1. Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, P. R. China
2. Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130, P. R. China
3. Department of Chemical & Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z3, Canada