Origin of Bismuth‐Rich Strategy in Bismuth Oxyhalide Photocatalysts

Recently, the bismuth‐rich strategy via increasing the bismuth content has been becoming one of the most appealing approaches to improve the photocatalytic performance of bismuth oxyhalides. However, insights into the mechanism behind the encouraging experiments are missing. Herein, we report the results of the theory‐led comprehensive picture of bismuth‐rich strategy in bismuth oxyhalide photocatalysts, selecting Bi 5 O 7 X ( X = F, Cl, Br, I) as a prototype. First‐principle calculations revealed that the strategy enables good n ‐type conductivity, large intrinsic internal electric field, high photoreduction ability and outstanding harvest of visible light, and particularly ranked the intrinsic activity of this family: Bi 5 O 7 F > Bi 5 O 7 I > Bi 5 O 7 Br > Bi 5 O 7 Cl. Designed experiments confirmed the theoretical predictions, and together, these results are expected to aid future development of advanced photocatalysts.