▎ 摘　　要

Gold nanoparticles have been extensively studied for their catalytic activity both theoretically and experimentally. The moire pattern formed by graphene supported on single crystal substrates creates a useful environment where the properties of Au nanoclusters can be studied, provided the structure and evolution of these clusters can be controlled. We used a genetic algorithm combined with DFT calculations to predict the lowest energy structures of a Au-8 cluster on graphene/Ru(0001). The most stable cluster forms a double-layer Au wall structure for Au-8 in the fcc region of the moire pattern, where the Au-8 cluster is most strongly adsorbed. Further calculations give estimates for the net diffusion barrier of Au-8 as an intact cluster on the surface. Our results are consistent with the Au island structure experimentally observed on graphene/Ru(0001), and support the hypothesis that Au clusters aggregate through Oswald ripening with Au dimers being the most important diffusing species. (C) 2014 Elsevier B.V. All rights reserved.