In this paper, the heterostructures between the BiOM (M = Cl, Br, I) (001) and the β-Bi2O3 (001) crystal facet, denoted as BiOM/β-Bi2O3, are reasonably constructed. The hybrid density functional approach investigates their electronic structures, optical absorption, band alignments, and photocatalytic activities. It is found that I-doped BiOM (M = Cl, Br) can make the type I heterostructures BiOM (M = Cl, Br)/β-Bi2O3 change to the direct Z-scheme with increasing I doping concentration. Under a higher I doping concentration, the BiOCl1–x I x /β-Bi2O3 has a stronger reduction potential than the BiOBr1–x I x /β-Bi2O3. Significantly, the BiOI/β-Bi2O3 is the direct Z-scheme heterojunction. Combining the direct Z-scheme heterostructure characters of BiOM1–x I x (M = Cl, Br)/β-Bi2O3 and BiOI/β-Bi2O3 with appropriate band alignments, their electrons and holes can be excited and separated highly effectively. The BiOM1–x I x (M = Cl, Br) or BiOI part has a higher reduction ability, gathers electrons, and works as the reduction catalyst. In contrast, the β-Bi2O3 part has a higher oxidation ability, gathers holes, and works as the oxidation catalyst. Remarkably, the O vacancy in bismuth oxyhalides can further improve the direct Z-scheme alignment structure, accelerate the separation and migration of the photogenerated electron–hole pairs, and also enormously intensify the visible light absorption. The synergistic effect of the direct Z-scheme band alignment character and O vacancy makes the BiOCl28/32I4/32(VO)/β-Bi2O3 and BiOI (VO)/β-Bi2O3 present superior photocatalytic activities. The calculated results can provide insights into the designs and preparations of the visible light response BiOM (M = Cl, Br, I)-based semiconductor photocatalysts.

In this work, all kinds of intrinsic point defects, unintentional N and H impurities and possible complex defects between impurities and native defects in α- and β-Bi2O3 with different growth...

In this work, we systematically investigate the photocatalytic mechanism of g-C3N4/BiOI (001) through hybrid functional calculations based on a first-principle theory. The staggered band structure is observed in the g-C3N4/BiOI...