nano clusters （NCs） with mean diameters of 2–10 nm exhibit unique catalytic properties. Several studies have shown that the key factors affecting the catalytic activity of poly‐mer‐stabilized Au NCs are control of the Au NC size, appropriate selection of polymers and optimi‐zation of the reaction conditions. This is because polymer‐stabilized Au NCs exhibit a clear size effect in several catalytic reactions, and the catalytic activity differs with the type of polymer used and the reaction conditions. In order to elucidate the reason underlying the catalytic activity of the polymer‐stabilized Au NCs, much attention is being devoted to the interplay of theoretical calcula‐tions and experiments in catalysis by polymer stabilized Au NCs. The present article mainly summa‐rizes our progress in understanding this interplay in polymer‐stabilized Au NC catalysis.
基金supported by the National Natural Science Foundation of China(21375132,21175138,21321003,21171114,91222202)the National Basic Research Program of China(2013CB834803)
文摘Protein protected gold nanoclusters have outstanding physical and chemical properties that make them excellent scaffolds for the construction of novel chemical and biological probes. In this study, a simple one-pot synthesis method was proposed for the preparation of fluorescent probes based on ovalbumin-stabilized gold nanoclusters. This strategy allowed the generation of water-soluble gold nanoclusters within 5 min. The as-prepared fluorescent probe exhibited a red fluorescence emission at 625 nm, and good thermostability. The fluorescent probe was applied to measure glucose concentrations based on the hydrogen peroxide-induced fluorescence quenching principle, and showed favorable biocompatibility, high sensitivity and good selectivity. As a result of the advantageous properties and performance of this fluorescent probe, the present assay allowed for the selective determination of glucose in the range of 5.0×10-6 to 10.0×10-3 mol/L with a detection limit of 1.0×10?6 mol/L. Moreover, the glucose content in urinary samples was analyzed using the constructed fluorescent probe: this indicated the potential of the fluorescent gold nanoclusters for applications in biological and clinical diagnosis and therapy.
文摘While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way
基金supported by the Recruitment Program of Global Youth Experts of China, Chinese Academy of Sciences (KJCX2.YW.H30)the National Natural Science Foundation of China (21533011, 21321063)
文摘In this work, we fabricated the poly（N-vinyl-2-pyrrolidone） （PVP）-stabilized ruthenium（0） nanoclusters by reduction of RuC13 using different reducing agents, and studied their catalytic activity in hydrogen generation from the decomposition of formic acid. It was demonstrated that N-vinyl-2-pyrrolidone （NVP）, which is a monomer of PVP, could promote the reaction by coordination with Ru nanoparticles. The Ru nanoparticles catalyst reduced by sodium borohydride （NaBH4） exhibited highest catalytic activity for the decomposition of formic acid into H2 and CO2. The turnover of numenber （TOF） value could reach 26113 h-1 at 80 ℃. We believe that the effective catalysts have potential of application in hydrogen storage by formic acid.
