Construction of a 0D/3D AgI/MOF-808 photocatalyst with a one-photon excitation pathway for enhancing the degradation of tetracycline hydrochloride: Mechanism, degradation pathway and DFT calculations

Abstract

One-photon excitation has been demonstrated to be ideal for improving photon utilization effectiveness. We synthesized a unique 0D/3D AgI/MOF-808 composite using a hydrothermal method combined with in situ precipitation. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations indicated the electron migration direction, confirming the presence of a one-photon excitation pathway. The 0D/3D AgI/MOF-808 exhibited both excellent adsorption (189.01 mg/g) and photocatalytic properties for tetracycline hydrochloride (TCH). Electrochemical and photoluminescence (PL) tests showed that 0D/3D AgI (40 wt%)/MOF-808 had the highest photogenerated carrier transport and separation efficiency, with a TCH degradation efficiency of 83.02 % and a degradation rate 14.32 times higher than that of bare AgI. Photon utilization efficiency, carrier separation, and adsorption capacity expansion all contributed to the photocatalytic performance. The effects of pH and inorganic anions on the composite photocatalyst during the photocatalytic reaction were also investigated. The capture experiment demonstrated that ·OH and ·O2– were the primary active groups. Additionally, the stability was enhanced because the migration of electrons in AgI effectively limited the reduction of Ag+ to Ag0. Possible attack sites during TCH degradation were predicted using the condensed FuKui function (CFF), and potential degradation pathways were determined using ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). The examination of the biotoxicity of TCH degradation intermediates demonstrated a reduction in their environmental risks.