Fig. 1. (Color online) The photo-generated carrier transport diagram (a) via one-photon excitation pathway and (b, c) in traditional heterostructure and 2D in-plane heterostructure.

Fig. 2. (Color online) (a) Schematic illustration for the synthesis of i-X (X = Cl, Br, I). (b, c) XRD patterns of CAU-17, B_i2O₃, i-Cl, BiOCl, i-I, and i-Br.

Fig. 3. (Color online) (a) SEM images, (b) TEM, (c) HR-TEM images, (d–f) EDS mapping images and (g) EDX line profile result of i-Cl sample; Atomic structures of (h) BiOCl (110) and (i) Bi₂O₃ (201).

Fig. 4. (Color online) XPS spectra of BiOCl, i-Cl, and Bi₂O₃ samples: (a) survey spectra, (b) Bi 4f, (c) O 1s, (d) Cl 2p.

Fig. 5. (Color online) (a) The photocatalytic RhB degradation curves and (b) first-order kinetic fitting of curves of i-Cl, t-Cl, Bi₂O_3, and BiOCl samples. (c) The photocatalytic TC degradation curves and (d) first-order kinetic fitting of curves of i-Cl, t-Cl, Bi₂O_3, and BiOCl samples.

Fig. 6. (Color online) (a) The photocatalytic RhB degradation curves and (b) first-order kinetic fitting of curves of i-Cl, t-Cl, Bi₂O_3, and BiOCl samples in mixed wastewater. (c) The photocatalytic TC degradation curves and (d) first-order kinetic fitting of curves of i-Cl, t-Cl, Bi₂O₃ and BiOCl samples in mixed wastewater.

Fig. 7. (Color online) (a) UV-Vis DRS spectra, (b) PL spectra, (c) SPV, (d) photocurrent responses, and (e) the EIS Nyquist plots of the samples.

Fig. 8. (Color online) (a) Kubelka-Munk transformed reflectance spectra, (b) VB spectra of BiOCl and Bi₂O₃. (c) Band structures of Bi₂O₃ and BiOCl before and after contact. (d) Charge density difference of BiOCl/Bi₂O₃ heterojunction. The work function of (e) BiOCl (110) and (f) Bi₂O₃ (201).

Fig. 9. (Color online) (a) The reactive species trapping experiment and (b) ESR spectra of the i-Cl sample under light irradiation. (c) A plausible mechanism for the photocatalytic degradation of RhB and TC under visible light over the i-Cl sample.