Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.787398
Title: Electrochemical metallization of cyanide adlayers : preparation and characterization
Author: Mwanda, Jonathan Amolo
ISNI:       0000 0004 7972 5177
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2019
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Abstract:
In this work, the fabrication of a metal deposit atop a cyanide adlayer on a Pt(111) surface in a M-CN-Pt(111) sandwich design is attempted. The methodology also known as electroless deposition comprises electrochemically reducing pre-adsorbed metal cations (Cu2+, Ag+ and Pd2+) on a cyanide modified Pt(111) in the absence of Mz+ in the electrolyte. The cyanide adlayer on Pt(111) forms a robust and stable monolayer with an ordered adlattice on Pt(111) presenting a unique adlayer for metallization. The successful immobilization of Ag+, Cu2+ and Pd2+ cations on the cyanide adlayer prior to electrochemical reduction is evidenced through cyclic voltammetry (CV) and scanning tunnelling microscopy (STM). Particularly in the case of Cu2+ and Ag+ the observation of a honeycomb pattern that corresponds to cation coordination to the cyanide adlayer is observed. Electrochemical reduction of pre-adsorbed Cu2+ results in the observation of reversible copper nanoislands that grow via an Otswald's ripening process on the cyanide selfassembled monolayer (SAM). In the case of pre-adsorbed Ag+ on the cyanide adlayer on Pt(111), the electrochemical reduction results in the formation of a AgPt surface alloy upon consecutive potential cycling. Electrochemical reduction of pre-adsorbed Pd2+ on the cyanide adlayer on Pt results in a direct deposit of Pd on the Pt substrate. The observed Pd island deposits increase in size up to a maximum of ca. 500 atoms with sequential potential cycling. These results clearly show that electrochemical reduction of the immobilized Mz+ cations (Cu2+, Pd2+ and Ag+) on a cyanide modified Pt(111) yields different results that in turn suggest the sensitivity of deposited metal/cation interaction to the SAM and more importantly the role of the nature of the cyanide SAM (Self assembled monolayer) in determining the outcome in synthesizing M-SAM-M structures.
Supervisor: Cuesta, Angel ; Macphee, Donald E. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.787398  DOI: Not available
Keywords: Electrochemical metallizing ; Electrolytic reduction ; Self-assembly (Chemistry) ; Cyanides
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