TiO2 quantum dots/reduced graphene oxide composite modified with Au for electrochemical oxidation reaction

Abstract

TiO2/graphene as catalyst substrate has attracted considerable attentions in the field of electrochemistry because of the synergistic effects bring from good chemical stability of TiO2 and intrinsic superior conductivity of graphene. In this work, TiO2 quantum dots are prepared on reduced graphene (TiO2QDs/RGO) by a novel supercritical CO2 fluid assisted hydrothermal method, following, the Au–TiO2QDs/RGO electrodes are achieved by electrodepositing Au on the TiO2QDs/RGO support. The obtained Au–TiO2QDs/RGO shows better electrocatalytic activity for glucose oxidation than the electrodes of Au-RGO, Au–P25 (commercial TiO2) and Au-Mixed P25/RGO. Specially, the lower the loading of Au, the more significant in performance of Au–TiO2QDs/RGO distinguishes from other three electrodes. The high activity is probably owing to the synergistic catalytic effects of TiO2QDs and Au, the quantum-sized TiO2QDs, as well as the co-substrate of RGO. All of these are beneficial to electron transfer and the release of poisoning intermediates thus promote the electrocatalytic oxidation of glucose. The study might offer some new clues for designing efficient hybrid catalysts in applications of electrocatalysis and energy conversion/storage.