Photoelectrochemical determination of hydrogen peroxide using a gold electrode modified with fluorescent gold nanoclusters and graphene oxide

Nanocomposites consisting of gold nanoclusters and graphene oxide (AuNC/GO) were prepared and investigated with respect to the design of new sensors for hydrogen peroxide (H 2 O 2 ). The AuNC/GO hybrid nanomaterials were deposited on a gold electrode by the layer-by-layer assembly method, where they showed enhanced photoelectrical and sensing properties. The presence of graphene oxide improves the photoinduced electron separation efficiency of the AuNCs, as well as the catalytic effect of AuNCs on the electroreduction of H 2 O 2 . Compared to an electrode modified with AuNCs only, the new electrodes display a more than ten-fold enhanced photocurrent at a working voltage of -500 mV (vs. Ag/AgCl), higher sensitivity for H 2 O 2 (25.76 nA⋅mM −1 ), lower LOD (2 μM) and extended linear range (from 30 μM to 5 mM). The sensors were applied to the determination of H 2 O 2 extracted from living human umbilical vein endothelial cells stimulated by angiotensin II. Graphene oxide (GO) not only improves the photoinduced charge separation efficiency of fluorescent gold nanoclusters (AuNCs) based photoelectrochemical sensors, but also enhances the catalytic property of AuNCs on the detection of hydrogen peroxide (H 2 O 2 ).