UCLA

The high dependency on fossil fuels to meet the world’s increasing demand for energy has led to an increase in carbon dioxide (CO2) emissions into the atmosphere, which could lead to irreversible environmental ramifications. Conversion of CO2 to value added chemicals and/or fuels is a promising strategy not only to mitigate anthropogenic CO2 emissions, but also to provide a renewable source of energy. Nonetheless, CO2 is a thermodynamically stable molecule that requires vast energy and an active catalyst to activate it. To address the issue of CO2 stability, thermodynamic analysis and material science are utilized in this work. In the first part of this thesis, Gibbs free energy minimization is employed to offer an insight into the thermodynamic behavior for the production of dimethyl ether and acetic acid from CO2 in atomic space. A set of temperatures, pressures, and hydrogen and oxygen atom-mole fractions are identified that allow for maximum production of dimethyl ether and acetic acid and minimum production of by-products, particularly CO2. In the second part of this thesis, for the first time, galvanic replacement is employed to synthesize In-based alloy catalysts where the surface structures are highly tailored and the host sites are highly controlled. The synthesized alloys show high stability, activity, and selectivity toward methanol formation, in the conversion of CO2 to methanol, and CO formation, in the reverse water gas shift reaction. This work offers a new approach for utilizing Gibbs free energy minimization in atomic space for CO2 based reactions. Additionally, it demonstrates the capability of galvanic replacement in synthesizing In-based alloys with well-defined surface structures.