Observation of Increased Dispersion of Pt and Mobility of Oxygen in Pt/g-Al2O3 Catalyst with La Modification in CO Oxidation

Thanawat Wandondaeng  -  Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Thailand
Chaowat Autthanit  -  Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Thailand
Bunjerd Jongsomjit  -  Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Thailand
*Piyasan Praserthdam  -  Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Thailand
Received: 22 Mar 2019; Revised: 6 Jun 2019; Accepted: 20 Jun 2019; Published: 1 Dec 2019; Available online: 30 Sep 2019.
Open Access Copyright (c) 2019 Bulletin of Chemical Reaction Engineering & Catalysis
License URL: http://creativecommons.org/licenses/by-sa/4.0

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The study focuses on an improvement of the catalytic activity via CO oxidation for Pt/g-Al2O3 catalyst by addition of La onto the support prior to impregnation with Pt metals. The molar ratios of La/Al were varied from 0.01 to 0.15. Based on temperature-programmed desorption (TPD) of CO2, La addition apparently resulted in increased basicity of the catalysts, which is related to increasing of oxygen mobility. However, when considered the Pt dispersion measured by CO chemisorption, it was found that Pt dispersion also increased with increasing the amount of La addition up to La/Al = 0.05. It is suggested that too high amount of La addition can inhibit the dispersion Pt due to surface coverage of La. It is worth noting that the catalytic activity toward CO oxidation essentially depends on both Pt dispersion and oxygen mobility and they can be superimposed on each other. Based on this study, the Pt/g-Al2O3 catalyst with La addition of La/Al molar ratio = 0.05 showed the highest activity due to its optimal Pt dispersion and oxygen mobility leading to its highest value of turnover frequency (TOF). Copyright © 2019 BCREC Group. All rights reserved


Keywords: Pt/g-Al2O3; La modification; Pt dispersion; CO oxidation; Oxygen mobility

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