Controlled Thiolate-Protected Gold and Alloy Clusters

Small metal clusters exhibit physical and chemical properties that differ substantially from those of corresponding bulk metals. Furthermore, the properties of clusters vary greatly depending on the number of constituent atoms. Metal clusters with these characteristics currently attract great attention in a wide range of fields as new nanoscale functional materials. In recent years, the techniques to precisely synthesize metal clusters protected with organic ligands and polymers with atomic precision have advanced dramatically. In addition, substantial knowledge of the size-specific physical/chemical properties exhibited by these metal clusters has been accumulated. In this chapter, we describe the precise synthesis methods of the most studied thiolate (SR)-protected gold clusters Aun(SR)m and their heteroatom-substituted clusters (alloy clusters)

Au25 cluster-loaded SrTiO3 water-splitting photocatalyst; preparation and elucidation of the effect of cocatalyst refinement on photocatalytic activity

Water-splitting photocatalysts have attracted much attention for decades as materials to produce clean and renewable hydrogen (H2) as a fuel. In this study, we succeeded in precisely loading ultrafine gold cocatalyst particles (Au25 clusters) on the water-splitting photocatalyst SrTiO3 using glutathionate-protected Au25 clusters as a precursor. Photocatalysis experiments using the obtained photocatalyst revealed that the ultraminiaturization of the Au cocatalyst on SrTiO3 improves its water-splitting activity. The main reason for this improvement was attributed to the acceleration of the H2-evolution reaction caused by the ultra-miniaturization of the cocatalyst. This effect of refining the cocatalyst differs from that of Au-loaded BaLa4Ti4O15. These results demonstrate that the effect of ultra-miniaturization of the cocatalyst on photocatalytic activity varies depending on the photocatalyst

Toward the Creation of Highly Active Photocatalysts That Convert Methane into Methanol

Methane exists abundantly around Japan as methane hydrate. As the effective use of such methane, the conversion of methane into methanol has recently attracted much attention. Photocatalytic reaction is one of the methods which convert methane into methanol without using much energy. However, it is indispensable to improve the photocatalytic activity for their practical use. Our group has attempted to improve the activity of mesoporous tungsten trioxide and titanium dioxide (m-WO3 and m-TiO2) photocatalysts, which convert methane into methanol, by loading the ultrafine metal clusters as cocatalyst on the photocatalysts. As a result, we have succeeded in loading ultrafine metal-cluster cocatalysts onto m-WO3 and m-TiO2 and thereby improving their photocatalytic activity. Our study also demonstrated that the kind of metal element suitable for each photocatalyst depends on the kind of the photocatalysts, and thereby it is important to select the metal clusters suitable for each photocatalyst for improving its photocatalytic activity

Ligand-Protected Gold Clusters

Small gold clusters with diameters less than or equal to 2 nm (below approximately 200 atoms) possess geometric and electronic structures different from bulk gold. When these gold clusters are protected by ligands, these clusters can be treated as chemical compounds. This review focuses on gold clusters protected by chalcogenate (thiolate, selenolate, or tellurolate) ligands and describes the methods by which these clusters are synthesized as well as their geometric/electronic structures and physical and chemical properties. Recent findings regarding ligand exchange reactions, which may be used to impart functionality to these compounds, are also described

STM/STSによる金サブナノクラスターの電子構造の研究

2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

STM/STSによる金サブナノクラスターの電子構造の研究

2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

STM/STSによる金サブナノクラスターの電子構造の研究

2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

STM/STSによる金サブナノクラスターの電子構造の研究

2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

Isolation and structural characterization of magic silver clusters protected by 4-(tert-butyl)benzyl mercaptan

Small silver clusters (average diameter of 1.2 nm) protected by 4-(tert-butyl)benzyl mercaptan (BBSH) were converted to stable, monodisperse clusters (2.1 nm) by a ripening process with excess amount of BBSH. Multiple characterizations of the isolated magic clusters revealed an approximate chemical composition of Ag∼280(SBB)∼120