1. Materials Science and Engineering Physical Science and Engineering Division King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
2. Department of Applied Physics The Hong Kong Polytechnic University Hung Hom, Kowloon, Hong Kong 999077 P. R. China
3. State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China
4. Advanced Membranes and Porous Materials Center KAUST Catalysis Center Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia