Detection and elimination of tetracycline: Constructing multi-mode carbon dots for ultra-sensitive visual assay and CDs/TiO2 for photocatalytic degradation

Ultrasensitive detection and degradation of tetracycline (TC) has gained increasing attention owing to their inevitable detriments to human and ecosystem. Many studies have focused on mono-functional detection or degradation. However, the design of multi-functional materials is still a challenge. Till now, a novel protocol applied to the consecutive detection and complete degradation of TC are rarely successfully reported. Herein, we not only developed a multi-mode optical carbon dots (CDs) for ultra-sensitive sensing, but also further manufactured CDs/TiO2 photocatalyst that can degrade TC 100 %, completely eliminating the TC for the first time. The as-prepared CDs can selectively detect TC with low detection limit of 5.2 nM and 10.7 nM within only 40 s, accompanied by wide linear interval of 1.0–50.0 μM and 50.0–250.0 μM, respectively. Therefore, the fabricated point-of-care testing platform can realize "in-situ" visual detection rapidly and efficiently. Furthermore, a highly active CDs/TiO2 photocatalyst was prepared by rationally modifying CDs on TiO2 and exhibited almost 100 % degradation behavior towards TC within 70 min. The mechanism of fluorescence quenching and photocatalysis were lucubrated. Notably, our proposed protocol can drive consecutive detection and elimination towards tetracycline, which powerfully reduces the potential harm and provides a new strategy for the eradication of pollutants.