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Understanding the nature of NH3-coordinated active sites and the complete reaction schemes for NH3-SCR using Cu-SAPO-34 catalysts.
Yang, Guangpeng; Ran, Jingyu; Du, Xuesen; Wang, Xiangmin; Ran, Zhilin; Chen, Yanrong; Zhang, Li; Crittenden, John.
Affiliation
  • Yang G; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China. ranjy@cqu.edu.cn xuesendu@cqu.edu.cn.
  • Ran J; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China. ranjy@cqu.edu.cn xuesendu@cqu.edu.cn.
  • Du X; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China. ranjy@cqu.edu.cn xuesendu@cqu.edu.cn.
  • Wang X; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China. ranjy@cqu.edu.cn xuesendu@cqu.edu.cn.
  • Ran Z; School of Transportation and Environment, Shenzhen Institute of Information Technology, Shenzhen, 518172, China.
  • Chen Y; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China. ranjy@cqu.edu.cn xuesendu@cqu.edu.cn.
  • Zhang L; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China. ranjy@cqu.edu.cn xuesendu@cqu.edu.cn.
  • Crittenden J; Brook Byers Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Phys Chem Chem Phys ; 23(8): 4700-4710, 2021 Mar 04.
Article in En | MEDLINE | ID: mdl-33595551
Cu-SAPO-34 zeolite catalysts show excellent NH3-SCR performance at low temperature, which is due to the catalytic capacity of copper species. Isolated CuII ions and CuIIOH are active sites, but their nature and role are not fully understood. This paper reports the DFT calculations in combination with ab initio thermodynamics to investigate NH3 and H2O coordination to copper species under typical NH3-SCR reaction conditions. In the reduction part of the NH3-SCR reaction, NH2NO and NH4NO2 intermediates will form on CuII-2NH3/3NH3 and CuIIOH-2NH3 complexes, respectively. The Brønsted acid sites are crucial for the decomposition of these intermediates, rather than copper species. Furthermore, the decomposition of NH2NO is more energetically favorable than NH4NO2 which are formed on the Brønsted acid sites. In the re-oxidation part of the NH3-SCR reaction, O2 dissociation and NO2 formation occur on CuI-2NH3 complexes in the presence of NO, and the regeneration of CuIIOH-2NH3 requires the participation of H2O. The proposed complete mechanisms highlight the importance of ligand coordinated copper species for intermediate formation and O2 activation in NH3-SCR.

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Phys Chem Chem Phys Journal subject: BIOFISICA / QUIMICA Year: 2021 Document type: Article Country of publication: United kingdom

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Phys Chem Chem Phys Journal subject: BIOFISICA / QUIMICA Year: 2021 Document type: Article Country of publication: United kingdom