Novel mesoporous cobalt-intercalated layered tetratitanates have been synthesized by assembling tetratitanate nanosheets with cobalt ions via an exfoliation-restacking route. It was revealed that the cobalt element in the resultant nanohybrids is bivalent. The nanohybrids have expanded specific surface areas of 110-121 m(2)/g and average pore diameters of about 3.5 nm. The mesopores are originated from the house-of-cards-type stacking of the intercalated crystallites. The introduction of cobalt ions made the nanohybrids exhibit distinct spectral responses in visible-light region due to the electronic transition from the valence band consisting of 0 2p orbitals to an electron acceptor lever (a conduction band minimum) consisting of Co 3d and Ti 3d orbitals. The intercalated nanohybrids exhibit good photocatalytic activities in the degradation of methylene blue under visible-light irradiation. (C) 2012 Elsevier B.V. All rights reserved.