Density Functional Theory Calculations on Surface Oxygen Vacancy Formation in Metal Oxides

Properties of materials may be significantly changed from intrinsic ones by making small physical and chemical changes in the form of defects. As a result, various point and extended defects are intentionally introduced to govern their chemical reactivity, catalytic, electrical, optical, and mechanical properties. One mechanism important in catalysis is the Mars-Van Krevelen mechanism that is frequently encountered. An example is where O vacancy sites on a metal oxide catalyst surface acts as the reaction site.

Accurate calculation of the surface vacancy formation energy based on first principles calculations require calculation of a surface model and is much more computationally expensive than a bulk calculation. Catalysts typically require a certain physical quantity to be within a certain range, hence rapid judgement of whether a candidate material is viable or not based on quantities (descriptors) that are easy to calculate can significantly accelerate the screening process. We report on correlations between descriptors that can be calculated at low cost and the O vacancy formation energy of various insulating binary oxide materials [Hinuma et al., J. Phys. Chem. C 2018, 122, 29435] as well as spinel oxides containing zinc.