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Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions

Hwang, Sang Youp
http://rave.ohiolink.edu/etdc/view?acc_num=akron1478705075812659

Abstract Details

, Doctor of Philosophy, University of Akron, Chemical Engineering.
Controllable nanoparticles with different morphology, alloy, composition, and sizes were investigated and analyzed. The nanoparticles, which act as a catalyst, are synthesized using solid state and wet chemistry method. The synthesized catalysts also were demonstrated for the various chemical reactions, such as CO oxidation and CO preferential oxidation (PROX). Group VIII metal nanoparticles with variant morphologies are synthesized under carbon monoxide atmosphere. The important roles of CO in determining the surface formation of growing particles are studied by both experiments and density functional theory calculations, which suggest different growth mechanisms for these metals. Alumina-supported platinum-silver alloy nanoparticle (Pt-Ag/Al2O3) catalysts have been prepared using a wet chemistry method and studied for the property in carbon monoxide oxidation reaction. The Pt-Ag alloy catalyst exhibits significantly improved activity and largely decreased activation energy barrier comparing to both pure Pt and pure Ag catalysts in the room temperature range. The Langmuir-Hinshelwood mechanism, in which surface Pt active sites chemisorb CO and adjacent Ag sites activate O2, was proposed and discussed for explaining the promoted CO oxidation kinetics on the Pt-Ag alloy. Octahedral Pt3Ni alloy nanoparticles on carbon and alumina supports are prepared and tested for CO preferential oxidation (PROX) in H2. Both catalysts exhibit much superior PROX property with high activity and 100% selectivity between around RT and 100 °C. The improved activity of the octahedral Pt3Ni has been attributed to bifunctional sites mechanism. The excellent selectivity is correlated with the unique surface geometry and electronic structure of the octahedral Pt3Ni. Pt/SiO2 catalysts with different Pt nanoparticle size are prepared using an impregnation method. The 2.4 nm Pt/SiO2 exhibits improved CO oxidation activity and turnover frequency (TOF) comparing to either bigger or smaller Pt catalysts. The different catalytic activities are related with the adsorption energy, which is caused by the different electronic structure such as d-band center and work function. Cubic and spherical PtMn alloy nanoparticles on alumina were synthesized and tested for CO preferential oxidation (PROX). Both catalysts exhibited 100% CO selectivity in a wide temperature window. The extended temperature windows for CO PROX on PtMn have been attributed to a low reducibility of Mn oxide. The findings of high selectivity in a broad temperature window were confirmed using various Pt alloy catalysts with a different reducibility of surface oxide.
Zhenmeng Peng, Dr. (Advisor)
George G. Chase, Dr. (Committee Member)
Jie Zheng, Dr. (Committee Member)
Xiaosheng Gao, Dr. (Committee Member)
Toshi Miyoshi, Dr. (Committee Member)
Chemical Engineering

Recommended Citations

Citations

  • Hwang, S. Y. (n.d.). Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1478705075812659

    APA Style (7th edition)

  • Hwang, Sang Youp. Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1478705075812659.

    MLA Style (8th edition)

  • Hwang, Sang Youp. "Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions." Doctoral dissertation, University of Akron. Accessed MAY 02, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=akron1478705075812659

    Chicago Manual of Style (17th edition)

akron1478705075812659
101
© , some rights reserved.Creative Commons License Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions by Sang Youp Hwang is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Akron and OhioLINK.