UC Berkeley

Light-assisted conversion of CO₂ into liquid fuels is one of several possible approaches to combating the rise of carbon dioxide emissions. Unfortunately, there are currently no known materials that are efficient, selective, or active enough to facilitate the photocatalytic CO₂ reduction reaction (CO₂RR) at an industrial scale. In this work, we employ density functional theory to explore potential tellurium-containing photocathodes for the CO₂RR by observing trends in adsorption properties arising from over 350 *H, 200 *CO, and 110 *CHO surface-adsorbate structures spanning 39 surfaces of 11 materials. Our results reveal a scaling relationship between *CHO and *H chemisorption energies and charge transfer values, while the scaling relation (typically found in transition metals) between *CO and *CHO adsorption energies is absent. We hypothesize the scaling relation between *H and *CHO to be related to the lone electron located on the bonding carbon atom, while the lack of scaling relation in *CO we attribute to the ability of the lone pair on the C atom to form multiple bonding modes. We compute two predominant orbital-level interactions in the *CO-surface bonds (either using s or p orbitals) in addition to bonding modes involving both σ and π interactions using the Crystal Orbital Hamiltonian Population analysis. We demonstrate that bonds involving the C s orbital are more chemisorptive than the C p orbitals of CO. In general, chemisorption trends demonstrate decreased *H competition with respect to *CO adsorption and enhanced *CHO stability. Finally, we uncover simple element-specific design rules with Te, Se, and Ga sites showing increased competition and Zn, Yb, Rb, Br, and Cl sites showing decreased competition for hydrogen adsorption. We anticipate that these trends will help further screen these materials for potential CO₂RR performance.