With the rise in the average global temperature due to human intervention, there is a need to reduce its increase to 1.5-2.0 ⁰C to achieve carbon neutral society by the end of the century.^1–3 One major contributor to this issue, is atmospheric CO2 which is emitted as a greenhouse gas from currently used fossil fuel dependent processes.⁴ Therefore, there is a need to improve the current state of the art CO2 capture, conversion and storage technologies.^5,6 In-situ spectroscopy techniques are a powerful tool for electrochemical reactions characterization under operating conditions. Vibrational spectroscopy, such as attenuated total reflection – surface enhanced infrared absorption spectroscopy (ATR-SEIRAS), allows the detection of species at the microenvironment of the catalyst surface.^7,8 Using ATR-SEIRAS supplies meaningful fundamental insights for the optimization of the electrocatalytic system by monitoring changes at the catalyst-electrolyte interface in real time.

Currently, the most promising approaches for electrochemical CO2 capture and conversion are electrolyzer technology and acid-base electrodialysis.^9–11 Electrolyzer technology consists of an electrolytic electrochemical cell that when coupled with renewable energy sources as a driving force, can produce viable chemicals that can contribute to multiple industries (e.g. chemical fuels, feedstock and additives) while minimizing CO₂ emissions from the energy source. The state-of-the-art configuration for a CO2 reduction electrolyzer consists of a membrane electrode assembly (MEA), with components in the following order: CO2 stream/cathode/catholyte/membrane/anolyte/anode.¹² The electrolyte used within the electrolyzer as catholyte or anolyte could be either in a solid, or liquid state.^12–14 Lastly, it is suggested that decoupling the process into two steps, CO2 reduction to CO and CO reduction to products, results in a more promising approach relative to a direct CO2 reduction to products.15 However, one limiting factor for the improvement of CO2 reduction electrolyzer technology is related to the choice of catalyst and its synthesis as different electrocatalysts and their synthesis route could affect their product distribution and activity. Therefore, there is a need for interfacial in-situ characterization techniques to probe the catalyst-electrolyte microenvironment. Doing so can support better understanding of these microenvironments to improve catalytic performance. This research project aims to advance ATR-SEIRAS systems to gain fundamental insights on electrochemical CO2 reduction in various conditions. Moreover, this work could contribute to a wide variety of fields and applications, as the main focus is on technique development demonstrated on CO2 reduction and this approach could be used for other electrocatalytic systems.

In this project we worked with the following objectives in mind:

Objective 1: Understanding of Spectro-electrochemical fundamentals while proposing an approach for the usage of ATR-SEIRAS for electrochemical CO₂ reduction.

Objective 2: Support an experimental-computational feedback loop with either experimentally guided simulations, or validation of models with experiments.

Objective 3: Advance the capabilities of in-situ Spectro-electrochemical ATR-SEIRAS towards bridging the gap between bench scale experiments and industrial needs.