[1] Guangxi Univ, Sch Resources Environm & Mat, Nanning 530004, Peoples R China
[2] Chinese Acad Sci, Beijing Inst Nanoenergy & Nanosyst, Beijing 101400, Peoples R China
[3] Guangxi Univ, Ctr Nanoenergy Res, Sch Phys Sci & Technol, Nanning 530004, Peoples R China
[4] Univ Chinese Acad Sci, Sch Nanosci & Technol, Beijing 100049, Peoples R China
[5] Georgia Inst Technol, Atlanta, GA 30332 USA