Acta Chimica Sinica ›› 2022, Vol. 80 ›› Issue (6): 788-796.DOI: 10.6023/A22010057 Previous Articles     Next Articles



张谭a,c, 余钟亮b,*(), 余嘉祺b, 万慧凝b, 包成宇b, 涂文强b, 杨颂c,d   

  1. a 太原理工大学省部共建煤基能源清洁高效利用国家重点实验室 太原 030024
    b 上饶师范学院化学与环境科学学院 上饶 334000
    c 山西省民用洁净燃料工程研究中心 太原 030024
    d 太原理工大学化学工程与技术学院 太原 030024
  • 投稿日期:2022-01-30 发布日期:2022-07-07
  • 通讯作者: 余钟亮
  • 基金资助:
    国家自然科学基金(22169017); 国家自然科学基金(51976226); 江西省教育厅科技项目(GJJ201709)

Chemical Looping Ammonia Synthesis with High Performance Supported Molybdenum-based Nitrogen Carrier

Tan Zhanga,c, Zhongliang Yub(), Jiaqi Yub, Huining Wanb, Chengyu Baob, Wenqiang Tub, Song Yangc,d   

  1. a State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, China
    b College of Chemistry and Environmental Sciences, Shangrao Normal University, Shangrao 334000, China
    c Shanxi Engineering Center of Civil Clean Fuel, Taiyuan 030024, China
    d College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, China
  • Received:2022-01-30 Published:2022-07-07
  • Contact: Zhongliang Yu
  • Supported by:
    National Natural Science Foundation of China(22169017); National Natural Science Foundation of China(51976226); Science and Technology Project of Jiangxi Education Department(GJJ201709)

Ammonia is not only a vital source of fertilizers production, but also a hydrogen carrier with high energy density, which has the potential to replace the traditional fossil fuels. However, the industrial route for ammonia production (Haber-Bosch process) is a highly energy-intensive process owing to the harsh operating conditions requirement. It is important to develop a novel ammonia synthesis process with mild operating conditions. Chemical looping ammonia synthesis (CLAS) is known to be an innovative and environmentally-friendly low-pressure ammonia synthesis technology, which separates the overall ammonia synthesis reaction into nitrogen release and replenish reactions facilitated with a nitrogen carrier (NC). NC with high efficiencies is the key to the the practical feasibility of CLAS technology. In this work, the supported molybdenum-based NCs were prepared with ammonium molybdate, hexamethylenetramine, and ZSM-5 zeolites through a facile pyrolysis method at different temperatures, and the performance of N-release, N-fixation, and the cyclic CLAS of NCs were studied in detail. The results indicate that the supported molybdenum-based NC pyrolyzed at 450 ℃ outperformed other NCs with an average NH3 production rate of ca. 20000 μmol•g-1•h-1, which is two or three orders of magnitude higher than that of the known metal nitrides under similar conditions. Bulk and surface analyses of NCs indicated the migration of lattice nitrogen of NC during the direct hydrogenation step for NH3 formation. At N-fixation stage, the nitrogen vacancy of molybdenum-based NC is expected to be recharged from N2. However, the low kinetics is an important problem of NC nitridation. With the introduction of H2, the nitridation kinetics of NC was significantly enhanced, improving the NC regeneration. During a 12-cycle test at 600 ℃ and atmospheric pressure, and the ammonia production rate was stabilized at ca. 1500 μmol•g-1•h-1 for each cycle. This article investigated the preliminary feasibility of the supported molybdenum-based nitride as NC during the process of CLAS and could provide a theoretical basis for the design and development of new types of NCs.

Key words: chemical looping ammonia synthesis, supported molybdenum-based nitrogen carrier, ammonia, nitrogen release, nitrogen fixation