Mo-doping induced band structures regulation in oxygen vacancies-rich Bi4O5Br2 nanosheets for improved visible-light photocatalysis

Photocatalysis is an effective, low-energy and environmentally friendly technology for the treatment of pollutants. Bi₄O₅Br₂, distinguished by its unique electronic structure, emerges as a promising photocatalyst among Bi_xO_yBr_z materials, yet it is hindered by significant photogenerated carrier recombination. Based on the instability of the Bi–O bond, this work utilizes the synergistic effect of Mo doping and oxygen vacancies (OVs) to enhance the bandgap structure of the modified Bi₄O₅Br₂, improving light absorption and facilitating charge separation. Among the samples, 3 % Mo-Bi₄O₅Br₂ exhibits the best photocatalytic performance, achieving a degradation rate of 98.40 % for Rhodamine B (Rh B) after 40 min of light exposure, with a degradation rate constant 3.28 times higher than that of undoped Bi₄O₅Br₂. Moreover, this catalyst maintains excellent catalytic activity after ten cycles and under various conditions, including the presence of coexisting ions, solution pH, and other organic dyes. The biocompatibility of the degradation products was explored using a mung bean sprouting experiment, and the degradation mechanism of Rh B was also discussed. This work enhances understanding of the effective degradation of organic pollutants through the synergistic effect of doping and OVs, and offers new insights into improving the photocatalytic activity of catalysts.