Photochemical synthesis of luminescent gold nanoclusters for catalytic reduction of 4-nitrophenol

Gold nanoclusters have recently emerged a new class of functional material whose unique intermediate properties between bulk nanoparticles and single molecule. In this study, we describe a photochemical route for the preparation of gold nanoclusters (AuNCs) with glutathione (GSH) as a ligand. The GSH stabilized AuNCs (GSH-AuNCs) display molecule-like transition in their UV-V is absorbance and an intense orange emission at 685 nm under the excitation wavelength of 405 nm. The quantum yield of the nanoclusters was about 2.5% calibrated by rhodamine 6G. The catalytic activity of GSH-AuNCs was explored on reduction reaction of 4-nitrophenol to 4-aminophenol. The results showed a non-pseudo-first-order kinetics with 3 values of the normalized rate constant (i.e. 2.14 × 10−2 s−1, 5.08 × 10−3 s−1 and 9.17 × 10−3 s−1 during the reaction) and negligible reaction induction time. This finding implies different reaction pathways compared to those catalyzed with glutathione protected Au nanoparticles.