University of Illinois Urbana-Champaign

Electrochemistry of well-defined rhodium(111) electrode and structural effects in heterogeneous electrocatalysis

Hourani, Mohammed Khair

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Description

Title
Electrochemistry of well-defined rhodium(111) electrode and structural effects in heterogeneous electrocatalysis
Author(s)
Hourani, Mohammed Khair
Issue Date
1989
Doctoral Committee Chair(s)
Wieckowski, Andrzej
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Chemistry, Analytical
  • Chemistry, Physical
Language
eng
Abstract
  • This thesis is composed of two parts. The first focuses on the surface electrochemistry of a well-defined Rh(111) electrode, while the second part deals with exploring the crystallographic effects in electrocatalysis.
  • Basic research was initiated by developing a method for the preparation of well-ordered and clean Rh(111) surface at atmospheric pressure. The resulting surface was characterized in situ by cyclic voltammetry in 0.1 M perchloric acid solution, and by the i-E profiles of silver underpotential deposition. Identical voltammetric data were obtained later using a UHV/electrochemistry transfer system, thereby proving the the reliability of our method.
  • The voltammetric characteristics of Rh(111) were disclosed for the first time in this study. The following electrochemical investigations were also conducted on the well-defined Rh(111) surface: adsorption of anions and the voltammetric response to their existence in the double layer region, order-disorder transition, and silver underpotential deposition. Additional studies included CO adsorption and electrooxidation, adsorption of oxygen, and adsorption of iodine from the liquid and gas phases.
  • The second part of the thesis, explores the crystallographic effects in electrocatalysis. This project involved a kinetic study of ethylene electroreduction on crystallographically modified electrodes. Electrochemical techniques were applied to prepare preferentially oriented platinum surfaces. The kinetics and turnover numbers for ethylene reduction on platinum surfaces were extracted from chronoamperometric profiles. The (100) preferential orientation showed 70% higher reactivity than the (111) orientation. The kinetic data, along with the surface crystallography influence on platinum reactivity, were modeled by assuming a rate determining step which involves combination of adsorbed hydrogen and an adsorbed ethyl radical.
Type of Resource
text
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http://hdl.handle.net/2142/22609
Copyright and License Information
Copyright 1989 Hourani, Mohammed Khair

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