1. State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China
2. School of Applied Chemistry and Engineering University of Science and Technology of China Hefei Anhui 230026 P. R. China
3. Key Laboratory of Preparation and Applications of Environmental Friendly Materials Ministry of Education Jilin Normal University Changchun 130103 P. R. China
4. Department of Chemistry Tsinghua University Beijing 100084 P. R. China