1. Tianjin Key Laboratory of Membrane and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, P. R. China
2. Department of Chemistry, School of Science, Tianjin University, Tianjin 300350, P. R. China
3. National Institute of Clean-and-Low-Carbon Energy, Future Science City, Changping District, Beijing 102211, P. R. China
4. School of Physics and Mathematics, CBC, Nanyang Technological University, Singapore 639798