| The upsurge in anthropogenic activities since the Industrial Revolution has led to an increase in atmospheric carbon dioxide (CO2) concentration that is a significant factor in global climate change. Attempts to curtail a further rise in atmospheric CO2 concentration include technology that captures and sequesters CO2 from local point sources where it is being emitted and/or capture and conversion technologies that transforms CO2 to other chemicals that can be used as raw materials, such that no additional consumption of fossil fuels is need to create these raw materials.;Currently, there are no large commercial processes that convert CO 2 to useful chemicals, save for the water-gas shift that leads to the Fischer-Tropsch process, but both of these reactions require a large amount of energy input. Simpler methods exist, such as the electrochemical conversion of CO2, which can be performed in aqueous solution at room temperature and atmospheric pressure. This CO2 utilization pathway, however, is not yet fully developed for several reasons: lack of a selective and robust catalyst, large energy input required for desirable products, and low rate of reaction.;The electrochemical CO2 reduction reaction (CO2RR) has been widely studied in recent years but is still in its infancy. This work addresses various challenges faced in the design of selective and active catalyst materials while also focusing on experimental design and providing insights into the CO2RR mechanism. Due to copper's (Cu) unique ability to convert CO2 to hydrocarbons and alcohols, Cu-based materials are of prime interest. Planar Cu foils served as a model catalyst for experimental parameter studies in this work, in which we found that gas and solution flow rates, as well as electrochemical cell design, play a crucial role in controlling the selectivity of the reaction. Cu foils were also used as a model in isotopic labelling experiments that provide insights into the CO2 RR mechanism, such that bicarbonate (HCO3-) was determined to be the primary proton donor in the reduction of CO 2 to hydrocarbons and alcohols. Unique nanostructured Cu materials were synthesized in the lab through etching of a Cu-Al alloy, creating a porous Cu of nano-size, herein described as nanoporous Cu. Increased CO2RR activity and unique selectivity was observed on nanoporous copper and could be further enhanced by making bimetallic variations of the material. Similar results were also obtained using Cu nanoparticles purchased elsewhere. |
