Effective immobilization of gold nanoparticles on core-shell thiol-functionalized GO coated TiO2 and their catalytic application in the reduction of 4-nitrophenol

We describe the synthesis of a hybrid nanomaterial comprising a core-shell titanium glycolate-thiolfunctionalized graphene composite (TG@GOS) as a support for the immobilization of gold nanoparticles. TG@GOS was synthesized via the thionation of TG@GO that involved-wrapping of titanium glycolate in graphene oxide. The interaction between gold and sulfur, mainly connected through the thiol functional group, is well known that strong covalent Au-S bond (bond strength similar to 40 kcal/mol) in comparison with other functional group such as hydroxyl and amine. Therefore, we propose that reduced gold ions could easily bind to thiol groups on TG@GOS and grow to nanoparticles using PVP as a surfactant. Herein, titanium glycolate was transformed to TiO2 by hydrolysis. The catalysts (TiO2@GOS@Au) were characterized by TEM, SEM, XRD, UV-vis spectroscopy and tested for the reduction of 4-nitrophenol in the presence of NaBH4. (C) 2015 Elsevier B.V. All rights reserved.