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Graphene oxide (GO) films mixed with polyethylenimine (PEI) were prepared by a layer-by-layer assembly (LBL) method, in which the GO component is then converted to reduced GO (rGO) in situ… Click to show full abstract
Graphene oxide (GO) films mixed with polyethylenimine (PEI) were prepared by a layer-by-layer assembly (LBL) method, in which the GO component is then converted to reduced GO (rGO) in situ through an electron transfer interaction with a polyoxometalate (POM) that is assembled on the outer surface. With this, devices were manufactured by spreading composite films of (PEI/rGO)n-POM with different numbers of PEI/rGO layers on ITO substrates. Cyclic voltammetry (CV) reveals that the catalytic activity for H2O2 of (PEI/rGO)n-POM films was significantly higher than that of similar films of (PEI/GO)n/PEI/POM manufactured LBL with the same number of layers, although the catalyst POM content of (PEI/rGO)n-POM was only half that of (PEI/GO)n/PEI/POM. The catalytic activity of (PEI/rGO)n-POM films first increases and then decreases as the number of PEI/rGO layers increases. The result shows that (PEI/rGO)3-POM films with three PEI/rGO layers exhibit the highest efficiency. Amperometric measurements of the (PEI/rGO)3-POM films showed improved current response, high sensitivity, wide linear range, low detection limit, and fast response for H2O2 detection. The enhanced catalytic property of (PEI/rGO)n-POM films is attributed to the electron transfer interaction and electrostatic interaction between POM and rGO.