1. Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, Hubei 430074, P. R. China
2. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
3. School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020, P. R. China