1. College of Chemistry Fuzhou University Fuzhou 350116 P. R. China
2. CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Provincial Key Laboratory of Nanomaterials Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter Fuzhou Fujian 350002 P. R. China
3. School of Materials Science and Engineering Fujian University of Technology Fuzhou 350108 P. R. China
4. University of Chinese Academy of Sciences Beijing 100049 P. R. China