Enhanced visible light photoelectrocatalytic degradation of tetracycline hydrochloride by I and P co-doped TiO2 photoelectrode.

Abstract Elimination of antibiotics such as tetracycline hydrochloride (TC) from wastewater is of great significance, but still faces challenges. Herein, for the first time, I and P co-doped TiO2 catalysts were prepared via a hydrolysis method. We also reported a simple method to prepare I and P co-doped TiO2 photoelectrodes, which exhibited preeminent photoelectrocatalytic (PEC) performance for the decomposition of TC. The synergistic effect of I and P co-doping could significantly improve the charge separation rate and enhance the light absorption capacity of TiO2, leading to an enhancement of PEC activity. The main factors affecting the PEC performance were investigated, and the highest degradation rate constant (4.20 × 10-2 min-1) was achieved when the doping content of P was 4 at.% (ITP-4 photoelectrode) at pH 11.02 under visible light. The Langmuir-Hinshelwood kinetic model and active species trapping experiments were selected to investigate the degradation mechanism of TC. The results suggest that the hydroxyl radicals and photogenerated holes were the main active species that were responsible for the decomposition of TC. Moreover, the degradation pathways of TC based on the intermediates also demonstrated that the hydroxyl radicals and holes showed a principal role in degrading TC.