Colorless Chemical Substance Detection in the Degradation of Tetracycline Based on Operando¹H Nuclear Magnetic Resonance Spectroscopy

The development of an efficient and durable photocatalyst is the key to the degradation of tetracycline (TC). However, the ability to monitor the concentration of TC accurately remains a significant challenge. The present work addresses this issue by applying an operando¹H NMR spectroscopy technology for monitoring the TC concentration using TiO₂photocatalysts with different oxygen vacancy concentrations. The application of operando NMR spectra compensates for the experimental error inherent in UV-vis spectrophotometry analyses caused by the destruction of the chromogenic group and thereby can accurately reflect the true degree of degradation. The TC degradation performances of the photocatalysts are evaluated systematically, and the obtained benzene ring concentrations are observed to contrast sharply with the corresponding TC concentration results obtained by UV-vis spectrophotometry. This research increases the availability, reliability, and accuracy of the test methods employed in TC degradation research and provides an experimental reference for the design of high-efficiency catalysts.