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143 results on '"Sui, Zhi-Jun"'

11. Enhanced C–H Bond Activation by a Concerted Mechanism: A Comparative Microkinetic Analysis of Propane Dehydrogenation over Single-Pt-Doped θ- and γ-Al2O3Catalysts

Author

Hu, Ping, Zeeshan, Muhammad, Yang, Ming-Lei, Lei, Ming, Sui, Zhi-Jun, Zhou, Xing-Gui, Chen, De, and Zhu, Yi-An

Abstract

Alumina is among the most widely used supports in the field of heterogeneous catalysis. In this work, DFT calculations and microkinetic analysis have been combined to examine the catalytic behaviors of θ- and γ-Al2O3-supported Pt single atom catalysts in propane dehydrogenation (PDH). Calculated results indicate oxygen vacancies may weaken the Lewis acid–base interactions between a pair of coadsorbed amphoteric species at the Al–O sites. Although the coadsorption cannot be strengthened at the Pt–O sites, the reaction intermediates involved are bound most tightly at the Pt sites. A concerted mechanism in which two C–H bonds are simultaneously activated is proposed on Pt-doped θ-Al2O3, which dominates the stepwise mechanism and gives rise to a high activity. In contrast, PDH cannot take place along the concerned pathway on Pt-doped γ-Al2O3because of the large surface distortion induced. These results provide a rational interpretation of the superior PDH performance of the θ-Al2O3-supported Pt catalyst.

Published
2024
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38. Effects of Oxygen Vacancy and Pt Doping on the Catalytic Performance of CeO2 in Propane Dehydrogenation: A First‐Principles Study.

Author

Zeeshan, Muhammad, Chang, Qing‐Yu, Zhang, Jun, Hu, Ping, Sui, Zhi‐Jun, Zhou, Xing‐Gui, Chen, De, and Zhu, Yi‐An

Subjects
CATALYTIC doping, CATALYSTS, DEHYDROGENATION, ACTIVATION energy, EXCESS electrons, DENSITY functional theory
Abstract

Main observation and conclusion: The catalytic properties of the CeO2 catalyst for propane dehydrogenation (PDH) are examined by employing the density functional theory calculations. Surface modifications and their effects on the surface reactivity are explored by creating the oxygen vacancy and single Pt atom doping. A comparative study between the binding energies of the different PDH reaction species reveals a considerable Lewis acid‐base interaction over the pristine and defective surfaces, which dominantly strengthens the bond formation between the adsorbates and the catalyst surface, resulting in the enhancement of surface reactivity. The creation of oxygen vacancy and doping the CeO2(111) surface with single Pt atoms changes the charge distribution over the surface on account of excess 4f electrons. This electronic change increases the bond formation abilities of the inactive Ce atom and hence increases the adsorption strength. Oxygen vacancy in the defective CeO2(111) surface migrates over the surface with the addition of an appropriate adsorbate. Moreover, it is revealed that the propylene is more strongly adsorbed on the single‐Pt‐atom‐doped CeO2(111) surface than the pristine and defective surfaces, which decreases the deep dehydrogenation energy barrier and ultimately results in the lowering of the selectivity. [ABSTRACT FROM AUTHOR]

Published
2021
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48. Self-adaptive structure and catalytic performance of the Pt–Sn/Al2O3propane dehydrogenation catalyst regenerated by dichloroethane oxychlorinationElectronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d2cy00921h

Author

Zhao, Fang-Cheng, Yang, Huan, Sui, Zhi-Jun, Zhu, Yi-An, Chen, De, and Zhou, Xing-Gui

Abstract

Oxychlorination regeneration is an important and effective regeneration method for Pt based catalysts for propane dehydrogenation. Cl2and HCl are usually adopted as the chlorine source, which may jeopardize equipment and impair health seriously. A safer and less corrosive chlorine source, dichloroethane, is applied to oxychlorination regeneration of a series of Pt–Sn/Al2O3catalysts after oxidation treatment. The catalysts are characterized by H2-TPR, CO-DRIFTS, HAADF-STEM, XPS, and UV-vis DRS and their catalytic performances are also tested. It's found that the catalyst structures are self-adaptive for catalyzing the propane dehydrogenation reaction during the oxidation and oxychlorination treatment, in which Sn species combines with the alumina support in the ionic state and Pt is highly dispersed through an oxychloroplatinum complex. Pt migrates to sites having a stronger interaction with the support, leading to higher activity and selectivity. The performance of the regenerated catalyst is a function of oxychlorination conditions, indicating the possible influence of the coordination of chloride species with Pt on catalytic performance.

Published
2022
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