1. School of Materials Science and Engineering Shandong University of Science and Technology Qingdao 266590 China
2. Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong 999077 China
3. Energy Institute, and Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong 999077 China