open access

https://hdl.handle.net/2115/87150

Factors determining surface oxygen vacancy formation energy in ternary spinel structure oxides with zinc

英語

2021-11-07

Royal Society of Chemistry

Physical chemistry chemical physics

23(41)

23768-23777

Spinel oxides are an important class of materials for heterogeneous catalysis including photocatalysis and electrocatalysis. The surface O vacancy formation energy (E-Ovac) is a critical quantity for catalyst performance because the surface of metal oxide catalysts often acts as a reaction site, for example, in the Mars-van Krevelen mechanism. However, experimental evaluation of E-Ovac is very challenging. We obtained the E-Ovac for (100), (110), and (111) surfaces of normal zinc-based spinel oxides ZnAl2O4, ZnGa2O4, ZnIn2O4, ZnV2O4, ZnCr2O4, ZnMn2O4, ZnFe2O4, and ZnCo2O4. The most stable surface is (100) for all compounds. The smallest E-Ovac for a surface is the largest in the (100) surface except for ZnCo2O4. For (100) and (110) surfaces, there is a good correlation, over all spinels, between the smallest E-Ovac for the surface and bulk formation energy, while the ionization potential correlates well in (111) surfaces. Machine learning over E-Ovac of all surface sites in all orientations and for all compounds to find the important factors, or descriptors, that decide the E-Ovac revealed that bulk and surface-dependent descriptors are the most important, namely the bulk formation energy, a Boolean descriptor of whether the surface is (111) or not, and the ionization potential, followed by geometrical descriptors that are different in each O site.

学術雑誌論文

Accepted Manuscript

1463-9076