A ternary Ag-polypyrrole-graphene oxide nanocomposite (Ag-PPy-GO) has been synthesized via in situ oxidative polymerization of pyrrole in the presence of graphene oxide using silver nitrate as an oxidant cum dopant. The formation of silver nanoparticles and the polymerization of pyrrole in the reaction occur simultaneously without addition of any other oxidant and reductant. The obtained Ag-PPy-GO nanocomposite was characterized by UV-vis, FT-IR, XRD, Raman, TGA, SEM, TEM, and EDX analysis. Further, the Ag-PPy-GO nanocomposite catalyzes the oxidation of hydroquinone (HQ) to benzoquinone (BQ) with H2O2 selectively in aqueous solution. The rate of HQ oxidation is found to be dependent on pH, concentrations of catalyst and HQ solvents, and interferences. The stability of the catalyst and the catalysis mechanism are investigated and discussed. (C) 2016 Elsevier Inc. All rights reserved.