1. Laboratory of Clean Energy Chemistry and MaterialsState Key Laboratory of Solid LubricationLanzhou Institute of Chemical PhysicsChinese Academy of Sciences Lanzhou 730000 P. R. China
2. Key Laboratory of Metallurgical Emission Reduction & Resources RecyclingAnhui University of TechnologyMinistry of Education Maanshan 243000 P. R. China
3. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100080 P. R. China
4. Department of PhysicsSchool of ScienceLanzhou University of Technology Lanzhou 730050 P. R. China
5. School of Materials Science and EngineeringShanghai University Shanghai 200444 P. R. China
6. Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of Sciences Dalian 116000 P. R. China