Biomineralization of Sulfate‐Reducing Bacteria In Situ‐Induced Preparation of Nano Fe2O3‐Fe(Ni)S/C as High‐Efficiency Oxygen Evolution Electrocatalyst

Abstract Transition metal‐based catalysts possess high catalytic activity for oxygen evolution reaction (OER). However, the preparation of high‐performance OER electrocatalysts using simple strategies with a low cost still faces a major challenge. Herein, this work presents an innovative, in situ‐induced preparation of the Fe 2 O 3 , FeS, and NiS nanoparticles, supported on carbon blacks (CBs) (denoted as Fe 2 O 3 ‐Fe(Ni)S/C) as a high‐efficiency oxygen evolution electrocatalyst by employing biomineralization. Biomineralization, a simple synthesis strategy, demonstrates a huge advantage in controlling the size of the Fe 2 O 3 and Fe(Ni)S nanoparticles, as well as achieving uniform nanoparticle distribution on carbon blacks. It is found that the electrocatalyst Fe 2 O 3 ‐Fe(Ni)S/C‐200 shows a good OER electrocatalytic activity with a small loading capacity, and it has a small overpotential and Tafel slope in 1 m KOH solution with values of 264 mV and 42 mV dec −1 , respectively, at a current density of 10 mA cm −2 . Additionally, it presents good electrochemical stability for over 24 h. The remarkable and robust electrocatalytic performance of Fe 2 O 3 ‐Fe(Ni)S/C‐200 is attributed to the synergistic effect of Fe 2 O 3 , FeS, and doped‐Ni species as well as its distinct 3D spherical structure. This approach indicates the promising applications of biomineralization for the bio‐preparation of functional materials and energy conversion.