Construction of novel Mn0.2Cd0.8S/Bi4O5Br2 Z-scheme heterojunction for highly efficient photocatalytic dye degradation

Abstract

Photocatalytic technology has received widespread attention as an effective means of treating organic pollutants in wastewater, but the development of effective and sustainable photocatalysts remains a serious challenge. In this study, a novel Mn_0.2Cd_0.8S (MCS)/Bi₄O₅Br₂ (BOB) heterojunction photocatalyst was successfully prepared by a two-step solvothermal method. The photocatalytic activity of the MCS/BOB heterojunction photocatalyst for degrading Rhodamine B (RhB) is significantly enhanced relative to Mn_0.2Cd_0.8S and Bi₄O₅Br₂. When the molar content of Mn_0.2Cd_0.8S was 15% of Bi₄O₅Br₂, the prepared 15% MCS/BOB had the best photocatalytic performance toward RhB with the degradation rate of 91.7% under 60 min of visible light irradiation. The apparent rate constant of 15% MCS/BOB is 10 and 7 times higher than that of Mn_0.2Cd_0.8S and Bi₄O₅Br₂, respectively. The excellent photocatalytic performance is associated with the increased specific surface area, extended light absorption range, and proper construction of Z-scheme heterojunction that facilitate effective charge separation and excellent redox capacity. In addition, the heterojunction photocatalyst shows remarkable photocatalytic stability. This study constructs a novel and effective Z-scheme heterojunction photocatalyst and promotes the exploration of photocatalyst in the purification of organic wastewater.