CuO/Cu nanorod skeleton supported Ru-doped CoO/NC nanocomposites for overall water splitting.

High overpotential and low stability are major challenges for hydrogen evolution reaction (HER)/oxygen evolution reaction (OER). Tuning the electronic structure of catalysts is regarded as a core strategy to enhance catalytic activity. Herein, we report CuO/Cu nanorod skeleton supported Ru doped cobalt oxide/nitrogen-doped carbon nanocomposites (Ru-CoO/NC/CuO/Cu, denoted as RCUF) as bifunctional catalysis. The one-dimensional/three-dimensional (1D/3D) nanostructure and defect-rich amorphous/crystalline phases of RCUF facilitates active site exposure and electron transport. Experimental characterization and density functional theory (DFT) calculation results indicate that Ru doping can optimize the electronic structure, which accelerates the water dissociation process and reduces the Gibbs free energy of the reaction intermediates. As expected, the optimal RCUF-900 exhibits low overpotential (25/205 mV at 10 mA cm) and high stability (100/100 h) for HER/OER. RCUF-900 has low voltage (1.54 V at 10 mA cm) and high stability (100 h) for overall water splitting. This work provides new insights into the design of advanced catalysts for overall water splitting.