1. National Institute for Materials Science Namiki 1-1 Tsukuba Ibaraki 305-0044 Japan
2. Graduate School of Science and TechnologySaitama University Shimo-Okubo 255 Saitama 338-8570 Japan
3. Department of Materials Science and EngineeringSchool of Materials and Chemical TechnologyTokyo Institute of Technology Ookayama 2-12-1 Meguro-ku Tokyo 152–8552 Japan
4. Department of Chemical System EngineeringThe University of Tokyo Hongo 7-3-1 Bunkyo-ku Tokyo 113-8656 Japan
5. State Key Laboratory of Coal ConversionInstitute of Coal ChemistryChinese Academy of Sciences Taiyuan 030001 China