Fig. 5. (Color online) (a) Schematic diagram of band energies for suitable polar materials for photocatalytic water splitting and (b) the anion orders in BaZrO
2S. Color code: Ba = purple, Zr = cyan, O = red, S = yellow. (c) DFT + U band gaps and tetrahedral rotation angles for the most stable BaZryTi
1–yO
2S structures. Adapted with permission from Ref. [
9]. Copyright 2019 The Royal Society of Chemistry.