Murray State University
Fundamental Studies of Electron Transfer Active Iridium Oxide Nanoparticles in Solutions and on Conducting Surfaces: STUDY 2 (Trent): The Effects of Film Architecture and Particle Chemistry on ProtonCoupled Electron Transfer at Mesoporous Films of Iridium Oxide Nanoparticles on Electrode Surfaces
Institution
Murray State University
Faculty Advisor/ Mentor
Lloyd P. Horne
Abstract
Iridium oxide (IrOx) nanoparticles are excellent catalysts for water oxidation and have potential utility in dye-sensitized photochemical cells. These nanoparticles undergo proton-coupled electron transfer (PCET) in aqueous solutions, thereby making their redox behavior sensitive to environmental pH. This work reports progress towards a detailed understanding of how the architecture of IrOx nanoparticle films and particle chemistry govern redox behavior. An anodic potential was applied to charge the IrOx nanoparticles to the +6 oxidation state, thereby catalyzing the 4 e/4 H+ oxidation of H2O into O2. This facilitates the flocculation, or adherence, of nanoparticles to the electrode interface. Consequently, a disk electrode was coated with a very thin, mesoporous film of 2 nm diameter IrOx nanoparticles. Strategies for controlling film formation, structure, and reproducibility were investigated. Corresponding voltammetry provided new insights into how these variables influence film electrochemistry.
Fundamental Studies of Electron Transfer Active Iridium Oxide Nanoparticles in Solutions and on Conducting Surfaces: STUDY 2 (Trent): The Effects of Film Architecture and Particle Chemistry on ProtonCoupled Electron Transfer at Mesoporous Films of Iridium Oxide Nanoparticles on Electrode Surfaces
Iridium oxide (IrOx) nanoparticles are excellent catalysts for water oxidation and have potential utility in dye-sensitized photochemical cells. These nanoparticles undergo proton-coupled electron transfer (PCET) in aqueous solutions, thereby making their redox behavior sensitive to environmental pH. This work reports progress towards a detailed understanding of how the architecture of IrOx nanoparticle films and particle chemistry govern redox behavior. An anodic potential was applied to charge the IrOx nanoparticles to the +6 oxidation state, thereby catalyzing the 4 e/4 H+ oxidation of H2O into O2. This facilitates the flocculation, or adherence, of nanoparticles to the electrode interface. Consequently, a disk electrode was coated with a very thin, mesoporous film of 2 nm diameter IrOx nanoparticles. Strategies for controlling film formation, structure, and reproducibility were investigated. Corresponding voltammetry provided new insights into how these variables influence film electrochemistry.