1. Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, 1 Xuefu Road, Xi’an 710127, P. R. China
2. State Energy Key Lab of Clean Coal Grading Conversion Modern Chemical Technology Department, Shaanxi Key Laboratory of Low Rank Coal Pyrolysis, Shaanxi Coal and Chemical Technology Institute Co., Ltd., 2 Jinye Road, Xi’an 710065, P. R. China