A characteristic anti-restack 3D BiOCl hierarchitecture constructed by ultrathin BiOCl nanosheets assembled substructures has been designed and synthesized via a facile hydrothermal route. The graphene-like ultrathin BiOCl nanosheets with thickness of about 3.7 nm expose the renowned energetically active (0 0 1) facet, enabling the fast separation and transport of photogenerated electron-hole pairs. Meanwhile, the multi-reflection of light and large surface area of the formed 3D nano-velvet substructures enhance the light harvest and molecule adsorption capability. Consequently, the resultants show a superior photocatalytic performance of 99% photodegradation and corresponding 74% mineralization for rhodamine B within 10 min, and an outstanding photocurrent response under solar light illumination. What is more, the unique microstructure efficiently overcomes the restack of ultrathin nanosheets. This work develops a feasible strategy that utilizes ultrathin nanosheets to design and synthesize anti-restack hierarchitectures for establishing efficacious photocatalytic and water splitting systems. (C) 2015 Elsevier B.V. All rights reserved.