Core–Shell Dendritic Superstructural Catalysts by Design for Highly Efficient and Stable Electrochemical Oxygen Evolution Reaction

Abstract Efficient, stable, and low‐cost oxygen evolution reaction (OER) catalysts are in great demand for the practical application of electrochemical water splitting for energy conversion and storage. This work reports a rationally designed and innovatively fabricated 3D core–shell dendritically porous OER catalyst that exhibits outstanding and highly reproducible performance. The porous superstructure provides not only substantially enhanced loading capacity of electrochemical catalysts, but also easy access of electrolyte to active catalysts. With a facile and designed sulfurization process followed by anodization, core–shell (FeCoNi)OOH@dendritic foam can be obtained and exhibits a remarkably low overpotential of 204.4 mV at a current density of 10 mA cm⁻², which are among the best of the reported FeCoNi OER catalysts. Such value is also highly reproducible and stable with over 18 h operation time. This excellent performance could be attributed to the synergism of trimetal chemistry, the unique structure with metal/metal sulfide as the conductive core and (oxy)hydroxide catalysts as the active shell, and the enhanced superstructural surface area. This work points toward a synergistic way based on rational design and innovative fabrication for creating scalable, stable, low‐cost, and high‐performance OER catalysts.