Influences of MgO(001) and TiO2(101) Supports on the Structures and Properties of Au Nanoclusters

Abstract

Due to the unique structures, photoelectric properties, good catalytic activity, and broad potential applications, gold nanoclusters (Au n ) received extensive attention in catalysis, bioengineering, environmental engineering, and so on. In the present work, the structures and properties of Au n adsorbed on the MgO(001) and TiO 2 (101) surfaces were investigated by density functional theory. The results showed that the catalytic properties of Au n will be enhanced when Au n is adsorbed on certain supports. Because the difference of the outer electronic structure of metals in supports, the direction of the charge transfer was different, thus inducing the different charge distribution on Au n . When Au n was adsorbed on MgO(001) [TiO 2 (101)] surface, Au n will have negative [positive] charges and thus higher catalytic activity in oxidation [reduction] reaction. The variation of surface charges caused by the support makes Au n possess different catalytic activity in different systems. Moreover, the electronic structure of the support will make an obvious influence on the s and d density of states of Au n , which should be the intrinsic reason that induces the variations of its structure and properties. These results should be an important theoretical reference for designing Au n as the photocatalyst applied to the different oxidation and reduction reactions.

Going for Gold(-Standard): Attaining Coupled Cluster Accuracy in Oxide-Supported Nanoclusters

“…43 There are even discrepancies in the global minimum structure prediction in the planar 2D regime for PBE, with some suggesting planar 2D structures that lie either perpendicular 37,43,44 or parallel to the surface. 19,41,45,46 By augmenting the PBE functional with the D3 dispersion correction, Engel et al 41 have actually found that planar parallel structures exist up until Au 19 �their largest studied nanocluster�and we show it extends up to Au 20 as well in this study. PBE-D3 is perhaps the most common DFT model used in surface chemistry, but alarmingly, these predictions by Engel et al 41 are in stark contrast to the 3D tetrahedral structure (see Figure 1) predicted by other studies 19,43,47 as well as strong experimental evidence.…”