Kazachkin, Dmitry V.
(2006)
ENSEMBLE SIZE EFFECT IN CATALYSIS BY PLATINUM-COPPER SILICA SUPPORTED BIMETALLIC CATALYSTS.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
The present study is of great importance both from industrial application side and from fundamental point of view. The work considers ecologically significant industrial processe - utilization of chlorinated hydrocarbons. Particularly, 1,2-dichloroethane utilization is chosen as a model reaction to study the kinetics of hydrogenation process in fixed batch flow reactor over Pt-Cu silica supported bimetallic catalysts. The fundamental part of the study includes correlation search between kinetics performance and electronic-structural properties of Pt-Cu bimetallic catalyst. Establishing correlation between electronic-structural properties and performance in chemical reactions are of prime significance for understanding of chemical nature of particular chemical systems. The understanding means the ability to govern the process that is of huge interest for industrial applications.The kinetic performance is determined directly by testing the selected catalyst in fixed bed reactor. The main characteristics derived from kinetics testing that are interesting for current study - selectivity and activity. The product of interest for presented process is ethylene, C2H4. The electronic-structural properties were derived mainly from the infrared-red (FTIR) study of carbon monoxide (CO) test molecule. The correlation between electronic-structural properties and kinetics performance are related to freshly pretreated catalyst.It was established that the selectivity toward C2H4 is a strong function of Cu/Pt atomic ratio that depends on the size of Pt ensembles: the smaller the size of Pt ensembles the higher selectivity toward C2H4. Activity slightly decreases as Cu/Pt ratio is increasing. The observed kinetics performance is rationalized based on knowledge derived from FTIR study and knowledge from previously published works.Structural sensitivity of C-Cl bond cleavage reaction is established for 1,2-dichloroethane hydrodechlorination. Elementary step of C-Cl bond cleavage is require 2-6 platinum atoms. Besides, the role of Cu as a main component responsible for C2H4 formation is shown experimentally. The structural dependence is rationalized in terms of ensemble size effect.The mechanism of 1,2-dichloroethane hydrodechlorination reaction for highly selective catalysts is explained in terms of independent role of Pt and Cu.
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| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
2 June 2006 |
| Date Type: |
Completion |
| Defense Date: |
23 January 2006 |
| Approval Date: |
2 June 2006 |
| Submission Date: |
22 February 2006 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Chemical Engineering |
| Degree: |
MSChE - Master of Science in Chemical Engineering |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Hydrodechlorination; Platinum-Copper Silica Supported Catalysts; Bimetallic Catalysts; PtCu/SiO2; 1-2-dichloroethane (1-2-DCE) |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-02222006-001930/, etd-02222006-001930 |
| Date Deposited: |
10 Nov 2011 19:31 |
| Last Modified: |
15 Nov 2016 13:36 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/6391 |
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