Surface studies of copper-based electrocatalysts in the reduction of carbon dioxide
File(s)
Author(s)
Bowers, Benjamin
Type
Thesis
Abstract
My work focused on the low temperature electrochemical CO2 reduction reaction, and specifically, in the study of copper-based catalytic materials. The reaction can provide fuel for delocalized systems and communities as well as replacing several fossil fuel derivatives for the chemical feedstock industry. Copper is a widely used catalyst due to an ability to produce several high value chained products. However, the metal still suffers from poor stability and selectivity which inhibits the adoption of the reaction in industrial processes. In Chapter 2, these problems are detailed, with an overview of the current avenues for improvement specified. There are several competing reactions dictated by the testing method, operating conditions and catalyst, making activity comparisons between groups challenging. Therefore, firstly, the methodology was detailed in Chapter 3 to improve the reproducibility of this work. Next, Chapter 4 describes the development of an electrochemical surface area measurement (ECSA) that can provide a direct comparison of activity across the field, allowing groups to evaluate activity more accurately. The method utilized the adsorption of CO and displacement of phosphate ions at Faradaic potential creating a peak of charge. This peak was related to the ECSA and was termed ‘CO displacement’. From this benchmarked performance, copper was attempted to be improved, firstly, via the addition of metal oxides nanoclusters in Chapter 5 and, secondly, the incorporation of copper within a Ruddlesdon-Popper Perovskite oxide in Chapter 6. In Chapter 5, the overpotential for the water dissociation reaction was related to selectivity, with the likelihood of protonation the proposed mechanism. In Chapter 6, the perovskite oxides were unstable sat negative potential, with a degradation mechanism involving the, electrochemically driven, near surface promotion of copper species elucidated via operando and ex-situ characterization techniques. Chapter 7 summarises the work and provides context into its impact on the field.
Version
Open Access
Date Issued
2024-04
Date Awarded
2024-11
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Steier, Ludmilla
Stephens, Ifan
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)