Developing a highly efficient and cost-effective catalyst for the oxygen evolution is urgent for the application of water splitting. Herein, we report a Co-based nanocubes (NBs) containing an low amount of ruthenium oxide RuO2/Co3O4 as an efficient electrocatalyst synthesized via a facile ion impregnation and calcine approach with Co-3(Co(CN)(6)) precursor. Owing to the close combination between Ru ions and Co-3(Co(CN)(6)), the good dispersion and small size of RuO2 nanoparticle can be achieved on the surface of Co3O4 nanotubes after calcination, suggesting the more active sites and better utilization of RuO2. The synergistic effect of RuO2/Co3O4 hybrid can provide the faster charge transfer process and the structural stability. The as-synthesized RuO2/Co3O4 NBs show the promising electrocatalytic performance for oxygen evolution reaction (OER) with lower overpotential (302 mV to reach 10 mA cm(-2)) and higher current density than state of the commercial RuO2 samples. The long-term stability of RuO2/Co3O4 NBs is obtained. Therefore, designing the ions impregnation into precursor may present a facile strategy for cost-effective electrocatalysts for OER. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.