1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, CAS, Changchun 130022, China
2. University of Science and Technology of China, Hefei 230026, P. R. China
3. Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
4. Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea