Molecularly-directed deposition of copper on polycrystalline Pt substrates /
by José J. Mercado Velázquez.
- 2019.
- 146 leaves ; graphics
Thesis (Master in Science-Chemistry) - Pontifical Catholic University of Puerto Rico.
Bibliografical references: leaves 130-134.
Electrochemical reactivity is sensitive to compositional and structural changes in the electrode surface. In this work Cyclic Voltammetry (CV) was used to correlate Current (i) vs Potential (V) curves that served as a fingerprint of the electrode surface composition and structure. This research outlined a new method to molecularly direct the deposition of copper using aromatic molecules such as hydroquinone, catechol, pyridine and aniline as guide probes at model Pt electrocatalyst surfaces. Results showed that bulk copper deposition var-ies as a function of the following experimental conditions: applied potential, electrochemical pretreatment, electrode surface structure and the molecular-guide probe used to chemically pretreat the Pt(poly) surfaces. It was found that copper was deposited preferentially to some specific surface domains of the platinum electrode when the deposition is guided by aromatic molecules. Using optical detection of bulk copper deposition at Pt surface, information about where the deposition specifically takes place was obtained with stereographic projection. It was possible to correlate at what kind of structural surface domain the deposition took place. It was found that copper, guided by the molecular probes, start its deposition in stepped and kinked surfaces avoiding the basal planes Pt(111), Pt(110) and Pt(100), with a preference for the Pt(100) four fold site. It was concluded that the different patterns of Cu(bulk) deposition obtained were due to selective ligand displacement between Cu and the probe molecules acting as surface modifiers on the Pt surface.
Pontificia Universidad Católica de Puerto Rico--Dissertations