Accepted Article Fabrication of Core-Shell Nanocomposites with Enhanced Photocatalytic Efficacy Authors: Ayman S. Al-Hussaini *a , Kareem R. Eltabie a and Mohamed E. R. Hassan a a Chemistry Department, Faculty of Science, Port Said University, 23 December Street, Port Said 42521, Egypt. * Corresponding author: Tel.: +20663657602; fax: +2663657601. : +201066822197. E-mail address: ayman_eldeen@yahoo.com. Keywords: Copolymerization; TiO 2 ; core-shell; nanocomposites; photocatalysis; resistivity. ABSTRACT: The current study establishes the unprecedented involvement in the evolution and production of novel core-shell nanocomposites composed of nanosized titanium dioxide and aniline-o- phenylenediamine copolymer. TiO 2 @copoly(aniline and o-phenylenediamine) (TiO 2 @PANI- o-PDA) core-shell nanocomposites were chemically synthesized in a molar ratio of 5:1 of the particular monomers and several weights of nano-TiO 2 via oxidative copolymerization. The construction of the TiO 2 @PANI-o-PDA core-shell nanocomposites was ascertained from FT- IR spectroscopy, UV-Vis spectra, and XRD. A reasonable thermal behavior for the original copolymer and TiO 2 @PANI-o-PDA core-shell nanocomposites was investigated. The bare PANI-o-PDA copolymer was thermally less stable than TiO 2 @PANI-o-PDA nanocomposites. The core-shell feature of the nanocomposites was examined to have core and shell sizes of 17 nm and 19 nm-26 nm, respectively. In addition, it was found that the addition of high ratio of the TiO 2 nanoparticles increases the electrical conductivity and consequently, lowers the electrical resistivity of TiO 2 @PANI-o-PDA core-shell nanocomposites. The hybrid photocatalysts exhibit dramatic photocatalytic efficacy of the methylene blue (MB) degradation under solar light irradiation. A plausible interpretation of the photocatalytic degradation results of MB was also demonstrated. Our setup introduces a facile, inexpensive, This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/pi.5662