Synthesis and structural characterization of ZnO doped with Co

► The hydrothermal synthesis is used to prepare Co-doped ZnO nanomaterials. ► XRD, XAFS and DAFS techniques are used to characterize the structures of Co-doped ZnO. ► The doped Co atoms in ZnO nanoparticles exhibit Co2+ and Co3+, and the Co3+ occupies the surface Zn vacancy sites. ► The occupancy of Co2+ to Co3+ tends to 1/3 with the increase of the Co-doped concentration x.