(427b) Electrochemistry with Oxygen: New Design Principles for Next Generation Electrocatalysts

The oxygen electrochemistry necessarily evolves around metal-oxides and their derivatives, since they are the most stable catalysts where the oxygen is both the building block and the intermediate of a reaction. In electrochemically active metal-oxides, the metal is almost exclusively a transition metal element of either 3d, 4d or 5d row. The transition metal-oxide (TMO) bulk structure, i.e., the metal-ligand high symmetry coordination environment defines the oxidization state, and the crystal field effects acting on TM-active site at the surface. Until now, no design rules account for the above affects across the periodic table and can be used to predict a next generation oxygen electrocatalysts.

In this talk, I will discuss our latest attempts in our group to establish the unified approach to understanding the oxygen surface reactivity of TMOs. I will share how the calculated trends for OH* an O* adsorption energies evolve across the 3d, 4d or 5d rows of the periodic table for surfaces of rutile-MO2 with octahedral sites [1]. Both the anti/bonding filling and coupling strength contribute to overall adsorption which can be quantified via COHP bond analysis. Extensions to dilute doping limit, changes upon oxidation state change, and effects beyond octahedral environment of the active will be discussed. Our theoretical hypothesis is directly put to test by OER experiments on Ir-doped WO3 catalyst [2] which achieves a breakthrough acidic performance. The work is supported by U.S. DOE BES, Catalysis Science Program to the SUNCAT Center for Interface Science and Catalysis.

[1] Unraveling Electronic Trends in O* and OH* Surface Adsorption in the MO2 Transition-metal Oxide Series, Comer, Abild-Pedersen,Bajdich, Winther, J. Phys. Chem C (2022)

[2] Efficient and Stable Acidic Water Oxidation Enabled by Low concentration, High-valence Iridium Sites, Sokaras*, Xiaolin Zheng*, and Michal Bajdich* et al. (under review in ACS Energy Letters)