Synthesis and enhanced photoelectrocatalytic activity of p-n junction Co3O4/TiO2 nanotube arrays

► Co3O4/TiO2 nanotube arrays (NTs) were prepared by an impregnating-deposition-decompostion method treatment. ► Co3O4/TiO2 NTs exhibit high photoelectrocatalytic (PEC) activity. ► The high PEC activity was attribute to the formation of p-n junction between Co3O4 and TiO2.