A nanoflower composite catalyst in situ grown on conductive iron foam: Revealing the enhancement of OER activity by cooperating of amorphous Ni based nanosheets with spinel NiFe2O4

Abstract

As a bottleneck step in electrochemical water splitting, oxygen evolution reaction (OER) seriously limits the development of large-scale electrochemical hydrogen production. Rational design and development of an efficient and stable OER electrocatalysts are of enormous importance but still challenging for electrochemical energy conversion. In this work, a unique nanoflower like electrocatalyst consisting of NiFe2O4 nanoparticles wrapped with amorphous Ni based nanosheet on the 3D porous iron foam (IF) substrate (named as Ni-ANS@NiFe2O4/IF) is proposed and the evolution of catalyst morphology and its effect on electrochemical activity were explored. Profiting from the unique nanoflower structure and the coupling of ample active substances with favorable conductive substrates, the prepared Ni-ANS@NiFe2O4/IF exhibits outstanding OER activity with low overpotential of 209, 251, 270 mV to reach a current density of 10, 100 and 200 mA cm−2, and admirable long-term stability. This work may broaden a new vision and avenue for the design of efficient OER catalysts.