Preparation of a Bi4O5I2/Bi2O2CO3 p-n heterojunction with enhanced photocatalytic degradation performance by a one-pot solvothermal method

Bi4O5I2/Bi2O2CO3 p-n heterojunction photocatalysts were synthesized by utilizing different ratios of solvent via a one-pot solvothermal method in the process of synthesizing Bi4O5I2 and Bi5O7I. The structure, morphology and photoelectric properties of the prepared samples were characterized by XRD, SEM, TEM, FTIR, XPS and DRS. Through the estimated photocatalytic degradation of pollutants such as tetracycline hydrochloride (TC) and rhodamine B (RhB), it was found that the Bi4O5I2/Bi2O2CO3 (the ratio of ethylene glycol and distilled water in the solvent was 3/5) heterojunction photocatalyst had the highest degradation, with the removal of up to 80.6% from all prepared samples within 30 min under visible light irradiation; this heterojunction also showed better RhB degradation performance. The presence of an internal electrostatic field between the p-type semiconductor Bi4O5I2 and n-type semiconductor Bi2O2CO3 effectively suppressed the recombination of photoinduced electron–hole pairs. Moreover, a feasible mechanism was proposed.