Role of the Support Effects on the Catalytic Activity of Gold Clusters: A Density Functional Theory Study

Catalysts

Min Gao¹  Andrey Lyalin¹ 

[1] Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan; E-Mails:

关键词: nanocatalysis;    gold clusters;    support effect;    interface effect;    oxygen activation;    hydrogen dissociation;   

DOI  :  10.3390/catal1010018

来源: mdpi

【 摘 要 】

It is demonstrated that the support effects play a crucial role in the gold nanocatalysis. Two types of support are considered—the “inert” support of hexagonal boron nitride (h-BN) with the N and B vacancy defects and the “active” support of rutile TiO₂(110). It is demonstrated that Au and Au₂ can be trapped effectively by the vacancy defects in h-BN. In that case, the strong adsorption on the surface defects is accompanied by the charge transfer to/from the adsorbate. The excess of the positive or negative charge on the supported gold clusters can considerably promote their catalytic activity. Therefore gold clusters supported on the defected h-BN surface can not be considered as pseudo-free clusters. We also demonstrate that the rutile TiO₂(110) support energetically promotes H₂ dissociation on gold clusters. We show that the formation of the OH group near the supported gold cluster is an important condition for H₂ dissociation. We demonstrate that the active sites towards H₂ dissociation on the supported Au_n are located at corners and edges of the gold cluster in the vicinity of the low coordinated oxygen atoms on TiO₂(110). Thus catalytic activity of a gold nanoparticle supported on the rutile TiO₂(110) surface is proportional to the length of the perimeter interface between the nanoparticle and the support.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.