Localized electron-accepted yellow-emission carbon dots encapsulated in UiO-66 for efficient visible-light driven photocatalytic activity

Metal organic frameworks (MOFs) possess a large surface area, inherent porosity and high crystallinity. Nevertheless, they lack electron acceptors, which limit the exploitation of their photocatalytic properties. Carbon dots (CDs) known for excellent optical properties can serve as localized electron acceptors. As a novel hybrid nanomaterial, the structure of CDs@MOFs effectively facilitates charge separation and carrier transfer, bring about a marked improvement of photocatalytic activity. In this study, yellow-emission carbon dots (YCDs) were encapsulated within zirconium-based metal organic framework (UiO-66) via a dynamic adsorption method. Compared with blue carbon dots (BCDs), the YCDs@UiO-66 exhibited superior degradation performance. It demonstrates that incorporation of YCDs broadens the UV absorption range of UiO-66, thereby enhancing light utilization. The degradation efficiency of YCDs@UiO-66 was 92.6%, whereas UiO-66 alone achieved only 63.1%. Notably, the results of the radical quenching experiment and electron paramagnetic resonance (EPR) revealed that h+ and •O2- played a prominent role in the photodegradation of tetracycline hydrochloride (TCH). This study highlights that the introducing YCDs in MOFs-mediated photocatalytic reactions is a viable strategy to improve catalytic efficiency.