UC Berkeley

Heterogeneous catalysis is a highly important research area in chemistry that can address the climate crisis. Advances in computational chemistry tools, particularly those based on density functional theory (DFT), have been employed to uncover the underlying physics of the operation of catalysts and have contributed to their more efficient design. In this dissertation, we develop and apply computational schemes using density functional theory (DFT) to a broad range of topics relevant to heterogeneous catalysis. In the first half of the dissertation, we combine orbital-optimized (OO) single-reference methods with the one-electron exact two-component (X2C) Hamiltonian to model the ionization of core-electrons. In Chapter 2, we present a non-orthogonal, quasi-degenerate perturbation theory (NO-QDPT) approach for treating the spin-orbit coupling of core-electrons. This scheme is applied to a broad range of ionizations across the periodic table in order to assess its performance and identify its limits. The NO-QDPT approach demonstrates near-quantitative agreement with experimental core-electron binding energies for third-row elements, though its accuracy decreases for later first-row transition metals. In the second half of the dissertation, elementary ion-transfer reactions are modeled via Constant Electrode Potential (CEP) calculations. In Chapter 3, the adiabatic, reversible electrodissolution of anodically polarized silver is modeled. By employing a hybrid implicit-explicit solvation model and the CEP protocol, the study successfully predicts reaction trajectories and free energy barriers that align with temperature-dependent experimental data. The findings reveal that the reaction barrier is a delicate competition between solvation, metal-metal bonding, and image charges. In Chapter 4, the role of hydroxide-mediated intermediates in cathodic copper degradation during the carbon dioxide reduction reaction (CO2RR) is studied. CEP calculations show that hydroxide-mediated dissolution of exposed surface Cu atoms is potentially viable. Specifically, the formation and subsequent dissolution of [Cu(OH)2]- from surface defects is found to be energetically accessible and is facilitated by the formation of an image quadrupole. Together, these findings demonstrate that refined computational treatments of the electrode surface can provide a fundamental understanding of the surface chemistry governing the durability of heterogeneous systems.