Controlled Loading of Small Au-n Clusters (n=10-39) onto BaLa4Ti4O15 Photocatalysts: Toward an Understanding of Size Effect of Cocatalyst on Water-Splitting Photocatalytic Activity

作者：Negishi Yuichi^*; Matsuura Yoshiki; Tomizawa Ryota; Kurashige Wataru; Niihori Yoshiki; Takayama Tomoaki; Iwase Akihide; Kudo Akihiko

来源：Journal of Physical Chemistry C, 2015, 119(20): 11224-11232.

DOI：10.1021/jp5122432

We have recently succeeded in loading extremely small monodisperse gold clusters (1.2 +/- 0.3 nm) as cocatalysts on a water-Splitting BaLa4Ti4O15 photocatalyst using a glutathione-protected Au-25 cluster (Au-25(SG)(18)) as a precursor; an improved photo catalytic activity of 2.6-fold was obtained when compared with that of BaLa4Ti4O15 onto which large gold nanoparticles (10-30 nm) were loaded. In the current study, the controlled loading of a series of ultrasmall Au-n clusters onto BaLa4Ti4O15 using various Au-n(SG)(m) clusters (n = 10, 15, 18, 22, 25, 29, 33, 39) was examined. The results revealed that the use of a highly stable cluster as a precursor is essential fat achieving control over the loading of the gold clusters. Additionally, the origin of the improved photocatalytic activity owing to the ultra miniaturization of the cocatalyst was reconsidered herein based on the photocatalytic activities of the obtained photocatalysts. The results strongly suggested that the activity per gold atom on the surface decreased significantly owing to the ultra miniaturization of the cocatalyst and that the origin of the improved activity is the increase in the number of surface gold atoms at a rate that overcomes the reduction effect in their activity.

• 出版日期2015-5-21