Organic-inorganic nano-materials have attracted growing attention due to their potential applications for optoelectronic devices, sensors, and heterogeneous catalysts. We reported here on the preparation of polynary nanocomposites composed of poly(4-vinylpyridine) (P4VP) functionalized multi-walled carbon nanotubes (MWNTP4VP), silica nanoparticles (nano-SiO2), viologens, and/or phosphomolybdic acid (PMA), in which the MWNTP4VP, nano-SiO2, and viologens were covalently connected while PMA was electrostatically adsorbed. Thermogravimetric analysis revealed that the nanocomposites were composed of about 40-45% MWNTs, 40-45% nanoSiO(2), as well as 10-15% organic species and others. The preparation processes and compositions of the nanocomposites were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Field emission transmission electron microscopic images revealed that the nano-SiO(2)BenV particles were strongly attached to the MWNTP4VP surfaces to form MWNTP4VP@nano-SiO(2)BenV triad nano-cores. Cyclic voltammo-grams of the MWNTP4VP@nano-SiO(2)BenV casting films showed three couples of redox waves in the potential range between -0.8 and 0 V (vs Ag/AgCl), designated to the electron transfer process of viologen substituents of MWNTP4VP@nano-SiO(2)BenV(2+) <-> MWNTP4VP@nano-SiO(2)BenV(+center dot) and their dimers. Further, three couples of redox waves were recorded for the casting films of MWNTP4VP@nanoSiO(2)BenV/PMA polynary nanocomposites in the potential range between -0.2 and 0.8 V, designated to three successive electron transfer processes of PMA. Finally, it was revealed that the present MWNTPVP@nano-SiO(2)BenV/PMA polynary composites could act as efficient heterogeneous catalysts for the electrocatalytic reduction of bromate. (C) 2017 Elsevier B.V. All rights reserved.