Preparation and photocatalytic performance study of dual Z-scheme Bi2Zr2O7/g-C3N4/Ag3PO4 for removal of antibiotics by visible-light

At present, the high re-combination rate of photogenerated carriers and the low redox capability of the photocatalyst are two factors that severely limit the improvement of photocatalytic performance. Herein, a dual Z-scheme photocatalyst bismuthzirconate/graphitic carbon nitride/silver phosphate (Bi 2 Zr 2 O 7 /g-C 3 N 4 /Ag 3 PO 4 (BCA)) was synthesized using a co-precipitation method, and a dual Z-scheme heterojunction photocatalytic system was established to decrease the high re-combination rate of photogenerated carriers and consequently improve the photocatalytic performance. The re-combination of electron-hole pairs (e − and h + ) in the valence band (VB) of g-C 3 N 4 increases the redox potential of e − and h + , leading to significant improvements in the redox capability of the photocatalyst and the efficiency of e − -h + separation. As a photosensitizer, Ag 3 PO 4 can enhance the visible light absorption capacity of the photocatalyst. The prepared photocatalyst showed strong stability, which was attributed to the efficient suppression of photo-corrosion of Ag 3 PO 4 by transferring the e − to the VB of g-C 3 N 4 . Tetracycline was degraded efficiently by BCA-10% (the BCA with 10 wt.% of AgPO 4 ) under visible light, and the degradation efficiency was up to 86.2%. This study experimentally suggested that the BCA photocatalyst has broad application prospects in removing antibiotic pollution.