1. State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
2. School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 10083, P. R. China
3. State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454003, P. R. China
4. Laboratory of Nanosystem and Hierarchy Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
5. New Energy (Photovoltaic) Industry Research Center, Qinghai University, Xining 810016, P. R. China