High-density and well-dispersed Ag nanoparticles (Ag NPs) with a mean size of 20 nm have been successfully supported on the surface of polyacrylamide functionalized polypyrrole/graphene oxide (PAM/PPy/GO) nanosheets. The obtained Ag/PAM/PPy/GO composite nanosheets exhibited an excellent catalytic activity for reduction of 4-nitrophenol by NaBH4 with the kinetic reaction rate constant of 3.38 x 10(-2) s(-1) due to the synergistic effect of all the components of the composite nanosheets. The corresponding catalytic mechanism has been revealed by investigating the effect of different components of Ag/PAM/PPy/GO composite nanosheets on the catalytic performance: GO with the excellent two-dimensional structures offered large surface area for the immobilization of more Ag NPs; PPy with a high electric conductivity promoted the electron transport in the reduction of 4-NP; PAM did not only act as a good linker between Ag NPs and PPy/GO nanosheets for the synthesis of Ag/PAM/PPy/GO composite nanosheets, but also could facilitate the efficient contact between 4-NP and Ag NPs; Ag NPs were the catalytic active site for the reduction of 4-NP, respectively. (c) 2017 Elsevier B.V. All rights reserved.