(296b) Role of Defects on CoOx nanoparticle Structure and Water Splitting Activity

One key process that can play a key role in advancing society’s sustainability is water splitting, which when paired with renewable energy sources can be a carbon free way to generate hydrogen fuel (H₂). The current best performing catalysts are made of Ir and Ru oxides materials therefore, advancements in earth abundant catalyst earth catalyst design are needed. Prior work focusing on earth abundant catalyst design has found that some binary and tertiary metal oxides of Mn, Ni, Fe, and Co perform better than their unary counterparts, but an understanding of why is lacking [1]. Using Density Functional Theory (DFT) calculations in conjunction with experiments on well-defined model systems, the reason behind the increase in performance can be systematically investigated. Previous studies of well-defined CoO_x nanoislands have provided valuable insights into the role of structure on activity [2-7]. Analysis of the role of nanoislands defects, such as Fe dopants, oxygen line defects and edges can provide further understanding of the role structure on oxide catalyst activity.

Investigation of CoO_x nanoislands has previously found undercoordinated edge sites are important for the activity of CoO_x nanoislands [2,5]. However, other types of defects their effects, such as Fe dopants and oxygen line defects, are less understood. It is known that reversible formation of oxygen line defects in bilayer CoO nanoislands exist, before a transition to the OER active CoO₂ phase takes place. DFT calculations have been done to investigate the formation of oxygen line defects to understand how these defects effect CoO_x nanoparticle’s structure and activity. Fe dopants defects how their presence changes these systems will also be presented. By looking at the role these defects have on structure and how those structural features effect activity, we hope to guide further design of oxide and mixed oxide catalysts for OER.