Visible-light-responsive K-doped g-C3N4/BiOBr hybrid photocatalyst with highly efficient degradation of Rhodamine B and tetracycline

Abstract A visible-light-responsive hybrid photocatalyst, K-doped g-C3N4/BiOBr, has been synthesized by K-doped g-C3N4 (K–CN) and BiOBr. The property of photocatalysts was characterized by XRD, FT-IR, TEM, SEM, DRS, PL, EIS and HPLC. The photocatalytic activity of K-doped g-C3N4/BiOBr was evaluated by degradation of Rhodamine B (RhB) and tetracycline hydrochloride under visible-light irradiation. The K-doped g-C3N4/BiOBr hybrid photocatalyst which contains K–CN with mass fraction of 20% (20K–CN/BiOBr) shows the best degradation efficiency of RhB. The degradation efficiency of RhB (20 mg/L) can be achieved to 99% and the degradation efficiency of tetracycline hydrochloride by BiOBr decreased with the increase of K-doped g-C3N4 doping. The results of photocurrent and EIS assumed that the tight coupling between K–CN and BiOBr can enhance the separating efficiency of photo-generated carrier. In addition, the capture experiment proof that h+ is the primary active substance in the system of reaction and ·OH is the auxiliary active substance. After five degradation experiments, the efficiency of the degradation of Rhodamine B by the sample can still reach 90%, which proves that the samples are stable. A new and efficient method is provided in this work to solve the pollution of organic dyes and antibiotics.