Synthesis of Ultrastable Ag Nanoplates/Polyethylenimine–Reduced Graphene Oxide and Its Application as a Versatile Electrochemical Sensor

Graphical Ultrastable hybrids : Ag nanoplates/polyethylenimine-modified reduced graphene oxide (AgP/PEI-rGO) hybrids show unexpected higher stability against Cl − and H 2 O 2 than either AgP or mixtures of PEI-rGO and AgP. The AgP/PEI-rGO hybrids show very wide linear response ranges and low detection limits in the electrochemical detection of H 2 O 2 , N 2 H 4 , and NaNO 2 (see scheme). Investigations on Ag nanostructures/reduced graphene oxide composites have been frequently reported, yet the morphology control of those loaded Ag nanocrystals is still challenging. We herein develop a facile method to grow triangular Ag nanoplates (AgP) on polyethylenimine-modified reduced graphene oxide (AgP/PEI-rGO). The AgP/PEI-rGO hybrids show unexpected high stability against chloride ions (Cl − ) and hydrogen peroxide (H 2 O 2 ), which is possibly due to the strong interaction between surface Ag atoms with the amine groups of PEI. In the chronoamperometry measurements for detecting H 2 O 2 , N 2 H 4 , and NaNO 2 , the AgP/PEI-rGO hybrid shows very wide linear ranges (usually 10 −6 –10 −2 mol L −1 for H 2 O 2 , N 2 H 4 , and NaNO 2 ) and low detection limits (down to ≈1×10 −7 mol L −1 ), which demonstrate the promising electrochemical sensor applications of these metal/graphene hybrids with well-defined morphologies and facets. In addition, this strategy could be extended to the deposition of other noble metals on rGO with controlled morphologies.