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Revealing the Janus Character of the Coke Precursor in the Propane Direct Dehydrogenation on Pt Catalysts from a kMC Simulation
Lian, Zan1,2; Ali, Sajjad1,3; Liu, TianFu1,2; Si, Chaowei1,2; Li, Bo1; Su, Dang Sheng1
Corresponding AuthorLi, Bo(boli@imr.ac.cn) ; Su, Dang Sheng(dssu@imr.ac.cn)
2018-05-01
Source PublicationACS CATALYSIS
ISSN2155-5435
Volume8Issue:5Pages:4694-4704
AbstractAs the commercial catalyst in the propane direct dehydrogenation (PDH) reaction, one of the biggest challenges of Pt catalysts is coke formation, which severely reduces activity and stability. In this work, a first-principles DFT-based kinetic Monte Carlo simulation (kMC) is performed to understand the origin of coke formation, and an effective method is proposed to curb coke. The conventional DFT calculations give a complete description of the reaction pathway of dehydrogenation to propylene, deep dehydrogenation, and C-C bond cracking. The rate-limiting step is identified as the dissociative adsorption of propane. Moreover, a comparison between different exchange-correlation functionals indicates the importance of van der Waals corrections for the adsorption of propane and propylene. The lateral interactions between the surface adsorbates are significant, which implies that mean field microkinetic modeling might not adequately describe the reaction process. There are two distinct stages in PDH, which are quick deactivation and steady state, respectively, as revealed from the kMC simulation. The precursor of coke mainly formed during the quick deactivation. The calculations indicate that the geometries of the active sites for the dehydrogenation and deep reactions are different. Therefore, the availability of surface sites is a crucial factor in the formation of propylene and side products. The active sites from quick deactivation are mainly occupied by C-2/C-1 species, which are hard to remove. On the other hand, the surface sites that are left are mainly active toward dehydrogenation to propylene due to the geometry constraint. Therefore, a stable activity and selectivity is reached. Furthermore, the effect of hydrogen molecules in the input stream is also explored. The calculations indicate that the inclusion of hydrogen in PDH reactants not only enhances the forward reactions to the propylene formation but also reduces the consumption of the resulted propylene during the reaction. Therefore, hydrogen is very helpful to the selectivity increase in PDH in addition to other effects. Overall, the current study lays out a solid base for the future optimization of the Pt catalysts in PDH and we propose that the fine control of the surface sites on Pt has paramount importance in reducing coke formation.
Keywordpropane dehydrogenation kinetic Monte Carlo density functional theory platinum catalyst coke
Funding OrganizationNSFC ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Institute of Metal Research ; State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP, SINOPEC) ; Special Program for Applied Research on Super Computation of the NSFC Guangdong Joint Fund (the second phase)
DOI10.1021/acscatal.8b00107
Indexed BySCI
Language英语
Funding ProjectNSFC[21573255] ; NSFC[51521091] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDA09030103] ; Institute of Metal Research[Y3NBA211A1] ; State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP, SINOPEC) ; Special Program for Applied Research on Super Computation of the NSFC Guangdong Joint Fund (the second phase)[U1501501]
WOS Research AreaChemistry
WOS SubjectChemistry, Physical
WOS IDWOS:000431727300104
PublisherAMER CHEMICAL SOC
Citation statistics
Cited Times:20[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.imr.ac.cn/handle/321006/128549
Collection中国科学院金属研究所
Corresponding AuthorLi, Bo; Su, Dang Sheng
Affiliation1.Chinese Acad Sci, Shenyang Natl Lab Mat Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China
2.Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Liaoning, Peoples R China
3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
Recommended Citation
GB/T 7714
Lian, Zan,Ali, Sajjad,Liu, TianFu,et al. Revealing the Janus Character of the Coke Precursor in the Propane Direct Dehydrogenation on Pt Catalysts from a kMC Simulation[J]. ACS CATALYSIS,2018,8(5):4694-4704.
APA Lian, Zan,Ali, Sajjad,Liu, TianFu,Si, Chaowei,Li, Bo,&Su, Dang Sheng.(2018).Revealing the Janus Character of the Coke Precursor in the Propane Direct Dehydrogenation on Pt Catalysts from a kMC Simulation.ACS CATALYSIS,8(5),4694-4704.
MLA Lian, Zan,et al."Revealing the Janus Character of the Coke Precursor in the Propane Direct Dehydrogenation on Pt Catalysts from a kMC Simulation".ACS CATALYSIS 8.5(2018):4694-4704.
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