Bionic sunflower-like structure of polydopamine-confined NiFe-based quantum dots for electrocatalytic oxygen evolution reaction

NiFe-based nanostructures have been attracting attentions as a promising non-noble metal electrocatalysts for oxygen evolution reaction in alkaline. In this paper, a bionic sunflower-like NiFe-polydopamine film was prepared via self-polymerization of dopamine-Ni2+/Fe3+ followed by partial pyrolysis process. In the films, NiO quantum dots are embedded in Fe-coupled polydopamine due to the space-confined effect of PDA. The selfactivation process effect led to in-situ reconstruction of the generation of NiOOH and the migration of Fe sites to NiOOH surface. Abundant Fe sites on the NiOOH surface facilitated formation of stable O* intermediate. Moreover, the coordination-confined effect of PDA for Fe ions in the PDA network gave the PDANF catalyst excellent durability. The NiFe-polydopamine film exhibited excellent intrinsic OER activity with a low overpotential of 254.1 mV for 10 mA cm-2 and an unprecedentedly low Tafel slope of 23.3 mV dec-1.