Preparation of bismuth modified electrodes for the CO2 reduction reaction
Usai, SaraORCID: 0000-0002-4254-0051
(2021)
Preparation of bismuth modified electrodes for the CO2 reduction reaction.
PhD thesis, Dublin City University.
In this work, several Bismuth electrodes were produced for the electrochemical reduction of CO2. Systematic studies were performed to investigate how modification of the surface of the electrodes would influence the catalytic activity of the system. The modifications were performed, by first, performing several electrodepositions, in order to obtain electrodeposits with different characteristics (Bi modified electrodes); and second, using co-catalysts (ionic liquids, ILs). During the electrodepositions, the morphology and distribution of the particles were investigated as a function of the deposition parameters with a view to optimising the bismuth surface coverage, the electrocatalytic properties and the meso to nano porosity so as to enhance mass transport. By controlling the waveform and additives within the deposition solution, several types of bismuth micro- to nano-structures could be produced ranging from fractals to approximately spherical particles. Bulk Bi electrodes were also produced so that a standard Bi electrode was set for comparison purposes. Finally, the Bi electrodes were then tested for the reduction of CO2 in aqueous solution in the absence and presence of commercial (1-Butyl-3-methylimidazolium tetrafluoroborate) and modified (1-carboxypropyl-3-methylimidazole tetrafluoroborate) ILs. The systems investigated within this work did not show high selectivity toward CO2 reduction and the main process at the electrode surface was the production of H2. The different parameters influenced the selectivity and the catalytic currents marginally. In addition, the modified Bi electrodes did not show a good stability during catalysis. For this reason, to try and increase the stability of the Bi catalysts, screen printed Bi electrodes were produced. The electrodes were produced first by preparing inks using Bi metal particles and then printing them on inert substrates. The obtained electrodes were characterised and finally tested via preliminary cyclic voltammetry experiments. This approach allowed more robust electrodes and higher reproducibility.
Metadata
Item Type:
Thesis (PhD)
Date of Award:
November 2021
Refereed:
No
Supervisor(s):
Forster, Robert J., Pryce, Mary and Walsh, James J.