1. School of Chemistry and Chemical Engineering Institute of Clean Energy and Materials Key Laboratory for Clean Energy and Materials Ministry of Education Guangzhou University Guangzhou Higher Education Mega Center No. 230, Wai Huan Xi Road Guangzhou 510006 P. R. China
2. Key Laboratory for Water Quality and Conservation of the Pearl River Delta Ministry of Education Guangzhou University Guangzhou Higher Education Mega Center No. 230, Wai Huan Xi Road Guangzhou 510006 P. R. China
3. School of Chemistry and Chemical Engineering Guangxi Key Laboratory of Electrochemical Energy Materials Guangxi University Nanning Guangxi 530004 P. R. China
4. Department of Chemistry and Biochemistry University of California Santa Cruz California 95064 USA