[1] Peking Univ, Dept Chem, State Key Lab Rare Earth Mat Chem & Applicat, Beijing 100871, Peoples R China
[2] Dalian Univ Technol, Ctr Nanomat & Sci, Carbon Res Lab, State Key Lab Fine Chem, Dalian 116012, Peoples R China
[3] Peking Univ, Sch Phys, Beijing 100871, Peoples R China