Preparation and photocatalytic performance study of dual Z-scheme BiZrO/g-CN/AgPO 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 (BiZrO/g-CN/AgPO (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-CN 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, AgPO 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 AgPO by transferring the e to the VB of g-CN. Tetracycline was degraded efficiently by BCA-10% (the BCA with 10 wt.% of AgPO) 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.