Insights into Ru Crystal Phase Regulated by Reducing Agent for the Catalytic Activity of Ammonia Synthesis  

还原剂调控的不同晶相纳米Ru催化剂对氨合成活性的影响

作　　者：WANG Dong-wei MA Zhan-wei LI Jing HU Bin 王东伟;马占伟;李静;胡斌(中国科学院兰州化学物理研究所低碳催化与二氧化碳利用全国重点实验室(筹)/羰基合成与选择氧化国家重点实验室,甘肃兰州730000;中国科学院大学,北京100049)

机构地区：[1]State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization/State Key Laboratory for Oxo Synthesis and Selective Oxidation,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《分子催化（中英文）》2024年第6期503-509,I0001,共8页Journal of Molecular Catalysis(China)

基　　金：The National Natural Science Foundation of China(22102194);The Science and Technology Plan of Gansu Province(24JRRA067,23ZDFA016);The Youth Innovation Promotion Association of CAS(2022427).

摘　　要：Ru nanoparticles with fcc and hcp crystal phases were obtained by chemical reduction method using different precursors and reducing agents,and their catalytic properties in ammonia synthesis were compared.The catalytic reaction rate(666.4μmol·h^(−1)·g^(−1))of fcc Ru catalyst is higher than that of hcp Ru(378.9μmol·h^(−1)·g^(−1))at the reaction temperature(400℃)and pressure(1 MPa).The results indicate that the exposed crystal faces have a certain impact on the catalytic activity.The dissociation ability to N_(2) of fcc Ru exposed(111)and(200)is better than that of hcp Ru exposed(100).When the ruthenium catalyst was loaded on rod-like CeO_(2) support,the ammonia synthesis activity was further improved.The ammonia synthesis activity of fcc Ru/CeO_(2) is 1.4 times higher than that of hcp Ru/CeO_(2) under the test conditions.通过调控前驱体和还原剂,采用化学还原法制备了具有不同晶相的Ru纳米颗粒,分别为fcc Ru和hcp Ru.研究了Ru晶相对氨合成反应活性的影响,发现fcc Ru主要暴露的(200)和(111)晶面对N_(2)的解离要优于传统hcp Ru的(100)晶面,具有较高的氨合成活性.在400℃,1 MPa的测试条件下,fcc Ru催化剂的反应速率为666.4μmol·h^(−1)·g^(−1),是hcp Ru(378.9μmol·h^(−1)·g^(−1))的1.76倍.进一步将两种晶相的Ru负载在CeO_(2)载体上,所得氨合成活性进一步提高,fcc Ru/CeO_(2)的氨合成活性仍高于hcp Ru/CeO_(2),说明Ru的晶相对氨合成活性的影响占主导因素.

关 键 词：Ru nanocatalyst crystal phase control ammonia synthesis 

分 类 号：O643.36[理学—物理化学]