By Iaroslavna Koavlenko

Faculty Mentor: Nicole Crowder

Abstract

One way to electrochemically reduce CO2 is to use modified electrode surfaces with bound transition-metal electrocatalysts. Optimal conditions for modifying copper surfaces with (2-azidoethyl) phosphonic acid in acetone have been identified, forming a self-assembled monolayer (SAM) via the tethering by aggregation and growth (T-BAG) method. The subsequently formed phosphonate film on the copper surfaces protects the modified electrodes from oxidation or side reactions on the copper. A copper-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction between the terminal azide group on the phosphonate and a synthesized terpyridine ligand with the necessary terminal alkyne substituent has been successfully carried out on the copper surface. This terpyridyl ligand was then used to bind a Cu (II)-based complex, serving as a suitable conduit for the electron transfer required for the electrochemical reduction of carbon dioxide. All surface modification reactions were first conducted in solution, and products were confirmed by Nuclear Magnetic Resonance (NMR) and Infrared Spectroscopy (IR). Specular Reflectance Infrared Spectroscopy was used to analyze the modified copper surfaces. Cyclic voltammetry (CV) was conducted on the modified copper surfaces to determine the redox potential of the developed electrocatalytic system. Additional CV trials are needed to identify the optimal potential and solvent for the electrochemical reduction of carbon dioxide. In future work, the synthesized catalyst system can be used in an electrochemical H-cell to reduce carbon dioxide into value-added chemicals such as those containing a C-C bond.