University of Illinois at Chicago, Department of Chemical Engineering, Chicago, IL 60607, USA.
Phys Chem Chem Phys. 2010 Feb 14;12(6):1264-70. doi: 10.1039/b914323h. Epub 2009 Dec 9.
The Al(2)O(3)/Ni(3)Al(111) surface has been used as a template for the nucleation and growth of rhodium clusters using an organometallic precursor: Rh(CO)(2)(acac). When Rh(CO)(2)(acac) is deposited on the Al(2)O(3)/Ni(3)Al(111) surface, the molecule is observed to bind preferentially to specific sites associated with the film superstructure (known as the dot structure) and appears to be stable at temperatures up to 473 K at which point some sintering and aggregation processes begin. Annealing the sample to 673 K results in further sintering of the metal deposits as well as an apparent loss in the coverage of rhodium species possibly due to a combination of desorption and deligation. After annealing to 873 K the coverage of rhodium species decreases by about 50% with respect to the initial deposited coverage. Our results suggest that using an organometallic precursor rather than metal atoms to form deposited metal particles on oxide substrates may result in increased resistance to sintering processes.
采用有机金属前驱体 Rh(CO)(2)(acac)，在 Al(2)O(3)/Ni(3)Al(111)表面上进行了铑团簇成核和生长的模板实验。当 Rh(CO)(2)(acac)沉积在 Al(2)O(3)/Ni(3)Al(111)表面上时，该分子优先结合到与薄膜超结构（称为点结构）相关的特定位置上，并且在高达 473 K 的温度下似乎稳定，此时开始发生一些烧结和聚集过程。将样品退火至 673 K 会导致金属沉积物进一步烧结，以及铑物种的覆盖率明显降低，这可能是由于解吸和脱配的结合。退火至 873 K 后，铑物种的覆盖率相对于初始沉积覆盖率降低了约 50%。我们的结果表明，在氧化物衬底上使用有机金属前驱体而不是金属原子来形成沉积金属颗粒，可能会增加对烧结过程的抵抗力。
