The project was supported by the Natural Science Foundation of Shandong Province, ChinaY2007B16;Scientific and Technological Innovation Project of Qingdao City, China06-02-2-13-jch;Research Project Grant of the State Key Physical Chemistry of Solid Surface, Xiamen University, China.山东省自然科学基金Y2007816;青岛科技创新计划6-02-2-13-ich;厦门大学固体表而物理化学国家重点实验室开放课题资助