Synthesis of Au nanoparticles decorated graphene oxide nanosheets: Noncovalent functionalization by TWEEN 20 in situ reduction of aqueous chloroaurate ions for hydrazine detection and catalytic reduction of 4-nitrophenol

► TWEEN 20 is used as a stabilizing agent for GO as well as a reducing and immobilizing agent for Au nanoparticles. ► The hydrazine sensor based on the nanocomposites has a fast amperometric response. ► The detection limit of the hydrazine sensor is estimated to be 78 nM. ► The nanocomposites also exhibit good catalytic activity toward 4-nitrophenol reduction.