Ru nanoclusters prepared by Ru-3(CO)(12) deposition on Au(111)

摘要

The adsorption and decomposition of Ru-3(CO)(12) on Au(1 1 1) at several substrate temperatures have been investigated by TDS, XPS and STM. The adsorption of Ru-3(CO)(12) is molecular at 90 K. Heating the surface covered with Ru-3(CO)(12) leads to the desorption of CO over a wide range of temperatures, which implies the gradual decomposition of the carbonyl molecules. The decarbonylation is complete at around 500 K, leaving metallic Ru on the surface. Carbonyl molecules are partially decomposed after adsorption at room temperature, forming islands of nanosized clusters preferentially located at the elbow sites of the Au(1 1 1) herringbone reconstruction. The remaining CO molecules desorb upon surface heat treatment, which promotes the mobility of the nascent metallic Ru nanoclusters and results in the non-coalescing aggregation of the nanoclusters. A recommended preparation of Ru nanoclusters is to deposit Ru-3(CO)(12) on gold at a substrate temperature of 500 K. This allows a fine control of Ru nanocluster coverages and lower level of carbon contamination in the deposited layer. (C) 2003 Elsevier Science B.V. All rights reserved. [References: 29]