Understanding and Taking Advantage of Carbon Quantum Dot-UiO-66-(OH) ₂ Composite-Enhanced Photoluminescence and Electrical Conductivity for Sulfur Dioxide and Sulfamethoxazole Sensing

High Resolution Image Download MS PowerPoint Slide We present a systematic study of the electronic effect of incorporating carbon quantum dot (CQD) nanomaterials within UiO-66-(OH) 2 . The composite material, entitled CQD-UiO-66-(OH) 2, exhibits remarkable improved fluorescence and electrical conductivity because of type I heterojunction band alignment, i.e., charge transfer from carbon quantum dots to UiO-66-(OH) 2 . Therefore, due to enhanced electronic properties, we evaluated CQD-UiO-66-(OH) 2 as a probe for sensing sulfur dioxide and sulfamethoxazole. Specifically, for SO 2 sensing using fluorescence spectroscopy, CQD-UiO-66-(OH) 2 shows 1605 times higher sensitivity than UiO-66-(OH) 2 and a lower limit of detection, i.e., from 330 to 14.2 ppm, for UiO-66-(OH) 2 and CQD-UiO-66-(OH) 2, respectively. Furthermore, SO 2 gas detection is also improved. For sulfamethoxazole (SMX), the engineering of a screen-printed electrode (SPE) with CQD-UiO-66-(OH) 2 allows to reach a detection limit down to 600 nM with a linearity up to 50 μM. Finally, the CQD-UiO-66-(OH) 2 -engineered SPE was tested in real wastewater samples, yielding satisfactory recoveries in the range of 87–118%.