Growth of coral-like PtAu-MnO2 binary nanocomposites on free-standing graphene paper for flexible nonenzymatic glucose sensors.

Abstract

The growing demand for compact point-of-care medical devices and portable instruments for on-site environmental sampling has stimulated intense research on flexible sensors that can be miniaturized and function under considerable physical deformation. This project reports a new type of flexible electrochemical biosensors based on free-standing graphene paper carrying binary nanocomposites of PtAu alloy and MnO2. The coral-like PtAu–MnO2 nanocomposites were grown on the substrate through a one-step template-free electrodeposition, leading to an intimate contact between the PtAu alloy and MnO2 matrix. The flexible electrode exhibited a unique set of structural and electrochemical properties such as better uniformity, larger active surface areas, and faster electron transfer in comparison with the control electrode prepared by tandem growth of MnO2 network and PtAu alloy in two steps. In non-enzymatic amperometric glucose detection, the PtAu–MnO2 binary nanostructure-decorated graphene paper had shown greatly enhanced sensing performance in terms of sensitivity, selectivity, durability, and tolerability to mechanical stress in comparison with control electrodes. The strategy of co-growth of metal and metal oxides on freestanding carbon substrates opens new possibility to develop high-performance flexible electrochemical sensors.