Polyaniline/mesoporous Cu2O core-shell nanocomposites with different mass ratios of polyaniline/mesoporous Cu2O were prepared using a hydrothermal method. For comparison, Cu2O nanoparticles and polyaniline/Cu2O nanoparticles were also prepared using a hydrothermal method. The catalytic performance of the samples during the photocatalytic oxidation of thiophene under visible-light irradiation was determined. The surface areas of the mesoporous and nanoparticulate Cu2O materials were 140 and 40 m(2)/g, respectively. Adding polyaniline to mesoporous and nanoparticulate Cu2O decreases the surface areas of the nanoparticles to 120 and 32 m(2)/g, respectively. TEM images reveal that the mesoporous and nanoparticulate Cu2O materials occur as uniform microspheres and spherical nanoparticles, respectively. The polyaniline/mesoporous Cu2O and polyaniline/Cu2O nanoparticles are core-shell and spherical nanoparticles, respectively. The photocatalytic degradation of thiophene under visible-light irradiation while using 4% polyaniline/mesoporous Cu2O was 2.87, 2.20, and 1.34 times more effective than that observed when using Cu2O nanoparticles, polyaniline/Cu2O nanoparticles, and mesoporous Cu2O, respectively. (C) 2014 Elsevier B.V. All rights reserved.