A Cr-FeOOH@Ni-P/NF binder-free electrode as an excellent oxygen evolution reaction electrocatalyst.

Refining the size of nanoparticles to exhibit larger specific surface areas and expose much more active sites is of great significance for enhancing the oxygen evolution reaction (OER) activity of the electrocatalyst, but still a tremendous challenge. Herein, a Cr-FeOOH@Ni2P-Ni5P4/NF (Cr-FeOOH@Ni-P/NF) catalyst was constructed by electrodepositing a layer of CrFe oxyhydroxides on the self-grown Ni-P nanoparticles, which exhibits ultrafine nanoparticles and thus superexcellent electrocatalytic OER performance. The final catalyst affords ultra-low overpotentials of 144 mV and 210 mV to achieve current densities of 10 and 50 mA cm-2, respectively. Meanwhile, it demonstrates robust stability for at least 80 hours with no activity decay. This strategy of refining nanoparticles on a three-dimensional electrode has once again been further demonstrated to be feasible and highly effective and opens a new door for the exploration of electrocatalysts with excellent comprehensive properties.