Nanocomposite is a kind of multiphase solid materials with nano-dimensional. It generally displays more preferable performance than its corresponding single precursors or conventional composite materials due to size effect and interfacial effect. Herein, we report the synthesis of a kind of nanocomposite via one pot route without using any surfactant or structure-directing agents. The structure, composition and morphology of the as-synthesized products were characterized by XRD, XPS, SEM, TEM and BET surface area measurements. The results revealed that the prepared nanocomposites were consisted of ZnO-loaded Co0.85Se nanocomposites. BET measurement showed the specific surface area of the nanocomposite was 66.5 m(2) g(-1) at 77.5 K. Interestingly, the ZnO-loaded Co0.85Se nanocomposites exhibit remarkable performance for the decomposition of hydrazine hydrate and catalytic hydrogenation of p-nitrophenol compared with individual component of Co0.85Se or ZnO. More importantly, the obtained nanocomposites have very excellent stability and reversibility as catalysts, indicating that the products can be potentially used in wastewater treatment. (C) 2016 Elsevier B.V. All rights reserved.