Cobalt selenite dihydrate (CoSeO3 center dot 2H(2)O) is spin-coated on conductive glass and used as counter electrode (CE) in dye-sensitized solar cells (DSSCs). Owing to CoSeO3 center dot 2H(2)O electrode good electrocatalytic activity, high conductivity and low resistance, the DSSC based on optimal CoSeO3 center dot 2H(2)O CE provides a power conversion efficiency of 8.90% under one sun irradiation from the front of DSSC, which is superior to the DSSC based on conventional Pt CE. Furthermore, when incorporating trace amounts of reduced graphene oxide (rGO) into CoSeO3 center dot 2H(2)O CE, the DSSC device achieves an improved power conversion efficiency of 9.89%. The research presented here indicates that hydration oxysalt can be used as efficient, stable and free-Pt counter electrode material and shows excellent prospects for application in DSSCs. (C) 2016 Elsevier B.V. All rights reserved.