CIESC Journal ›› 2021, Vol. 72 ›› Issue (3): 1382-1391.DOI: 10.11949/0438-1157.20200876

• Catalysis, kinetics and reactors • Previous Articles     Next Articles

DFT study on reduction of NO over Pd atom anchored on single-vacancy graphene

ZHANG Fangfang1(),HAN Min1,ZHAO Juan1,LING Lixia1(),ZHANG Riguang2,WANG Baojun2   

  1. 1.College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
    2.Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
  • Received:2020-07-03 Revised:2020-09-03 Online:2021-03-05 Published:2021-03-05
  • Contact: LING Lixia

单空缺石墨烯负载的Pd单原子催化剂上NO还原的密度泛函理论研究

张芳芳1(),韩敏1,赵娟1,凌丽霞1(),章日光2,王宝俊2   

  1. 1.太原理工大学化学化工学院,山西 太原 030024
    2.太原理工大学煤科学与技术教育部和山西省重点实验室,山西 太原 030024
  • 通讯作者: 凌丽霞
  • 作者简介:张芳芳(1993—),女,硕士研究生,2585840998@qq.com
  • 基金资助:
    国家自然科学基金重点项目(21736007);国家自然科学基金面上项目(21576178);山西省回国留学人员科研资助项目(2016-030)

Abstract:

The mechanism of NO reduction with H2 on Pd atom anchored on single-vacancy graphene (Pd/SVG) was studied by the density functional theory (DFT) method. The formation pathways of N2 and NH3 by NO reduction on Pd/SVG were explored. The activation of NO to HNO on Pd/SVG is more likely to occur, and the energy barrier is 67.0 kJ·mol-1, showing a very high catalytic activity. The mechanisms of NO reduction with H2 to N2 and NH3 on Pd/SVG were clarified. The favorable formation route of N2 is that the hydrogenation of NO leads to HNO, HNO continues to hydrogenate through intermediates NH2O and NH2OH, and then NH2OH dissociates to generate NH2 and OH. The generated NH2 intermediate combines with NO to form NH2NO, and then NHNOH was formed by the isomerization of NH2NO, finally NHNOH was dissociated to N2 and H2O. From NO activation to the formation of intermediate NH2, the favorable route of NH3 is the same as that of N2, and then NH2 hydrogenation leads to NH3. The energy barriers of rate-determining steps for the formation of N2 and NH3 are 144.3 and 86.4 kJ·mol-1, respectively. In addition, Pd/SVG catalyst shows higher selectivity to NH3 than N2, indicating that NH3 is the main product. This study will provide a theoretical reference for the experiment and industrial application of H2 reduction of NO on graphene-supported Pd-based catalysts.

Key words: Pd single atom catalyst, reactivity, SCR, hydrogen, density functional theory

摘要:

采用密度泛函理论(DFT)方法对单空缺石墨烯负载的Pd单原子(Pd/SVG)催化剂上H2还原NO的反应进行了研究,探究了Pd/SVG上NO还原生成N2和NH3的路径。在Pd/SVG上NO容易加氢形成HNO,需要的活化能为67.0 kJ·mol-1,显示了极高的催化活性。N2生成的有利路径为NO活化生成HNO后,HNO继续加氢生成中间体NH2O和NH2OH,然后NH2OH解离生成NH2和OH,生成的NH2中间体结合NO形成NH2NO,然后NH2NO异构化形成的NHNOH再经解离生成N2与H2O,这个过程中的决速步骤为NH2NO分子内氢转移生成NHNOH,能垒为144.3 kJ·mol-1。对于NH3的生成,从NO的活化到中间体NH2的形成与N2的形成过程相同,最后NH2加氢即可形成NH3,这个过程中的决速步骤为NH2O加氢生成NH2OH,能垒为86.4 kJ·mol-1。比较生成N2和NH3的决速步能垒可见,Pd/SVG催化剂上NO经H2还原更容易形成NH3。本研究为石墨烯负载型Pd基催化剂上H2还原NO的实验及工业应用提供理论参考。

关键词: Pd单原子催化剂, 活性, 选择催化还原, H2, 密度泛函理论

CLC Number: