Interconnected phosphorus-doped CoO-nanoparticles nanotube with three-dimensional accessible surface enables high-performance electrochemical oxidation

The ability to create nanomaterials with hollow micro- or nanostructures renders their applications in fields such as catalysis, controlled delivery and lightweight composites. Herein, we report a simple three-step route to Cu₂O/Cu nanotubes populated by interconnected, phosphorus-doped CoO nanoparticles (denoted P–CoO–Cu₂O/Cu-NTs). They possess three-dimensional (3D) accessible surface, thereby greatly favoring the exposure of active sites and electrolyte transport for efficient electrocatalysis. Notably, the integrated electrochemical tests and theoretical calculation reveal that the P-doping imparts the optimization of the electronic structures of CoO, enhancing its conductivity, facilitating the in-situ formation of active CoOOH species during oxygen evolution reaction (OER), and suitably regulating free energy for adsorption of the OER intermediates. Consequently, the P–CoO–Cu₂O/Cu-NTs exhibit outstanding performance for OER and urea oxidation reaction (UOR) with the overpotential of 261 mV and potential of 1.43 V vs RHE, respectively, at 10 mA cm⁻², outperforming most of non-precious metal electrocatalysts and RuO₂. As such, the three-step approach involving the use of Cu nanowires as template to yield Cu₂O/Cu nanotubular yet porous scaffold may stand out as a robust strategy for judicious crafting of interconnected heteroatom-doped metal oxides for high-performance electrocatalysis.