Optimization of the Synthesis of Water-Soluble Quantum Dots and their Use as Photocatalysts

DIEGO FLORES-OÑA; JUAN E. ARGÜELLO; RAQUEL E. GALIAN; JULIA PEREZ-PRIETO

Lisboa

Jornada; 4as Jornadas Ibéricas de Fotoquímica; 2014

Quantum Dots (QDs) are semiconductor nanoparticles with unique size-dependent optical and electronic properties. Water-dispersible QDs have interest in the photocatalytic production of hydroxyl radicals (°OH), whose generation can be analyzed by a fluorimetric assay which uses terephthalate as a probe for photochemically generated hydroxyl radical. [1] Regarding the effect of the reaction conditions used for the preparation of water-dispersible CdSe and CdS QDs (CdX), more studies are needed aimed to a better control and improvement of the photocatalytic performance of these nanoparticles. To optimize their synthesis we have studied the effect of the reaction time and pH, as well as the ligand structure on their features. The QDs were synthesized following a previously described methodology with some modifications.[2],[3] The use of mercaptopropionic acid and mercaptosuccinic acid as capping ligands prevents the QD aggregation and provides their aqueous dispersibility. Their capacity to produce °OH in the hydroxylation of terephtalate is compared with that of the QDs supported on TiO2. The efficiency of both types of photocatalysts, one homogeneous and the other heterogeneous, in the oxidation of aromatic compounds (toluene and benzene) and in the transformation of heterocycles, such as quinoxaline References [1] Ipe, B. I.; Lehnig, M.; Niemeyer, C.M. Small 2005, 1 (7), 706-709. [2] Kaur, G.; Tripathi, S. Mater. Chem. Phys. 2014, 2, 514-523. [3] Kumar, P.; Kukkar, D.; Deep, A.; Sharma, S.; Bharadwaj, L. Adv. Mat. Lett. 2012, 3 (6), 471-475. Acknowledgements: We thank to SENESCYT, the Spanish Ministry of Economy and Competitiveness (Project CTQ2011-27758), and University of Valencia (UV-INV-EPCB-115480, Investigador invitado VLC-CAMPUS) for their support to this research.