Topological Synthesis of 2D High-Entropy Multimetallic (Oxy)hydroxide for Enhanced Lattice Oxygen Oxidation Mechanism.

Owing to sluggish reaction kinetics and high potential, oxygen evolution reaction (OER) electrocatalysts face a trade-off between activity and stability. Herein, an innovative topological strategy is presented for preparing 2D multimetallic (oxy)hydroxide, including ternary CoFeZn, quaternary CoFeMnZn, and high-entropy CoFeMnCuZn. The key to the synthesis lies in using Ca-rich brownmillerite oxide as a precursor, which possesses inherent structural flexibility enabling tailored elemental adjustments and topologically transforms from a point-shared structure of metal-oxygen octahedrons into an edge-shared structure under alkaline conditions.

Facet Engineering and Pore Design Boost Dynamic Fe Exchange in Oxygen Evolution Catalysis to Break the Activity-Stability Trade-Off.

The oxygen evolution reaction (OER) plays a vital role in renewable energy technologies, including in fuel cells, metal-air batteries, and water splitting; however, the currently available catalysts still suffer from unsatisfactory performance due to the sluggish OER kinetics. Herein, we developed a new catalyst with high efficiency in which the dynamic exchange mechanism of active Fe sites in the OER was regulated by crystal plane engineering and pore structure design. High-density nanoholes were created on cobalt hydroxide as the catalyst host, and then Fe species were filled inside the nanoholes.

Mesoporous Single Crystals with Fe-Rich Skin for Ultralow Overpotential in Oxygen Evolution Catalysis.

The oxygen evolution reaction (OER) is a key reaction in water splitting and metal-air batteries, and transition metal hydroxides have demonstrated the most electrocatalytic efficiency. Making the hydroxides thinner for more surface commonly fails to increase the active site number, because the real active sites are the edges. Up to now, the overpotentials of most state-of-the-art OER electrocatalysts at a current density of 10 mA cm (η ) are still larger than 200 mV.